// SPDX-License-Identifier: MIT
pragma solidity ^0.5.0;


/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

/**
 * @title Roles
 * @dev Library for managing addresses assigned to a Role.
 */
library Roles {
    struct Role {
        mapping (address => bool) bearer;
    }

    /**
     * @dev give an account access to this role
     */
    function add(Role storage role, address account) internal {
        require(account != address(0));
        require(!has(role, account));

        role.bearer[account] = true;
    }

    /**
     * @dev remove an account's access to this role
     */
    function remove(Role storage role, address account) internal {
        require(account != address(0));
        require(has(role, account));

        role.bearer[account] = false;
    }

    /**
     * @dev check if an account has this role
     * @return bool
     */
    function has(Role storage role, address account) internal view returns (bool) {
        require(account != address(0));
        return role.bearer[account];
    }
}

/**
 * @title ChainlinkConversionPath
 *
 * @notice ChainlinkConversionPath is a contract allowing to compute conversion rate from a Chainlink aggretators
 */
interface ChainlinkConversionPath {


  /**
  * @notice Computes the rate from a list of conversion
  * @param _path List of addresses representing the currencies for the conversions
  * @return rate the rate
  * @return oldestRateTimestamp he oldest timestamp of the path
  * @return decimals of the conversion rate
  */
  function getRate(
    address[] calldata _path
  )
    external
    view
    returns (uint256 rate, uint256 oldestRateTimestamp, uint256 decimals);
}

interface IERC20FeeProxy {
  event TransferWithReferenceAndFee(
    address tokenAddress,
    address to,
    uint256 amount,
    bytes indexed paymentReference,
    uint256 feeAmount,
    address feeAddress
  );

  function transferFromWithReferenceAndFee(
    address _tokenAddress,
    address _to,
    uint256 _amount,
    bytes calldata _paymentReference,
    uint256 _feeAmount,
    address _feeAddress
    ) external;
}


/**
 * @title ERC20ConversionProxy
 */
contract ERC20ConversionProxy {
  using SafeMath for uint256;

  address public paymentProxy;
  ChainlinkConversionPath public chainlinkConversionPath;

  constructor(address _paymentProxyAddress, address _chainlinkConversionPathAddress) public {
    paymentProxy = _paymentProxyAddress;
    chainlinkConversionPath = ChainlinkConversionPath(_chainlinkConversionPathAddress);
  }

  // Event to declare a transfer with a reference
  event TransferWithConversionAndReference(
    uint256 amount,
    address currency,
    bytes indexed paymentReference,
    uint256 feeAmount,
    uint256 maxRateTimespan
  );

  /**
   * @notice Performs an ERC20 token transfer with a reference computing the amount based on a fiat amount
   * @param _to Transfer recipient
   * @param _requestAmount request amount
   * @param _path conversion path
   * @param _paymentReference Reference of the payment related
   * @param _feeAmount The amount of the payment fee
   * @param _feeAddress The fee recipient
   * @param _maxToSpend amount max that we can spend on the behalf of the user
   * @param _maxRateTimespan max time span with the oldestrate, ignored if zero
   */
  function transferFromWithReferenceAndFee(
    address _to,
    uint256 _requestAmount,
    address[] calldata _path,
    bytes calldata _paymentReference,
    uint256 _feeAmount,
    address _feeAddress,
    uint256 _maxToSpend,
    uint256 _maxRateTimespan
  ) external
  {
    (uint256 amountToPay, uint256 amountToPayInFees) = getConversions(_path, _requestAmount, _feeAmount, _maxRateTimespan);

    require(amountToPay.add(amountToPayInFees) <= _maxToSpend, "Amount to pay is over the user limit");

    // Pay the request and fees
    (bool status, ) = paymentProxy.delegatecall(
      abi.encodeWithSignature(
        "transferFromWithReferenceAndFee(address,address,uint256,bytes,uint256,address)",
        // payment currency
        _path[_path.length - 1],
        _to,
        amountToPay,
        _paymentReference,
        amountToPayInFees,
        _feeAddress
      )
    );
    require(status, "transferFromWithReferenceAndFee failed");

    // Event to declare a transfer with a reference
    emit TransferWithConversionAndReference(
      _requestAmount,
      // request currency
      _path[0],
      _paymentReference,
      _feeAmount,
      _maxRateTimespan
    );
  }

  function getConversions(
    address[] memory _path,
    uint256 _requestAmount,
    uint256 _feeAmount,
    uint256 _maxRateTimespan
  ) internal
    view
    returns (uint256 amountToPay, uint256 amountToPayInFees)
  {
    (uint256 rate, uint256 oldestTimestampRate, uint256 decimals) = chainlinkConversionPath.getRate(_path);

    // Check rate timespan
    require(_maxRateTimespan == 0 || block.timestamp.sub(oldestTimestampRate) <= _maxRateTimespan, "aggregator rate is outdated");
    
    // Get the amount to pay in the crypto currency chosen
    amountToPay = _requestAmount.mul(rate).div(decimals);
    amountToPayInFees = _feeAmount.mul(rate).div(decimals);
  }
}

pragma solidity ^0.4.17;

/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        assert(c / a == b);
        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // assert(b > 0); // Solidity automatically throws when dividing by 0
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
        return c;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        assert(b <= a);
        return a - b;
    }

    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        assert(c >= a);
        return c;
    }
}

/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
    address public owner;

    /**
      * @dev The Ownable constructor sets the original `owner` of the contract to the sender
      * account.
      */
    function Ownable() public {
        owner = msg.sender;
    }

    /**
      * @dev Throws if called by any account other than the owner.
      */
    modifier onlyOwner() {
        require(msg.sender == owner);
        _;
    }

    /**
    * @dev Allows the current owner to transfer control of the contract to a newOwner.
    * @param newOwner The address to transfer ownership to.
    */
    function transferOwnership(address newOwner) public onlyOwner {
        if (newOwner != address(0)) {
            owner = newOwner;
        }
    }

}

/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20Basic {
    uint public _totalSupply;
    function totalSupply() public constant returns (uint);
    function balanceOf(address who) public constant returns (uint);
    function transfer(address to, uint value) public;
    event Transfer(address indexed from, address indexed to, uint value);
}

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20 is ERC20Basic {
    function allowance(address owner, address spender) public constant returns (uint);
    function transferFrom(address from, address to, uint value) public;
    function approve(address spender, uint value) public;
    event Approval(address indexed owner, address indexed spender, uint value);
}

/**
 * @title Basic token
 * @dev Basic version of StandardToken, with no allowances.
 */
contract BasicToken is Ownable, ERC20Basic {
    using SafeMath for uint;

    mapping(address => uint) public balances;

    // additional variables for use if transaction fees ever became necessary
    uint public basisPointsRate = 0;
    uint public maximumFee = 0;

    /**
    * @dev Fix for the ERC20 short address attack.
    */
    modifier onlyPayloadSize(uint size) {
        require(!(msg.data.length < size + 4));
        _;
    }

    /**
    * @dev transfer token for a specified address
    * @param _to The address to transfer to.
    * @param _value The amount to be transferred.
    */
    function transfer(address _to, uint _value) public onlyPayloadSize(2 * 32) {
        uint fee = (_value.mul(basisPointsRate)).div(10000);
        if (fee > maximumFee) {
            fee = maximumFee;
        }
        uint sendAmount = _value.sub(fee);
        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(sendAmount);
        if (fee > 0) {
            balances[owner] = balances[owner].add(fee);
            Transfer(msg.sender, owner, fee);
        }
        Transfer(msg.sender, _to, sendAmount);
    }

    /**
    * @dev Gets the balance of the specified address.
    * @param _owner The address to query the the balance of.
    * @return An uint representing the amount owned by the passed address.
    */
    function balanceOf(address _owner) public constant returns (uint balance) {
        return balances[_owner];
    }

}

/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * @dev https://github.com/ethereum/EIPs/issues/20
 * @dev Based oncode by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract StandardToken is BasicToken, ERC20 {

    mapping (address => mapping (address => uint)) public allowed;

    uint public constant MAX_UINT = 2**256 - 1;

    /**
    * @dev Transfer tokens from one address to another
    * @param _from address The address which you want to send tokens from
    * @param _to address The address which you want to transfer to
    * @param _value uint the amount of tokens to be transferred
    */
    function transferFrom(address _from, address _to, uint _value) public onlyPayloadSize(3 * 32) {
        var _allowance = allowed[_from][msg.sender];

        // Check is not needed because sub(_allowance, _value) will already throw if this condition is not met
        // if (_value > _allowance) throw;

        uint fee = (_value.mul(basisPointsRate)).div(10000);
        if (fee > maximumFee) {
            fee = maximumFee;
        }
        if (_allowance < MAX_UINT) {
            allowed[_from][msg.sender] = _allowance.sub(_value);
        }
        uint sendAmount = _value.sub(fee);
        balances[_from] = balances[_from].sub(_value);
        balances[_to] = balances[_to].add(sendAmount);
        if (fee > 0) {
            balances[owner] = balances[owner].add(fee);
            Transfer(_from, owner, fee);
        }
        Transfer(_from, _to, sendAmount);
    }

    /**
    * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
    * @param _spender The address which will spend the funds.
    * @param _value The amount of tokens to be spent.
    */
    function approve(address _spender, uint _value) public onlyPayloadSize(2 * 32) {

        // To change the approve amount you first have to reduce the addresses`
        //  allowance to zero by calling `approve(_spender, 0)` if it is not
        //  already 0 to mitigate the race condition described here:
        //  https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
        require(!((_value != 0) && (allowed[msg.sender][_spender] != 0)));

        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
    }

    /**
    * @dev Function to check the amount of tokens than an owner allowed to a spender.
    * @param _owner address The address which owns the funds.
    * @param _spender address The address which will spend the funds.
    * @return A uint specifying the amount of tokens still available for the spender.
    */
    function allowance(address _owner, address _spender) public constant returns (uint remaining) {
        return allowed[_owner][_spender];
    }

}


/**
 * @title Pausable
 * @dev Base contract which allows children to implement an emergency stop mechanism.
 */
contract Pausable is Ownable {
  event Pause();
  event Unpause();

  bool public paused = false;


  /**
   * @dev Modifier to make a function callable only when the contract is not paused.
   */
  modifier whenNotPaused() {
    require(!paused);
    _;
  }

  /**
   * @dev Modifier to make a function callable only when the contract is paused.
   */
  modifier whenPaused() {
    require(paused);
    _;
  }

  /**
   * @dev called by the owner to pause, triggers stopped state
   */
  function pause() onlyOwner whenNotPaused public {
    paused = true;
    Pause();
  }

  /**
   * @dev called by the owner to unpause, returns to normal state
   */
  function unpause() onlyOwner whenPaused public {
    paused = false;
    Unpause();
  }
}

contract BlackList is Ownable, BasicToken {

    /////// Getters to allow the same blacklist to be used also by other contracts (including upgraded Tether) ///////
    function getBlackListStatus(address _maker) external constant returns (bool) {
        return isBlackListed[_maker];
    }

    function getOwner() external constant returns (address) {
        return owner;
    }

    mapping (address => bool) public isBlackListed;
    
    function addBlackList (address _evilUser) public onlyOwner {
        isBlackListed[_evilUser] = true;
        AddedBlackList(_evilUser);
    }

    function removeBlackList (address _clearedUser) public onlyOwner {
        isBlackListed[_clearedUser] = false;
        RemovedBlackList(_clearedUser);
    }

    function destroyBlackFunds (address _blackListedUser) public onlyOwner {
        require(isBlackListed[_blackListedUser]);
        uint dirtyFunds = balanceOf(_blackListedUser);
        balances[_blackListedUser] = 0;
        _totalSupply -= dirtyFunds;
        DestroyedBlackFunds(_blackListedUser, dirtyFunds);
    }

    event DestroyedBlackFunds(address _blackListedUser, uint _balance);

    event AddedBlackList(address _user);

    event RemovedBlackList(address _user);

}

contract UpgradedStandardToken is StandardToken{
    // those methods are called by the legacy contract
    // and they must ensure msg.sender to be the contract address
    function transferByLegacy(address from, address to, uint value) public;
    function transferFromByLegacy(address sender, address from, address spender, uint value) public;
    function approveByLegacy(address from, address spender, uint value) public;
}

contract TetherToken is Pausable, StandardToken, BlackList {

    string public name;
    string public symbol;
    uint public decimals;
    address public upgradedAddress;
    bool public deprecated;

    //  The contract can be initialized with a number of tokens
    //  All the tokens are deposited to the owner address
    //
    // @param _balance Initial supply of the contract
    // @param _name Token Name
    // @param _symbol Token symbol
    // @param _decimals Token decimals
    function TetherToken(uint _initialSupply, string _name, string _symbol, uint _decimals) public {
        _totalSupply = _initialSupply;
        name = _name;
        symbol = _symbol;
        decimals = _decimals;
        balances[owner] = _initialSupply;
        deprecated = false;
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function transfer(address _to, uint _value) public whenNotPaused {
        require(!isBlackListed[msg.sender]);
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).transferByLegacy(msg.sender, _to, _value);
        } else {
            return super.transfer(_to, _value);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function transferFrom(address _from, address _to, uint _value) public whenNotPaused {
        require(!isBlackListed[_from]);
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).transferFromByLegacy(msg.sender, _from, _to, _value);
        } else {
            return super.transferFrom(_from, _to, _value);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function balanceOf(address who) public constant returns (uint) {
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).balanceOf(who);
        } else {
            return super.balanceOf(who);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function approve(address _spender, uint _value) public onlyPayloadSize(2 * 32) {
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).approveByLegacy(msg.sender, _spender, _value);
        } else {
            return super.approve(_spender, _value);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function allowance(address _owner, address _spender) public constant returns (uint remaining) {
        if (deprecated) {
            return StandardToken(upgradedAddress).allowance(_owner, _spender);
        } else {
            return super.allowance(_owner, _spender);
        }
    }

    // deprecate current contract in favour of a new one
    function deprecate(address _upgradedAddress) public onlyOwner {
        deprecated = true;
        upgradedAddress = _upgradedAddress;
        Deprecate(_upgradedAddress);
    }

    // deprecate current contract if favour of a new one
    function totalSupply() public constant returns (uint) {
        if (deprecated) {
            return StandardToken(upgradedAddress).totalSupply();
        } else {
            return _totalSupply;
        }
    }

    // Issue a new amount of tokens
    // these tokens are deposited into the owner address
    //
    // @param _amount Number of tokens to be issued
    function issue(uint amount) public onlyOwner {
        require(_totalSupply + amount > _totalSupply);
        require(balances[owner] + amount > balances[owner]);

        balances[owner] += amount;
        _totalSupply += amount;
        Issue(amount);
    }

    // Redeem tokens.
    // These tokens are withdrawn from the owner address
    // if the balance must be enough to cover the redeem
    // or the call will fail.
    // @param _amount Number of tokens to be issued
    function redeem(uint amount) public onlyOwner {
        require(_totalSupply >= amount);
        require(balances[owner] >= amount);

        _totalSupply -= amount;
        balances[owner] -= amount;
        Redeem(amount);
    }

    function setParams(uint newBasisPoints, uint newMaxFee) public onlyOwner {
        // Ensure transparency by hardcoding limit beyond which fees can never be added
        require(newBasisPoints < 20);
        require(newMaxFee < 50);

        basisPointsRate = newBasisPoints;
        maximumFee = newMaxFee.mul(10**decimals);

        Params(basisPointsRate, maximumFee);
    }

    // Called when new token are issued
    event Issue(uint amount);

    // Called when tokens are redeemed
    event Redeem(uint amount);

    // Called when contract is deprecated
    event Deprecate(address newAddress);

    // Called if contract ever adds fees
    event Params(uint feeBasisPoints, uint maxFee);
}

// SPDX-License-Identifier: MIT
pragma solidity >=0.4.25 <0.7.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

/**
 * @title Roles
 * @dev Library for managing addresses assigned to a Role.
 */
library Roles {
    struct Role {
        mapping (address => bool) bearer;
    }

    /**
     * @dev give an account access to this role
     */
    function add(Role storage role, address account) internal {
        require(account != address(0));
        require(!has(role, account));

        role.bearer[account] = true;
    }

    /**
     * @dev remove an account's access to this role
     */
    function remove(Role storage role, address account) internal {
        require(account != address(0));
        require(has(role, account));

        role.bearer[account] = false;
    }

    /**
     * @dev check if an account has this role
     * @return bool
     */
    function has(Role storage role, address account) internal view returns (bool) {
        require(account != address(0));
        return role.bearer[account];
    }
}


/**
 * @title WhitelistAdminRole
 * @dev WhitelistAdmins are responsible for assigning and removing Whitelisted accounts.
 */
contract WhitelistAdminRole {
    using Roles for Roles.Role;

    event WhitelistAdminAdded(address indexed account);
    event WhitelistAdminRemoved(address indexed account);

    Roles.Role private _whitelistAdmins;

    constructor () internal {
        _addWhitelistAdmin(msg.sender);
    }

    modifier onlyWhitelistAdmin() {
        require(isWhitelistAdmin(msg.sender));
        _;
    }

    function isWhitelistAdmin(address account) public view returns (bool) {
        return _whitelistAdmins.has(account);
    }

    function addWhitelistAdmin(address account) public onlyWhitelistAdmin {
        _addWhitelistAdmin(account);
    }

    function renounceWhitelistAdmin() public {
        _removeWhitelistAdmin(msg.sender);
    }

    function _addWhitelistAdmin(address account) internal {
        _whitelistAdmins.add(account);
        emit WhitelistAdminAdded(account);
    }

    function _removeWhitelistAdmin(address account) internal {
        _whitelistAdmins.remove(account);
        emit WhitelistAdminRemoved(account);
    }
}

interface ERC20fraction {
  function decimals() external view returns (uint8);
}

interface AggregatorFraction {
  function decimals() external view returns (uint8);
  function latestAnswer() external view returns (int256);
  function latestTimestamp() external view returns (uint256);
}


/**
 * @title ChainlinkConversionPath
 *
 * @notice ChainlinkConversionPath is a contract computing currency conversion rates based on Chainlink aggretators
 */
contract ChainlinkConversionPath is WhitelistAdminRole {
  using SafeMath for uint256;

  uint constant DECIMALS = 1e18;

  // Mapping of Chainlink aggregators (input currency => output currency => contract address)
  // input & output currencies are the addresses of the ERC20 contracts OR the sha3("currency code")
  mapping(address => mapping(address => address)) public allAggregators;

  // declare a new aggregator
  event AggregatorUpdated(address _input, address _output, address _aggregator);

  /**
    * @notice Update an aggregator
    * @param _input address representing the input currency
    * @param _output address representing the output currency
    * @param _aggregator address of the aggregator contract
  */
  function updateAggregator(address _input, address _output, address _aggregator)
    external
    onlyWhitelistAdmin
  {
    allAggregators[_input][_output] = _aggregator;
    emit AggregatorUpdated(_input, _output, _aggregator);
  }

  /**
    * @notice Update a list of aggregators
    * @param _inputs list of addresses representing the input currencies
    * @param _outputs list of addresses representing the output currencies
    * @param _aggregators list of addresses of the aggregator contracts
  */
  function updateAggregatorsList(address[] calldata _inputs, address[] calldata _outputs, address[] calldata _aggregators)
    external
    onlyWhitelistAdmin
  {
    require(_inputs.length == _outputs.length, "arrays must have the same length");
    require(_inputs.length == _aggregators.length, "arrays must have the same length");

    // For every conversions of the path
    for (uint i; i < _inputs.length; i++) {
      allAggregators[_inputs[i]][_outputs[i]] = _aggregators[i];
      emit AggregatorUpdated(_inputs[i], _outputs[i], _aggregators[i]);
    }
  }

  /**
  * @notice Computes the conversion of an amount through a list of intermediate conversions
  * @param _amountIn Amount to convert
  * @param _path List of addresses representing the currencies for the intermediate conversions
  * @return result The result after all the conversions
  * @return oldestRateTimestamp The oldest timestamp of the path
  */
  function getConversion(
    uint256 _amountIn,
    address[] calldata _path
  )
    external
    view
    returns (uint256 result, uint256 oldestRateTimestamp)
  {
    (uint256 rate, uint256 timestamp, uint256 decimals) = getRate(_path);

    // initialize the result
    result = _amountIn.mul(rate).div(decimals);

    oldestRateTimestamp = timestamp;
  }

  /**
  * @notice Computes the conversion rate from a list of currencies
  * @param _path List of addresses representing the currencies for the conversions
  * @return rate The rate
  * @return oldestRateTimestamp The oldest timestamp of the path
  * @return decimals of the conversion rate
  */
  function getRate(
    address[] memory _path
  )
    public
    view
    returns (uint256 rate, uint256 oldestRateTimestamp, uint256 decimals)
  {
    // initialize the result with 18 decimals (for more precision)
    rate = DECIMALS;
    decimals = DECIMALS;
    oldestRateTimestamp = block.timestamp;

    // For every conversion of the path
    for (uint i; i < _path.length - 1; i++) {
      (AggregatorFraction aggregator, bool reverseAggregator, uint256 decimalsInput, uint256 decimalsOutput) = getAggregatorAndDecimals(_path[i], _path[i + 1]);

      // store the latest timestamp of the path
      uint256 currentTimestamp = aggregator.latestTimestamp();
      if (currentTimestamp < oldestRateTimestamp) {
        oldestRateTimestamp = currentTimestamp;
      }

      // get the rate of the current step
      uint256 currentRate = uint256(aggregator.latestAnswer());
      // get the number of decimals of the current rate
      uint256 decimalsAggregator = uint256(aggregator.decimals());

      // mul with the difference of decimals before the current rate computation (for more precision)
      if (decimalsAggregator > decimalsInput) {
        rate = rate.mul(10**(decimalsAggregator-decimalsInput));
      }
      if (decimalsAggregator < decimalsOutput) {
        rate = rate.mul(10**(decimalsOutput-decimalsAggregator));
      }

      // Apply the current rate (if path uses an aggregator in the reverse way, div instead of mul)
      if (reverseAggregator) {
        rate = rate.mul(10**decimalsAggregator).div(currentRate);
      } else {
        rate = rate.mul(currentRate).div(10**decimalsAggregator);
      }

