/**
 *Submitted for verification at Etherscan.io on 2020-05-13
*/
/*
 * source        https://github.com/lukso-network/rICO-smart-contracts
 * @name       LUKSO Token
 * @author      Micky Socaci <micky@binarzone.com>, Fabian Vogelsteller <@frozeman>
 * @license     Apachae 2.0
 */

/**
 * @dev Implementation of the `IERC777` interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using `_mint`.
 *
 * Support for ERC20 is included in this contract, as specified by the EIP: both
 * the ERC777 and ERC20 interfaces can be safely used when interacting with it.
 * Both `IERC777.Sent` and `IERC20.Transfer` events are emitted on token
 * movements.
 *
 * Additionally, the `granularity` value is hard-coded to `1`, meaning that there
 * are no special restrictions in the amount of tokens that created, moved, or
 * destroyed. This makes integration with ERC20 applications seamless.
 */

pragma solidity ^0.5.0;


interface IERC777 {
    
    function name() external view returns (string memory);

    
    function symbol() external view returns (string memory);

    
    function granularity() external view returns (uint256);

    
    function totalSupply() external view returns (uint256);

    
    function balanceOf(address owner) external view returns (uint256);

    
    function send(address recipient, uint256 amount, bytes calldata data) external;

    
    function burn(uint256 amount, bytes calldata data) external;

    
    function isOperatorFor(address operator, address tokenHolder) external view returns (bool);

    
    function authorizeOperator(address operator) external;

    
    function revokeOperator(address operator) external;

    
    function defaultOperators() external view returns (address[] memory);

    
    function operatorSend(
        address sender,
        address recipient,
        uint256 amount,
        bytes calldata data,
        bytes calldata operatorData
    ) external;

    
    function operatorBurn(
        address account,
        uint256 amount,
        bytes calldata data,
        bytes calldata operatorData
    ) external;

    event Sent(
        address indexed operator,
        address indexed from,
        address indexed to,
        uint256 amount,
        bytes data,
        bytes operatorData
    );

    event Minted(address indexed operator, address indexed to, uint256 amount, bytes data, bytes operatorData);

    event Burned(address indexed operator, address indexed from, uint256 amount, bytes data, bytes operatorData);

    event AuthorizedOperator(address indexed operator, address indexed tokenHolder);

    event RevokedOperator(address indexed operator, address indexed tokenHolder);
}

interface IERC777Recipient {
    
    function tokensReceived(
        address operator,
        address from,
        address to,
        uint256 amount,
        bytes calldata userData,
        bytes calldata operatorData
    ) external;
}

interface IERC777Sender {
    
    function tokensToSend(
        address operator,
        address from,
        address to,
        uint256 amount,
        bytes calldata userData,
        bytes calldata operatorData
    ) external;
}

interface IERC20 {
    
    function totalSupply() external view returns (uint256);

    
    function balanceOf(address account) external view returns (uint256);

    
    function transfer(address recipient, uint256 amount) external returns (bool);

    
    function allowance(address owner, address spender) external view returns (uint256);

    
    function approve(address spender, uint256 amount) external returns (bool);

    
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    
    event Transfer(address indexed from, address indexed to, uint256 value);

    
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

library SafeMath {
    
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SafeMath: subtraction overflow");
        uint256 c = a - b;

        return c;
    }

    
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        
        
        
        if (a == 0) {
            return 0;
        }

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

        return c;
    }

    
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        
        require(b > 0, "SafeMath: division by zero");
        uint256 c = a / b;
        

        return c;
    }

    
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0, "SafeMath: modulo by zero");
        return a % b;
    }
}

library Address {
    
    function isContract(address account) internal view returns (bool) {
        
        
        
        
        
        
        
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        
        assembly { codehash := extcodehash(account) }
        return (codehash != 0x0 && codehash != accountHash);
    }

    
    function toPayable(address account) internal pure returns (address payable) {
        return address(uint160(account));
    }
}

interface IERC1820Registry {
    
    function setManager(address account, address newManager) external;

    
    function getManager(address account) external view returns (address);

    
    function setInterfaceImplementer(address account, bytes32 interfaceHash, address implementer) external;

    
    function getInterfaceImplementer(address account, bytes32 interfaceHash) external view returns (address);

    
    function interfaceHash(string calldata interfaceName) external pure returns (bytes32);

    
    function updateERC165Cache(address account, bytes4 interfaceId) external;

    
    function implementsERC165Interface(address account, bytes4 interfaceId) external view returns (bool);

    
    function implementsERC165InterfaceNoCache(address account, bytes4 interfaceId) external view returns (bool);

    event InterfaceImplementerSet(address indexed account, bytes32 indexed interfaceHash, address indexed implementer);

    event ManagerChanged(address indexed account, address indexed newManager);
}

contract ERC777 is IERC777, IERC20 {
    using SafeMath for uint256;
    using Address for address;

    IERC1820Registry private _erc1820 = IERC1820Registry(0x1820a4B7618BdE71Dce8cdc73aAB6C95905faD24);

    mapping(address => uint256) private _balances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    
    

    
    bytes32 constant private TOKENS_SENDER_INTERFACE_HASH =
        0x29ddb589b1fb5fc7cf394961c1adf5f8c6454761adf795e67fe149f658abe895;

    
    bytes32 constant private TOKENS_RECIPIENT_INTERFACE_HASH =
        0xb281fc8c12954d22544db45de3159a39272895b169a852b314f9cc762e44c53b;

    
    address[] private _defaultOperatorsArray;

    
    mapping(address => bool) private _defaultOperators;

    
    mapping(address => mapping(address => bool)) private _operators;
    mapping(address => mapping(address => bool)) private _revokedDefaultOperators;

    
    mapping (address => mapping (address => uint256)) private _allowances;

    
    constructor(
        string memory name,
        string memory symbol,
        address[] memory defaultOperators
    ) public {
        _name = name;
        _symbol = symbol;

        _defaultOperatorsArray = defaultOperators;
        for (uint256 i = 0; i < _defaultOperatorsArray.length; i++) {
            _defaultOperators[_defaultOperatorsArray[i]] = true;
        }

        
        _erc1820.setInterfaceImplementer(address(this), keccak256("ERC777Token"), address(this));
        _erc1820.setInterfaceImplementer(address(this), keccak256("ERC20Token"), address(this));
    }

    
    function name() public view returns (string memory) {
        return _name;
    }

    
    function symbol() public view returns (string memory) {
        return _symbol;
    }

    
    function decimals() public pure returns (uint8) {
        return 18;
    }

    
    function granularity() public view returns (uint256) {
        return 1;
    }

    
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    
    function balanceOf(address tokenHolder) public view returns (uint256) {
        return _balances[tokenHolder];
    }

    
    function send(address recipient, uint256 amount, bytes calldata data) external {
        _send(msg.sender, msg.sender, recipient, amount, data, "", true);
    }

    
    function transfer(address recipient, uint256 amount) external returns (bool) {
        require(recipient != address(0), "ERC777: transfer to the zero address");

        address from = msg.sender;

        _callTokensToSend(from, from, recipient, amount, "", "");

        _move(from, from, recipient, amount, "", "");

        _callTokensReceived(from, from, recipient, amount, "", "", false);

        return true;
    }

    
    function burn(uint256 amount, bytes calldata data) external {
        _burn(msg.sender, msg.sender, amount, data, "");
    }

    
    function isOperatorFor(
        address operator,
        address tokenHolder
    ) public view returns (bool) {
        return operator == tokenHolder ||
            (_defaultOperators[operator] && !_revokedDefaultOperators[tokenHolder][operator]) ||
            _operators[tokenHolder][operator];
    }

    
    function authorizeOperator(address operator) external {
        require(msg.sender != operator, "ERC777: authorizing self as operator");

        if (_defaultOperators[operator]) {
            delete _revokedDefaultOperators[msg.sender][operator];
        } else {
            _operators[msg.sender][operator] = true;
        }

        emit AuthorizedOperator(operator, msg.sender);
    }

    
    function revokeOperator(address operator) external {
        require(operator != msg.sender, "ERC777: revoking self as operator");

        if (_defaultOperators[operator]) {
            _revokedDefaultOperators[msg.sender][operator] = true;
        } else {
            delete _operators[msg.sender][operator];
        }

        emit RevokedOperator(operator, msg.sender);
    }

    
    function defaultOperators() public view returns (address[] memory) {
        return _defaultOperatorsArray;
    }

    
    function operatorSend(
        address sender,
        address recipient,
        uint256 amount,
        bytes calldata data,
        bytes calldata operatorData
    )
    external
    {
        require(isOperatorFor(msg.sender, sender), "ERC777: caller is not an operator for holder");
        _send(msg.sender, sender, recipient, amount, data, operatorData, true);
    }

    
    function operatorBurn(address account, uint256 amount, bytes calldata data, bytes calldata operatorData) external {
        require(isOperatorFor(msg.sender, account), "ERC777: caller is not an operator for holder");
        _burn(msg.sender, account, amount, data, operatorData);
    }

    
    function allowance(address holder, address spender) public view returns (uint256) {
        return _allowances[holder][spender];
    }

    
    function approve(address spender, uint256 value) external returns (bool) {
        address holder = msg.sender;
        _approve(holder, spender, value);
        return true;
    }

   
    function transferFrom(address holder, address recipient, uint256 amount) external returns (bool) {
        require(recipient != address(0), "ERC777: transfer to the zero address");
        require(holder != address(0), "ERC777: transfer from the zero address");

        address spender = msg.sender;

        _callTokensToSend(spender, holder, recipient, amount, "", "");

        _move(spender, holder, recipient, amount, "", "");
        _approve(holder, spender, _allowances[holder][spender].sub(amount));

        _callTokensReceived(spender, holder, recipient, amount, "", "", false);

        return true;
    }

    
    function _mint(
        address operator,
        address account,
        uint256 amount,
        bytes memory userData,
        bytes memory operatorData
    )
    internal
    {
        require(account != address(0), "ERC777: mint to the zero address");

        
        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);

        _callTokensReceived(operator, address(0), account, amount, userData, operatorData, true);

        emit Minted(operator, account, amount, userData, operatorData);
        emit Transfer(address(0), account, amount);
    }

    
    function _send(
        address operator,
        address from,
        address to,
        uint256 amount,
        bytes memory userData,
        bytes memory operatorData,
        bool requireReceptionAck
    )
        private
    {
        require(from != address(0), "ERC777: send from the zero address");
        require(to != address(0), "ERC777: send to the zero address");

        _callTokensToSend(operator, from, to, amount, userData, operatorData);

        _move(operator, from, to, amount, userData, operatorData);

        _callTokensReceived(operator, from, to, amount, userData, operatorData, requireReceptionAck);
    }

    
    function _burn(
        address operator,
        address from,
        uint256 amount,
        bytes memory data,
        bytes memory operatorData
    )
        internal
    {
        require(from != address(0), "ERC777: burn from the zero address");

        _callTokensToSend(operator, from, address(0), amount, data, operatorData);

        
        _totalSupply = _totalSupply.sub(amount);
        _balances[from] = _balances[from].sub(amount);

        emit Burned(operator, from, amount, data, operatorData);
        emit Transfer(from, address(0), amount);
    }

    function _move(
        address operator,
        address from,
        address to,
        uint256 amount,
        bytes memory userData,
        bytes memory operatorData
    )
        internal
    {
        _balances[from] = _balances[from].sub(amount);
        _balances[to] = _balances[to].add(amount);

        emit Sent(operator, from, to, amount, userData, operatorData);
        emit Transfer(from, to, amount);
    }

    function _approve(address holder, address spender, uint256 value) private {
        
        
        
        require(spender != address(0), "ERC777: approve to the zero address");

        _allowances[holder][spender] = value;
        emit Approval(holder, spender, value);
    }

    
    function _callTokensToSend(
        address operator,
        address from,
        address to,
        uint256 amount,
        bytes memory userData,
        bytes memory operatorData
    )
        private
    {
        address implementer = _erc1820.getInterfaceImplementer(from, TOKENS_SENDER_INTERFACE_HASH);
        if (implementer != address(0)) {
            IERC777Sender(implementer).tokensToSend(operator, from, to, amount, userData, operatorData);
        }
    }

    
    function _callTokensReceived(
        address operator,
        address from,
        address to,
        uint256 amount,
        bytes memory userData,
        bytes memory operatorData,
        bool requireReceptionAck
    )
        private
    {
        address implementer = _erc1820.getInterfaceImplementer(to, TOKENS_RECIPIENT_INTERFACE_HASH);
        if (implementer != address(0)) {
            IERC777Recipient(implementer).tokensReceived(operator, from, to, amount, userData, operatorData);
        } else if (requireReceptionAck) {
            require(!to.isContract(), "ERC777: token recipient contract has no implementer for ERC777TokensRecipient");
        }
    }
}

interface ReversibleICO {
    function getParticipantReservedTokens(address) external view returns (uint256);
}

contract ReversibleICOToken is ERC777 {

    ReversibleICO public rICO;

    bool public frozen; 
    bool public initialized; 
    
    
    address public deployingAddress;
    address public tokenGenesisAddress; 
    address public migrationAddress; 
    address public freezerAddress; 
    address public rescuerAddress; 

    
    event SetRICOaddress(address indexed rICOAddress);
    event SetMigrationAddress(address indexed migrationAddress);
    event Frozen(address indexed freezerAddress);
    event Unfrozen(address indexed freezerAddress);
    event RemovedFreezer(address indexed freezerAddress);
    event ChangedRICO(address indexed rICOAddress, address indexed rescuerAddress);


    

    constructor(
        string memory name,
        string memory symbol,
        address[] memory _defaultOperators
    )
    ERC777(name, symbol, _defaultOperators)
    public
    {
        deployingAddress = msg.sender;
    }

    
    function init(
        address _ricoAddress,
        address _freezerAddress,
        address _rescuerAddress,
        address _tokenGenesisAddress,
        uint256 _initialSupply
    )
    public
    isNotInitialized
    onlyDeployingAddress
    {
        require(_freezerAddress != address(0), "_freezerAddress cannot be 0x");
        require(_rescuerAddress != address(0), "_rescuerAddress cannot be 0x");
        require(_tokenGenesisAddress != address(0), "_tokenGenesisAddress cannot be 0x");

        tokenGenesisAddress = _tokenGenesisAddress;
        freezerAddress = _freezerAddress;
        rescuerAddress = _rescuerAddress;

        _mint(_tokenGenesisAddress, _tokenGenesisAddress, _initialSupply, "", "");

        if(_ricoAddress != address(0)) {
            rICO = ReversibleICO(_ricoAddress);
            emit SetRICOaddress(_ricoAddress);
        }

        initialized = true;
    }

    function setRICOaddress(address _ricoAddress)
    public
    onlyTokenGenesisAddress
    {
        require(address(rICO) == address(0), "rICO address already set!");
        require(_ricoAddress != address(0), "rICO address cannot be 0x.");

        rICO = ReversibleICO(_ricoAddress);
        emit SetRICOaddress(_ricoAddress);
    }

    
    function setMigrationAddress(address _migrationAddress)
    public
    onlyTokenGenesisAddress
    {
        migrationAddress = _migrationAddress;
        emit SetMigrationAddress(migrationAddress);
    }


    
    function removeFreezer()
    public
    onlyFreezerAddress
    isNotFrozen
    {
        freezerAddress = address(0);
        emit RemovedFreezer(freezerAddress);
    }

    function freeze() public onlyFreezerAddress {
        frozen = true;
        emit Frozen(freezerAddress);
    }

    function unfreeze() public onlyFreezerAddress {
        frozen = false;
        emit Unfrozen(freezerAddress);
    }

    
    function changeRICO(address _newRicoAddress)
    public
    onlyRescuerAddress
    isFrozen
    {
        rICO = ReversibleICO(_newRicoAddress);
        emit ChangedRICO(_newRicoAddress, rescuerAddress);
    }

    
    function getLockedBalance(address _owner) public view returns(uint256) {
        
        if(address(rICO) != address(0)) {
            return rICO.getParticipantReservedTokens(_owner);
        } else {
            return 0;
        }
    }

    function getUnlockedBalance(address _owner) public view returns(uint256) {
        uint256 balance = balanceOf(_owner);

        
        if(address(rICO) != address(0)) {
            uint256 locked = rICO.getParticipantReservedTokens(_owner);

            if(balance > 0 && locked > 0) {
                if(balance >= locked) {
                    return balance.sub(locked);
                } else {
                    return 0;
                }
            }
        }

        return balance;
    }


    

    
    
    function _move(
        address _operator,
        address _from,
        address _to,
        uint256 _amount,
        bytes memory _userData,
        bytes memory _operatorData
    )
    internal
    isNotFrozen
    isInitialized
    {

        
        if(
            _to == address(rICO) ||
            _to == migrationAddress
        ) {
            
            require(_amount <= balanceOf(_from), "Sending failed: Insufficient funds");

        } else {
            
            require(_amount <= getUnlockedBalance(_from), "Sending failed: Insufficient funds");
        }