      // div with the difference of decimals AFTER the current rate computation (for more precision)
      if (decimalsAggregator < decimalsInput) {
        rate = rate.div(10**(decimalsInput-decimalsAggregator));
      }
      if (decimalsAggregator > decimalsOutput) {
        rate = rate.div(10**(decimalsAggregator-decimalsOutput));
      }
    }
  }

  /**
  * @notice Gets aggregators and decimals of two currencies
  * @param _input input Address
  * @param _output output Address
  * @return aggregator to get the rate between the two currencies
  * @return reverseAggregator true if the aggregator returned give the rate from _output to _input
  * @return decimalsInput decimals of _input
  * @return decimalsOutput decimals of _output
  */
  function getAggregatorAndDecimals(address _input, address _output)
    private
    view
    returns (AggregatorFraction aggregator, bool reverseAggregator, uint256 decimalsInput, uint256 decimalsOutput)
  {
    // Try to get the right aggregator for the conversion
    aggregator = AggregatorFraction(allAggregators[_input][_output]);
    reverseAggregator = false;

    // if no aggregator found we try to find an aggregator in the reverse way
    if (address(aggregator) == address(0x00)) {
      aggregator = AggregatorFraction(allAggregators[_output][_input]);
      reverseAggregator = true;
    }

    require(address(aggregator) != address(0x00), "No aggregator found");

    // get the decimals for the two currencies
    decimalsInput = getDecimals(_input);
    decimalsOutput = getDecimals(_output);
  }

  /**
  * @notice Gets decimals from an address currency
  * @param _addr address to check
  * @return decimals number of decimals
  */
  function getDecimals(address _addr)
    private
    view
    returns (uint256 decimals)
  {
    // by default we assume it is FIAT so 8 decimals
    decimals = 8;
    // if address is the hash of the ETH currency
    if (_addr == address(0xF5AF88e117747e87fC5929F2ff87221B1447652E)) {
      decimals = 18;
    } else if (isContract(_addr)) {
      // otherwise, we get the decimals from the erc20 directly
      decimals = ERC20fraction(_addr).decimals();
    }
  }

  /**
  * @notice Checks if an address is a contract
  * @param _addr Address to check
  * @return true if the address hosts a contract, false otherwise
  */
  function isContract(address _addr)
    private
    view
    returns (bool)
  {
    uint32 size;
    // solium-disable security/no-inline-assembly
    assembly {
      size := extcodesize(_addr)
    }
    return (size > 0);
  }
}

pragma solidity 0.6.6;


/**
 * @title The Owned contract
 * @notice A contract with helpers for basic contract ownership.
 */
contract Owned {

  address payable public owner;
  address private pendingOwner;

  event OwnershipTransferRequested(
    address indexed from,
    address indexed to
  );
  event OwnershipTransferred(
    address indexed from,
    address indexed to
  );

  constructor() public {
    owner = msg.sender;
  }

  /**
   * @dev Allows an owner to begin transferring ownership to a new address,
   * pending.
   */
  function transferOwnership(address _to)
    external
    onlyOwner()
  {
    pendingOwner = _to;

    emit OwnershipTransferRequested(owner, _to);
  }

  /**
   * @dev Allows an ownership transfer to be completed by the recipient.
   */
  function acceptOwnership()
    external
  {
    require(msg.sender == pendingOwner, "Must be proposed owner");

    address oldOwner = owner;
    owner = msg.sender;
    pendingOwner = address(0);

    emit OwnershipTransferred(oldOwner, msg.sender);
  }

  /**
   * @dev Reverts if called by anyone other than the contract owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner, "Only callable by owner");
    _;
  }

}

interface AggregatorInterface {
  function latestAnswer() external view returns (int256);
  function latestTimestamp() external view returns (uint256);
  function latestRound() external view returns (uint256);
  function getAnswer(uint256 roundId) external view returns (int256);
  function getTimestamp(uint256 roundId) external view returns (uint256);

  event AnswerUpdated(int256 indexed current, uint256 indexed roundId, uint256 updatedAt);
  event NewRound(uint256 indexed roundId, address indexed startedBy, uint256 startedAt);
}

interface AggregatorV3Interface {

  function decimals() external view returns (uint8);
  function description() external view returns (string memory);
  function version() external view returns (uint256);

  // getRoundData and latestRoundData should both raise "No data present"
  // if they do not have data to report, instead of returning unset values
  // which could be misinterpreted as actual reported values.
  function getRoundData(uint80 _roundId)
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );
  function latestRoundData()
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );

}

interface AggregatorV2V3Interface is AggregatorInterface, AggregatorV3Interface
{
}

/**
 * @title A trusted proxy for updating where current answers are read from
 * @notice This contract provides a consistent address for the
 * CurrentAnwerInterface but delegates where it reads from to the owner, who is
 * trusted to update it.
 */
contract AggregatorProxy is AggregatorV2V3Interface, Owned {

  struct Phase {
    uint16 id;
    AggregatorV2V3Interface aggregator;
  }
  Phase private currentPhase;
  AggregatorV2V3Interface public proposedAggregator;
  mapping(uint16 => AggregatorV2V3Interface) public phaseAggregators;

  uint256 constant private PHASE_OFFSET = 64;
  uint256 constant private PHASE_SIZE = 16;
  uint256 constant private MAX_ID = 2**(PHASE_OFFSET+PHASE_SIZE) - 1;

  constructor(address _aggregator) public Owned() {
    setAggregator(_aggregator);
  }

  /**
   * @notice Reads the current answer from aggregator delegated to.
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestAnswer()
    public
    view
    virtual
    override
    returns (int256 answer)
  {
    return currentPhase.aggregator.latestAnswer();
  }

  /**
   * @notice Reads the last updated height from aggregator delegated to.
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestTimestamp()
    public
    view
    virtual
    override
    returns (uint256 updatedAt)
  {
    return currentPhase.aggregator.latestTimestamp();
  }

  /**
   * @notice get past rounds answers
   * @param _roundId the answer number to retrieve the answer for
   *
   * @dev #[deprecated] Use getRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended getRoundData
   * instead which includes better verification information.
   */
  function getAnswer(uint256 _roundId)
    public
    view
    virtual
    override
    returns (int256 answer)
  {
    if (_roundId > MAX_ID) return 0;

    (uint16 phaseId, uint64 aggregatorRoundId) = parseIds(_roundId);
    AggregatorV2V3Interface aggregator = phaseAggregators[phaseId];
    if (address(aggregator) == address(0)) return 0;

    return aggregator.getAnswer(aggregatorRoundId);
  }

  /**
   * @notice get block timestamp when an answer was last updated
   * @param _roundId the answer number to retrieve the updated timestamp for
   *
   * @dev #[deprecated] Use getRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended getRoundData
   * instead which includes better verification information.
   */
  function getTimestamp(uint256 _roundId)
    public
    view
    virtual
    override
    returns (uint256 updatedAt)
  {
    if (_roundId > MAX_ID) return 0;

    (uint16 phaseId, uint64 aggregatorRoundId) = parseIds(_roundId);
    AggregatorV2V3Interface aggregator = phaseAggregators[phaseId];
    if (address(aggregator) == address(0)) return 0;

    return aggregator.getTimestamp(aggregatorRoundId);
  }

  /**
   * @notice get the latest completed round where the answer was updated. This
   * ID includes the proxy's phase, to make sure round IDs increase even when
   * switching to a newly deployed aggregator.
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestRound()
    public
    view
    virtual
    override
    returns (uint256 roundId)
  {
    Phase memory phase = currentPhase; // cache storage reads
    return addPhase(phase.id, uint64(phase.aggregator.latestRound()));
  }

  /**
   * @notice get data about a round. Consumers are encouraged to check
   * that they're receiving fresh data by inspecting the updatedAt and
   * answeredInRound return values.
   * Note that different underlying implementations of AggregatorV3Interface
   * have slightly different semantics for some of the return values. Consumers
   * should determine what implementations they expect to receive
   * data from and validate that they can properly handle return data from all
   * of them.
   * @param _roundId the requested round ID as presented through the proxy, this
   * is made up of the aggregator's round ID with the phase ID encoded in the
   * two highest order bytes
   * @return roundId is the round ID from the aggregator for which the data was
   * retrieved combined with an phase to ensure that round IDs get larger as
   * time moves forward.
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @dev Note that answer and updatedAt may change between queries.
   */
  function getRoundData(uint80 _roundId)
    public
    view
    virtual
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    (uint16 phaseId, uint64 aggregatorRoundId) = parseIds(_roundId);

    (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 ansIn
    ) = phaseAggregators[phaseId].getRoundData(aggregatorRoundId);

    return addPhaseIds(roundId, answer, startedAt, updatedAt, ansIn, phaseId);
  }

  /**
   * @notice get data about the latest round. Consumers are encouraged to check
   * that they're receiving fresh data by inspecting the updatedAt and
   * answeredInRound return values.
   * Note that different underlying implementations of AggregatorV3Interface
   * have slightly different semantics for some of the return values. Consumers
   * should determine what implementations they expect to receive
   * data from and validate that they can properly handle return data from all
   * of them.
   * @return roundId is the round ID from the aggregator for which the data was
   * retrieved combined with an phase to ensure that round IDs get larger as
   * time moves forward.
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @dev Note that answer and updatedAt may change between queries.
   */
  function latestRoundData()
    public
    view
    virtual
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    Phase memory current = currentPhase; // cache storage reads

    (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 ansIn
    ) = current.aggregator.latestRoundData();

    return addPhaseIds(roundId, answer, startedAt, updatedAt, ansIn, current.id);
  }

  /**
   * @notice Used if an aggregator contract has been proposed.
   * @param _roundId the round ID to retrieve the round data for
   * @return roundId is the round ID for which data was retrieved
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
  */
  function proposedGetRoundData(uint80 _roundId)
    public
    view
    virtual
    hasProposal()
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return proposedAggregator.getRoundData(_roundId);
  }

  /**
   * @notice Used if an aggregator contract has been proposed.
   * @return roundId is the round ID for which data was retrieved
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
  */
  function proposedLatestRoundData()
    public
    view
    virtual
    hasProposal()
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return proposedAggregator.latestRoundData();
  }

  /**
   * @notice returns the current phase's aggregator address.
   */
  function aggregator()
    external
    view
    returns (address)
  {
    return address(currentPhase.aggregator);
  }

  /**
   * @notice returns the current phase's ID.
   */
  function phaseId()
    external
    view
    returns (uint16)
  {
    return currentPhase.id;
  }

  /**
   * @notice represents the number of decimals the aggregator responses represent.
   */
  function decimals()
    external
    view
    override
    returns (uint8)
  {
    return currentPhase.aggregator.decimals();
  }

  /**
   * @notice the version number representing the type of aggregator the proxy
   * points to.
   */
  function version()
    external
    view
    override
    returns (uint256)
  {
    return currentPhase.aggregator.version();
  }

  /**
   * @notice returns the description of the aggregator the proxy points to.
   */
  function description()
    external
    view
    override
    returns (string memory)
  {
    return currentPhase.aggregator.description();
  }

  /**
   * @notice Allows the owner to propose a new address for the aggregator
   * @param _aggregator The new address for the aggregator contract
   */
  function proposeAggregator(address _aggregator)
    external
    onlyOwner()
  {
    proposedAggregator = AggregatorV2V3Interface(_aggregator);
  }

  /**
   * @notice Allows the owner to confirm and change the address
   * to the proposed aggregator
   * @dev Reverts if the given address doesn't match what was previously
   * proposed
   * @param _aggregator The new address for the aggregator contract
   */
  function confirmAggregator(address _aggregator)
    external
    onlyOwner()
  {
    require(_aggregator == address(proposedAggregator), "Invalid proposed aggregator");
    delete proposedAggregator;
    setAggregator(_aggregator);
  }


  /*
   * Internal
   */

  function setAggregator(address _aggregator)
    internal
  {
    uint16 id = currentPhase.id + 1;
    currentPhase = Phase(id, AggregatorV2V3Interface(_aggregator));
    phaseAggregators[id] = AggregatorV2V3Interface(_aggregator);
  }

  function addPhase(
    uint16 _phase,
    uint64 _originalId
  )
    internal
    view
    returns (uint80)
  {
    return uint80(uint256(_phase) << PHASE_OFFSET | _originalId);
  }

  function parseIds(
    uint256 _roundId
  )
    internal
    view
    returns (uint16, uint64)
  {
    uint16 phaseId = uint16(_roundId >> PHASE_OFFSET);
    uint64 aggregatorRoundId = uint64(_roundId);

    return (phaseId, aggregatorRoundId);
  }

  function addPhaseIds(
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound,
      uint16 phaseId
  )
    internal
    view
    returns (uint80, int256, uint256, uint256, uint80)
  {
    return (
      addPhase(phaseId, uint64(roundId)),
      answer,
      startedAt,
      updatedAt,
      addPhase(phaseId, uint64(answeredInRound))
    );
  }

  /*
   * Modifiers
   */

  modifier hasProposal() {
    require(address(proposedAggregator) != address(0), "No proposed aggregator present");
    _;
  }

}

interface AccessControllerInterface {
  function hasAccess(address user, bytes calldata data) external view returns (bool);
}

/**
 * @title External Access Controlled Aggregator Proxy
 * @notice A trusted proxy for updating where current answers are read from
 * @notice This contract provides a consistent address for the
 * Aggregator and AggregatorV3Interface but delegates where it reads from to the owner, who is
 * trusted to update it.
 * @notice Only access enabled addresses are allowed to access getters for
 * aggregated answers and round information.
 */
contract EACAggregatorProxy is AggregatorProxy {

  AccessControllerInterface public accessController;

  constructor(
    address _aggregator,
    address _accessController
  )
    public
    AggregatorProxy(_aggregator)
  {
    setController(_accessController);
  }

  /**
   * @notice Allows the owner to update the accessController contract address.
   * @param _accessController The new address for the accessController contract
   */
  function setController(address _accessController)
    public
    onlyOwner()
  {
    accessController = AccessControllerInterface(_accessController);
  }

  /**
   * @notice Reads the current answer from aggregator delegated to.
   * @dev overridden function to add the checkAccess() modifier
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestAnswer()
    public
    view
    override
    checkAccess()
    returns (int256)
  {
    return super.latestAnswer();
  }

  /**
   * @notice get the latest completed round where the answer was updated. This
   * ID includes the proxy's phase, to make sure round IDs increase even when
   * switching to a newly deployed aggregator.
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestTimestamp()
    public
    view
    override
    checkAccess()
    returns (uint256)
  {
    return super.latestTimestamp();
  }

  /**
   * @notice get past rounds answers
   * @param _roundId the answer number to retrieve the answer for
   * @dev overridden function to add the checkAccess() modifier
   *
   * @dev #[deprecated] Use getRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended getRoundData
   * instead which includes better verification information.
   */
  function getAnswer(uint256 _roundId)
    public
    view
    override
    checkAccess()
    returns (int256)
  {
    return super.getAnswer(_roundId);
  }

  /**
   * @notice get block timestamp when an answer was last updated
   * @param _roundId the answer number to retrieve the updated timestamp for
   * @dev overridden function to add the checkAccess() modifier
   *
   * @dev #[deprecated] Use getRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended getRoundData
   * instead which includes better verification information.
   */
  function getTimestamp(uint256 _roundId)
    public
    view
    override
    checkAccess()
    returns (uint256)
  {
    return super.getTimestamp(_roundId);
  }

  /**
   * @notice get the latest completed round where the answer was updated
   * @dev overridden function to add the checkAccess() modifier
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestRound()
    public
    view
    override
    checkAccess()
    returns (uint256)
  {
    return super.latestRound();
  }

  /**
   * @notice get data about a round. Consumers are encouraged to check
   * that they're receiving fresh data by inspecting the updatedAt and
   * answeredInRound return values.
   * Note that different underlying implementations of AggregatorV3Interface
   * have slightly different semantics for some of the return values. Consumers
   * should determine what implementations they expect to receive
   * data from and validate that they can properly handle return data from all
   * of them.
   * @param _roundId the round ID to retrieve the round data for
   * @return roundId is the round ID from the aggregator for which the data was
   * retrieved combined with a phase to ensure that round IDs get larger as
   * time moves forward.
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @dev Note that answer and updatedAt may change between queries.
   */
  function getRoundData(uint80 _roundId)
    public
    view
    checkAccess()
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.getRoundData(_roundId);
  }

  /**
   * @notice get data about the latest round. Consumers are encouraged to check
   * that they're receiving fresh data by inspecting the updatedAt and
   * answeredInRound return values.
   * Note that different underlying implementations of AggregatorV3Interface
   * have slightly different semantics for some of the return values. Consumers
   * should determine what implementations they expect to receive
   * data from and validate that they can properly handle return data from all
   * of them.
   * @return roundId is the round ID from the aggregator for which the data was
   * retrieved combined with a phase to ensure that round IDs get larger as
   * time moves forward.
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @dev Note that answer and updatedAt may change between queries.
   */
  function latestRoundData()
    public
    view
    checkAccess()
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.latestRoundData();
  }

  /**
   * @notice Used if an aggregator contract has been proposed.
   * @param _roundId the round ID to retrieve the round data for
   * @return roundId is the round ID for which data was retrieved
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
  */
  function proposedGetRoundData(uint80 _roundId)
    public
    view
    checkAccess()
    hasProposal()
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.proposedGetRoundData(_roundId);
  }

  /**
   * @notice Used if an aggregator contract has been proposed.
   * @return roundId is the round ID for which data was retrieved
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
  */
  function proposedLatestRoundData()
    public
    view
    checkAccess()
    hasProposal()
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.proposedLatestRoundData();
  }