        ERC777._move(_operator, _from, _to, _amount, _userData, _operatorData);
    }

    
    function _burn(
        address _operator,
        address _from,
        uint256 _amount,
        bytes memory _data,
        bytes memory _operatorData
    )
    internal
    isNotFrozen
    isInitialized
    {
        require(_amount <= getUnlockedBalance(_from), "Burning failed: Insufficient funds");
        ERC777._burn(_operator, _from, _amount, _data, _operatorData);
    }


    
    
    modifier onlyDeployingAddress() {
        require(msg.sender == deployingAddress, "Only the deployer can call this method.");
        _;
    }

    
    modifier onlyTokenGenesisAddress() {
        require(msg.sender == tokenGenesisAddress, "Only the tokenGenesisAddress can call this method.");
        _;
    }

    
    modifier onlyFreezerAddress() {
        require(msg.sender == freezerAddress, "Only the freezer address can call this method.");
        _;
    }

    
    modifier onlyRescuerAddress() {
        require(msg.sender == rescuerAddress, "Only the rescuer address can call this method.");
        _;
    }

    
    modifier isInitialized() {
        require(initialized == true, "Contract must be initialized.");
        _;
    }

    
    modifier isNotInitialized() {
        require(initialized == false, "Contract is already initialized.");
        _;
    }

    
    modifier isFrozen() {
        require(frozen == true, "Token contract not frozen.");
        _;
    }

    
    modifier isNotFrozen() {
        require(frozen == false, "Token contract is frozen!");
        _;
    }
}

// File: contracts/interfaces/IUniswapV2Pair.sol

pragma solidity >=0.5.0;

interface IUniswapV2Pair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    function factory() external view returns (address);
    function token0() external view returns (address);
    function token1() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}

// File: contracts/interfaces/IUniswapV2ERC20.sol

pragma solidity >=0.5.0;

interface IUniswapV2ERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;
}

// File: contracts/libraries/SafeMath.sol

pragma solidity =0.5.16;

// a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)

library SafeMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x, 'ds-math-add-overflow');
    }

    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x, 'ds-math-sub-underflow');
    }

    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');
    }
}

// File: contracts/UniswapV2ERC20.sol

pragma solidity =0.5.16;



contract UniswapV2ERC20 is IUniswapV2ERC20 {
    using SafeMath for uint;

    string public constant name = 'Uniswap V2';
    string public constant symbol = 'UNI-V2';
    uint8 public constant decimals = 18;
    uint  public totalSupply;
    mapping(address => uint) public balanceOf;
    mapping(address => mapping(address => uint)) public allowance;

    bytes32 public DOMAIN_SEPARATOR;
    // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
    mapping(address => uint) public nonces;

    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    constructor() public {
        uint chainId;
        assembly {
            chainId := chainid
        }
        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),
                keccak256(bytes(name)),
                keccak256(bytes('1')),
                chainId,
                address(this)
            )
        );
    }

    function _mint(address to, uint value) internal {
        totalSupply = totalSupply.add(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(address(0), to, value);
    }

    function _burn(address from, uint value) internal {
        balanceOf[from] = balanceOf[from].sub(value);
        totalSupply = totalSupply.sub(value);
        emit Transfer(from, address(0), value);
    }

    function _approve(address owner, address spender, uint value) private {
        allowance[owner][spender] = value;
        emit Approval(owner, spender, value);
    }

    function _transfer(address from, address to, uint value) private {
        balanceOf[from] = balanceOf[from].sub(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(from, to, value);
    }

    function approve(address spender, uint value) external returns (bool) {
        _approve(msg.sender, spender, value);
        return true;
    }

    function transfer(address to, uint value) external returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    function transferFrom(address from, address to, uint value) external returns (bool) {
        if (allowance[from][msg.sender] != uint(-1)) {
            allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);
        }
        _transfer(from, to, value);
        return true;
    }

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external {
        require(deadline >= block.timestamp, 'UniswapV2: EXPIRED');
        bytes32 digest = keccak256(
            abi.encodePacked(
                '\x19\x01',
                DOMAIN_SEPARATOR,
                keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))
            )
        );
        address recoveredAddress = ecrecover(digest, v, r, s);
        require(recoveredAddress != address(0) && recoveredAddress == owner, 'UniswapV2: INVALID_SIGNATURE');
        _approve(owner, spender, value);
    }
}

// File: contracts/libraries/Math.sol

pragma solidity =0.5.16;

// a library for performing various math operations

library Math {
    function min(uint x, uint y) internal pure returns (uint z) {
        z = x < y ? x : y;
    }

    // babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
    function sqrt(uint y) internal pure returns (uint z) {
        if (y > 3) {
            z = y;
            uint x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
    }
}

// File: contracts/libraries/UQ112x112.sol

pragma solidity =0.5.16;

// a library for handling binary fixed point numbers (https://en.wikipedia.org/wiki/Q_(number_format))

// range: [0, 2**112 - 1]
// resolution: 1 / 2**112

library UQ112x112 {
    uint224 constant Q112 = 2**112;

    // encode a uint112 as a UQ112x112
    function encode(uint112 y) internal pure returns (uint224 z) {
        z = uint224(y) * Q112; // never overflows
    }

    // divide a UQ112x112 by a uint112, returning a UQ112x112
    function uqdiv(uint224 x, uint112 y) internal pure returns (uint224 z) {
        z = x / uint224(y);
    }
}

// File: contracts/interfaces/IERC20.sol

pragma solidity >=0.5.0;

interface IERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);
}

// File: contracts/interfaces/IUniswapV2Factory.sol

pragma solidity >=0.5.0;

interface IUniswapV2Factory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

// File: contracts/interfaces/IUniswapV2Callee.sol

pragma solidity >=0.5.0;

interface IUniswapV2Callee {
    function uniswapV2Call(address sender, uint amount0, uint amount1, bytes calldata data) external;
}

// File: contracts/UniswapV2Pair.sol

pragma solidity =0.5.16;








contract UniswapV2Pair is IUniswapV2Pair, UniswapV2ERC20 {
    using SafeMath  for uint;
    using UQ112x112 for uint224;

    uint public constant MINIMUM_LIQUIDITY = 10**3;
    bytes4 private constant SELECTOR = bytes4(keccak256(bytes('transfer(address,uint256)')));

    address public factory;
    address public token0;
    address public token1;

    uint112 private reserve0;           // uses single storage slot, accessible via getReserves
    uint112 private reserve1;           // uses single storage slot, accessible via getReserves
    uint32  private blockTimestampLast; // uses single storage slot, accessible via getReserves

    uint public price0CumulativeLast;
    uint public price1CumulativeLast;
    uint public kLast; // reserve0 * reserve1, as of immediately after the most recent liquidity event

    uint private unlocked = 1;
    modifier lock() {
        require(unlocked == 1, 'UniswapV2: LOCKED');
        unlocked = 0;
        _;
        unlocked = 1;
    }

    function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast) {
        _reserve0 = reserve0;
        _reserve1 = reserve1;
        _blockTimestampLast = blockTimestampLast;
    }

    function _safeTransfer(address token, address to, uint value) private {
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(SELECTOR, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'UniswapV2: TRANSFER_FAILED');
    }

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

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

    // called once by the factory at time of deployment
    function initialize(address _token0, address _token1) external {
        require(msg.sender == factory, 'UniswapV2: FORBIDDEN'); // sufficient check
        token0 = _token0;
        token1 = _token1;
    }

    // update reserves and, on the first call per block, price accumulators
    function _update(uint balance0, uint balance1, uint112 _reserve0, uint112 _reserve1) private {
        require(balance0 <= uint112(-1) && balance1 <= uint112(-1), 'UniswapV2: OVERFLOW');
        uint32 blockTimestamp = uint32(block.timestamp % 2**32);
        uint32 timeElapsed = blockTimestamp - blockTimestampLast; // overflow is desired
        if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {
            // * never overflows, and + overflow is desired
            price0CumulativeLast += uint(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) * timeElapsed;
            price1CumulativeLast += uint(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) * timeElapsed;
        }
        reserve0 = uint112(balance0);
        reserve1 = uint112(balance1);
        blockTimestampLast = blockTimestamp;
        emit Sync(reserve0, reserve1);
    }