  /**
   * @dev reverts if the caller does not have access by the accessController
   * contract or is the contract itself.
   */
  modifier checkAccess() {
    AccessControllerInterface ac = accessController;
    require(address(ac) == address(0) || ac.hasAccess(msg.sender, msg.data), "No access");
    _;
  }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.7.1;
import "./OffchainAggregator.sol";
import "./SimpleReadAccessController.sol";
/**
 * @notice Wrapper of OffchainAggregator which checks read access on Aggregator-interface methods
 */
contract AccessControlledOffchainAggregator is OffchainAggregator, SimpleReadAccessController {
  constructor(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission,
    address _link,
    address _validator,
    int192 _minAnswer,
    int192 _maxAnswer,
    AccessControllerInterface _billingAccessController,
    AccessControllerInterface _requesterAccessController,
    uint8 _decimals,
    string memory description
  )
    OffchainAggregator(
      _maximumGasPrice,
      _reasonableGasPrice,
      _microLinkPerEth,
      _linkGweiPerObservation,
      _linkGweiPerTransmission,
      _link,
      _validator,
      _minAnswer,
      _maxAnswer,
      _billingAccessController,
      _requesterAccessController,
      _decimals,
      description
    ) {
    }
  /*
   * v2 Aggregator interface
   */
  /// @inheritdoc OffchainAggregator
  function latestAnswer()
    public
    override
    view
    checkAccess()
    returns (int256)
  {
    return super.latestAnswer();
  }
  /// @inheritdoc OffchainAggregator
  function latestTimestamp()
    public
    override
    view
    checkAccess()
    returns (uint256)
  {
    return super.latestTimestamp();
  }
  /// @inheritdoc OffchainAggregator
  function latestRound()
    public
    override
    view
    checkAccess()
    returns (uint256)
  {
    return super.latestRound();
  }
  /// @inheritdoc OffchainAggregator
  function getAnswer(uint256 _roundId)
    public
    override
    view
    checkAccess()
    returns (int256)
  {
    return super.getAnswer(_roundId);
  }
  /// @inheritdoc OffchainAggregator
  function getTimestamp(uint256 _roundId)
    public
    override
    view
    checkAccess()
    returns (uint256)
  {
    return super.getTimestamp(_roundId);
  }
  /*
   * v3 Aggregator interface
   */
  /// @inheritdoc OffchainAggregator
  function description()
    public
    override
    view
    checkAccess()
    returns (string memory)
  {
    return super.description();
  }
  /// @inheritdoc OffchainAggregator
  function getRoundData(uint80 _roundId)
    public
    override
    view
    checkAccess()
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.getRoundData(_roundId);
  }
  /// @inheritdoc OffchainAggregator
  function latestRoundData()
    public
    override
    view
    checkAccess()
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.latestRoundData();
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "./AccessControllerInterface.sol";
import "./AggregatorV2V3Interface.sol";
import "./AggregatorValidatorInterface.sol";
import "./LinkTokenInterface.sol";
import "./Owned.sol";
import "./OffchainAggregatorBilling.sol";
/**
  * @notice Onchain verification of reports from the offchain reporting protocol
  * @dev For details on its operation, see the offchain reporting protocol design
  * @dev doc, which refers to this contract as simply the "contract".
*/
contract OffchainAggregator is Owned, OffchainAggregatorBilling, AggregatorV2V3Interface {
  uint256 constant private maxUint32 = (1 << 32) - 1;
  // Storing these fields used on the hot path in a HotVars variable reduces the
  // retrieval of all of them to a single SLOAD. If any further fields are
  // added, make sure that storage of the struct still takes at most 32 bytes.
  struct HotVars {
    // Provides 128 bits of security against 2nd pre-image attacks, but only
    // 64 bits against collisions. This is acceptable, since a malicious owner has
    // easier way of messing up the protocol than to find hash collisions.
    bytes16 latestConfigDigest;
    uint40 latestEpochAndRound; // 32 most sig bits for epoch, 8 least sig bits for round
    // Current bound assumed on number of faulty/dishonest oracles participating
    // in the protocol, this value is referred to as f in the design
    uint8 threshold;
    // Chainlink Aggregators expose a roundId to consumers. The offchain reporting
    // protocol does not use this id anywhere. We increment it whenever a new
    // transmission is made to provide callers with contiguous ids for successive
    // reports.
    uint32 latestAggregatorRoundId;
  }
  HotVars internal s_hotVars;
  // Transmission records the median answer from the transmit transaction at
  // time timestamp
  struct Transmission {
    int192 answer; // 192 bits ought to be enough for anyone
    uint64 timestamp;
  }
  mapping(uint32 /* aggregator round ID */ => Transmission) internal s_transmissions;
  // incremented each time a new config is posted. This count is incorporated
  // into the config digest, to prevent replay attacks.
  uint32 internal s_configCount;
  uint32 internal s_latestConfigBlockNumber; // makes it easier for offchain systems
                                             // to extract config from logs.
  // Lowest answer the system is allowed to report in response to transmissions
  int192 immutable public minAnswer;
  // Highest answer the system is allowed to report in response to transmissions
  int192 immutable public maxAnswer;
  /*
   * @param _maximumGasPrice highest gas price for which transmitter will be compensated
   * @param _reasonableGasPrice transmitter will receive reward for gas prices under this value
   * @param _microLinkPerEth reimbursement per ETH of gas cost, in 1e-6LINK units
   * @param _linkGweiPerObservation reward to oracle for contributing an observation to a successfully transmitted report, in 1e-9LINK units
   * @param _linkGweiPerTransmission reward to transmitter of a successful report, in 1e-9LINK units
   * @param _link address of the LINK contract
   * @param _validator address of validator contract (must satisfy AggregatorValidatorInterface)
   * @param _minAnswer lowest answer the median of a report is allowed to be
   * @param _maxAnswer highest answer the median of a report is allowed to be
   * @param _billingAccessController access controller for billing admin functions
   * @param _requesterAccessController access controller for requesting new rounds
   * @param _decimals answers are stored in fixed-point format, with this many digits of precision
   * @param _description short human-readable description of observable this contract's answers pertain to
   */
  constructor(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission,
    address _link,
    address _validator,
    int192 _minAnswer,
    int192 _maxAnswer,
    AccessControllerInterface _billingAccessController,
    AccessControllerInterface _requesterAccessController,
    uint8 _decimals,
    string memory _description
  )
    OffchainAggregatorBilling(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission, _link,
      _billingAccessController
    )
  {
    decimals = _decimals;
    s_description = _description;
    setRequesterAccessController(_requesterAccessController);
    setValidator(_validator);
    minAnswer = _minAnswer;
    maxAnswer = _maxAnswer;
  }
  /*
   * Config logic
   */
  /**
   * @notice triggers a new run of the offchain reporting protocol
   * @param previousConfigBlockNumber block in which the previous config was set, to simplify historic analysis
   * @param configCount ordinal number of this config setting among all config settings over the life of this contract
   * @param signers ith element is address ith oracle uses to sign a report
   * @param transmitters ith element is address ith oracle uses to transmit a report via the transmit method
   * @param threshold maximum number of faulty/dishonest oracles the protocol can tolerate while still working correctly
   * @param encodedConfigVersion version of the serialization format used for "encoded" parameter
   * @param encoded serialized data used by oracles to configure their offchain operation
   */
  event ConfigSet(
    uint32 previousConfigBlockNumber,
    uint64 configCount,
    address[] signers,
    address[] transmitters,
    uint8 threshold,
    uint64 encodedConfigVersion,
    bytes encoded
  );
  // Reverts transaction if config args are invalid
  modifier checkConfigValid (
    uint256 _numSigners, uint256 _numTransmitters, uint256 _threshold
  ) {
    require(_numSigners <= maxNumOracles, "too many signers");
    require(_threshold > 0, "threshold must be positive");
    require(
      _numSigners == _numTransmitters,
      "oracle addresses out of registration"
    );
    require(_numSigners > 3*_threshold, "faulty-oracle threshold too high");
    _;
  }
  /**
   * @notice sets offchain reporting protocol configuration incl. participating oracles
   * @param _signers addresses with which oracles sign the reports
   * @param _transmitters addresses oracles use to transmit the reports
   * @param _threshold number of faulty oracles the system can tolerate
   * @param _encodedConfigVersion version number for offchainEncoding schema
   * @param _encoded encoded off-chain oracle configuration
   */
  function setConfig(
    address[] calldata _signers,
    address[] calldata _transmitters,
    uint8 _threshold,
    uint64 _encodedConfigVersion,
    bytes calldata _encoded
  )
    external
    checkConfigValid(_signers.length, _transmitters.length, _threshold)
    onlyOwner()
  {
    while (s_signers.length != 0) { // remove any old signer/transmitter addresses
      uint lastIdx = s_signers.length - 1;
      address signer = s_signers[lastIdx];
      address transmitter = s_transmitters[lastIdx];
      payOracle(transmitter);
      delete s_oracles[signer];
      delete s_oracles[transmitter];
      s_signers.pop();
      s_transmitters.pop();
    }
    for (uint i = 0; i < _signers.length; i++) { // add new signer/transmitter addresses
      require(
        s_oracles[_signers[i]].role == Role.Unset,
        "repeated signer address"
      );
      s_oracles[_signers[i]] = Oracle(uint8(i), Role.Signer);
      require(s_payees[_transmitters[i]] != address(0), "payee must be set");
      require(
        s_oracles[_transmitters[i]].role == Role.Unset,
        "repeated transmitter address"
      );
      s_oracles[_transmitters[i]] = Oracle(uint8(i), Role.Transmitter);
      s_signers.push(_signers[i]);
      s_transmitters.push(_transmitters[i]);
    }
    s_hotVars.threshold = _threshold;
    uint32 previousConfigBlockNumber = s_latestConfigBlockNumber;
    s_latestConfigBlockNumber = uint32(block.number);
    s_configCount += 1;
    uint64 configCount = s_configCount;
    {
      s_hotVars.latestConfigDigest = configDigestFromConfigData(
        address(this),
        configCount,
        _signers,
        _transmitters,
        _threshold,
        _encodedConfigVersion,
        _encoded
      );
      s_hotVars.latestEpochAndRound = 0;
    }
    emit ConfigSet(
      previousConfigBlockNumber,
      configCount,
      _signers,
      _transmitters,
      _threshold,
      _encodedConfigVersion,
      _encoded
    );
  }
  function configDigestFromConfigData(
    address _contractAddress,
    uint64 _configCount,
    address[] calldata _signers,
    address[] calldata _transmitters,
    uint8 _threshold,
    uint64 _encodedConfigVersion,
    bytes calldata _encodedConfig
  ) internal pure returns (bytes16) {
    return bytes16(keccak256(abi.encode(_contractAddress, _configCount,
      _signers, _transmitters, _threshold, _encodedConfigVersion, _encodedConfig
    )));
  }
  /**
   * @notice information about current offchain reporting protocol configuration
   * @return configCount ordinal number of current config, out of all configs applied to this contract so far
   * @return blockNumber block at which this config was set
   * @return configDigest domain-separation tag for current config (see configDigestFromConfigData)
   */
  function latestConfigDetails()
    external
    view
    returns (
      uint32 configCount,
      uint32 blockNumber,
      bytes16 configDigest
    )
  {
    return (s_configCount, s_latestConfigBlockNumber, s_hotVars.latestConfigDigest);
  }
  /**
   * @return list of addresses permitted to transmit reports to this contract
   * @dev The list will match the order used to specify the transmitter during setConfig
   */
  function transmitters()
    external
    view
    returns(address[] memory)
  {
      return s_transmitters;
  }
  /*
   * On-chain validation logc
   */
  // Maximum gas the validation logic can use
  uint256 private constant VALIDATOR_GAS_LIMIT = 100000;
  // Contract containing the validation logic
  AggregatorValidatorInterface private s_validator;
  /**
   * @notice indicates that the address of the validator contract has been set
   * @param previous setting of the address prior to this event
   * @param current the new value for the address
   */
  event ValidatorUpdated(
    address indexed previous,
    address indexed current
  );
  /**
   * @notice address of the contract which does external data validation
   * @return validator address
   */
  function validator()
    external
    view
    returns (AggregatorValidatorInterface)
  {
    return s_validator;
  }
  /**
   * @notice sets the address which does external data validation
   * @param _newValidator designates the address of the new validation contract
   */
  function setValidator(address _newValidator)
    public
    onlyOwner()
  {
    address previous = address(s_validator);
    if (previous != _newValidator) {
      s_validator = AggregatorValidatorInterface(_newValidator);
      emit ValidatorUpdated(previous, _newValidator);
    }
  }
  function validateAnswer(
    uint32 _aggregatorRoundId,
    int256 _answer
  )
    private
  {
    AggregatorValidatorInterface av = s_validator; // cache storage reads
    if (address(av) == address(0)) return;
    uint32 prevAggregatorRoundId = _aggregatorRoundId - 1;
    int256 prevAggregatorRoundAnswer = s_transmissions[prevAggregatorRoundId].answer;
    // We do not want the validator to ever prevent reporting, so we limit its
    // gas usage and catch any errors that may arise.
    try av.validate{gas: VALIDATOR_GAS_LIMIT}(
      prevAggregatorRoundId,
      prevAggregatorRoundAnswer,
      _aggregatorRoundId,
      _answer
    ) {} catch {}
  }
  /*
   * requestNewRound logic
   */
  AccessControllerInterface internal s_requesterAccessController;
  /**
   * @notice emitted when a new requester access controller contract is set
   * @param old the address prior to the current setting
   * @param current the address of the new access controller contract
   */
  event RequesterAccessControllerSet(AccessControllerInterface old, AccessControllerInterface current);
  /**
   * @notice emitted to immediately request a new round
   * @param requester the address of the requester
   * @param configDigest the latest transmission's configDigest
   * @param epoch the latest transmission's epoch
   * @param round the latest transmission's round
   */
  event RoundRequested(address indexed requester, bytes16 configDigest, uint32 epoch, uint8 round);
  /**
   * @notice address of the requester access controller contract
   * @return requester access controller address
   */
  function requesterAccessController()
    external
    view
    returns (AccessControllerInterface)
  {
    return s_requesterAccessController;
  }
  /**
   * @notice sets the requester access controller
   * @param _requesterAccessController designates the address of the new requester access controller
   */
  function setRequesterAccessController(AccessControllerInterface _requesterAccessController)
    public
    onlyOwner()
  {
    AccessControllerInterface oldController = s_requesterAccessController;
    if (_requesterAccessController != oldController) {
      s_requesterAccessController = AccessControllerInterface(_requesterAccessController);
      emit RequesterAccessControllerSet(oldController, _requesterAccessController);
    }
  }
  /**
   * @notice immediately requests a new round
   * @return the aggregatorRoundId of the next round. Note: The report for this round may have been
   * transmitted (but not yet mined) *before* requestNewRound() was even called. There is *no*
   * guarantee of causality between the request and the report at aggregatorRoundId.
   */
  function requestNewRound() external returns (uint80) {
    require(msg.sender == owner || s_requesterAccessController.hasAccess(msg.sender, msg.data),
      "Only owner&requester can call");
    HotVars memory hotVars = s_hotVars;
    emit RoundRequested(
      msg.sender,
      hotVars.latestConfigDigest,
      uint32(s_hotVars.latestEpochAndRound >> 8),
      uint8(s_hotVars.latestEpochAndRound)
    );
    return hotVars.latestAggregatorRoundId + 1;
  }
  /*
   * Transmission logic
   */
  /**
   * @notice indicates that a new report was transmitted
   * @param aggregatorRoundId the round to which this report was assigned
   * @param answer median of the observations attached this report
   * @param transmitter address from which the report was transmitted
   * @param observations observations transmitted with this report
   * @param rawReportContext signature-replay-prevention domain-separation tag
   */
  event NewTransmission(
    uint32 indexed aggregatorRoundId,
    int192 answer,
    address transmitter,
    int192[] observations,
    bytes observers,
    bytes32 rawReportContext
  );
  // decodeReport is used to check that the solidity and go code are using the
  // same format. See TestOffchainAggregator.testDecodeReport and TestReportParsing
  function decodeReport(bytes memory _report)
    internal
    pure
    returns (
      bytes32 rawReportContext,
      bytes32 rawObservers,
      int192[] memory observations
    )
  {
    (rawReportContext, rawObservers, observations) = abi.decode(_report,
      (bytes32, bytes32, int192[]));
  }
  // Used to relieve stack pressure in transmit
  struct ReportData {
    HotVars hotVars; // Only read from storage once
    bytes observers; // ith element is the index of the ith observer
    int192[] observations; // ith element is the ith observation
    bytes vs; // jth element is the v component of the jth signature
    bytes32 rawReportContext;
  }
  /*
   * @notice details about the most recent report
   * @return configDigest domain separation tag for the latest report
   * @return epoch epoch in which the latest report was generated
   * @return round OCR round in which the latest report was generated
   * @return latestAnswer median value from latest report
   * @return latestTimestamp when the latest report was transmitted
   */
  function latestTransmissionDetails()
    external
    view
    returns (
      bytes16 configDigest,
      uint32 epoch,
      uint8 round,
      int192 latestAnswer,
      uint64 latestTimestamp
    )
  {
    require(msg.sender == tx.origin, "Only callable by EOA");
    return (
      s_hotVars.latestConfigDigest,
      uint32(s_hotVars.latestEpochAndRound >> 8),
      uint8(s_hotVars.latestEpochAndRound),
      s_transmissions[s_hotVars.latestAggregatorRoundId].answer,
      s_transmissions[s_hotVars.latestAggregatorRoundId].timestamp
    );
  }
  // The constant-length components of the msg.data sent to transmit.
  // See the "If we wanted to call sam" example on for example reasoning
  // https://solidity.readthedocs.io/en/v0.7.2/abi-spec.html
  uint16 private constant TRANSMIT_MSGDATA_CONSTANT_LENGTH_COMPONENT =
    4 + // function selector
    32 + // word containing start location of abiencoded _report value
    32 + // word containing location start of abiencoded  _rs value
    32 + // word containing start location of abiencoded _ss value
    32 + // _rawVs value
    32 + // word containing length of _report
    32 + // word containing length _rs
    32 + // word containing length of _ss
    0; // placeholder
  function expectedMsgDataLength(
    bytes calldata _report, bytes32[] calldata _rs, bytes32[] calldata _ss
  ) private pure returns (uint256 length)
  {
    // calldata will never be big enough to make this overflow
    return uint256(TRANSMIT_MSGDATA_CONSTANT_LENGTH_COMPONENT) +
      _report.length + // one byte pure entry in _report
      _rs.length * 32 + // 32 bytes per entry in _rs
      _ss.length * 32 + // 32 bytes per entry in _ss
      0; // placeholder
  }
  /**
   * @notice transmit is called to post a new report to the contract
   * @param _report serialized report, which the signatures are signing. See parsing code below for format. The ith element of the observers component must be the index in s_signers of the address for the ith signature
   * @param _rs ith element is the R components of the ith signature on report. Must have at most maxNumOracles entries
   * @param _ss ith element is the S components of the ith signature on report. Must have at most maxNumOracles entries
   * @param _rawVs ith element is the the V component of the ith signature
   */
  function transmit(
    // NOTE: If these parameters are changed, expectedMsgDataLength and/or
    // TRANSMIT_MSGDATA_CONSTANT_LENGTH_COMPONENT need to be changed accordingly
    bytes calldata _report,
    bytes32[] calldata _rs, bytes32[] calldata _ss, bytes32 _rawVs // signatures
  )
    external
  {
    uint256 initialGas = gasleft(); // This line must come first
    // Make sure the transmit message-length matches the inputs. Otherwise, the
    // transmitter could append an arbitrarily long (up to gas-block limit)
    // string of 0 bytes, which we would reimburse at a rate of 16 gas/byte, but
    // which would only cost the transmitter 4 gas/byte. (Appendix G of the
    // yellow paper, p. 25, for G_txdatazero and EIP 2028 for G_txdatanonzero.)
    // This could amount to reimbursement profit of 36 million gas, given a 3MB
    // zero tail.
    require(msg.data.length == expectedMsgDataLength(_report, _rs, _ss),
      "transmit message too long");
    ReportData memory r; // Relieves stack pressure
    {
      r.hotVars = s_hotVars; // cache read from storage
      bytes32 rawObservers;
      (r.rawReportContext, rawObservers, r.observations) = abi.decode(
        _report, (bytes32, bytes32, int192[])
      );
      // rawReportContext consists of:
      // 11-byte zero padding
      // 16-byte configDigest
      // 4-byte epoch
      // 1-byte round
      bytes16 configDigest = bytes16(r.rawReportContext << 88);
      require(
        r.hotVars.latestConfigDigest == configDigest,
        "configDigest mismatch"
      );
      uint40 epochAndRound = uint40(uint256(r.rawReportContext));
      // direct numerical comparison works here, because
      //
      //   ((e,r) <= (e',r')) implies (epochAndRound <= epochAndRound')
      //
      // because alphabetic ordering implies e <= e', and if e = e', then r<=r',
      // so e*256+r <= e'*256+r', because r, r' < 256
      require(r.hotVars.latestEpochAndRound < epochAndRound, "stale report");
      require(_rs.length > r.hotVars.threshold, "not enough signatures");
      require(_rs.length <= maxNumOracles, "too many signatures");
      require(_ss.length == _rs.length, "signatures out of registration");
      require(r.observations.length <= maxNumOracles,
              "num observations out of bounds");
      require(r.observations.length > 2 * r.hotVars.threshold,
              "too few values to trust median");
      // Copy signature parities in bytes32 _rawVs to bytes r.v
      r.vs = new bytes(_rs.length);
      for (uint8 i = 0; i < _rs.length; i++) {
        r.vs[i] = _rawVs[i];
      }
      // Copy observer identities in bytes32 rawObservers to bytes r.observers
      r.observers = new bytes(r.observations.length);
      bool[maxNumOracles] memory seen;
      for (uint8 i = 0; i < r.observations.length; i++) {
        uint8 observerIdx = uint8(rawObservers[i]);
        require(!seen[observerIdx], "observer index repeated");
        seen[observerIdx] = true;
        r.observers[i] = rawObservers[i];
      }
      Oracle memory transmitter = s_oracles[msg.sender];
      require( // Check that sender is authorized to report
        transmitter.role == Role.Transmitter &&
        msg.sender == s_transmitters[transmitter.index],
        "unauthorized transmitter"
      );
      // record epochAndRound here, so that we don't have to carry the local
      // variable in transmit. The change is reverted if something fails later.
      r.hotVars.latestEpochAndRound = epochAndRound;
    }
    { // Verify signatures attached to report
      bytes32 h = keccak256(_report);
      bool[maxNumOracles] memory signed;
      Oracle memory o;
      for (uint i = 0; i < _rs.length; i++) {
        address signer = ecrecover(h, uint8(r.vs[i])+27, _rs[i], _ss[i]);
        o = s_oracles[signer];
        require(o.role == Role.Signer, "address not authorized to sign");
        require(!signed[o.index], "non-unique signature");
        signed[o.index] = true;
      }
    }
    { // Check the report contents, and record the result
      for (uint i = 0; i < r.observations.length - 1; i++) {
        bool inOrder = r.observations[i] <= r.observations[i+1];
        require(inOrder, "observations not sorted");
      }
      int192 median = r.observations[r.observations.length/2];
      require(minAnswer <= median && median <= maxAnswer, "median is out of min-max range");
      r.hotVars.latestAggregatorRoundId++;
      s_transmissions[r.hotVars.latestAggregatorRoundId] =
        Transmission(median, uint64(block.timestamp));
      emit NewTransmission(
        r.hotVars.latestAggregatorRoundId,
        median,
        msg.sender,
        r.observations,
        r.observers,
        r.rawReportContext
      );
      // Emit these for backwards compatability with offchain consumers
      // that only support legacy events
      emit NewRound(
        r.hotVars.latestAggregatorRoundId,
        address(0x0), // use zero address since we don't have anybody "starting" the round here
        block.timestamp
      );
      emit AnswerUpdated(
        median,
        r.hotVars.latestAggregatorRoundId,
        block.timestamp
      );
      validateAnswer(r.hotVars.latestAggregatorRoundId, median);
    }
    s_hotVars = r.hotVars;
    assert(initialGas < maxUint32);
    reimburseAndRewardOracles(uint32(initialGas), r.observers);
  }
  /*
   * v2 Aggregator interface
   */
  /**
   * @notice median from the most recent report
   */
  function latestAnswer()
    public
    override
    view
    virtual
    returns (int256)
  {
    return s_transmissions[s_hotVars.latestAggregatorRoundId].answer;
  }
  /**
   * @notice timestamp of block in which last report was transmitted
   */
  function latestTimestamp()
    public
    override
    view
    virtual
    returns (uint256)
  {
    return s_transmissions[s_hotVars.latestAggregatorRoundId].timestamp;
  }
  /**
   * @notice Aggregator round (NOT OCR round) in which last report was transmitted
   */
  function latestRound()
    public
    override
    view
    virtual
    returns (uint256)
  {
    return s_hotVars.latestAggregatorRoundId;
  }
  /**
   * @notice median of report from given aggregator round (NOT OCR round)
   * @param _roundId the aggregator round of the target report
   */
  function getAnswer(uint256 _roundId)
    public
    override
    view
    virtual
    returns (int256)
  {
    if (_roundId > 0xFFFFFFFF) { return 0; }
    return s_transmissions[uint32(_roundId)].answer;
  }
  /**
   * @notice timestamp of block in which report from given aggregator round was transmitted
   * @param _roundId aggregator round (NOT OCR round) of target report
   */
  function getTimestamp(uint256 _roundId)
    public
    override
    view
    virtual
    returns (uint256)
  {
    if (_roundId > 0xFFFFFFFF) { return 0; }
    return s_transmissions[uint32(_roundId)].timestamp;
  }
  /*
   * v3 Aggregator interface
   */
  string constant private V3_NO_DATA_ERROR = "No data present";
  /**
   * @return answers are stored in fixed-point format, with this many digits of precision
   */
  uint8 immutable public override decimals;
  /**
   * @notice aggregator contract version
   */
  uint256 constant public override version = 4;
  string internal s_description;
  /**
   * @notice human-readable description of observable this contract is reporting on
   */
  function description()
    public
    override
    view
    virtual
    returns (string memory)
  {
    return s_description;
  }
  /**
   * @notice details for the given aggregator round
   * @param _roundId target aggregator round (NOT OCR round). Must fit in uint32
   * @return roundId _roundId
   * @return answer median of report from given _roundId
   * @return startedAt timestamp of block in which report from given _roundId was transmitted
   * @return updatedAt timestamp of block in which report from given _roundId was transmitted
   * @return answeredInRound _roundId
   */
  function getRoundData(uint80 _roundId)
    public
    override
    view
    virtual
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    require(_roundId <= 0xFFFFFFFF, V3_NO_DATA_ERROR);
    Transmission memory transmission = s_transmissions[uint32(_roundId)];
    return (
      _roundId,
      transmission.answer,
      transmission.timestamp,
      transmission.timestamp,
      _roundId
    );
  }
  /**
   * @notice aggregator details for the most recently transmitted report
   * @return roundId aggregator round of latest report (NOT OCR round)
   * @return answer median of latest report
   * @return startedAt timestamp of block containing latest report
   * @return updatedAt timestamp of block containing latest report
   * @return answeredInRound aggregator round of latest report
   */
  function latestRoundData()
    public
    override
    view
    virtual
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    roundId = s_hotVars.latestAggregatorRoundId;
    // Skipped for compatability with existing FluxAggregator in which latestRoundData never reverts.
    // require(roundId != 0, V3_NO_DATA_ERROR);
    Transmission memory transmission = s_transmissions[uint32(roundId)];
    return (
      roundId,
      transmission.answer,
      transmission.timestamp,
      transmission.timestamp,
      roundId
    );
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
interface AccessControllerInterface {
  function hasAccess(address user, bytes calldata data) external view returns (bool);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "./AggregatorInterface.sol";
import "./AggregatorV3Interface.sol";
interface AggregatorV2V3Interface is AggregatorInterface, AggregatorV3Interface
{
}// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
interface AggregatorInterface {
  function latestAnswer() external view returns (int256);
  function latestTimestamp() external view returns (uint256);
  function latestRound() external view returns (uint256);
  function getAnswer(uint256 roundId) external view returns (int256);
  function getTimestamp(uint256 roundId) external view returns (uint256);
  event AnswerUpdated(int256 indexed current, uint256 indexed roundId, uint256 updatedAt);
  event NewRound(uint256 indexed roundId, address indexed startedBy, uint256 startedAt);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
interface AggregatorV3Interface {
  function decimals() external view returns (uint8);
  function description() external view returns (string memory);
  function version() external view returns (uint256);
  // getRoundData and latestRoundData should both raise "No data present"
  // if they do not have data to report, instead of returning unset values
  // which could be misinterpreted as actual reported values.
  function getRoundData(uint80 _roundId)
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );
  function latestRoundData()
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
interface AggregatorValidatorInterface {
  function validate(
    uint256 previousRoundId,
    int256 previousAnswer,
    uint256 currentRoundId,
    int256 currentAnswer
  ) external returns (bool);
}// SPDX-License-Identifier: MIT
pragma solidity ^0.7.1;
interface LinkTokenInterface {
  function allowance(address owner, address spender) external view returns (uint256 remaining);
  function approve(address spender, uint256 value) external returns (bool success);
  function balanceOf(address owner) external view returns (uint256 balance);
  function decimals() external view returns (uint8 decimalPlaces);
  function decreaseApproval(address spender, uint256 addedValue) external returns (bool success);
  function increaseApproval(address spender, uint256 subtractedValue) external;
  function name() external view returns (string memory tokenName);
  function symbol() external view returns (string memory tokenSymbol);
  function totalSupply() external view returns (uint256 totalTokensIssued);
  function transfer(address to, uint256 value) external returns (bool success);
  function transferAndCall(address to, uint256 value, bytes calldata data) external returns (bool success);
  function transferFrom(address from, address to, uint256 value) external returns (bool success);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
/**
 * @title The Owned contract
 * @notice A contract with helpers for basic contract ownership.
 */
contract Owned {
  address payable public owner;
  address private pendingOwner;
  event OwnershipTransferRequested(
    address indexed from,
    address indexed to
  );
  event OwnershipTransferred(
    address indexed from,
    address indexed to
  );
  constructor() {
    owner = msg.sender;
  }
  /**
   * @dev Allows an owner to begin transferring ownership to a new address,
   * pending.
   */
  function transferOwnership(address _to)
    external
    onlyOwner()
  {
    pendingOwner = _to;
    emit OwnershipTransferRequested(owner, _to);
  }
  /**
   * @dev Allows an ownership transfer to be completed by the recipient.
   */
  function acceptOwnership()
    external
  {
    require(msg.sender == pendingOwner, "Must be proposed owner");
    address oldOwner = owner;
    owner = msg.sender;
    pendingOwner = address(0);
    emit OwnershipTransferred(oldOwner, msg.sender);
  }
  /**
   * @dev Reverts if called by anyone other than the contract owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner, "Only callable by owner");
    _;
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "./AccessControllerInterface.sol";
import "./LinkTokenInterface.sol";
import "./Owned.sol";
/**
 * @notice tracks administration of oracle-reward and gas-reimbursement parameters.
 * @dev
 * If you read or change this, be sure to read or adjust the comments. They
 * track the units of the values under consideration, and are crucial to
 * the readability of the operations it specifies.
 * @notice
 * Trust Model:
 * Nothing in this contract prevents a billing admin from setting insane
 * values for the billing parameters in setBilling. Oracles
 * participating in this contract should regularly check that the
 * parameters make sense. Similarly, the outstanding obligations of this
 * contract to the oracles can exceed the funds held by the contract.
 * Oracles participating in this contract should regularly check that it
 * holds sufficient funds and stop interacting with it if funding runs
 * out.
 * This still leaves oracles with some risk due to TOCTOU issues.
 * However, since the sums involved are pretty small (Ethereum
 * transactions aren't that expensive in the end) and an oracle would
 * likely stop participating in a contract it repeatedly lost money on,
 * this risk is deemed acceptable. Oracles should also regularly
 * withdraw any funds in the contract to prevent issues where the
 * contract becomes underfunded at a later time, and different oracles
 * are competing for the left-over funds.
 * Finally, note that any change to the set of oracles or to the billing
 * parameters will trigger payout of all oracles first (using the old
 * parameters), a billing admin cannot take away funds that are already
 * marked for payment.
*/
contract OffchainAggregatorBilling is Owned {
  // Maximum number of oracles the offchain reporting protocol is designed for
  uint256 constant internal maxNumOracles = 31;
  // Parameters for oracle payments
  struct Billing {
    // Highest compensated gas price, in ETH-gwei uints
    uint32 maximumGasPrice;
    // If gas price is less (in ETH-gwei units), transmitter gets half the savings
    uint32 reasonableGasPrice;
    // Pay transmitter back this much LINK per unit eth spent on gas
    // (1e-6LINK/ETH units)
    uint32 microLinkPerEth;
    // Fixed LINK reward for each observer, in LINK-gwei units
    uint32 linkGweiPerObservation;
    // Fixed reward for transmitter, in linkGweiPerObservation units
    uint32 linkGweiPerTransmission;
  }
  Billing internal s_billing;
  /**
  * @return LINK token contract used for billing
  */
  LinkTokenInterface immutable public LINK;
  AccessControllerInterface internal s_billingAccessController;
  // ith element is number of observation rewards due to ith process, plus one.
  // This is expected to saturate after an oracle has submitted 65,535
  // observations, or about 65535/(3*24*20) = 45 days, given a transmission
  // every 3 minutes.
  //
  // This is always one greater than the actual value, so that when the value is
  // reset to zero, we don't end up with a zero value in storage (which would
  // result in a higher gas cost, the next time the value is incremented.)
  // Calculations using this variable need to take that offset into account.
  uint16[maxNumOracles] internal s_oracleObservationsCounts;
  // Addresses at which oracles want to receive payments, by transmitter address
  mapping (address /* transmitter */ => address /* payment address */)
    internal
    s_payees;
  // Payee addresses which must be approved by the owner
  mapping (address /* transmitter */ => address /* payment address */)
    internal
    s_proposedPayees;
  // LINK-wei-denominated reimbursements for gas used by transmitters.
  //
  // This is always one greater than the actual value, so that when the value is
  // reset to zero, we don't end up with a zero value in storage (which would
  // result in a higher gas cost, the next time the value is incremented.)
  // Calculations using this variable need to take that offset into account.
  //
  // Argument for overflow safety:
  // We have the following maximum intermediate values:
  // - 2**40 additions to this variable (epochAndRound is a uint40)
  // - 2**32 gas price in ethgwei/gas
  // - 1e9 ethwei/ethgwei
  // - 2**32 gas since the block gas limit is at ~20 million
  // - 2**32 (microlink/eth)
  // And we have 2**40 * 2**32 * 1e9 * 2**32 * 2**32 < 2**166
  // (we also divide in some places, but that only makes the value smaller)
  // We can thus safely use uint256 intermediate values for the computation
  // updating this variable.
  uint256[maxNumOracles] internal s_gasReimbursementsLinkWei;
  // Used for s_oracles[a].role, where a is an address, to track the purpose
  // of the address, or to indicate that the address is unset.
  enum Role {
    // No oracle role has been set for address a
    Unset,
    // Signing address for the s_oracles[a].index'th oracle. I.e., report
    // signatures from this oracle should ecrecover back to address a.
    Signer,
    // Transmission address for the s_oracles[a].index'th oracle. I.e., if a
    // report is received by OffchainAggregator.transmit in which msg.sender is
    // a, it is attributed to the s_oracles[a].index'th oracle.
    Transmitter
  }
  struct Oracle {
    uint8 index; // Index of oracle in s_signers/s_transmitters
    Role role;   // Role of the address which mapped to this struct
  }
  mapping (address /* signer OR transmitter address */ => Oracle)
    internal s_oracles;
  // s_signers contains the signing address of each oracle
  address[] internal s_signers;
  // s_transmitters contains the transmission address of each oracle,
  // i.e. the address the oracle actually sends transactions to the contract from
  address[] internal s_transmitters;
  uint256 constant private  maxUint16 = (1 << 16) - 1;
  uint256 constant internal maxUint128 = (1 << 128) - 1;
  constructor(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission,
    address _link,
    AccessControllerInterface _billingAccessController
  )
  {
    setBillingInternal(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission);
    setBillingAccessControllerInternal(_billingAccessController);
    LINK = LinkTokenInterface(_link);
    uint16[maxNumOracles] memory counts; // See s_oracleObservationsCounts docstring
    uint256[maxNumOracles] memory gas; // see s_gasReimbursementsLinkWei docstring
    for (uint8 i = 0; i < maxNumOracles; i++) {
      counts[i] = 1;
      gas[i] = 1;
    }
    s_oracleObservationsCounts = counts;
    s_gasReimbursementsLinkWei = gas;
  }
  /**
   * @notice emitted when billing parameters are set
   * @param maximumGasPrice highest gas price for which transmitter will be compensated
   * @param reasonableGasPrice transmitter will receive reward for gas prices under this value
   * @param microLinkPerEth reimbursement per ETH of gas cost, in 1e-6LINK units
   * @param linkGweiPerObservation reward to oracle for contributing an observation to a successfully transmitted report, in 1e-9LINK units
   * @param linkGweiPerTransmission reward to transmitter of a successful report, in 1e-9LINK units
   */
  event BillingSet(
    uint32 maximumGasPrice,
    uint32 reasonableGasPrice,
    uint32 microLinkPerEth,
    uint32 linkGweiPerObservation,
    uint32 linkGweiPerTransmission
  );
  function setBillingInternal(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission
  )
    internal
  {
    s_billing = Billing(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission);
    emit BillingSet(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission);
  }
  /**
   * @notice sets billing parameters
   * @param _maximumGasPrice highest gas price for which transmitter will be compensated
   * @param _reasonableGasPrice transmitter will receive reward for gas prices under this value
   * @param _microLinkPerEth reimbursement per ETH of gas cost, in 1e-6LINK units
   * @param _linkGweiPerObservation reward to oracle for contributing an observation to a successfully transmitted report, in 1e-9LINK units
   * @param _linkGweiPerTransmission reward to transmitter of a successful report, in 1e-9LINK units
   * @dev access control provided by billingAccessController
   */
  function setBilling(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission
  )
    external
  {
    AccessControllerInterface access = s_billingAccessController;
    require(msg.sender == owner || access.hasAccess(msg.sender, msg.data),
      "Only owner&billingAdmin can call");
    payOracles();
    setBillingInternal(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission);
  }
  /**
   * @notice gets billing parameters
   * @param maximumGasPrice highest gas price for which transmitter will be compensated
   * @param reasonableGasPrice transmitter will receive reward for gas prices under this value
   * @param microLinkPerEth reimbursement per ETH of gas cost, in 1e-6LINK units
   * @param linkGweiPerObservation reward to oracle for contributing an observation to a successfully transmitted report, in 1e-9LINK units
   * @param linkGweiPerTransmission reward to transmitter of a successful report, in 1e-9LINK units
   */
  function getBilling()
    external
    view
    returns (
      uint32 maximumGasPrice,
      uint32 reasonableGasPrice,
      uint32 microLinkPerEth,
      uint32 linkGweiPerObservation,
      uint32 linkGweiPerTransmission
    )
  {
    Billing memory billing = s_billing;
    return (
      billing.maximumGasPrice,
      billing.reasonableGasPrice,
      billing.microLinkPerEth,
      billing.linkGweiPerObservation,
      billing.linkGweiPerTransmission
    );
  }
  /**
   * @notice emitted when a new access-control contract is set
   * @param old the address prior to the current setting
   * @param current the address of the new access-control contract
   */
  event BillingAccessControllerSet(AccessControllerInterface old, AccessControllerInterface current);
  function setBillingAccessControllerInternal(AccessControllerInterface _billingAccessController)
    internal
  {
    AccessControllerInterface oldController = s_billingAccessController;
    if (_billingAccessController != oldController) {
      s_billingAccessController = _billingAccessController;
      emit BillingAccessControllerSet(
        oldController,
        _billingAccessController
      );
    }
  }
  /**
   * @notice sets billingAccessController
   * @param _billingAccessController new billingAccessController contract address
   * @dev only owner can call this
   */
  function setBillingAccessController(AccessControllerInterface _billingAccessController)
    external
    onlyOwner
  {
    setBillingAccessControllerInternal(_billingAccessController);
  }
  /**
   * @notice gets billingAccessController
   * @return address of billingAccessController contract
   */
  function billingAccessController()
    external
    view
    returns (AccessControllerInterface)
  {
    return s_billingAccessController;
  }
  /**
   * @notice withdraws an oracle's payment from the contract
   * @param _transmitter the transmitter address of the oracle
   * @dev must be called by oracle's payee address
   */
  function withdrawPayment(address _transmitter)
    external
  {
    require(msg.sender == s_payees[_transmitter], "Only payee can withdraw");
    payOracle(_transmitter);
  }
  /**
   * @notice query an oracle's payment amount
   * @param _transmitter the transmitter address of the oracle
   */
  function owedPayment(address _transmitter)
    public
    view
    returns (uint256)
  {
    Oracle memory oracle = s_oracles[_transmitter];
    if (oracle.role == Role.Unset) { return 0; }
    Billing memory billing = s_billing;
    uint256 linkWeiAmount =
      uint256(s_oracleObservationsCounts[oracle.index] - 1) *
      uint256(billing.linkGweiPerObservation) *
      (1 gwei);
    linkWeiAmount += s_gasReimbursementsLinkWei[oracle.index] - 1;
    return linkWeiAmount;
  }
  /**
   * @notice emitted when an oracle has been paid LINK
   * @param transmitter address from which the oracle sends reports to the transmit method
   * @param payee address to which the payment is sent
   * @param amount amount of LINK sent
   */
  event OraclePaid(address transmitter, address payee, uint256 amount);
  // payOracle pays out _transmitter's balance to the corresponding payee, and zeros it out
  function payOracle(address _transmitter)
    internal
  {
    Oracle memory oracle = s_oracles[_transmitter];
    uint256 linkWeiAmount = owedPayment(_transmitter);
    if (linkWeiAmount > 0) {
      address payee = s_payees[_transmitter];
      // Poses no re-entrancy issues, because LINK.transfer does not yield
      // control flow.
      require(LINK.transfer(payee, linkWeiAmount), "insufficient funds");
      s_oracleObservationsCounts[oracle.index] = 1; // "zero" the counts. see var's docstring
      s_gasReimbursementsLinkWei[oracle.index] = 1; // "zero" the counts. see var's docstring
      emit OraclePaid(_transmitter, payee, linkWeiAmount);
    }
  }
  // payOracles pays out all transmitters, and zeros out their balances.
  //
  // It's much more gas-efficient to do this as a single operation, to avoid
  // hitting storage too much.
  function payOracles()
    internal
  {
    Billing memory billing = s_billing;
    uint16[maxNumOracles] memory observationsCounts = s_oracleObservationsCounts;
    uint256[maxNumOracles] memory gasReimbursementsLinkWei =
      s_gasReimbursementsLinkWei;
    address[] memory transmitters = s_transmitters;
    for (uint transmitteridx = 0; transmitteridx < transmitters.length; transmitteridx++) {
      uint256 reimbursementAmountLinkWei = gasReimbursementsLinkWei[transmitteridx] - 1;
      uint256 obsCount = observationsCounts[transmitteridx] - 1;
      uint256 linkWeiAmount =
        obsCount * uint256(billing.linkGweiPerObservation) * (1 gwei) + reimbursementAmountLinkWei;
      if (linkWeiAmount > 0) {
          address payee = s_payees[transmitters[transmitteridx]];
          // Poses no re-entrancy issues, because LINK.transfer does not yield
          // control flow.
          require(LINK.transfer(payee, linkWeiAmount), "insufficient funds");
          observationsCounts[transmitteridx] = 1;       // "zero" the counts.
          gasReimbursementsLinkWei[transmitteridx] = 1; // "zero" the counts.
          emit OraclePaid(transmitters[transmitteridx], payee, linkWeiAmount);
        }
    }
    // "Zero" the accounting storage variables
    s_oracleObservationsCounts = observationsCounts;
    s_gasReimbursementsLinkWei = gasReimbursementsLinkWei;
  }
  function oracleRewards(
    bytes memory observers,
    uint16[maxNumOracles] memory observations
  )
    internal
    pure
    returns (uint16[maxNumOracles] memory)
  {
    // reward each observer-participant with the observer reward
    for (uint obsIdx = 0; obsIdx < observers.length; obsIdx++) {
      uint8 observer = uint8(observers[obsIdx]);
      observations[observer] = saturatingAddUint16(observations[observer], 1);
    }
    return observations;
  }
  // This value needs to change if maxNumOracles is increased, or the accounting
  // calculations at the bottom of reimburseAndRewardOracles change.
  //
  // To recalculate it, run the profiler as described in
  // ../../profile/README.md, and add up the gas-usage values reported for the
  // lines in reimburseAndRewardOracles following the "gasLeft = gasleft()"
  // line. E.g., you will see output like this:
  //
  //      7        uint256 gasLeft = gasleft();
  //     29        uint256 gasCostEthWei = transmitterGasCostEthWei(
  //      9          uint256(initialGas),
  //      3          gasPrice,
  //      3          callDataGasCost,
  //      3          gasLeft
  //      .
  //      .
  //      .
  //     59        uint256 gasCostLinkWei = (gasCostEthWei * billing.microLinkPerEth)/ 1e6;
  //      .
  //      .
  //      .
  //   5047        s_gasReimbursementsLinkWei[txOracle.index] =
  //    856          s_gasReimbursementsLinkWei[txOracle.index] + gasCostLinkWei +
  //     26          uint256(billing.linkGweiPerTransmission) * (1 gwei);
  //
  // If those were the only lines to be accounted for, you would add up
  // 29+9+3+3+3+59+5047+856+26=6035.
  uint256 internal constant accountingGasCost = 6035;
  // Uncomment the following declaration to compute the remaining gas cost after
  // above gasleft(). (This must exist in a base class to OffchainAggregator, so
  // it can't go in TestOffchainAggregator.)
  //
  // uint256 public gasUsedInAccounting;
  // Gas price at which the transmitter should be reimbursed, in ETH-gwei/gas
  function impliedGasPrice(
    uint256 txGasPrice,         // ETH-gwei/gas units
    uint256 reasonableGasPrice, // ETH-gwei/gas units
    uint256 maximumGasPrice     // ETH-gwei/gas units
  )
    internal
    pure
    returns (uint256)
  {
    // Reward the transmitter for choosing an efficient gas price: if they manage
    // to come in lower than considered reasonable, give them half the savings.
    //
    // The following calculations are all in units of gwei/gas, i.e. 1e-9ETH/gas
    uint256 gasPrice = txGasPrice;
    if (txGasPrice < reasonableGasPrice) {
      // Give transmitter half the savings for coming in under the reasonable gas price
      gasPrice += (reasonableGasPrice - txGasPrice) / 2;
    }
    // Don't reimburse a gas price higher than maximumGasPrice
    return min(gasPrice, maximumGasPrice);
  }
  // gas reimbursement due the transmitter, in ETH-wei
  //
  // If this function is changed, accountingGasCost needs to change, too. See
  // its docstring
  function transmitterGasCostEthWei(
    uint256 initialGas,
    uint256 gasPrice, // ETH-gwei/gas units
    uint256 callDataCost, // gas units
    uint256 gasLeft
  )
    internal
    pure
    returns (uint128 gasCostEthWei)
  {
    require(initialGas >= gasLeft, "gasLeft cannot exceed initialGas");
    uint256 gasUsed = // gas units
      initialGas - gasLeft + // observed gas usage
      callDataCost + accountingGasCost; // estimated gas usage
    // gasUsed is in gas units, gasPrice is in ETH-gwei/gas units; convert to ETH-wei
    uint256 fullGasCostEthWei = gasUsed * gasPrice * (1 gwei);
    assert(fullGasCostEthWei < maxUint128); // the entire ETH supply fits in a uint128...
    return uint128(fullGasCostEthWei);
  }
  /**
   * @notice withdraw any available funds left in the contract, up to _amount, after accounting for the funds due to participants in past reports
   * @param _recipient address to send funds to
   * @param _amount maximum amount to withdraw, denominated in LINK-wei.
   * @dev access control provided by billingAccessController
   */
  function withdrawFunds(address _recipient, uint256 _amount)
    external
  {
    require(msg.sender == owner || s_billingAccessController.hasAccess(msg.sender, msg.data),
      "Only owner&billingAdmin can call");
    uint256 linkDue = totalLINKDue();
    uint256 linkBalance = LINK.balanceOf(address(this));
    require(linkBalance >= linkDue, "insufficient balance");
    require(LINK.transfer(_recipient, min(linkBalance - linkDue, _amount)), "insufficient funds");
  }
  // Total LINK due to participants in past reports.
  function totalLINKDue()
    internal
    view
    returns (uint256 linkDue)
  {
    // Argument for overflow safety: We do all computations in
    // uint256s. The inputs to linkDue are:
    // - the <= 31 observation rewards each of which has less than
    //   64 bits (32 bits for billing.linkGweiPerObservation, 32 bits
    //   for wei/gwei conversion). Hence 69 bits are sufficient for this part.
    // - the <= 31 gas reimbursements, each of which consists of at most 166
    //   bits (see s_gasReimbursementsLinkWei docstring). Hence 171 bits are
    //   sufficient for this part
    // In total, 172 bits are enough.
    uint16[maxNumOracles] memory observationCounts = s_oracleObservationsCounts;
    for (uint i = 0; i < maxNumOracles; i++) {
      linkDue += observationCounts[i] - 1; // Stored value is one greater than actual value
    }
    Billing memory billing = s_billing;
    // Convert linkGweiPerObservation to uint256, or this overflows!
    linkDue *= uint256(billing.linkGweiPerObservation) * (1 gwei);
    address[] memory transmitters = s_transmitters;
    uint256[maxNumOracles] memory gasReimbursementsLinkWei =
      s_gasReimbursementsLinkWei;
    for (uint i = 0; i < transmitters.length; i++) {
      linkDue += uint256(gasReimbursementsLinkWei[i]-1); // Stored value is one greater than actual value
    }
  }
  /**
   * @notice allows oracles to check that sufficient LINK balance is available
   * @return availableBalance LINK available on this contract, after accounting for outstanding obligations. can become negative
   */
  function linkAvailableForPayment()
    external
    view
    returns (int256 availableBalance)
  {
    // there are at most one billion LINK, so this cast is safe
    int256 balance = int256(LINK.balanceOf(address(this)));
    // according to the argument in the definition of totalLINKDue,
    // totalLINKDue is never greater than 2**172, so this cast is safe
    int256 due = int256(totalLINKDue());
    // safe from overflow according to above sizes
    return int256(balance) - int256(due);
  }
  /**
   * @notice number of observations oracle is due to be reimbursed for
   * @param _signerOrTransmitter address used by oracle for signing or transmitting reports
   */
  function oracleObservationCount(address _signerOrTransmitter)
    external
    view
    returns (uint16)
  {
    Oracle memory oracle = s_oracles[_signerOrTransmitter];
    if (oracle.role == Role.Unset) { return 0; }
    return s_oracleObservationsCounts[oracle.index] - 1;
  }
  function reimburseAndRewardOracles(
    uint32 initialGas,
    bytes memory observers
  )
    internal
  {
    Oracle memory txOracle = s_oracles[msg.sender];
    Billing memory billing = s_billing;
    // Reward oracles for providing observations. Oracles are not rewarded
    // for providing signatures, because signing is essentially free.
    s_oracleObservationsCounts =
      oracleRewards(observers, s_oracleObservationsCounts);
    // Reimburse transmitter of the report for gas usage
    require(txOracle.role == Role.Transmitter,
      "sent by undesignated transmitter"
    );
    uint256 gasPrice = impliedGasPrice(
      tx.gasprice / (1 gwei), // convert to ETH-gwei units
      billing.reasonableGasPrice,
      billing.maximumGasPrice
    );
    // The following is only an upper bound, as it ignores the cheaper cost for
    // 0 bytes. Safe from overflow, because calldata just isn't that long.
    uint256 callDataGasCost = 16 * msg.data.length;
    // If any changes are made to subsequent calculations, accountingGasCost
    // needs to change, too.
    uint256 gasLeft = gasleft();
    uint256 gasCostEthWei = transmitterGasCostEthWei(
      uint256(initialGas),
      gasPrice,
      callDataGasCost,
      gasLeft
    );
    // microLinkPerEth is 1e-6LINK/ETH units, gasCostEthWei is 1e-18ETH units
    // (ETH-wei), product is 1e-24LINK-wei units, dividing by 1e6 gives
    // 1e-18LINK units, i.e. LINK-wei units
    // Safe from over/underflow, since all components are non-negative,
    // gasCostEthWei will always fit into uint128 and microLinkPerEth is a
    // uint32 (128+32 < 256!).
    uint256 gasCostLinkWei = (gasCostEthWei * billing.microLinkPerEth)/ 1e6;
    // Safe from overflow, because gasCostLinkWei < 2**160 and
    // billing.linkGweiPerTransmission * (1 gwei) < 2**64 and we increment
    // s_gasReimbursementsLinkWei[txOracle.index] at most 2**40 times.
    s_gasReimbursementsLinkWei[txOracle.index] =
      s_gasReimbursementsLinkWei[txOracle.index] + gasCostLinkWei +
      uint256(billing.linkGweiPerTransmission) * (1 gwei); // convert from linkGwei to linkWei
    // Uncomment next line to compute the remaining gas cost after above gasleft().
    // See OffchainAggregatorBilling.accountingGasCost docstring for more information.
    //
    // gasUsedInAccounting = gasLeft - gasleft();
  }
  /*
   * Payee management
   */
  /**
   * @notice emitted when a transfer of an oracle's payee address has been initiated
   * @param transmitter address from which the oracle sends reports to the transmit method
   * @param current the payeee address for the oracle, prior to this setting
   * @param proposed the proposed new payee address for the oracle
   */
  event PayeeshipTransferRequested(
    address indexed transmitter,
    address indexed current,
    address indexed proposed
  );
  /**
   * @notice emitted when a transfer of an oracle's payee address has been completed
   * @param transmitter address from which the oracle sends reports to the transmit method
   * @param current the payeee address for the oracle, prior to this setting
   */
  event PayeeshipTransferred(
    address indexed transmitter,
    address indexed previous,
    address indexed current
  );
  /**
   * @notice sets the payees for transmitting addresses
   * @param _transmitters addresses oracles use to transmit the reports
   * @param _payees addresses of payees corresponding to list of transmitters
   * @dev must be called by owner
   * @dev cannot be used to change payee addresses, only to initially populate them
   */
  function setPayees(
    address[] calldata _transmitters,
    address[] calldata _payees
  )
    external
    onlyOwner()
  {
    require(_transmitters.length == _payees.length, "transmitters.size != payees.size");
    for (uint i = 0; i < _transmitters.length; i++) {
      address transmitter = _transmitters[i];
      address payee = _payees[i];
      address currentPayee = s_payees[transmitter];
      bool zeroedOut = currentPayee == address(0);
      require(zeroedOut || currentPayee == payee, "payee already set");
      s_payees[transmitter] = payee;
      if (currentPayee != payee) {
        emit PayeeshipTransferred(transmitter, currentPayee, payee);
      }
    }
  }
  /**
   * @notice first step of payeeship transfer (safe transfer pattern)
   * @param _transmitter transmitter address of oracle whose payee is changing
   * @param _proposed new payee address
   * @dev can only be called by payee address
   */
  function transferPayeeship(
    address _transmitter,
    address _proposed
  )
    external
  {
      require(msg.sender == s_payees[_transmitter], "only current payee can update");
      require(msg.sender != _proposed, "cannot transfer to self");
      address previousProposed = s_proposedPayees[_transmitter];
      s_proposedPayees[_transmitter] = _proposed;
      if (previousProposed != _proposed) {
        emit PayeeshipTransferRequested(_transmitter, msg.sender, _proposed);
      }
  }
  /**
   * @notice second step of payeeship transfer (safe transfer pattern)
   * @param _transmitter transmitter address of oracle whose payee is changing
   * @dev can only be called by proposed new payee address
   */
  function acceptPayeeship(
    address _transmitter
  )
    external
  {
    require(msg.sender == s_proposedPayees[_transmitter], "only proposed payees can accept");
    address currentPayee = s_payees[_transmitter];
    s_payees[_transmitter] = msg.sender;
    s_proposedPayees[_transmitter] = address(0);
    emit PayeeshipTransferred(_transmitter, currentPayee, msg.sender);
  }
  /*
   * Helper functions
   */
  function saturatingAddUint16(uint16 _x, uint16 _y)
    internal
    pure
    returns (uint16)
  {
    return uint16(min(uint256(_x)+uint256(_y), maxUint16));
  }
  function min(uint256 a, uint256 b)
    internal
    pure
    returns (uint256)
  {
    if (a < b) { return a; }
    return b;
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.1;
import "./SimpleWriteAccessController.sol";
/**
 * @title SimpleReadAccessController
 * @notice Gives access to:
 * - any externally owned account (note that offchain actors can always read
 * any contract storage regardless of onchain access control measures, so this
 * does not weaken the access control while improving usability)
 * - accounts explicitly added to an access list
 * @dev SimpleReadAccessController is not suitable for access controlling writes
 * since it grants any externally owned account access! See
 * SimpleWriteAccessController for that.
 */
contract SimpleReadAccessController is SimpleWriteAccessController {
  /**
   * @notice Returns the access of an address
   * @param _user The address to query
   */
  function hasAccess(
    address _user,
    bytes memory _calldata
  )
    public
    view
    virtual
    override
    returns (bool)
  {
    return super.hasAccess(_user, _calldata) || _user == tx.origin;
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "./Owned.sol";
import "./AccessControllerInterface.sol";
/**
 * @title SimpleWriteAccessController
 * @notice Gives access to accounts explicitly added to an access list by the
 * controller's owner.
 * @dev does not make any special permissions for externally, see
 * SimpleReadAccessController for that.
 */
contract SimpleWriteAccessController is AccessControllerInterface, Owned {
  bool public checkEnabled;
  mapping(address => bool) internal accessList;
  event AddedAccess(address user);
  event RemovedAccess(address user);
  event CheckAccessEnabled();
  event CheckAccessDisabled();
  constructor()
  {
    checkEnabled = true;
  }
  /**
   * @notice Returns the access of an address
   * @param _user The address to query
   */
  function hasAccess(
    address _user,
    bytes memory
  )
    public
    view
    virtual
    override
    returns (bool)
  {
    return accessList[_user] || !checkEnabled;
  }
  /**
   * @notice Adds an address to the access list
   * @param _user The address to add
   */
  function addAccess(address _user) external onlyOwner() {
    addAccessInternal(_user);
  }
  function addAccessInternal(address _user) internal {
    if (!accessList[_user]) {
      accessList[_user] = true;
      emit AddedAccess(_user);
    }
  }
  /**
   * @notice Removes an address from the access list
   * @param _user The address to remove
   */
  function removeAccess(address _user)
    external
    onlyOwner()
  {
    if (accessList[_user]) {
      accessList[_user] = false;
      emit RemovedAccess(_user);
    }
  }
  /**
   * @notice makes the access check enforced
   */
  function enableAccessCheck()
    external
    onlyOwner()
  {
    if (!checkEnabled) {
      checkEnabled = true;
      emit CheckAccessEnabled();
    }
  }
  /**
   * @notice makes the access check unenforced
   */
  function disableAccessCheck()
    external
    onlyOwner()
  {
    if (checkEnabled) {
      checkEnabled = false;
      emit CheckAccessDisabled();
    }
  }
  /**
   * @dev reverts if the caller does not have access
   */
  modifier checkAccess() {
    require(hasAccess(msg.sender, msg.data), "No access");
    _;
  }
}

pragma solidity 0.6.6;


/**
 * @title The Owned contract
 * @notice A contract with helpers for basic contract ownership.
 */
contract Owned {

  address public owner;
  address private pendingOwner;

  event OwnershipTransferRequested(
    address indexed from,
    address indexed to
  );
  event OwnershipTransferred(
    address indexed from,
    address indexed to
  );

  constructor() public {
    owner = msg.sender;
  }

  /**
   * @dev Allows an owner to begin transferring ownership to a new address,
   * pending.
   */
  function transferOwnership(address _to)
    external
    onlyOwner()
  {
    pendingOwner = _to;

    emit OwnershipTransferRequested(owner, _to);
  }

  /**
   * @dev Allows an ownership transfer to be completed by the recipient.
   */
  function acceptOwnership()
    external
  {
    require(msg.sender == pendingOwner, "Must be proposed owner");

    address oldOwner = owner;
    owner = msg.sender;
    pendingOwner = address(0);

    emit OwnershipTransferred(oldOwner, msg.sender);
  }

  /**
   * @dev Reverts if called by anyone other than the contract owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner, "Only callable by owner");
    _;
  }

}

interface AggregatorInterface {
  function latestAnswer() external view returns (int256);
  function latestTimestamp() external view returns (uint256);
  function latestRound() external view returns (uint256);
  function getAnswer(uint256 roundId) external view returns (int256);
  function getTimestamp(uint256 roundId) external view returns (uint256);

  event AnswerUpdated(int256 indexed current, uint256 indexed roundId, uint256 updatedAt);
  event NewRound(uint256 indexed roundId, address indexed startedBy, uint256 startedAt);
}

interface AggregatorV3Interface {

  function decimals() external view returns (uint8);
  function description() external view returns (string memory);
  function version() external view returns (uint256);

  // getRoundData and latestRoundData should both raise "No data present"
  // if they do not have data to report, instead of returning unset values
  // which could be misinterpreted as actual reported values.
  function getRoundData(uint80 _roundId)
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );
  function latestRoundData()
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );

}

interface AggregatorV2V3Interface is AggregatorInterface, AggregatorV3Interface
{
}

/**
 * @title A trusted proxy for updating where current answers are read from
 * @notice This contract provides a consistent address for the
 * CurrentAnwerInterface but delegates where it reads from to the owner, who is
 * trusted to update it.
 */
contract AggregatorProxy is AggregatorV2V3Interface, Owned {

  struct Phase {
    uint16 id;
    AggregatorV2V3Interface aggregator;
  }
  Phase private currentPhase;
  AggregatorV2V3Interface public proposedAggregator;
  mapping(uint16 => AggregatorV2V3Interface) public phaseAggregators;

  uint256 constant private PHASE_OFFSET = 64;
  uint256 constant private PHASE_SIZE = 16;
  uint256 constant private MAX_ID = 2**(PHASE_OFFSET+PHASE_SIZE) - 1;

  constructor(address _aggregator) public Owned() {
    setAggregator(_aggregator);
  }

  /**
   * @notice Reads the current answer from aggregator delegated to.
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestAnswer()
    public
    view
    virtual
    override
    returns (int256 answer)
  {
    return currentPhase.aggregator.latestAnswer();
  }

  /**
   * @notice Reads the last updated height from aggregator delegated to.
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestTimestamp()
    public
    view
    virtual
    override
    returns (uint256 updatedAt)
  {
    return currentPhase.aggregator.latestTimestamp();
  }

  /**
   * @notice get past rounds answers
   * @param _roundId the answer number to retrieve the answer for
   *
   * @dev #[deprecated] Use getRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended getRoundData
   * instead which includes better verification information.
   */
  function getAnswer(uint256 _roundId)
    public
    view
    virtual
    override
    returns (int256 answer)
  {
    if (_roundId > MAX_ID) return 0;

    (uint16 phaseId, uint64 aggregatorRoundId) = parseIds(_roundId);
    AggregatorV2V3Interface aggregator = phaseAggregators[phaseId];
    if (address(aggregator) == address(0)) return 0;

    return aggregator.getAnswer(aggregatorRoundId);
  }

  /**
   * @notice get block timestamp when an answer was last updated
   * @param _roundId the answer number to retrieve the updated timestamp for
   *
   * @dev #[deprecated] Use getRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended getRoundData
   * instead which includes better verification information.
   */
  function getTimestamp(uint256 _roundId)
    public
    view
    virtual
    override
    returns (uint256 updatedAt)
  {
    if (_roundId > MAX_ID) return 0;

    (uint16 phaseId, uint64 aggregatorRoundId) = parseIds(_roundId);
    AggregatorV2V3Interface aggregator = phaseAggregators[phaseId];
    if (address(aggregator) == address(0)) return 0;

    return aggregator.getTimestamp(aggregatorRoundId);
  }

  /**
   * @notice get the latest completed round where the answer was updated. This
   * ID includes the proxy's phase, to make sure round IDs increase even when
   * switching to a newly deployed aggregator.
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestRound()
    public
    view
    virtual
    override
    returns (uint256 roundId)
  {
    Phase memory phase = currentPhase; // cache storage reads
    return addPhase(phase.id, uint64(phase.aggregator.latestRound()));
  }

  /**
   * @notice get data about a round. Consumers are encouraged to check
   * that they're receiving fresh data by inspecting the updatedAt and
   * answeredInRound return values.
   * Note that different underlying implementations of AggregatorV3Interface
   * have slightly different semantics for some of the return values. Consumers
   * should determine what implementations they expect to receive
   * data from and validate that they can properly handle return data from all
   * of them.
   * @param _roundId the requested round ID as presented through the proxy, this
   * is made up of the aggregator's round ID with the phase ID encoded in the
   * two highest order bytes
   * @return roundId is the round ID from the aggregator for which the data was
   * retrieved combined with an phase to ensure that round IDs get larger as
   * time moves forward.
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @dev Note that answer and updatedAt may change between queries.
   */
  function getRoundData(uint80 _roundId)
    public
    view
    virtual
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    (uint16 phaseId, uint64 aggregatorRoundId) = parseIds(_roundId);

    (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 ansIn
    ) = phaseAggregators[phaseId].getRoundData(aggregatorRoundId);

    return addPhaseIds(roundId, answer, startedAt, updatedAt, ansIn, phaseId);
  }

  /**
   * @notice get data about the latest round. Consumers are encouraged to check
   * that they're receiving fresh data by inspecting the updatedAt and
   * answeredInRound return values.
   * Note that different underlying implementations of AggregatorV3Interface
   * have slightly different semantics for some of the return values. Consumers
   * should determine what implementations they expect to receive
   * data from and validate that they can properly handle return data from all
   * of them.
   * @return roundId is the round ID from the aggregator for which the data was
   * retrieved combined with an phase to ensure that round IDs get larger as
   * time moves forward.
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @dev Note that answer and updatedAt may change between queries.
   */
  function latestRoundData()
    public
    view
    virtual
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    Phase memory current = currentPhase; // cache storage reads

    (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 ansIn
    ) = current.aggregator.latestRoundData();

    return addPhaseIds(roundId, answer, startedAt, updatedAt, ansIn, current.id);
  }

  /**
   * @notice Used if an aggregator contract has been proposed.
   * @param _roundId the round ID to retrieve the round data for
   * @return roundId is the round ID for which data was retrieved
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
  */
  function proposedGetRoundData(uint80 _roundId)
    public
    view
    virtual
    hasProposal()
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return proposedAggregator.getRoundData(_roundId);
  }

  /**
   * @notice Used if an aggregator contract has been proposed.
   * @return roundId is the round ID for which data was retrieved
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
  */
  function proposedLatestRoundData()
    public
    view
    virtual
    hasProposal()
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return proposedAggregator.latestRoundData();
  }

  /**
   * @notice returns the current phase's aggregator address.
   */
  function aggregator()
    external
    view
    returns (address)
  {
    return address(currentPhase.aggregator);
  }

  /**
   * @notice returns the current phase's ID.
   */
  function phaseId()
    external
    view
    returns (uint16)
  {
    return currentPhase.id;
  }

  /**
   * @notice represents the number of decimals the aggregator responses represent.
   */
  function decimals()
    external
    view
    override
    returns (uint8)
  {
    return currentPhase.aggregator.decimals();
  }

  /**
   * @notice the version number representing the type of aggregator the proxy
   * points to.
   */
  function version()
    external
    view
    override
    returns (uint256)
  {
    return currentPhase.aggregator.version();
  }

  /**
   * @notice returns the description of the aggregator the proxy points to.
   */
  function description()
    external
    view
    override
    returns (string memory)
  {
    return currentPhase.aggregator.description();
  }

  /**
   * @notice Allows the owner to propose a new address for the aggregator
   * @param _aggregator The new address for the aggregator contract
   */
  function proposeAggregator(address _aggregator)
    external
    onlyOwner()
  {
    proposedAggregator = AggregatorV2V3Interface(_aggregator);
  }

  /**
   * @notice Allows the owner to confirm and change the address
   * to the proposed aggregator
   * @dev Reverts if the given address doesn't match what was previously
   * proposed
   * @param _aggregator The new address for the aggregator contract
   */
  function confirmAggregator(address _aggregator)
    external
    onlyOwner()
  {
    require(_aggregator == address(proposedAggregator), "Invalid proposed aggregator");
    delete proposedAggregator;
    setAggregator(_aggregator);
  }


  /*
   * Internal
   */

  function setAggregator(address _aggregator)
    internal
  {
    uint16 id = currentPhase.id + 1;
    currentPhase = Phase(id, AggregatorV2V3Interface(_aggregator));
    phaseAggregators[id] = AggregatorV2V3Interface(_aggregator);
  }

  function addPhase(
    uint16 _phase,
    uint64 _originalId
  )
    internal
    view
    returns (uint80)
  {
    return uint80(uint256(_phase) << PHASE_OFFSET | _originalId);
  }

  function parseIds(
    uint256 _roundId
  )
    internal
    view
    returns (uint16, uint64)
  {
    uint16 phaseId = uint16(_roundId >> PHASE_OFFSET);
    uint64 aggregatorRoundId = uint64(_roundId);

    return (phaseId, aggregatorRoundId);
  }

  function addPhaseIds(
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound,
      uint16 phaseId
  )
    internal
    view
    returns (uint80, int256, uint256, uint256, uint80)
  {
    return (
      addPhase(phaseId, uint64(roundId)),
      answer,
      startedAt,
      updatedAt,
      addPhase(phaseId, uint64(answeredInRound))
    );
  }

  /*
   * Modifiers
   */

  modifier hasProposal() {
    require(address(proposedAggregator) != address(0), "No proposed aggregator present");
    _;
  }

}

interface AccessControllerInterface {
  function hasAccess(address user, bytes calldata data) external view returns (bool);
}

/**
 * @title External Access Controlled Aggregator Proxy
 * @notice A trusted proxy for updating where current answers are read from
 * @notice This contract provides a consistent address for the
 * Aggregator and AggregatorV3Interface but delegates where it reads from to the owner, who is
 * trusted to update it.
 * @notice Only access enabled addresses are allowed to access getters for
 * aggregated answers and round information.
 */
contract EACAggregatorProxy is AggregatorProxy {

  AccessControllerInterface public accessController;

  constructor(
    address _aggregator,
    address _accessController
  )
    public
    AggregatorProxy(_aggregator)
  {
    setController(_accessController);
  }