    // if fee is on, mint liquidity equivalent to 1/6th of the growth in sqrt(k)
    function _mintFee(uint112 _reserve0, uint112 _reserve1) private returns (bool feeOn) {
        address feeTo = IUniswapV2Factory(factory).feeTo();
        feeOn = feeTo != address(0);
        uint _kLast = kLast; // gas savings
        if (feeOn) {
            if (_kLast != 0) {
                uint rootK = Math.sqrt(uint(_reserve0).mul(_reserve1));
                uint rootKLast = Math.sqrt(_kLast);
                if (rootK > rootKLast) {
                    uint numerator = totalSupply.mul(rootK.sub(rootKLast));
                    uint denominator = rootK.mul(5).add(rootKLast);
                    uint liquidity = numerator / denominator;
                    if (liquidity > 0) _mint(feeTo, liquidity);
                }
            }
        } else if (_kLast != 0) {
            kLast = 0;
        }
    }

    // this low-level function should be called from a contract which performs important safety checks
    function mint(address to) external lock returns (uint liquidity) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        uint balance0 = IERC20(token0).balanceOf(address(this));
        uint balance1 = IERC20(token1).balanceOf(address(this));
        uint amount0 = balance0.sub(_reserve0);
        uint amount1 = balance1.sub(_reserve1);

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        if (_totalSupply == 0) {
            liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);
           _mint(address(0), MINIMUM_LIQUIDITY); // permanently lock the first MINIMUM_LIQUIDITY tokens
        } else {
            liquidity = Math.min(amount0.mul(_totalSupply) / _reserve0, amount1.mul(_totalSupply) / _reserve1);
        }
        require(liquidity > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_MINTED');
        _mint(to, liquidity);

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Mint(msg.sender, amount0, amount1);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function burn(address to) external lock returns (uint amount0, uint amount1) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        address _token0 = token0;                                // gas savings
        address _token1 = token1;                                // gas savings
        uint balance0 = IERC20(_token0).balanceOf(address(this));
        uint balance1 = IERC20(_token1).balanceOf(address(this));
        uint liquidity = balanceOf[address(this)];

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        amount0 = liquidity.mul(balance0) / _totalSupply; // using balances ensures pro-rata distribution
        amount1 = liquidity.mul(balance1) / _totalSupply; // using balances ensures pro-rata distribution
        require(amount0 > 0 && amount1 > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_BURNED');
        _burn(address(this), liquidity);
        _safeTransfer(_token0, to, amount0);
        _safeTransfer(_token1, to, amount1);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Burn(msg.sender, amount0, amount1, to);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external lock {
        require(amount0Out > 0 || amount1Out > 0, 'UniswapV2: INSUFFICIENT_OUTPUT_AMOUNT');
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        require(amount0Out < _reserve0 && amount1Out < _reserve1, 'UniswapV2: INSUFFICIENT_LIQUIDITY');

        uint balance0;
        uint balance1;
        { // scope for _token{0,1}, avoids stack too deep errors
        address _token0 = token0;
        address _token1 = token1;
        require(to != _token0 && to != _token1, 'UniswapV2: INVALID_TO');
        if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out); // optimistically transfer tokens
        if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out); // optimistically transfer tokens
        if (data.length > 0) IUniswapV2Callee(to).uniswapV2Call(msg.sender, amount0Out, amount1Out, data);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));
        }
        uint amount0In = balance0 > _reserve0 - amount0Out ? balance0 - (_reserve0 - amount0Out) : 0;
        uint amount1In = balance1 > _reserve1 - amount1Out ? balance1 - (_reserve1 - amount1Out) : 0;
        require(amount0In > 0 || amount1In > 0, 'UniswapV2: INSUFFICIENT_INPUT_AMOUNT');
        { // scope for reserve{0,1}Adjusted, avoids stack too deep errors
        uint balance0Adjusted = balance0.mul(1000).sub(amount0In.mul(3));
        uint balance1Adjusted = balance1.mul(1000).sub(amount1In.mul(3));
        require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(1000**2), 'UniswapV2: K');
        }

        _update(balance0, balance1, _reserve0, _reserve1);
        emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);
    }

    // force balances to match reserves
    function skim(address to) external lock {
        address _token0 = token0; // gas savings
        address _token1 = token1; // gas savings
        _safeTransfer(_token0, to, IERC20(_token0).balanceOf(address(this)).sub(reserve0));
        _safeTransfer(_token1, to, IERC20(_token1).balanceOf(address(this)).sub(reserve1));
    }

    // force reserves to match balances
    function sync() external lock {
        _update(IERC20(token0).balanceOf(address(this)), IERC20(token1).balanceOf(address(this)), reserve0, reserve1);
    }
}

// Copyright (C) 2015, 2016, 2017 Dapphub

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

pragma solidity ^0.4.18;

contract WETH9 {
    string public name     = "Wrapped Ether";
    string public symbol   = "WETH";
    uint8  public decimals = 18;

    event  Approval(address indexed src, address indexed guy, uint wad);
    event  Transfer(address indexed src, address indexed dst, uint wad);
    event  Deposit(address indexed dst, uint wad);
    event  Withdrawal(address indexed src, uint wad);

    mapping (address => uint)                       public  balanceOf;
    mapping (address => mapping (address => uint))  public  allowance;

    function() public payable {
        deposit();
    }
    function deposit() public payable {
        balanceOf[msg.sender] += msg.value;
        Deposit(msg.sender, msg.value);
    }
    function withdraw(uint wad) public {
        require(balanceOf[msg.sender] >= wad);
        balanceOf[msg.sender] -= wad;
        msg.sender.transfer(wad);
        Withdrawal(msg.sender, wad);
    }

    function totalSupply() public view returns (uint) {
        return this.balance;
    }

    function approve(address guy, uint wad) public returns (bool) {
        allowance[msg.sender][guy] = wad;
        Approval(msg.sender, guy, wad);
        return true;
    }

    function transfer(address dst, uint wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        returns (bool)
    {
        require(balanceOf[src] >= wad);

        if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {
            require(allowance[src][msg.sender] >= wad);
            allowance[src][msg.sender] -= wad;
        }

        balanceOf[src] -= wad;
        balanceOf[dst] += wad;

        Transfer(src, dst, wad);

        return true;
    }
}


/*
                    GNU GENERAL PUBLIC LICENSE
                       Version 3, 29 June 2007

 Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

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  Developers that use the GNU GPL protect your rights with two steps:
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*/

/* ERC1820 Pseudo-introspection Registry Contract
 * This standard defines a universal registry smart contract where any address (contract or regular account) can
 * register which interface it supports and which smart contract is responsible for its implementation.
 *
 * Written in 2019 by Jordi Baylina and Jacques Dafflon
 *
 * To the extent possible under law, the author(s) have dedicated all copyright and related and neighboring rights to
 * this software to the public domain worldwide. This software is distributed without any warranty.
 *
 * You should have received a copy of the CC0 Public Domain Dedication along with this software. If not, see
 * <http://creativecommons.org/publicdomain/zero/1.0/>.
 *
 *    ███████╗██████╗  ██████╗ ██╗ █████╗ ██████╗  ██████╗
 *    ██╔════╝██╔══██╗██╔════╝███║██╔══██╗╚════██╗██╔═████╗
 *    █████╗  ██████╔╝██║     ╚██║╚█████╔╝ █████╔╝██║██╔██║
 *    ██╔══╝  ██╔══██╗██║      ██║██╔══██╗██╔═══╝ ████╔╝██║
 *    ███████╗██║  ██║╚██████╗ ██║╚█████╔╝███████╗╚██████╔╝
 *    ╚══════╝╚═╝  ╚═╝ ╚═════╝ ╚═╝ ╚════╝ ╚══════╝ ╚═════╝
 *
 *    ██████╗ ███████╗ ██████╗ ██╗███████╗████████╗██████╗ ██╗   ██╗
 *    ██╔══██╗██╔════╝██╔════╝ ██║██╔════╝╚══██╔══╝██╔══██╗╚██╗ ██╔╝
 *    ██████╔╝█████╗  ██║  ███╗██║███████╗   ██║   ██████╔╝ ╚████╔╝
 *    ██╔══██╗██╔══╝  ██║   ██║██║╚════██║   ██║   ██╔══██╗  ╚██╔╝
 *    ██║  ██║███████╗╚██████╔╝██║███████║   ██║   ██║  ██║   ██║
 *    ╚═╝  ╚═╝╚══════╝ ╚═════╝ ╚═╝╚══════╝   ╚═╝   ╚═╝  ╚═╝   ╚═╝
 *
 */
pragma solidity 0.5.3;
// IV is value needed to have a vanity address starting with '0x1820'.
// IV: 53759

/// @dev The interface a contract MUST implement if it is the implementer of
/// some (other) interface for any address other than itself.
interface ERC1820ImplementerInterface {
    /// @notice Indicates whether the contract implements the interface 'interfaceHash' for the address 'addr' or not.
    /// @param interfaceHash keccak256 hash of the name of the interface
    /// @param addr Address for which the contract will implement the interface
    /// @return ERC1820_ACCEPT_MAGIC only if the contract implements 'interfaceHash' for the address 'addr'.
    function canImplementInterfaceForAddress(bytes32 interfaceHash, address addr) external view returns(bytes32);
}


/// @title ERC1820 Pseudo-introspection Registry Contract
/// @author Jordi Baylina and Jacques Dafflon
/// @notice This contract is the official implementation of the ERC1820 Registry.
/// @notice For more details, see https://eips.ethereum.org/EIPS/eip-1820
contract ERC1820Registry {
    /// @notice ERC165 Invalid ID.
    bytes4 constant internal INVALID_ID = 0xffffffff;
    /// @notice Method ID for the ERC165 supportsInterface method (= `bytes4(keccak256('supportsInterface(bytes4)'))`).
    bytes4 constant internal ERC165ID = 0x01ffc9a7;
    /// @notice Magic value which is returned if a contract implements an interface on behalf of some other address.
    bytes32 constant internal ERC1820_ACCEPT_MAGIC = keccak256(abi.encodePacked("ERC1820_ACCEPT_MAGIC"));

    /// @notice mapping from addresses and interface hashes to their implementers.
    mapping(address => mapping(bytes32 => address)) internal interfaces;
    /// @notice mapping from addresses to their manager.
    mapping(address => address) internal managers;
    /// @notice flag for each address and erc165 interface to indicate if it is cached.
    mapping(address => mapping(bytes4 => bool)) internal erc165Cached;

    /// @notice Indicates a contract is the 'implementer' of 'interfaceHash' for 'addr'.
    event InterfaceImplementerSet(address indexed addr, bytes32 indexed interfaceHash, address indexed implementer);
    /// @notice Indicates 'newManager' is the address of the new manager for 'addr'.
    event ManagerChanged(address indexed addr, address indexed newManager);

    /// @notice Query if an address implements an interface and through which contract.
    /// @param _addr Address being queried for the implementer of an interface.
    /// (If '_addr' is the zero address then 'msg.sender' is assumed.)
    /// @param _interfaceHash Keccak256 hash of the name of the interface as a string.
    /// E.g., 'web3.utils.keccak256("ERC777TokensRecipient")' for the 'ERC777TokensRecipient' interface.
    /// @return The address of the contract which implements the interface '_interfaceHash' for '_addr'
    /// or '0' if '_addr' did not register an implementer for this interface.
    function getInterfaceImplementer(address _addr, bytes32 _interfaceHash) external view returns (address) {
        address addr = _addr == address(0) ? msg.sender : _addr;
        if (isERC165Interface(_interfaceHash)) {
            bytes4 erc165InterfaceHash = bytes4(_interfaceHash);
            return implementsERC165Interface(addr, erc165InterfaceHash) ? addr : address(0);
        }
        return interfaces[addr][_interfaceHash];
    }

    /// @notice Sets the contract which implements a specific interface for an address.
    /// Only the manager defined for that address can set it.
    /// (Each address is the manager for itself until it sets a new manager.)
    /// @param _addr Address for which to set the interface.
    /// (If '_addr' is the zero address then 'msg.sender' is assumed.)
    /// @param _interfaceHash Keccak256 hash of the name of the interface as a string.
    /// E.g., 'web3.utils.keccak256("ERC777TokensRecipient")' for the 'ERC777TokensRecipient' interface.
    /// @param _implementer Contract address implementing '_interfaceHash' for '_addr'.
    function setInterfaceImplementer(address _addr, bytes32 _interfaceHash, address _implementer) external {
        address addr = _addr == address(0) ? msg.sender : _addr;
        require(getManager(addr) == msg.sender, "Not the manager");

        require(!isERC165Interface(_interfaceHash), "Must not be an ERC165 hash");
        if (_implementer != address(0) && _implementer != msg.sender) {
            require(
                ERC1820ImplementerInterface(_implementer)
                    .canImplementInterfaceForAddress(_interfaceHash, addr) == ERC1820_ACCEPT_MAGIC,
                "Does not implement the interface"
            );
        }
        interfaces[addr][_interfaceHash] = _implementer;
        emit InterfaceImplementerSet(addr, _interfaceHash, _implementer);
    }

    /// @notice Sets '_newManager' as manager for '_addr'.
    /// The new manager will be able to call 'setInterfaceImplementer' for '_addr'.
    /// @param _addr Address for which to set the new manager.
    /// @param _newManager Address of the new manager for 'addr'. (Pass '0x0' to reset the manager to '_addr'.)
    function setManager(address _addr, address _newManager) external {
        require(getManager(_addr) == msg.sender, "Not the manager");
        managers[_addr] = _newManager == _addr ? address(0) : _newManager;
        emit ManagerChanged(_addr, _newManager);
    }

    /// @notice Get the manager of an address.
    /// @param _addr Address for which to return the manager.
    /// @return Address of the manager for a given address.
    function getManager(address _addr) public view returns(address) {
        // By default the manager of an address is the same address
        if (managers[_addr] == address(0)) {
            return _addr;
        } else {
            return managers[_addr];
        }
    }

    /// @notice Compute the keccak256 hash of an interface given its name.
    /// @param _interfaceName Name of the interface.
    /// @return The keccak256 hash of an interface name.
    function interfaceHash(string calldata _interfaceName) external pure returns(bytes32) {
        return keccak256(abi.encodePacked(_interfaceName));
    }

    /* --- ERC165 Related Functions --- */
    /* --- Developed in collaboration with William Entriken. --- */

    /// @notice Updates the cache with whether the contract implements an ERC165 interface or not.
    /// @param _contract Address of the contract for which to update the cache.
    /// @param _interfaceId ERC165 interface for which to update the cache.
    function updateERC165Cache(address _contract, bytes4 _interfaceId) external {
        interfaces[_contract][_interfaceId] = implementsERC165InterfaceNoCache(
            _contract, _interfaceId) ? _contract : address(0);
        erc165Cached[_contract][_interfaceId] = true;
    }

    /// @notice Checks whether a contract implements an ERC165 interface or not.
    //  If the result is not cached a direct lookup on the contract address is performed.
    //  If the result is not cached or the cached value is out-of-date, the cache MUST be updated manually by calling
    //  'updateERC165Cache' with the contract address.
    /// @param _contract Address of the contract to check.
    /// @param _interfaceId ERC165 interface to check.
    /// @return True if '_contract' implements '_interfaceId', false otherwise.
    function implementsERC165Interface(address _contract, bytes4 _interfaceId) public view returns (bool) {
        if (!erc165Cached[_contract][_interfaceId]) {
            return implementsERC165InterfaceNoCache(_contract, _interfaceId);
        }
        return interfaces[_contract][_interfaceId] == _contract;
    }

    /// @notice Checks whether a contract implements an ERC165 interface or not without using nor updating the cache.
    /// @param _contract Address of the contract to check.
    /// @param _interfaceId ERC165 interface to check.
    /// @return True if '_contract' implements '_interfaceId', false otherwise.
    function implementsERC165InterfaceNoCache(address _contract, bytes4 _interfaceId) public view returns (bool) {
        uint256 success;
        uint256 result;

        (success, result) = noThrowCall(_contract, ERC165ID);
        if (success == 0 || result == 0) {
            return false;
        }

        (success, result) = noThrowCall(_contract, INVALID_ID);
        if (success == 0 || result != 0) {
            return false;
        }

        (success, result) = noThrowCall(_contract, _interfaceId);
        if (success == 1 && result == 1) {
            return true;
        }
        return false;
    }

    /// @notice Checks whether the hash is a ERC165 interface (ending with 28 zeroes) or not.
    /// @param _interfaceHash The hash to check.
    /// @return True if '_interfaceHash' is an ERC165 interface (ending with 28 zeroes), false otherwise.
    function isERC165Interface(bytes32 _interfaceHash) internal pure returns (bool) {
        return _interfaceHash & 0x00000000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF == 0;
    }