  /**
   * @notice Allows the owner to update the accessController contract address.
   * @param _accessController The new address for the accessController contract
   */
  function setController(address _accessController)
    public
    onlyOwner()
  {
    accessController = AccessControllerInterface(_accessController);
  }

  /**
   * @notice Reads the current answer from aggregator delegated to.
   * @dev overridden function to add the checkAccess() modifier
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestAnswer()
    public
    view
    override
    checkAccess()
    returns (int256)
  {
    return super.latestAnswer();
  }

  /**
   * @notice get the latest completed round where the answer was updated. This
   * ID includes the proxy's phase, to make sure round IDs increase even when
   * switching to a newly deployed aggregator.
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestTimestamp()
    public
    view
    override
    checkAccess()
    returns (uint256)
  {
    return super.latestTimestamp();
  }

  /**
   * @notice get past rounds answers
   * @param _roundId the answer number to retrieve the answer for
   * @dev overridden function to add the checkAccess() modifier
   *
   * @dev #[deprecated] Use getRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended getRoundData
   * instead which includes better verification information.
   */
  function getAnswer(uint256 _roundId)
    public
    view
    override
    checkAccess()
    returns (int256)
  {
    return super.getAnswer(_roundId);
  }

  /**
   * @notice get block timestamp when an answer was last updated
   * @param _roundId the answer number to retrieve the updated timestamp for
   * @dev overridden function to add the checkAccess() modifier
   *
   * @dev #[deprecated] Use getRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended getRoundData
   * instead which includes better verification information.
   */
  function getTimestamp(uint256 _roundId)
    public
    view
    override
    checkAccess()
    returns (uint256)
  {
    return super.getTimestamp(_roundId);
  }

  /**
   * @notice get the latest completed round where the answer was updated
   * @dev overridden function to add the checkAccess() modifier
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestRound()
    public
    view
    override
    checkAccess()
    returns (uint256)
  {
    return super.latestRound();
  }

  /**
   * @notice get data about a round. Consumers are encouraged to check
   * that they're receiving fresh data by inspecting the updatedAt and
   * answeredInRound return values.
   * Note that different underlying implementations of AggregatorV3Interface
   * have slightly different semantics for some of the return values. Consumers
   * should determine what implementations they expect to receive
   * data from and validate that they can properly handle return data from all
   * of them.
   * @param _roundId the round ID to retrieve the round data for
   * @return roundId is the round ID from the aggregator for which the data was
   * retrieved combined with a phase to ensure that round IDs get larger as
   * time moves forward.
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @dev Note that answer and updatedAt may change between queries.
   */
  function getRoundData(uint80 _roundId)
    public
    view
    checkAccess()
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.getRoundData(_roundId);
  }

  /**
   * @notice get data about the latest round. Consumers are encouraged to check
   * that they're receiving fresh data by inspecting the updatedAt and
   * answeredInRound return values.
   * Note that different underlying implementations of AggregatorV3Interface
   * have slightly different semantics for some of the return values. Consumers
   * should determine what implementations they expect to receive
   * data from and validate that they can properly handle return data from all
   * of them.
   * @return roundId is the round ID from the aggregator for which the data was
   * retrieved combined with a phase to ensure that round IDs get larger as
   * time moves forward.
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @dev Note that answer and updatedAt may change between queries.
   */
  function latestRoundData()
    public
    view
    checkAccess()
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.latestRoundData();
  }

  /**
   * @notice Used if an aggregator contract has been proposed.
   * @param _roundId the round ID to retrieve the round data for
   * @return roundId is the round ID for which data was retrieved
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
  */
  function proposedGetRoundData(uint80 _roundId)
    public
    view
    checkAccess()
    hasProposal()
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.proposedGetRoundData(_roundId);
  }

  /**
   * @notice Used if an aggregator contract has been proposed.
   * @return roundId is the round ID for which data was retrieved
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
  */
  function proposedLatestRoundData()
    public
    view
    checkAccess()
    hasProposal()
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.proposedLatestRoundData();
  }

  /**
   * @dev reverts if the caller does not have access by the accessController
   * contract or is the contract itself.
   */
  modifier checkAccess() {
    AccessControllerInterface ac = accessController;
    require(address(ac) == address(0) || ac.hasAccess(msg.sender, msg.data), "No access");
    _;
  }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.7.1;
import "./OffchainAggregator.sol";
import "./SimpleReadAccessController.sol";
/**
 * @notice Wrapper of OffchainAggregator which checks read access on Aggregator-interface methods
 */
contract AccessControlledOffchainAggregator is OffchainAggregator, SimpleReadAccessController {
  constructor(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission,
    address _link,
    address _validator,
    int192 _minAnswer,
    int192 _maxAnswer,
    AccessControllerInterface _billingAccessController,
    AccessControllerInterface _requesterAccessController,
    uint8 _decimals,
    string memory description
  )
    OffchainAggregator(
      _maximumGasPrice,
      _reasonableGasPrice,
      _microLinkPerEth,
      _linkGweiPerObservation,
      _linkGweiPerTransmission,
      _link,
      _validator,
      _minAnswer,
      _maxAnswer,
      _billingAccessController,
      _requesterAccessController,
      _decimals,
      description
    ) {
    }
  /*
   * v2 Aggregator interface
   */
  /// @inheritdoc OffchainAggregator
  function latestAnswer()
    public
    override
    view
    checkAccess()
    returns (int256)
  {
    return super.latestAnswer();
  }
  /// @inheritdoc OffchainAggregator
  function latestTimestamp()
    public
    override
    view
    checkAccess()
    returns (uint256)
  {
    return super.latestTimestamp();
  }
  /// @inheritdoc OffchainAggregator
  function latestRound()
    public
    override
    view
    checkAccess()
    returns (uint256)
  {
    return super.latestRound();
  }
  /// @inheritdoc OffchainAggregator
  function getAnswer(uint256 _roundId)
    public
    override
    view
    checkAccess()
    returns (int256)
  {
    return super.getAnswer(_roundId);
  }
  /// @inheritdoc OffchainAggregator
  function getTimestamp(uint256 _roundId)
    public
    override
    view
    checkAccess()
    returns (uint256)
  {
    return super.getTimestamp(_roundId);
  }
  /*
   * v3 Aggregator interface
   */
  /// @inheritdoc OffchainAggregator
  function description()
    public
    override
    view
    checkAccess()
    returns (string memory)
  {
    return super.description();
  }
  /// @inheritdoc OffchainAggregator
  function getRoundData(uint80 _roundId)
    public
    override
    view
    checkAccess()
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.getRoundData(_roundId);
  }
  /// @inheritdoc OffchainAggregator
  function latestRoundData()
    public
    override
    view
    checkAccess()
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.latestRoundData();
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "./AccessControllerInterface.sol";
import "./AggregatorV2V3Interface.sol";
import "./AggregatorValidatorInterface.sol";
import "./LinkTokenInterface.sol";
import "./Owned.sol";
import "./OffchainAggregatorBilling.sol";
/**
  * @notice Onchain verification of reports from the offchain reporting protocol
  * @dev For details on its operation, see the offchain reporting protocol design
  * @dev doc, which refers to this contract as simply the "contract".
*/
contract OffchainAggregator is Owned, OffchainAggregatorBilling, AggregatorV2V3Interface {
  uint256 constant private maxUint32 = (1 << 32) - 1;
  // Storing these fields used on the hot path in a HotVars variable reduces the
  // retrieval of all of them to a single SLOAD. If any further fields are
  // added, make sure that storage of the struct still takes at most 32 bytes.
  struct HotVars {
    // Provides 128 bits of security against 2nd pre-image attacks, but only
    // 64 bits against collisions. This is acceptable, since a malicious owner has
    // easier way of messing up the protocol than to find hash collisions.
    bytes16 latestConfigDigest;
    uint40 latestEpochAndRound; // 32 most sig bits for epoch, 8 least sig bits for round
    // Current bound assumed on number of faulty/dishonest oracles participating
    // in the protocol, this value is referred to as f in the design
    uint8 threshold;
    // Chainlink Aggregators expose a roundId to consumers. The offchain reporting
    // protocol does not use this id anywhere. We increment it whenever a new
    // transmission is made to provide callers with contiguous ids for successive
    // reports.
    uint32 latestAggregatorRoundId;
  }
  HotVars internal s_hotVars;
  // Transmission records the median answer from the transmit transaction at
  // time timestamp
  struct Transmission {
    int192 answer; // 192 bits ought to be enough for anyone
    uint64 timestamp;
  }
  mapping(uint32 /* aggregator round ID */ => Transmission) internal s_transmissions;
  // incremented each time a new config is posted. This count is incorporated
  // into the config digest, to prevent replay attacks.
  uint32 internal s_configCount;
  uint32 internal s_latestConfigBlockNumber; // makes it easier for offchain systems
                                             // to extract config from logs.
  // Lowest answer the system is allowed to report in response to transmissions
  int192 immutable public minAnswer;
  // Highest answer the system is allowed to report in response to transmissions
  int192 immutable public maxAnswer;
  /*
   * @param _maximumGasPrice highest gas price for which transmitter will be compensated
   * @param _reasonableGasPrice transmitter will receive reward for gas prices under this value
   * @param _microLinkPerEth reimbursement per ETH of gas cost, in 1e-6LINK units
   * @param _linkGweiPerObservation reward to oracle for contributing an observation to a successfully transmitted report, in 1e-9LINK units
   * @param _linkGweiPerTransmission reward to transmitter of a successful report, in 1e-9LINK units
   * @param _link address of the LINK contract
   * @param _validator address of validator contract (must satisfy AggregatorValidatorInterface)
   * @param _minAnswer lowest answer the median of a report is allowed to be
   * @param _maxAnswer highest answer the median of a report is allowed to be
   * @param _billingAccessController access controller for billing admin functions
   * @param _requesterAccessController access controller for requesting new rounds
   * @param _decimals answers are stored in fixed-point format, with this many digits of precision
   * @param _description short human-readable description of observable this contract's answers pertain to
   */
  constructor(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission,
    address _link,
    address _validator,
    int192 _minAnswer,
    int192 _maxAnswer,
    AccessControllerInterface _billingAccessController,
    AccessControllerInterface _requesterAccessController,
    uint8 _decimals,
    string memory _description
  )
    OffchainAggregatorBilling(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission, _link,
      _billingAccessController
    )
  {
    decimals = _decimals;
    s_description = _description;
    setRequesterAccessController(_requesterAccessController);
    setValidator(_validator);
    minAnswer = _minAnswer;
    maxAnswer = _maxAnswer;
  }
  /*
   * Config logic
   */
  /**
   * @notice triggers a new run of the offchain reporting protocol
   * @param previousConfigBlockNumber block in which the previous config was set, to simplify historic analysis
   * @param configCount ordinal number of this config setting among all config settings over the life of this contract
   * @param signers ith element is address ith oracle uses to sign a report
   * @param transmitters ith element is address ith oracle uses to transmit a report via the transmit method
   * @param threshold maximum number of faulty/dishonest oracles the protocol can tolerate while still working correctly
   * @param encodedConfigVersion version of the serialization format used for "encoded" parameter
   * @param encoded serialized data used by oracles to configure their offchain operation
   */
  event ConfigSet(
    uint32 previousConfigBlockNumber,
    uint64 configCount,
    address[] signers,
    address[] transmitters,
    uint8 threshold,
    uint64 encodedConfigVersion,
    bytes encoded
  );
  // Reverts transaction if config args are invalid
  modifier checkConfigValid (
    uint256 _numSigners, uint256 _numTransmitters, uint256 _threshold
  ) {
    require(_numSigners <= maxNumOracles, "too many signers");
    require(_threshold > 0, "threshold must be positive");
    require(
      _numSigners == _numTransmitters,
      "oracle addresses out of registration"
    );
    require(_numSigners > 3*_threshold, "faulty-oracle threshold too high");
    _;
  }
  /**
   * @notice sets offchain reporting protocol configuration incl. participating oracles
   * @param _signers addresses with which oracles sign the reports
   * @param _transmitters addresses oracles use to transmit the reports
   * @param _threshold number of faulty oracles the system can tolerate
   * @param _encodedConfigVersion version number for offchainEncoding schema
   * @param _encoded encoded off-chain oracle configuration
   */
  function setConfig(
    address[] calldata _signers,
    address[] calldata _transmitters,
    uint8 _threshold,
    uint64 _encodedConfigVersion,
    bytes calldata _encoded
  )
    external
    checkConfigValid(_signers.length, _transmitters.length, _threshold)
    onlyOwner()
  {
    while (s_signers.length != 0) { // remove any old signer/transmitter addresses
      uint lastIdx = s_signers.length - 1;
      address signer = s_signers[lastIdx];
      address transmitter = s_transmitters[lastIdx];
      payOracle(transmitter);
      delete s_oracles[signer];
      delete s_oracles[transmitter];
      s_signers.pop();
      s_transmitters.pop();
    }
    for (uint i = 0; i < _signers.length; i++) { // add new signer/transmitter addresses
      require(
        s_oracles[_signers[i]].role == Role.Unset,
        "repeated signer address"
      );
      s_oracles[_signers[i]] = Oracle(uint8(i), Role.Signer);
      require(s_payees[_transmitters[i]] != address(0), "payee must be set");
      require(
        s_oracles[_transmitters[i]].role == Role.Unset,
        "repeated transmitter address"
      );
      s_oracles[_transmitters[i]] = Oracle(uint8(i), Role.Transmitter);
      s_signers.push(_signers[i]);
      s_transmitters.push(_transmitters[i]);
    }
    s_hotVars.threshold = _threshold;
    uint32 previousConfigBlockNumber = s_latestConfigBlockNumber;
    s_latestConfigBlockNumber = uint32(block.number);
    s_configCount += 1;
    uint64 configCount = s_configCount;
    {
      s_hotVars.latestConfigDigest = configDigestFromConfigData(
        address(this),
        configCount,
        _signers,
        _transmitters,
        _threshold,
        _encodedConfigVersion,
        _encoded
      );
      s_hotVars.latestEpochAndRound = 0;
    }
    emit ConfigSet(
      previousConfigBlockNumber,
      configCount,
      _signers,
      _transmitters,
      _threshold,
      _encodedConfigVersion,
      _encoded
    );
  }
  function configDigestFromConfigData(
    address _contractAddress,
    uint64 _configCount,
    address[] calldata _signers,
    address[] calldata _transmitters,
    uint8 _threshold,
    uint64 _encodedConfigVersion,
    bytes calldata _encodedConfig
  ) internal pure returns (bytes16) {
    return bytes16(keccak256(abi.encode(_contractAddress, _configCount,
      _signers, _transmitters, _threshold, _encodedConfigVersion, _encodedConfig
    )));
  }
  /**
   * @notice information about current offchain reporting protocol configuration
   * @return configCount ordinal number of current config, out of all configs applied to this contract so far
   * @return blockNumber block at which this config was set
   * @return configDigest domain-separation tag for current config (see configDigestFromConfigData)
   */
  function latestConfigDetails()
    external
    view
    returns (
      uint32 configCount,
      uint32 blockNumber,
      bytes16 configDigest
    )
  {
    return (s_configCount, s_latestConfigBlockNumber, s_hotVars.latestConfigDigest);
  }
  /**
   * @return list of addresses permitted to transmit reports to this contract
   * @dev The list will match the order used to specify the transmitter during setConfig
   */
  function transmitters()
    external
    view
    returns(address[] memory)
  {
      return s_transmitters;
  }
  /*
   * On-chain validation logc
   */
  // Maximum gas the validation logic can use
  uint256 private constant VALIDATOR_GAS_LIMIT = 100000;
  // Contract containing the validation logic
  AggregatorValidatorInterface private s_validator;
  /**
   * @notice indicates that the address of the validator contract has been set
   * @param previous setting of the address prior to this event
   * @param current the new value for the address
   */
  event ValidatorUpdated(
    address indexed previous,
    address indexed current
  );
  /**
   * @notice address of the contract which does external data validation
   * @return validator address
   */
  function validator()
    external
    view
    returns (AggregatorValidatorInterface)
  {
    return s_validator;
  }
  /**
   * @notice sets the address which does external data validation
   * @param _newValidator designates the address of the new validation contract
   */
  function setValidator(address _newValidator)
    public
    onlyOwner()
  {
    address previous = address(s_validator);
    if (previous != _newValidator) {
      s_validator = AggregatorValidatorInterface(_newValidator);
      emit ValidatorUpdated(previous, _newValidator);
    }
  }
  function validateAnswer(
    uint32 _aggregatorRoundId,
    int256 _answer
  )
    private
  {
    AggregatorValidatorInterface av = s_validator; // cache storage reads
    if (address(av) == address(0)) return;
    uint32 prevAggregatorRoundId = _aggregatorRoundId - 1;
    int256 prevAggregatorRoundAnswer = s_transmissions[prevAggregatorRoundId].answer;
    // We do not want the validator to ever prevent reporting, so we limit its
    // gas usage and catch any errors that may arise.
    try av.validate{gas: VALIDATOR_GAS_LIMIT}(
      prevAggregatorRoundId,
      prevAggregatorRoundAnswer,
      _aggregatorRoundId,
      _answer
    ) {} catch {}
  }
  /*
   * requestNewRound logic
   */
  AccessControllerInterface internal s_requesterAccessController;
  /**
   * @notice emitted when a new requester access controller contract is set
   * @param old the address prior to the current setting
   * @param current the address of the new access controller contract
   */
  event RequesterAccessControllerSet(AccessControllerInterface old, AccessControllerInterface current);
  /**
   * @notice emitted to immediately request a new round
   * @param requester the address of the requester
   * @param configDigest the latest transmission's configDigest
   * @param epoch the latest transmission's epoch
   * @param round the latest transmission's round
   */
  event RoundRequested(address indexed requester, bytes16 configDigest, uint32 epoch, uint8 round);
  /**
   * @notice address of the requester access controller contract
   * @return requester access controller address
   */
  function requesterAccessController()
    external
    view
    returns (AccessControllerInterface)
  {
    return s_requesterAccessController;
  }
  /**
   * @notice sets the requester access controller
   * @param _requesterAccessController designates the address of the new requester access controller
   */
  function setRequesterAccessController(AccessControllerInterface _requesterAccessController)
    public
    onlyOwner()
  {
    AccessControllerInterface oldController = s_requesterAccessController;
    if (_requesterAccessController != oldController) {
      s_requesterAccessController = AccessControllerInterface(_requesterAccessController);
      emit RequesterAccessControllerSet(oldController, _requesterAccessController);
    }
  }
  /**
   * @notice immediately requests a new round
   * @return the aggregatorRoundId of the next round. Note: The report for this round may have been
   * transmitted (but not yet mined) *before* requestNewRound() was even called. There is *no*
   * guarantee of causality between the request and the report at aggregatorRoundId.
   */
  function requestNewRound() external returns (uint80) {
    require(msg.sender == owner || s_requesterAccessController.hasAccess(msg.sender, msg.data),
      "Only owner&requester can call");
    HotVars memory hotVars = s_hotVars;
    emit RoundRequested(
      msg.sender,
      hotVars.latestConfigDigest,
      uint32(s_hotVars.latestEpochAndRound >> 8),
      uint8(s_hotVars.latestEpochAndRound)
    );
    return hotVars.latestAggregatorRoundId + 1;
  }
  /*
   * Transmission logic
   */
  /**
   * @notice indicates that a new report was transmitted
   * @param aggregatorRoundId the round to which this report was assigned
   * @param answer median of the observations attached this report
   * @param transmitter address from which the report was transmitted
   * @param observations observations transmitted with this report
   * @param rawReportContext signature-replay-prevention domain-separation tag
   */
  event NewTransmission(
    uint32 indexed aggregatorRoundId,
    int192 answer,
    address transmitter,
    int192[] observations,
    bytes observers,
    bytes32 rawReportContext
  );
  // decodeReport is used to check that the solidity and go code are using the
  // same format. See TestOffchainAggregator.testDecodeReport and TestReportParsing
  function decodeReport(bytes memory _report)
    internal
    pure
    returns (
      bytes32 rawReportContext,
      bytes32 rawObservers,
      int192[] memory observations
    )
  {
    (rawReportContext, rawObservers, observations) = abi.decode(_report,
      (bytes32, bytes32, int192[]));
  }
  // Used to relieve stack pressure in transmit
  struct ReportData {
    HotVars hotVars; // Only read from storage once
    bytes observers; // ith element is the index of the ith observer
    int192[] observations; // ith element is the ith observation
    bytes vs; // jth element is the v component of the jth signature
    bytes32 rawReportContext;
  }
  /*
   * @notice details about the most recent report
   * @return configDigest domain separation tag for the latest report
   * @return epoch epoch in which the latest report was generated
   * @return round OCR round in which the latest report was generated
   * @return latestAnswer median value from latest report
   * @return latestTimestamp when the latest report was transmitted
   */
  function latestTransmissionDetails()
    external
    view
    returns (
      bytes16 configDigest,
      uint32 epoch,
      uint8 round,
      int192 latestAnswer,
      uint64 latestTimestamp
    )
  {
    require(msg.sender == tx.origin, "Only callable by EOA");
    return (
      s_hotVars.latestConfigDigest,
      uint32(s_hotVars.latestEpochAndRound >> 8),
      uint8(s_hotVars.latestEpochAndRound),
      s_transmissions[s_hotVars.latestAggregatorRoundId].answer,
      s_transmissions[s_hotVars.latestAggregatorRoundId].timestamp
    );
  }
  // The constant-length components of the msg.data sent to transmit.
  // See the "If we wanted to call sam" example on for example reasoning
  // https://solidity.readthedocs.io/en/v0.7.2/abi-spec.html
  uint16 private constant TRANSMIT_MSGDATA_CONSTANT_LENGTH_COMPONENT =
    4 + // function selector
    32 + // word containing start location of abiencoded _report value
    32 + // word containing location start of abiencoded  _rs value
    32 + // word containing start location of abiencoded _ss value
    32 + // _rawVs value
    32 + // word containing length of _report
    32 + // word containing length _rs
    32 + // word containing length of _ss
    0; // placeholder
  function expectedMsgDataLength(
    bytes calldata _report, bytes32[] calldata _rs, bytes32[] calldata _ss
  ) private pure returns (uint256 length)
  {
    // calldata will never be big enough to make this overflow
    return uint256(TRANSMIT_MSGDATA_CONSTANT_LENGTH_COMPONENT) +
      _report.length + // one byte pure entry in _report
      _rs.length * 32 + // 32 bytes per entry in _rs
      _ss.length * 32 + // 32 bytes per entry in _ss
      0; // placeholder
  }
  /**
   * @notice transmit is called to post a new report to the contract
   * @param _report serialized report, which the signatures are signing. See parsing code below for format. The ith element of the observers component must be the index in s_signers of the address for the ith signature
   * @param _rs ith element is the R components of the ith signature on report. Must have at most maxNumOracles entries
   * @param _ss ith element is the S components of the ith signature on report. Must have at most maxNumOracles entries
   * @param _rawVs ith element is the the V component of the ith signature
   */
  function transmit(
    // NOTE: If these parameters are changed, expectedMsgDataLength and/or
    // TRANSMIT_MSGDATA_CONSTANT_LENGTH_COMPONENT need to be changed accordingly
    bytes calldata _report,
    bytes32[] calldata _rs, bytes32[] calldata _ss, bytes32 _rawVs // signatures
  )
    external
  {
    uint256 initialGas = gasleft(); // This line must come first
    // Make sure the transmit message-length matches the inputs. Otherwise, the
    // transmitter could append an arbitrarily long (up to gas-block limit)
    // string of 0 bytes, which we would reimburse at a rate of 16 gas/byte, but
    // which would only cost the transmitter 4 gas/byte. (Appendix G of the
    // yellow paper, p. 25, for G_txdatazero and EIP 2028 for G_txdatanonzero.)
    // This could amount to reimbursement profit of 36 million gas, given a 3MB
    // zero tail.
    require(msg.data.length == expectedMsgDataLength(_report, _rs, _ss),
      "transmit message too long");
    ReportData memory r; // Relieves stack pressure
    {
      r.hotVars = s_hotVars; // cache read from storage
      bytes32 rawObservers;
      (r.rawReportContext, rawObservers, r.observations) = abi.decode(
        _report, (bytes32, bytes32, int192[])
      );
      // rawReportContext consists of:
      // 11-byte zero padding
      // 16-byte configDigest
      // 4-byte epoch
      // 1-byte round
      bytes16 configDigest = bytes16(r.rawReportContext << 88);
      require(
        r.hotVars.latestConfigDigest == configDigest,
        "configDigest mismatch"
      );
      uint40 epochAndRound = uint40(uint256(r.rawReportContext));
      // direct numerical comparison works here, because
      //
      //   ((e,r) <= (e',r')) implies (epochAndRound <= epochAndRound')
      //
      // because alphabetic ordering implies e <= e', and if e = e', then r<=r',
      // so e*256+r <= e'*256+r', because r, r' < 256
      require(r.hotVars.latestEpochAndRound < epochAndRound, "stale report");
      require(_rs.length > r.hotVars.threshold, "not enough signatures");
      require(_rs.length <= maxNumOracles, "too many signatures");
      require(_ss.length == _rs.length, "signatures out of registration");
      require(r.observations.length <= maxNumOracles,
              "num observations out of bounds");
      require(r.observations.length > 2 * r.hotVars.threshold,
              "too few values to trust median");
      // Copy signature parities in bytes32 _rawVs to bytes r.v
      r.vs = new bytes(_rs.length);
      for (uint8 i = 0; i < _rs.length; i++) {
        r.vs[i] = _rawVs[i];
      }
      // Copy observer identities in bytes32 rawObservers to bytes r.observers
      r.observers = new bytes(r.observations.length);
      bool[maxNumOracles] memory seen;
      for (uint8 i = 0; i < r.observations.length; i++) {
        uint8 observerIdx = uint8(rawObservers[i]);
        require(!seen[observerIdx], "observer index repeated");
        seen[observerIdx] = true;
        r.observers[i] = rawObservers[i];
      }
      Oracle memory transmitter = s_oracles[msg.sender];
      require( // Check that sender is authorized to report
        transmitter.role == Role.Transmitter &&
        msg.sender == s_transmitters[transmitter.index],
        "unauthorized transmitter"
      );
      // record epochAndRound here, so that we don't have to carry the local
      // variable in transmit. The change is reverted if something fails later.
      r.hotVars.latestEpochAndRound = epochAndRound;
    }
    { // Verify signatures attached to report
      bytes32 h = keccak256(_report);
      bool[maxNumOracles] memory signed;
      Oracle memory o;
      for (uint i = 0; i < _rs.length; i++) {
        address signer = ecrecover(h, uint8(r.vs[i])+27, _rs[i], _ss[i]);
        o = s_oracles[signer];
        require(o.role == Role.Signer, "address not authorized to sign");
        require(!signed[o.index], "non-unique signature");
        signed[o.index] = true;
      }
    }
    { // Check the report contents, and record the result
      for (uint i = 0; i < r.observations.length - 1; i++) {
        bool inOrder = r.observations[i] <= r.observations[i+1];
        require(inOrder, "observations not sorted");
      }
      int192 median = r.observations[r.observations.length/2];
      require(minAnswer <= median && median <= maxAnswer, "median is out of min-max range");
      r.hotVars.latestAggregatorRoundId++;
      s_transmissions[r.hotVars.latestAggregatorRoundId] =
        Transmission(median, uint64(block.timestamp));
      emit NewTransmission(
        r.hotVars.latestAggregatorRoundId,
        median,
        msg.sender,
        r.observations,
        r.observers,
        r.rawReportContext
      );
      // Emit these for backwards compatability with offchain consumers
      // that only support legacy events
      emit NewRound(
        r.hotVars.latestAggregatorRoundId,
        address(0x0), // use zero address since we don't have anybody "starting" the round here
        block.timestamp
      );
      emit AnswerUpdated(
        median,
        r.hotVars.latestAggregatorRoundId,
        block.timestamp
      );
      validateAnswer(r.hotVars.latestAggregatorRoundId, median);
    }
    s_hotVars = r.hotVars;
    assert(initialGas < maxUint32);
    reimburseAndRewardOracles(uint32(initialGas), r.observers);
  }
  /*
   * v2 Aggregator interface
   */
  /**
   * @notice median from the most recent report
   */
  function latestAnswer()
    public
    override
    view
    virtual
    returns (int256)
  {
    return s_transmissions[s_hotVars.latestAggregatorRoundId].answer;
  }
  /**
   * @notice timestamp of block in which last report was transmitted
   */
  function latestTimestamp()
    public
    override
    view
    virtual
    returns (uint256)
  {
    return s_transmissions[s_hotVars.latestAggregatorRoundId].timestamp;
  }
  /**
   * @notice Aggregator round (NOT OCR round) in which last report was transmitted
   */
  function latestRound()
    public
    override
    view
    virtual
    returns (uint256)
  {
    return s_hotVars.latestAggregatorRoundId;
  }
  /**
   * @notice median of report from given aggregator round (NOT OCR round)
   * @param _roundId the aggregator round of the target report
   */
  function getAnswer(uint256 _roundId)
    public
    override
    view
    virtual
    returns (int256)
  {
    if (_roundId > 0xFFFFFFFF) { return 0; }
    return s_transmissions[uint32(_roundId)].answer;
  }
  /**
   * @notice timestamp of block in which report from given aggregator round was transmitted
   * @param _roundId aggregator round (NOT OCR round) of target report
   */
  function getTimestamp(uint256 _roundId)
    public
    override
    view
    virtual
    returns (uint256)
  {
    if (_roundId > 0xFFFFFFFF) { return 0; }
    return s_transmissions[uint32(_roundId)].timestamp;
  }
  /*
   * v3 Aggregator interface
   */
  string constant private V3_NO_DATA_ERROR = "No data present";
  /**
   * @return answers are stored in fixed-point format, with this many digits of precision
   */
  uint8 immutable public override decimals;
  /**
   * @notice aggregator contract version
   */
  uint256 constant public override version = 4;
  string internal s_description;
  /**
   * @notice human-readable description of observable this contract is reporting on
   */
  function description()
    public
    override
    view
    virtual
    returns (string memory)
  {
    return s_description;
  }
  /**
   * @notice details for the given aggregator round
   * @param _roundId target aggregator round (NOT OCR round). Must fit in uint32
   * @return roundId _roundId
   * @return answer median of report from given _roundId
   * @return startedAt timestamp of block in which report from given _roundId was transmitted
   * @return updatedAt timestamp of block in which report from given _roundId was transmitted
   * @return answeredInRound _roundId
   */
  function getRoundData(uint80 _roundId)
    public
    override
    view
    virtual
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    require(_roundId <= 0xFFFFFFFF, V3_NO_DATA_ERROR);
    Transmission memory transmission = s_transmissions[uint32(_roundId)];
    return (
      _roundId,
      transmission.answer,
      transmission.timestamp,
      transmission.timestamp,
      _roundId
    );
  }
  /**
   * @notice aggregator details for the most recently transmitted report
   * @return roundId aggregator round of latest report (NOT OCR round)
   * @return answer median of latest report
   * @return startedAt timestamp of block containing latest report
   * @return updatedAt timestamp of block containing latest report
   * @return answeredInRound aggregator round of latest report
   */
  function latestRoundData()
    public
    override
    view
    virtual
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    roundId = s_hotVars.latestAggregatorRoundId;
    // Skipped for compatability with existing FluxAggregator in which latestRoundData never reverts.
    // require(roundId != 0, V3_NO_DATA_ERROR);
    Transmission memory transmission = s_transmissions[uint32(roundId)];
    return (
      roundId,
      transmission.answer,
      transmission.timestamp,
      transmission.timestamp,
      roundId
    );
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
interface AccessControllerInterface {
  function hasAccess(address user, bytes calldata data) external view returns (bool);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "./AggregatorInterface.sol";
import "./AggregatorV3Interface.sol";
interface AggregatorV2V3Interface is AggregatorInterface, AggregatorV3Interface
{
}// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
interface AggregatorInterface {
  function latestAnswer() external view returns (int256);
  function latestTimestamp() external view returns (uint256);
  function latestRound() external view returns (uint256);
  function getAnswer(uint256 roundId) external view returns (int256);
  function getTimestamp(uint256 roundId) external view returns (uint256);
  event AnswerUpdated(int256 indexed current, uint256 indexed roundId, uint256 updatedAt);
  event NewRound(uint256 indexed roundId, address indexed startedBy, uint256 startedAt);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
interface AggregatorV3Interface {
  function decimals() external view returns (uint8);
  function description() external view returns (string memory);
  function version() external view returns (uint256);
  // getRoundData and latestRoundData should both raise "No data present"
  // if they do not have data to report, instead of returning unset values
  // which could be misinterpreted as actual reported values.
  function getRoundData(uint80 _roundId)
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );
  function latestRoundData()
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
interface AggregatorValidatorInterface {
  function validate(
    uint256 previousRoundId,
    int256 previousAnswer,
    uint256 currentRoundId,
    int256 currentAnswer
  ) external returns (bool);
}// SPDX-License-Identifier: MIT
pragma solidity ^0.7.1;
interface LinkTokenInterface {
  function allowance(address owner, address spender) external view returns (uint256 remaining);
  function approve(address spender, uint256 value) external returns (bool success);
  function balanceOf(address owner) external view returns (uint256 balance);
  function decimals() external view returns (uint8 decimalPlaces);