    /// @dev Make a call on a contract without throwing if the function does not exist.
    function noThrowCall(address _contract, bytes4 _interfaceId)
        internal view returns (uint256 success, uint256 result)
    {
        bytes4 erc165ID = ERC165ID;

        assembly {
            let x := mload(0x40)               // Find empty storage location using "free memory pointer"
            mstore(x, erc165ID)                // Place signature at beginning of empty storage
            mstore(add(x, 0x04), _interfaceId) // Place first argument directly next to signature

            success := staticcall(
                30000,                         // 30k gas
                _contract,                     // To addr
                x,                             // Inputs are stored at location x
                0x24,                          // Inputs are 36 (4 + 32) bytes long
                x,                             // Store output over input (saves space)
                0x20                           // Outputs are 32 bytes long
            )

            result := mload(x)                 // Load the result
        }
    }
}

/*
 * Submitted for verification at etherscan.io on 2020-06-10
 *
 *   ________            ____                           _ __    __        ______________
 *  /_  __/ /_  ___     / __ \___ _   _____  __________(_) /_  / /__     /  _/ ____/ __ \
 *   / / / __ \/ _ \   / /_/ / _ \ | / / _ \/ ___/ ___/ / __ \/ / _ \    / // /   / / / /
 *  / / / / / /  __/  / _, _/  __/ |/ /  __/ /  (__  ) / /_/ / /  __/  _/ // /___/ /_/ /
 * /_/ /_/ /_/\___/  /_/ |_|\___/|___/\___/_/  /____/_/_.___/_/\___/  /___/\____/\____/
 *
 *
 * source      https://github.com/lukso-network/rICO-smart-contracts
 * @name       Reversible ICO
 * @author     Fabian Vogelsteller <@frozeman>, Micky Socaci <micky@binarzone.com>, Marjorie Hernandez <marjorie@lukso.io>
 * @license    Apache 2.0
 *
 * Readme more about it here https://medium.com/lukso/rico-the-reversible-ico-5392bf64318b
 */

pragma solidity ^0.5.0;


library SafeMath {
    
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SafeMath: subtraction overflow");
        uint256 c = a - b;

        return c;
    }

    
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        
        
        
        if (a == 0) {
            return 0;
        }

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

        return c;
    }

    
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        
        require(b > 0, "SafeMath: division by zero");
        uint256 c = a / b;
        

        return c;
    }

    
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0, "SafeMath: modulo by zero");
        return a % b;
    }
}

interface IERC777 {
    
    function name() external view returns (string memory);

    
    function symbol() external view returns (string memory);

    
    function granularity() external view returns (uint256);

    
    function totalSupply() external view returns (uint256);

    
    function balanceOf(address owner) external view returns (uint256);

    
    function send(address recipient, uint256 amount, bytes calldata data) external;

    
    function burn(uint256 amount, bytes calldata data) external;

    
    function isOperatorFor(address operator, address tokenHolder) external view returns (bool);

    
    function authorizeOperator(address operator) external;

    
    function revokeOperator(address operator) external;

    
    function defaultOperators() external view returns (address[] memory);

    
    function operatorSend(
        address sender,
        address recipient,
        uint256 amount,
        bytes calldata data,
        bytes calldata operatorData
    ) external;

    
    function operatorBurn(
        address account,
        uint256 amount,
        bytes calldata data,
        bytes calldata operatorData
    ) external;

    event Sent(
        address indexed operator,
        address indexed from,
        address indexed to,
        uint256 amount,
        bytes data,
        bytes operatorData
    );

    event Minted(address indexed operator, address indexed to, uint256 amount, bytes data, bytes operatorData);

    event Burned(address indexed operator, address indexed from, uint256 amount, bytes data, bytes operatorData);

    event AuthorizedOperator(address indexed operator, address indexed tokenHolder);

    event RevokedOperator(address indexed operator, address indexed tokenHolder);
}

interface IERC777Recipient {
    
    function tokensReceived(
        address operator,
        address from,
        address to,
        uint256 amount,
        bytes calldata userData,
        bytes calldata operatorData
    ) external;
}

interface IERC1820Registry {
    
    function setManager(address account, address newManager) external;

    
    function getManager(address account) external view returns (address);

    
    function setInterfaceImplementer(address account, bytes32 interfaceHash, address implementer) external;

    
    function getInterfaceImplementer(address account, bytes32 interfaceHash) external view returns (address);

    
    function interfaceHash(string calldata interfaceName) external pure returns (bytes32);

    
    function updateERC165Cache(address account, bytes4 interfaceId) external;

    
    function implementsERC165Interface(address account, bytes4 interfaceId) external view returns (bool);

    
    function implementsERC165InterfaceNoCache(address account, bytes4 interfaceId) external view returns (bool);

    event InterfaceImplementerSet(address indexed account, bytes32 indexed interfaceHash, address indexed implementer);

    event ManagerChanged(address indexed account, address indexed newManager);
}

contract ReversibleICO is IERC777Recipient {


    
    using SafeMath for uint256;

    
    IERC1820Registry private ERC1820 = IERC1820Registry(0x1820a4B7618BdE71Dce8cdc73aAB6C95905faD24);
    bytes32 constant private TOKENS_RECIPIENT_INTERFACE_HASH = keccak256("ERC777TokensRecipient");


    
    
    bool public initialized;

    
    bool public frozen;
    uint256 public frozenPeriod;
    uint256 public freezeStart;


    
    
    address public deployingAddress;
    
    address public tokenAddress;
    
    address public projectAddress;
    
    address public whitelistingAddress;
    
    address public freezerAddress;
    
    address public rescuerAddress;


    
    
    uint256 public initialTokenSupply;
    
    uint256 public tokenSupply;
    
    uint256 public committedETH;
    
    uint256 public pendingETH;
    
    uint256 public canceledETH;
    
    uint256 public withdrawnETH;
    
    uint256 public projectWithdrawCount;
    
    uint256 public projectWithdrawnETH;

    
    uint256 public minContribution = 0.1 ether;
    uint256 public maxContribution = 4000 ether;

    mapping(uint8 => Stage) public stages;
    uint8 public stageCount;

    
    mapping(address => Participant) public participants;
    
    mapping(uint256 => address) public participantsById;
    
    uint256 public participantCount;

    
    
    uint256 public commitPhasePrice;
    
    uint256 public commitPhaseStartBlock;
    
    uint256 public commitPhaseEndBlock;
    
    uint256 public commitPhaseBlockCount;


    
    
    uint256 public buyPhaseStartBlock;
    
    uint256 public buyPhaseEndBlock;
    
    uint256 public buyPhaseBlockCount;

    
    
    uint256 internal _projectCurrentlyReservedETH;
    
    uint256 internal _projectUnlockedETH;
    
    uint256 internal _projectLastBlock;


    

    
    struct Stage {
        uint256 tokenLimit; 
        uint256 tokenPrice;
    }

    
    struct Participant {
        bool whitelisted;
        uint32 contributions;
        uint32 withdraws;
        uint256 firstContributionBlock;
        uint256 reservedTokens;
        uint256 committedETH;
        uint256 pendingETH;

        uint256 _currentReservedTokens;
        uint256 _unlockedTokens;
        uint256 _lastBlock;

        mapping(uint8 => ParticipantStageDetails) stages;
    }

    struct ParticipantStageDetails {
        uint256 pendingETH;
    }

    
    event PendingContributionAdded(address indexed participantAddress, uint256 indexed amount, uint32 indexed contributionId, uint8 stageId);
    event PendingContributionsCanceled(address indexed participantAddress, uint256 indexed amount, uint32 indexed contributionId);

    event WhitelistApproved(address indexed participantAddress, uint256 indexed pendingETH, uint32 indexed contributions);
    event WhitelistRejected(address indexed participantAddress, uint256 indexed pendingETH, uint32 indexed contributions);

    event ContributionsAccepted(address indexed participantAddress, uint256 indexed ethAmount, uint256 indexed tokenAmount, uint8 stageId);

    event ProjectWithdraw(address indexed projectAddress, uint256 indexed amount, uint32 indexed withdrawCount);
    event ParticipantWithdraw(address indexed participantAddress, uint256 indexed ethAmount, uint256 indexed tokenAmount, uint32 withdrawCount);

    event StageChanged(uint8 indexed stageId, uint256 indexed tokenLimit, uint256 indexed tokenPrice, uint256 effectiveBlockNumber);
    event WhitelistingAddressChanged(address indexed whitelistingAddress, uint8 indexed stageId, uint256 indexed effectiveBlockNumber);
    event FreezerAddressChanged(address indexed freezerAddress, uint8 indexed stageId, uint256 indexed effectiveBlockNumber);

    event SecurityFreeze(address indexed freezerAddress, uint8 indexed stageId, uint256 indexed effectiveBlockNumber);
    event SecurityUnfreeze(address indexed freezerAddress, uint8 indexed stageId, uint256 indexed effectiveBlockNumber);
    event SecurityDisableEscapeHatch(address indexed freezerAddress, uint8 indexed stageId, uint256 indexed effectiveBlockNumber);
    event SecurityEscapeHatch(address indexed rescuerAddress, address indexed to, uint8 indexed stageId, uint256 effectiveBlockNumber);


    event TransferEvent (
        uint8 indexed typeId,
        address indexed relatedAddress,
        uint256 indexed value
    );

    enum TransferTypes {
        NOT_SET, 
        WHITELIST_REJECTED, 
        CONTRIBUTION_CANCELED, 
        CONTRIBUTION_ACCEPTED_OVERFLOW, 
        PARTICIPANT_WITHDRAW, 
        PARTICIPANT_WITHDRAW_OVERFLOW, 
        PROJECT_WITHDRAWN, 
        FROZEN_ESCAPEHATCH_TOKEN, 
        FROZEN_ESCAPEHATCH_ETH 
    }


    

    
    constructor() public {
        deployingAddress = msg.sender;
        ERC1820.setInterfaceImplementer(address(this), TOKENS_RECIPIENT_INTERFACE_HASH, address(this));
    }

    
    function init(
        address _tokenAddress,
        address _whitelistingAddress,
        address _freezerAddress,
        address _rescuerAddress,
        address _projectAddress,
        uint256 _commitPhaseStartBlock,
        uint256 _buyPhaseStartBlock,
        uint256 _buyPhaseEndBlock,
        uint256 _initialPrice,
        uint8 _stageCount, 
        uint256 _stageTokenLimitIncrease,
        uint256 _stagePriceIncrease
    )
    public
    onlyDeployingAddress
    isNotInitialized
    {
        require(_tokenAddress != address(0), "_tokenAddress cannot be 0x");
        require(_whitelistingAddress != address(0), "_whitelistingAddress cannot be 0x");
        require(_freezerAddress != address(0), "_freezerAddress cannot be 0x");
        require(_rescuerAddress != address(0), "_rescuerAddress cannot be 0x");
        require(_projectAddress != address(0), "_projectAddress cannot be 0x");
        

        
        tokenAddress = _tokenAddress;
        whitelistingAddress = _whitelistingAddress;
        freezerAddress = _freezerAddress;
        rescuerAddress = _rescuerAddress;
        projectAddress = _projectAddress;

        
        commitPhaseStartBlock = _commitPhaseStartBlock;
        commitPhaseEndBlock = _buyPhaseStartBlock.sub(1);
        commitPhaseBlockCount = commitPhaseEndBlock.sub(commitPhaseStartBlock).add(1);
        commitPhasePrice = _initialPrice;

        stageCount = _stageCount;


        
        Stage storage commitPhase = stages[0];
        commitPhase.tokenLimit = _stageTokenLimitIncrease;
        commitPhase.tokenPrice = _initialPrice;


        
        uint256 previousStageTokenLimit = _stageTokenLimitIncrease;

        
        for (uint8 i = 1; i <= _stageCount; i++) {
            
            Stage storage byStage = stages[i];
            
            byStage.tokenLimit = previousStageTokenLimit.add(_stageTokenLimitIncrease);
            
            previousStageTokenLimit = byStage.tokenLimit;
            
            byStage.tokenPrice = _initialPrice.add(_stagePriceIncrease.mul(i));
        }

        
        
        buyPhaseStartBlock = _buyPhaseStartBlock;
        
        buyPhaseEndBlock = _buyPhaseEndBlock;
        
        buyPhaseBlockCount = buyPhaseEndBlock.sub(buyPhaseStartBlock).add(1);

        
        initialized = true;
    }

    

    

    
    function()
    external
    payable
    isInitialized
    isNotFrozen
    {
        Participant storage participantStats = participants[msg.sender];

        
        if (participantStats.whitelisted == true && participantStats.contributions > 0) {
            commit();

        
        } else {
            require(msg.value < minContribution, 'To contribute call commit() [0x3c7a3aff] and send ETH along.');

            
            cancelPendingContributions(msg.sender, msg.value);
        }
    }

    
    function tokensReceived(
        address,
        address _from,
        address,
        uint256 _amount,
        bytes calldata,
        bytes calldata
    )
    external
    isInitialized
    isNotFrozen
    {
        
        
        require(msg.sender == tokenAddress, "Unknown token contract sent tokens.");

        
        if (_from == projectAddress) {
            
            tokenSupply = tokenSupply.add(_amount);
            initialTokenSupply = initialTokenSupply.add(_amount);

            
        } else {
            withdraw(_from, _amount);
        }
    }

    
    function commit()
    public
    payable
    isInitialized
    isNotFrozen
    isRunning
    {
        
        require(msg.value >= minContribution, "Value sent is less than the minimum contribution.");

        
        uint8 currentStage = getCurrentStage();
        Participant storage participantStats = participants[msg.sender];
        ParticipantStageDetails storage byStage = participantStats.stages[currentStage];

        require(participantStats.committedETH.add(msg.value) <= maxContribution, "Value sent is larger than the maximum contribution.");

        
        if (participantStats.contributions == 0) {
            
            participantsById[participantCount] = msg.sender;
            
            participantCount++;
        }

        
        participantStats.contributions++;
        participantStats.pendingETH = participantStats.pendingETH.add(msg.value);
        byStage.pendingETH = byStage.pendingETH.add(msg.value);

        
        pendingETH = pendingETH.add(msg.value);

        emit PendingContributionAdded(
            msg.sender,
            msg.value,
            uint32(participantStats.contributions),
            currentStage
        );

        
        if (participantStats.whitelisted == true) {
            acceptContributions(msg.sender);
        }
    }

    
    function cancel()
    external
    payable
    isInitialized
    isNotFrozen
    {
        cancelPendingContributions(msg.sender, msg.value);
    }

    
    function whitelist(address[] calldata _addresses, bool _approve)
    external
    onlyWhitelistingAddress
    isInitialized
    isNotFrozen
    isRunning
    {
        
        require(_addresses.length > 0, "No addresses given to whitelist.");

        for (uint256 i = 0; i < _addresses.length; i++) {
            address participantAddress = _addresses[i];

            Participant storage participantStats = participants[participantAddress];

            if (_approve) {
                if (participantStats.whitelisted == false) {
                    
                    participantStats.whitelisted = true;
                    emit WhitelistApproved(participantAddress, participantStats.pendingETH, uint32(participantStats.contributions));
                }

                
                acceptContributions(participantAddress);

            } else {
                participantStats.whitelisted = false;
                emit WhitelistRejected(participantAddress, participantStats.pendingETH, uint32(participantStats.contributions));

                
                cancelPendingContributions(participantAddress, 0);
            }
        }
    }

    
    function projectTokenWithdraw(uint256 _tokenAmount)
    external
    onlyProjectAddress
    isInitialized
    {
        require(_tokenAmount <= tokenSupply, "Requested amount too high, not enough tokens available.");

        
        tokenSupply = tokenSupply.sub(_tokenAmount);
        initialTokenSupply = initialTokenSupply.sub(_tokenAmount);

        
        
        IERC777(tokenAddress).send(projectAddress, _tokenAmount, "");
    }

    
    function projectWithdraw(uint256 _ethAmount)
    external
    onlyProjectAddress
    isInitialized
    isNotFrozen
    {
        
        calcProjectAllocation();

        
        uint256 availableForWithdraw = _projectUnlockedETH.sub(projectWithdrawnETH);

        require(_ethAmount <= availableForWithdraw, "Requested amount too high, not enough ETH unlocked.");

        
        projectWithdrawCount++;
        projectWithdrawnETH = projectWithdrawnETH.add(_ethAmount);

        
        emit ProjectWithdraw(
            projectAddress,
            _ethAmount,
            uint32(projectWithdrawCount)
        );
        emit TransferEvent(
            uint8(TransferTypes.PROJECT_WITHDRAWN),
            projectAddress,
            _ethAmount
        );

        
        address(uint160(projectAddress)).transfer(_ethAmount);
    }


    function changeStage(uint8 _stageId, uint256 _tokenLimit, uint256 _tokenPrice)
    external
    onlyProjectAddress
    isInitialized
    {
        stages[_stageId].tokenLimit = _tokenLimit;
        stages[_stageId].tokenPrice = _tokenPrice;

        if(_stageId > stageCount) {
            stageCount = _stageId;
        }

        emit StageChanged(_stageId, _tokenLimit, _tokenPrice, getCurrentEffectiveBlockNumber());
    }


    function changeWhitelistingAddress(address _newAddress)
    external
    onlyProjectAddress
    isInitialized
    {
        whitelistingAddress = _newAddress;
        emit WhitelistingAddressChanged(whitelistingAddress, getCurrentStage(), getCurrentEffectiveBlockNumber());
    }


    function changeFreezerAddress(address _newAddress)
    external
    onlyProjectAddress
    isInitialized
    {
        freezerAddress = _newAddress;
        emit FreezerAddressChanged(freezerAddress, getCurrentStage(), getCurrentEffectiveBlockNumber());
    }