  function decreaseApproval(address spender, uint256 addedValue) external returns (bool success);
  function increaseApproval(address spender, uint256 subtractedValue) external;
  function name() external view returns (string memory tokenName);
  function symbol() external view returns (string memory tokenSymbol);
  function totalSupply() external view returns (uint256 totalTokensIssued);
  function transfer(address to, uint256 value) external returns (bool success);
  function transferAndCall(address to, uint256 value, bytes calldata data) external returns (bool success);
  function transferFrom(address from, address to, uint256 value) external returns (bool success);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
/**
 * @title The Owned contract
 * @notice A contract with helpers for basic contract ownership.
 */
contract Owned {
  address payable public owner;
  address private pendingOwner;
  event OwnershipTransferRequested(
    address indexed from,
    address indexed to
  );
  event OwnershipTransferred(
    address indexed from,
    address indexed to
  );
  constructor() {
    owner = msg.sender;
  }
  /**
   * @dev Allows an owner to begin transferring ownership to a new address,
   * pending.
   */
  function transferOwnership(address _to)
    external
    onlyOwner()
  {
    pendingOwner = _to;
    emit OwnershipTransferRequested(owner, _to);
  }
  /**
   * @dev Allows an ownership transfer to be completed by the recipient.
   */
  function acceptOwnership()
    external
  {
    require(msg.sender == pendingOwner, "Must be proposed owner");
    address oldOwner = owner;
    owner = msg.sender;
    pendingOwner = address(0);
    emit OwnershipTransferred(oldOwner, msg.sender);
  }
  /**
   * @dev Reverts if called by anyone other than the contract owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner, "Only callable by owner");
    _;
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "./AccessControllerInterface.sol";
import "./LinkTokenInterface.sol";
import "./Owned.sol";
/**
 * @notice tracks administration of oracle-reward and gas-reimbursement parameters.
 * @dev
 * If you read or change this, be sure to read or adjust the comments. They
 * track the units of the values under consideration, and are crucial to
 * the readability of the operations it specifies.
 * @notice
 * Trust Model:
 * Nothing in this contract prevents a billing admin from setting insane
 * values for the billing parameters in setBilling. Oracles
 * participating in this contract should regularly check that the
 * parameters make sense. Similarly, the outstanding obligations of this
 * contract to the oracles can exceed the funds held by the contract.
 * Oracles participating in this contract should regularly check that it
 * holds sufficient funds and stop interacting with it if funding runs
 * out.
 * This still leaves oracles with some risk due to TOCTOU issues.
 * However, since the sums involved are pretty small (Ethereum
 * transactions aren't that expensive in the end) and an oracle would
 * likely stop participating in a contract it repeatedly lost money on,
 * this risk is deemed acceptable. Oracles should also regularly
 * withdraw any funds in the contract to prevent issues where the
 * contract becomes underfunded at a later time, and different oracles
 * are competing for the left-over funds.
 * Finally, note that any change to the set of oracles or to the billing
 * parameters will trigger payout of all oracles first (using the old
 * parameters), a billing admin cannot take away funds that are already
 * marked for payment.
*/
contract OffchainAggregatorBilling is Owned {
  // Maximum number of oracles the offchain reporting protocol is designed for
  uint256 constant internal maxNumOracles = 31;
  // Parameters for oracle payments
  struct Billing {
    // Highest compensated gas price, in ETH-gwei uints
    uint32 maximumGasPrice;
    // If gas price is less (in ETH-gwei units), transmitter gets half the savings
    uint32 reasonableGasPrice;
    // Pay transmitter back this much LINK per unit eth spent on gas
    // (1e-6LINK/ETH units)
    uint32 microLinkPerEth;
    // Fixed LINK reward for each observer, in LINK-gwei units
    uint32 linkGweiPerObservation;
    // Fixed reward for transmitter, in linkGweiPerObservation units
    uint32 linkGweiPerTransmission;
  }
  Billing internal s_billing;
  /**
  * @return LINK token contract used for billing
  */
  LinkTokenInterface immutable public LINK;
  AccessControllerInterface internal s_billingAccessController;
  // ith element is number of observation rewards due to ith process, plus one.
  // This is expected to saturate after an oracle has submitted 65,535
  // observations, or about 65535/(3*24*20) = 45 days, given a transmission
  // every 3 minutes.
  //
  // This is always one greater than the actual value, so that when the value is
  // reset to zero, we don't end up with a zero value in storage (which would
  // result in a higher gas cost, the next time the value is incremented.)
  // Calculations using this variable need to take that offset into account.
  uint16[maxNumOracles] internal s_oracleObservationsCounts;
  // Addresses at which oracles want to receive payments, by transmitter address
  mapping (address /* transmitter */ => address /* payment address */)
    internal
    s_payees;
  // Payee addresses which must be approved by the owner
  mapping (address /* transmitter */ => address /* payment address */)
    internal
    s_proposedPayees;
  // LINK-wei-denominated reimbursements for gas used by transmitters.
  //
  // This is always one greater than the actual value, so that when the value is
  // reset to zero, we don't end up with a zero value in storage (which would
  // result in a higher gas cost, the next time the value is incremented.)
  // Calculations using this variable need to take that offset into account.
  //
  // Argument for overflow safety:
  // We have the following maximum intermediate values:
  // - 2**40 additions to this variable (epochAndRound is a uint40)
  // - 2**32 gas price in ethgwei/gas
  // - 1e9 ethwei/ethgwei
  // - 2**32 gas since the block gas limit is at ~20 million
  // - 2**32 (microlink/eth)
  // And we have 2**40 * 2**32 * 1e9 * 2**32 * 2**32 < 2**166
  // (we also divide in some places, but that only makes the value smaller)
  // We can thus safely use uint256 intermediate values for the computation
  // updating this variable.
  uint256[maxNumOracles] internal s_gasReimbursementsLinkWei;
  // Used for s_oracles[a].role, where a is an address, to track the purpose
  // of the address, or to indicate that the address is unset.
  enum Role {
    // No oracle role has been set for address a
    Unset,
    // Signing address for the s_oracles[a].index'th oracle. I.e., report
    // signatures from this oracle should ecrecover back to address a.
    Signer,
    // Transmission address for the s_oracles[a].index'th oracle. I.e., if a
    // report is received by OffchainAggregator.transmit in which msg.sender is
    // a, it is attributed to the s_oracles[a].index'th oracle.
    Transmitter
  }
  struct Oracle {
    uint8 index; // Index of oracle in s_signers/s_transmitters
    Role role;   // Role of the address which mapped to this struct
  }
  mapping (address /* signer OR transmitter address */ => Oracle)
    internal s_oracles;
  // s_signers contains the signing address of each oracle
  address[] internal s_signers;
  // s_transmitters contains the transmission address of each oracle,
  // i.e. the address the oracle actually sends transactions to the contract from
  address[] internal s_transmitters;
  uint256 constant private  maxUint16 = (1 << 16) - 1;
  uint256 constant internal maxUint128 = (1 << 128) - 1;
  constructor(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission,
    address _link,
    AccessControllerInterface _billingAccessController
  )
  {
    setBillingInternal(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission);
    setBillingAccessControllerInternal(_billingAccessController);
    LINK = LinkTokenInterface(_link);
    uint16[maxNumOracles] memory counts; // See s_oracleObservationsCounts docstring
    uint256[maxNumOracles] memory gas; // see s_gasReimbursementsLinkWei docstring
    for (uint8 i = 0; i < maxNumOracles; i++) {
      counts[i] = 1;
      gas[i] = 1;
    }
    s_oracleObservationsCounts = counts;
    s_gasReimbursementsLinkWei = gas;
  }
  /**
   * @notice emitted when billing parameters are set
   * @param maximumGasPrice highest gas price for which transmitter will be compensated
   * @param reasonableGasPrice transmitter will receive reward for gas prices under this value
   * @param microLinkPerEth reimbursement per ETH of gas cost, in 1e-6LINK units
   * @param linkGweiPerObservation reward to oracle for contributing an observation to a successfully transmitted report, in 1e-9LINK units
   * @param linkGweiPerTransmission reward to transmitter of a successful report, in 1e-9LINK units
   */
  event BillingSet(
    uint32 maximumGasPrice,
    uint32 reasonableGasPrice,
    uint32 microLinkPerEth,
    uint32 linkGweiPerObservation,
    uint32 linkGweiPerTransmission
  );
  function setBillingInternal(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission
  )
    internal
  {
    s_billing = Billing(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission);
    emit BillingSet(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission);
  }
  /**
   * @notice sets billing parameters
   * @param _maximumGasPrice highest gas price for which transmitter will be compensated
   * @param _reasonableGasPrice transmitter will receive reward for gas prices under this value
   * @param _microLinkPerEth reimbursement per ETH of gas cost, in 1e-6LINK units
   * @param _linkGweiPerObservation reward to oracle for contributing an observation to a successfully transmitted report, in 1e-9LINK units
   * @param _linkGweiPerTransmission reward to transmitter of a successful report, in 1e-9LINK units
   * @dev access control provided by billingAccessController
   */
  function setBilling(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission
  )
    external
  {
    AccessControllerInterface access = s_billingAccessController;
    require(msg.sender == owner || access.hasAccess(msg.sender, msg.data),
      "Only owner&billingAdmin can call");
    payOracles();
    setBillingInternal(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission);
  }
  /**
   * @notice gets billing parameters
   * @param maximumGasPrice highest gas price for which transmitter will be compensated
   * @param reasonableGasPrice transmitter will receive reward for gas prices under this value
   * @param microLinkPerEth reimbursement per ETH of gas cost, in 1e-6LINK units
   * @param linkGweiPerObservation reward to oracle for contributing an observation to a successfully transmitted report, in 1e-9LINK units
   * @param linkGweiPerTransmission reward to transmitter of a successful report, in 1e-9LINK units
   */
  function getBilling()
    external
    view
    returns (
      uint32 maximumGasPrice,
      uint32 reasonableGasPrice,
      uint32 microLinkPerEth,
      uint32 linkGweiPerObservation,
      uint32 linkGweiPerTransmission
    )
  {
    Billing memory billing = s_billing;
    return (
      billing.maximumGasPrice,
      billing.reasonableGasPrice,
      billing.microLinkPerEth,
      billing.linkGweiPerObservation,
      billing.linkGweiPerTransmission
    );
  }
  /**
   * @notice emitted when a new access-control contract is set
   * @param old the address prior to the current setting
   * @param current the address of the new access-control contract
   */
  event BillingAccessControllerSet(AccessControllerInterface old, AccessControllerInterface current);
  function setBillingAccessControllerInternal(AccessControllerInterface _billingAccessController)
    internal
  {
    AccessControllerInterface oldController = s_billingAccessController;
    if (_billingAccessController != oldController) {
      s_billingAccessController = _billingAccessController;
      emit BillingAccessControllerSet(
        oldController,
        _billingAccessController
      );
    }
  }
  /**
   * @notice sets billingAccessController
   * @param _billingAccessController new billingAccessController contract address
   * @dev only owner can call this
   */
  function setBillingAccessController(AccessControllerInterface _billingAccessController)
    external
    onlyOwner
  {
    setBillingAccessControllerInternal(_billingAccessController);
  }
  /**
   * @notice gets billingAccessController
   * @return address of billingAccessController contract
   */
  function billingAccessController()
    external
    view
    returns (AccessControllerInterface)
  {
    return s_billingAccessController;
  }
  /**
   * @notice withdraws an oracle's payment from the contract
   * @param _transmitter the transmitter address of the oracle
   * @dev must be called by oracle's payee address
   */
  function withdrawPayment(address _transmitter)
    external
  {
    require(msg.sender == s_payees[_transmitter], "Only payee can withdraw");
    payOracle(_transmitter);
  }
  /**
   * @notice query an oracle's payment amount
   * @param _transmitter the transmitter address of the oracle
   */
  function owedPayment(address _transmitter)
    public
    view
    returns (uint256)
  {
    Oracle memory oracle = s_oracles[_transmitter];
    if (oracle.role == Role.Unset) { return 0; }
    Billing memory billing = s_billing;
    uint256 linkWeiAmount =
      uint256(s_oracleObservationsCounts[oracle.index] - 1) *
      uint256(billing.linkGweiPerObservation) *
      (1 gwei);
    linkWeiAmount += s_gasReimbursementsLinkWei[oracle.index] - 1;
    return linkWeiAmount;
  }
  /**
   * @notice emitted when an oracle has been paid LINK
   * @param transmitter address from which the oracle sends reports to the transmit method
   * @param payee address to which the payment is sent
   * @param amount amount of LINK sent
   */
  event OraclePaid(address transmitter, address payee, uint256 amount);
  // payOracle pays out _transmitter's balance to the corresponding payee, and zeros it out
  function payOracle(address _transmitter)
    internal
  {
    Oracle memory oracle = s_oracles[_transmitter];
    uint256 linkWeiAmount = owedPayment(_transmitter);
    if (linkWeiAmount > 0) {
      address payee = s_payees[_transmitter];
      // Poses no re-entrancy issues, because LINK.transfer does not yield
      // control flow.
      require(LINK.transfer(payee, linkWeiAmount), "insufficient funds");
      s_oracleObservationsCounts[oracle.index] = 1; // "zero" the counts. see var's docstring
      s_gasReimbursementsLinkWei[oracle.index] = 1; // "zero" the counts. see var's docstring
      emit OraclePaid(_transmitter, payee, linkWeiAmount);
    }
  }
  // payOracles pays out all transmitters, and zeros out their balances.
  //
  // It's much more gas-efficient to do this as a single operation, to avoid
  // hitting storage too much.
  function payOracles()
    internal
  {
    Billing memory billing = s_billing;
    uint16[maxNumOracles] memory observationsCounts = s_oracleObservationsCounts;
    uint256[maxNumOracles] memory gasReimbursementsLinkWei =
      s_gasReimbursementsLinkWei;
    address[] memory transmitters = s_transmitters;
    for (uint transmitteridx = 0; transmitteridx < transmitters.length; transmitteridx++) {
      uint256 reimbursementAmountLinkWei = gasReimbursementsLinkWei[transmitteridx] - 1;
      uint256 obsCount = observationsCounts[transmitteridx] - 1;
      uint256 linkWeiAmount =
        obsCount * uint256(billing.linkGweiPerObservation) * (1 gwei) + reimbursementAmountLinkWei;
      if (linkWeiAmount > 0) {
          address payee = s_payees[transmitters[transmitteridx]];
          // Poses no re-entrancy issues, because LINK.transfer does not yield
          // control flow.
          require(LINK.transfer(payee, linkWeiAmount), "insufficient funds");
          observationsCounts[transmitteridx] = 1;       // "zero" the counts.
          gasReimbursementsLinkWei[transmitteridx] = 1; // "zero" the counts.
          emit OraclePaid(transmitters[transmitteridx], payee, linkWeiAmount);
        }
    }
    // "Zero" the accounting storage variables
    s_oracleObservationsCounts = observationsCounts;
    s_gasReimbursementsLinkWei = gasReimbursementsLinkWei;
  }
  function oracleRewards(
    bytes memory observers,
    uint16[maxNumOracles] memory observations
  )
    internal
    pure
    returns (uint16[maxNumOracles] memory)
  {
    // reward each observer-participant with the observer reward
    for (uint obsIdx = 0; obsIdx < observers.length; obsIdx++) {
      uint8 observer = uint8(observers[obsIdx]);
      observations[observer] = saturatingAddUint16(observations[observer], 1);
    }
    return observations;
  }
  // This value needs to change if maxNumOracles is increased, or the accounting
  // calculations at the bottom of reimburseAndRewardOracles change.
  //
  // To recalculate it, run the profiler as described in
  // ../../profile/README.md, and add up the gas-usage values reported for the
  // lines in reimburseAndRewardOracles following the "gasLeft = gasleft()"
  // line. E.g., you will see output like this:
  //
  //      7        uint256 gasLeft = gasleft();
  //     29        uint256 gasCostEthWei = transmitterGasCostEthWei(
  //      9          uint256(initialGas),
  //      3          gasPrice,
  //      3          callDataGasCost,
  //      3          gasLeft
  //      .
  //      .
  //      .
  //     59        uint256 gasCostLinkWei = (gasCostEthWei * billing.microLinkPerEth)/ 1e6;
  //      .
  //      .
  //      .
  //   5047        s_gasReimbursementsLinkWei[txOracle.index] =
  //    856          s_gasReimbursementsLinkWei[txOracle.index] + gasCostLinkWei +
  //     26          uint256(billing.linkGweiPerTransmission) * (1 gwei);
  //
  // If those were the only lines to be accounted for, you would add up
  // 29+9+3+3+3+59+5047+856+26=6035.
  uint256 internal constant accountingGasCost = 6035;
  // Uncomment the following declaration to compute the remaining gas cost after
  // above gasleft(). (This must exist in a base class to OffchainAggregator, so
  // it can't go in TestOffchainAggregator.)
  //
  // uint256 public gasUsedInAccounting;
  // Gas price at which the transmitter should be reimbursed, in ETH-gwei/gas
  function impliedGasPrice(
    uint256 txGasPrice,         // ETH-gwei/gas units
    uint256 reasonableGasPrice, // ETH-gwei/gas units
    uint256 maximumGasPrice     // ETH-gwei/gas units
  )
    internal
    pure
    returns (uint256)
  {
    // Reward the transmitter for choosing an efficient gas price: if they manage
    // to come in lower than considered reasonable, give them half the savings.
    //
    // The following calculations are all in units of gwei/gas, i.e. 1e-9ETH/gas
    uint256 gasPrice = txGasPrice;
    if (txGasPrice < reasonableGasPrice) {
      // Give transmitter half the savings for coming in under the reasonable gas price
      gasPrice += (reasonableGasPrice - txGasPrice) / 2;
    }
    // Don't reimburse a gas price higher than maximumGasPrice
    return min(gasPrice, maximumGasPrice);
  }
  // gas reimbursement due the transmitter, in ETH-wei
  //
  // If this function is changed, accountingGasCost needs to change, too. See
  // its docstring
  function transmitterGasCostEthWei(
    uint256 initialGas,
    uint256 gasPrice, // ETH-gwei/gas units
    uint256 callDataCost, // gas units
    uint256 gasLeft
  )
    internal
    pure
    returns (uint128 gasCostEthWei)
  {
    require(initialGas >= gasLeft, "gasLeft cannot exceed initialGas");
    uint256 gasUsed = // gas units
      initialGas - gasLeft + // observed gas usage
      callDataCost + accountingGasCost; // estimated gas usage
    // gasUsed is in gas units, gasPrice is in ETH-gwei/gas units; convert to ETH-wei
    uint256 fullGasCostEthWei = gasUsed * gasPrice * (1 gwei);
    assert(fullGasCostEthWei < maxUint128); // the entire ETH supply fits in a uint128...
    return uint128(fullGasCostEthWei);
  }
  /**
   * @notice withdraw any available funds left in the contract, up to _amount, after accounting for the funds due to participants in past reports
   * @param _recipient address to send funds to
   * @param _amount maximum amount to withdraw, denominated in LINK-wei.
   * @dev access control provided by billingAccessController
   */
  function withdrawFunds(address _recipient, uint256 _amount)
    external
  {
    require(msg.sender == owner || s_billingAccessController.hasAccess(msg.sender, msg.data),
      "Only owner&billingAdmin can call");
    uint256 linkDue = totalLINKDue();
    uint256 linkBalance = LINK.balanceOf(address(this));
    require(linkBalance >= linkDue, "insufficient balance");
    require(LINK.transfer(_recipient, min(linkBalance - linkDue, _amount)), "insufficient funds");
  }
  // Total LINK due to participants in past reports.
  function totalLINKDue()
    internal
    view
    returns (uint256 linkDue)
  {
    // Argument for overflow safety: We do all computations in
    // uint256s. The inputs to linkDue are:
    // - the <= 31 observation rewards each of which has less than
    //   64 bits (32 bits for billing.linkGweiPerObservation, 32 bits
    //   for wei/gwei conversion). Hence 69 bits are sufficient for this part.
    // - the <= 31 gas reimbursements, each of which consists of at most 166
    //   bits (see s_gasReimbursementsLinkWei docstring). Hence 171 bits are
    //   sufficient for this part
    // In total, 172 bits are enough.
    uint16[maxNumOracles] memory observationCounts = s_oracleObservationsCounts;
    for (uint i = 0; i < maxNumOracles; i++) {
      linkDue += observationCounts[i] - 1; // Stored value is one greater than actual value
    }
    Billing memory billing = s_billing;
    // Convert linkGweiPerObservation to uint256, or this overflows!
    linkDue *= uint256(billing.linkGweiPerObservation) * (1 gwei);
    address[] memory transmitters = s_transmitters;
    uint256[maxNumOracles] memory gasReimbursementsLinkWei =
      s_gasReimbursementsLinkWei;
    for (uint i = 0; i < transmitters.length; i++) {
      linkDue += uint256(gasReimbursementsLinkWei[i]-1); // Stored value is one greater than actual value
    }
  }
  /**
   * @notice allows oracles to check that sufficient LINK balance is available
   * @return availableBalance LINK available on this contract, after accounting for outstanding obligations. can become negative
   */
  function linkAvailableForPayment()
    external
    view
    returns (int256 availableBalance)
  {
    // there are at most one billion LINK, so this cast is safe
    int256 balance = int256(LINK.balanceOf(address(this)));
    // according to the argument in the definition of totalLINKDue,
    // totalLINKDue is never greater than 2**172, so this cast is safe
    int256 due = int256(totalLINKDue());
    // safe from overflow according to above sizes
    return int256(balance) - int256(due);
  }
  /**
   * @notice number of observations oracle is due to be reimbursed for
   * @param _signerOrTransmitter address used by oracle for signing or transmitting reports
   */
  function oracleObservationCount(address _signerOrTransmitter)
    external
    view
    returns (uint16)
  {
    Oracle memory oracle = s_oracles[_signerOrTransmitter];
    if (oracle.role == Role.Unset) { return 0; }
    return s_oracleObservationsCounts[oracle.index] - 1;
  }
  function reimburseAndRewardOracles(
    uint32 initialGas,
    bytes memory observers
  )
    internal
  {
    Oracle memory txOracle = s_oracles[msg.sender];
    Billing memory billing = s_billing;
    // Reward oracles for providing observations. Oracles are not rewarded
    // for providing signatures, because signing is essentially free.
    s_oracleObservationsCounts =
      oracleRewards(observers, s_oracleObservationsCounts);
    // Reimburse transmitter of the report for gas usage
    require(txOracle.role == Role.Transmitter,
      "sent by undesignated transmitter"
    );
    uint256 gasPrice = impliedGasPrice(
      tx.gasprice / (1 gwei), // convert to ETH-gwei units
      billing.reasonableGasPrice,
      billing.maximumGasPrice
    );
    // The following is only an upper bound, as it ignores the cheaper cost for
    // 0 bytes. Safe from overflow, because calldata just isn't that long.
    uint256 callDataGasCost = 16 * msg.data.length;
    // If any changes are made to subsequent calculations, accountingGasCost
    // needs to change, too.
    uint256 gasLeft = gasleft();
    uint256 gasCostEthWei = transmitterGasCostEthWei(
      uint256(initialGas),
      gasPrice,
      callDataGasCost,
      gasLeft
    );
    // microLinkPerEth is 1e-6LINK/ETH units, gasCostEthWei is 1e-18ETH units
    // (ETH-wei), product is 1e-24LINK-wei units, dividing by 1e6 gives
    // 1e-18LINK units, i.e. LINK-wei units
    // Safe from over/underflow, since all components are non-negative,
    // gasCostEthWei will always fit into uint128 and microLinkPerEth is a
    // uint32 (128+32 < 256!).
    uint256 gasCostLinkWei = (gasCostEthWei * billing.microLinkPerEth)/ 1e6;
    // Safe from overflow, because gasCostLinkWei < 2**160 and
    // billing.linkGweiPerTransmission * (1 gwei) < 2**64 and we increment
    // s_gasReimbursementsLinkWei[txOracle.index] at most 2**40 times.
    s_gasReimbursementsLinkWei[txOracle.index] =
      s_gasReimbursementsLinkWei[txOracle.index] + gasCostLinkWei +
      uint256(billing.linkGweiPerTransmission) * (1 gwei); // convert from linkGwei to linkWei
    // Uncomment next line to compute the remaining gas cost after above gasleft().
    // See OffchainAggregatorBilling.accountingGasCost docstring for more information.
    //
    // gasUsedInAccounting = gasLeft - gasleft();
  }
  /*
   * Payee management
   */
  /**
   * @notice emitted when a transfer of an oracle's payee address has been initiated
   * @param transmitter address from which the oracle sends reports to the transmit method
   * @param current the payeee address for the oracle, prior to this setting
   * @param proposed the proposed new payee address for the oracle
   */
  event PayeeshipTransferRequested(
    address indexed transmitter,
    address indexed current,
    address indexed proposed
  );
  /**
   * @notice emitted when a transfer of an oracle's payee address has been completed
   * @param transmitter address from which the oracle sends reports to the transmit method
   * @param current the payeee address for the oracle, prior to this setting
   */
  event PayeeshipTransferred(
    address indexed transmitter,
    address indexed previous,
    address indexed current
  );
  /**
   * @notice sets the payees for transmitting addresses
   * @param _transmitters addresses oracles use to transmit the reports
   * @param _payees addresses of payees corresponding to list of transmitters
   * @dev must be called by owner
   * @dev cannot be used to change payee addresses, only to initially populate them
   */
  function setPayees(
    address[] calldata _transmitters,
    address[] calldata _payees
  )
    external
    onlyOwner()
  {
    require(_transmitters.length == _payees.length, "transmitters.size != payees.size");
    for (uint i = 0; i < _transmitters.length; i++) {
      address transmitter = _transmitters[i];
      address payee = _payees[i];
      address currentPayee = s_payees[transmitter];
      bool zeroedOut = currentPayee == address(0);
      require(zeroedOut || currentPayee == payee, "payee already set");
      s_payees[transmitter] = payee;
      if (currentPayee != payee) {
        emit PayeeshipTransferred(transmitter, currentPayee, payee);
      }
    }
  }
  /**
   * @notice first step of payeeship transfer (safe transfer pattern)
   * @param _transmitter transmitter address of oracle whose payee is changing
   * @param _proposed new payee address
   * @dev can only be called by payee address
   */
  function transferPayeeship(
    address _transmitter,
    address _proposed
  )
    external
  {
      require(msg.sender == s_payees[_transmitter], "only current payee can update");
      require(msg.sender != _proposed, "cannot transfer to self");
      address previousProposed = s_proposedPayees[_transmitter];
      s_proposedPayees[_transmitter] = _proposed;
      if (previousProposed != _proposed) {
        emit PayeeshipTransferRequested(_transmitter, msg.sender, _proposed);
      }
  }
  /**
   * @notice second step of payeeship transfer (safe transfer pattern)
   * @param _transmitter transmitter address of oracle whose payee is changing
   * @dev can only be called by proposed new payee address
   */
  function acceptPayeeship(
    address _transmitter
  )
    external
  {
    require(msg.sender == s_proposedPayees[_transmitter], "only proposed payees can accept");
    address currentPayee = s_payees[_transmitter];
    s_payees[_transmitter] = msg.sender;
    s_proposedPayees[_transmitter] = address(0);
    emit PayeeshipTransferred(_transmitter, currentPayee, msg.sender);
  }
  /*
   * Helper functions
   */
  function saturatingAddUint16(uint16 _x, uint16 _y)
    internal
    pure
    returns (uint16)
  {
    return uint16(min(uint256(_x)+uint256(_y), maxUint16));
  }
  function min(uint256 a, uint256 b)
    internal
    pure
    returns (uint256)
  {
    if (a < b) { return a; }
    return b;
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.1;
import "./SimpleWriteAccessController.sol";
/**
 * @title SimpleReadAccessController
 * @notice Gives access to:
 * - any externally owned account (note that offchain actors can always read
 * any contract storage regardless of onchain access control measures, so this
 * does not weaken the access control while improving usability)
 * - accounts explicitly added to an access list
 * @dev SimpleReadAccessController is not suitable for access controlling writes
 * since it grants any externally owned account access! See
 * SimpleWriteAccessController for that.
 */
contract SimpleReadAccessController is SimpleWriteAccessController {
  /**
   * @notice Returns the access of an address
   * @param _user The address to query
   */
  function hasAccess(
    address _user,
    bytes memory _calldata
  )
    public
    view
    virtual
    override
    returns (bool)
  {
    return super.hasAccess(_user, _calldata) || _user == tx.origin;
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "./Owned.sol";
import "./AccessControllerInterface.sol";
/**
 * @title SimpleWriteAccessController
 * @notice Gives access to accounts explicitly added to an access list by the
 * controller's owner.
 * @dev does not make any special permissions for externally, see
 * SimpleReadAccessController for that.
 */
contract SimpleWriteAccessController is AccessControllerInterface, Owned {
  bool public checkEnabled;
  mapping(address => bool) internal accessList;
  event AddedAccess(address user);
  event RemovedAccess(address user);
  event CheckAccessEnabled();
  event CheckAccessDisabled();
  constructor()
  {
    checkEnabled = true;
  }
  /**
   * @notice Returns the access of an address
   * @param _user The address to query
   */
  function hasAccess(
    address _user,
    bytes memory
  )
    public
    view
    virtual
    override
    returns (bool)
  {
    return accessList[_user] || !checkEnabled;
  }
  /**
   * @notice Adds an address to the access list
   * @param _user The address to add
   */
  function addAccess(address _user) external onlyOwner() {
    addAccessInternal(_user);
  }
  function addAccessInternal(address _user) internal {
    if (!accessList[_user]) {
      accessList[_user] = true;
      emit AddedAccess(_user);
    }
  }
  /**
   * @notice Removes an address from the access list
   * @param _user The address to remove
   */
  function removeAccess(address _user)
    external
    onlyOwner()
  {
    if (accessList[_user]) {
      accessList[_user] = false;
      emit RemovedAccess(_user);
    }
  }
  /**
   * @notice makes the access check enforced
   */
  function enableAccessCheck()
    external
    onlyOwner()
  {
    if (!checkEnabled) {
      checkEnabled = true;
      emit CheckAccessEnabled();
    }
  }
  /**
   * @notice makes the access check unenforced
   */
  function disableAccessCheck()
    external
    onlyOwner()
  {
    if (checkEnabled) {
      checkEnabled = false;
      emit CheckAccessDisabled();
    }
  }
  /**
   * @dev reverts if the caller does not have access
   */
  modifier checkAccess() {
    require(hasAccess(msg.sender, msg.data), "No access");
    _;
  }
}

pragma solidity ^0.5.0;


/**
 * @title ERC20FeeProxy
 * @notice This contract performs an ERC20 token transfer, with a Fee sent to a third address and stores a reference
 */
contract ERC20FeeProxy {
  // Event to declare a transfer with a reference
  event TransferWithReferenceAndFee(
    address tokenAddress,
    address to,
    uint256 amount,
    bytes indexed paymentReference,
    uint256 feeAmount,
    address feeAddress
  );

  // Fallback function returns funds to the sender
  function() external payable {
    revert("not payable fallback");
  }

  /**
    * @notice Performs a ERC20 token transfer with a reference and a transfer to a second address for the payment of a fee
    * @param _tokenAddress Address of the ERC20 token smart contract
    * @param _to Transfer recipient
    * @param _amount Amount to transfer
    * @param _paymentReference Reference of the payment related
    * @param _feeAmount The amount of the payment fee
    * @param _feeAddress The fee recipient
    */
  function transferFromWithReferenceAndFee(
    address _tokenAddress,
    address _to,
    uint256 _amount,
    bytes calldata _paymentReference,
    uint256 _feeAmount,
    address _feeAddress
    ) external
    {
    require(safeTransferFrom(_tokenAddress, _to, _amount), "payment transferFrom() failed");
    if (_feeAmount > 0 && _feeAddress != address(0)) {
      require(safeTransferFrom(_tokenAddress, _feeAddress, _feeAmount), "fee transferFrom() failed");
    }
    emit TransferWithReferenceAndFee(
      _tokenAddress,
      _to,
      _amount,
      _paymentReference,
      _feeAmount,
      _feeAddress
    );
  }

  /**
   * @notice Call transferFrom ERC20 function and validates the return data of a ERC20 contract call.
   * @dev This is necessary because of non-standard ERC20 tokens that don't have a return value.
   * @return The return value of the ERC20 call, returning true for non-standard tokens
   */
  function safeTransferFrom(address _tokenAddress, address _to, uint256 _amount) internal returns (bool result) {
    /* solium-disable security/no-inline-assembly */
    // check if the address is a contract
    assembly {
      if iszero(extcodesize(_tokenAddress)) { revert(0, 0) }
    }
    
    // solium-disable-next-line security/no-low-level-calls
    (bool success, ) = _tokenAddress.call(abi.encodeWithSignature(
      "transferFrom(address,address,uint256)",
      msg.sender,
      _to,
      _amount
    ));

    assembly {
        switch returndatasize()
        case 0 { // not a standard erc20
            result := 1
        }
        case 32 { // standard erc20
            returndatacopy(0, 0, 32)
            result := mload(0)
        }
        default { // anything else, should revert for safety
            revert(0, 0)
        }
    }

    require(success, "transferFrom() has been reverted");

    /* solium-enable security/no-inline-assembly */
    return result;
  }
}