    

    
    function freeze()
    external
    onlyFreezerAddress
    isNotFrozen
    {
        frozen = true;
        freezeStart = getCurrentEffectiveBlockNumber();

        
        emit SecurityFreeze(freezerAddress, getCurrentStage(), freezeStart);
    }

    
    function unfreeze()
    external
    onlyFreezerAddress
    isFrozen
    {
        uint256 currentBlock = getCurrentEffectiveBlockNumber();

        frozen = false;
        frozenPeriod = frozenPeriod.add(
            currentBlock.sub(freezeStart)
        );

        
        emit SecurityUnfreeze(freezerAddress, getCurrentStage(), currentBlock);
    }

    
    function disableEscapeHatch()
    external
    onlyFreezerAddress
    isNotFrozen
    {
        freezerAddress = address(0);
        rescuerAddress = address(0);

        
        emit SecurityDisableEscapeHatch(freezerAddress, getCurrentStage(), getCurrentEffectiveBlockNumber());
    }

    
    function escapeHatch(address _to)
    external
    onlyRescuerAddress
    isFrozen
    {
        require(getCurrentEffectiveBlockNumber() == freezeStart.add(18000), 'Let it cool.. Wait at least ~3 days (18000 blk) before moving anything.');

        uint256 tokenBalance = IERC777(tokenAddress).balanceOf(address(this));
        uint256 ethBalance = address(this).balance;

        
        
        IERC777(tokenAddress).send(_to, tokenBalance, "");

        
        address(uint160(_to)).transfer(ethBalance);

        
        emit SecurityEscapeHatch(rescuerAddress, _to, getCurrentStage(), getCurrentEffectiveBlockNumber());

        emit TransferEvent(uint8(TransferTypes.FROZEN_ESCAPEHATCH_TOKEN), _to, tokenBalance);
        emit TransferEvent(uint8(TransferTypes.FROZEN_ESCAPEHATCH_ETH), _to, ethBalance);
    }


    

    
    function getUnlockedProjectETH() public view returns (uint256) {

        
        uint256 newlyUnlockedEth = calcUnlockedAmount(_projectCurrentlyReservedETH, _projectLastBlock);

        return _projectUnlockedETH
        .add(newlyUnlockedEth);
    }

    
    function getAvailableProjectETH() public view returns (uint256) {
        return getUnlockedProjectETH()
            .sub(projectWithdrawnETH);
    }

    
    function getParticipantReservedTokens(address _participantAddress) public view returns (uint256) {
        Participant storage participantStats = participants[_participantAddress];

        if(participantStats._currentReservedTokens == 0) {
            return 0;
        }

        return participantStats._currentReservedTokens.sub(
            calcUnlockedAmount(participantStats._currentReservedTokens, participantStats._lastBlock)
        );
    }

    
    function getParticipantUnlockedTokens(address _participantAddress) public view returns (uint256) {
        Participant storage participantStats = participants[_participantAddress];

        return participantStats._unlockedTokens.add(
            calcUnlockedAmount(participantStats._currentReservedTokens, participantStats._lastBlock)
        );
    }

    
    function getAvailableTokenAtCurrentStage() public view returns (uint256) {
        return stages[getCurrentStage()].tokenLimit.sub(
            initialTokenSupply.sub(tokenSupply)
        );
    }


    
    function getCurrentStage() public view returns (uint8) {
        return getStageByTokenLimit(
            initialTokenSupply.sub(tokenSupply)
        );
    }

    
    function getCurrentPrice() public view returns (uint256) {
        return getPriceAtStage(getCurrentStage());
    }


    
    function getPriceAtStage(uint8 _stageId) public view returns (uint256) {
        if (_stageId <= stageCount) {
            return stages[_stageId].tokenPrice;
        }
        return stages[stageCount].tokenPrice;
    }


    
    function getPriceForTokenLimit(uint256 _tokenLimit) public view returns (uint256) {
        return getPriceAtStage(getStageByTokenLimit(_tokenLimit));
    }

    
    function getStageByTokenLimit(uint256 _tokenLimit) public view returns (uint8) {

        
        for (uint8 stageId = 0; stageId <= stageCount; stageId++) {
            if(_tokenLimit <= stages[stageId].tokenLimit) {
                return stageId;
            }
        }
        
        return stageCount;
    }

    
    function committableEthAtStage(uint8 _stageId, uint8 _currentStage) public view returns (uint256) {
        uint256 supply;

        
        if(_stageId < _currentStage) {
            return 0;

        
        } else if(_stageId >= stageCount) {
            supply = tokenSupply;

        
        } else if(_stageId == _currentStage) {
            supply = stages[_currentStage].tokenLimit.sub(
                initialTokenSupply.sub(tokenSupply)
            );

        
        } else if(_stageId > _currentStage) {
            supply = stages[_stageId].tokenLimit.sub(stages[_stageId - 1].tokenLimit); 
        }

        return getEthAmountForTokensAtStage(
            supply
        , _stageId);
    }

    
    function getEthAmountForTokensAtStage(uint256 _tokenAmount, uint8 _stageId) public view returns (uint256) {
        return _tokenAmount
        .mul(stages[_stageId].tokenPrice)
        .div(10 ** 18);
    }

    
    function getTokenAmountForEthAtStage(uint256 _ethAmount, uint8 _stageId) public view returns (uint256) {
        return _ethAmount
        .mul(10 ** 18)
        .div(stages[_stageId].tokenPrice);
    }

    
    function getCurrentBlockNumber() public view returns (uint256) {
        return uint256(block.number);
    }

    
    function getCurrentEffectiveBlockNumber() public view returns (uint256) {
        return uint256(block.number)
        .sub(frozenPeriod); 
    }

    
    function calcUnlockedAmount(uint256 _amount, uint256 _lastBlock) public view returns (uint256) {

        uint256 currentBlock = getCurrentEffectiveBlockNumber();

        if(_amount == 0) {
            return 0;
        }

        
        if (currentBlock >= buyPhaseStartBlock && currentBlock < buyPhaseEndBlock) {

            
            uint256 lastBlock = _lastBlock;
            if(lastBlock < buyPhaseStartBlock) {
                lastBlock = buyPhaseStartBlock.sub(1); 
            }

            
            uint256 passedBlocks = currentBlock.sub(lastBlock);

            
            uint256 totalBlockCount = buyPhaseEndBlock.sub(lastBlock);

            return _amount.mul(
                passedBlocks.mul(10 ** 20)
                .div(totalBlockCount)
            ).div(10 ** 20);

            
        } else if (currentBlock >= buyPhaseEndBlock) {
            return _amount;
        }
        
        return 0;
    }

    


    
    function sanityCheckProject() internal view {
        
        require(
            committedETH == _projectCurrentlyReservedETH.add(_projectUnlockedETH),
            'Project Sanity check failed! Reserved + Unlock must equal committedETH'
        );

        
        require(
            address(this).balance == _projectUnlockedETH.add(_projectCurrentlyReservedETH).add(pendingETH).sub(projectWithdrawnETH),
            'Project sanity check failed! balance = Unlock + Reserved - Withdrawn'
        );
    }

    
    function sanityCheckParticipant(address _participantAddress) internal view {
        Participant storage participantStats = participants[_participantAddress];

        
        require(
            participantStats.reservedTokens == participantStats._currentReservedTokens.add(participantStats._unlockedTokens),
            'Participant Sanity check failed! Reser. + Unlock must equal totalReser'
        );
    }

    
    function calcProjectAllocation() internal {

        uint256 newlyUnlockedEth = calcUnlockedAmount(_projectCurrentlyReservedETH, _projectLastBlock);

        
        _projectCurrentlyReservedETH = _projectCurrentlyReservedETH.sub(newlyUnlockedEth);
        _projectUnlockedETH = _projectUnlockedETH.add(newlyUnlockedEth);
        _projectLastBlock = getCurrentEffectiveBlockNumber();

        sanityCheckProject();
    }

    
    function calcParticipantAllocation(address _participantAddress) internal {
        Participant storage participantStats = participants[_participantAddress];

        
        participantStats._unlockedTokens = getParticipantUnlockedTokens(_participantAddress);
        participantStats._currentReservedTokens = getParticipantReservedTokens(_participantAddress);

        
        participantStats._lastBlock = getCurrentEffectiveBlockNumber();

        
        calcProjectAllocation();
    }

    
    function cancelPendingContributions(address _participantAddress, uint256 _sentValue)
    internal
    isInitialized
    isNotFrozen
    {
        Participant storage participantStats = participants[_participantAddress];
        uint256 participantPendingEth = participantStats.pendingETH;

        
        if(participantPendingEth == 0) {
            
            if(_sentValue > 0) {
                address(uint160(_participantAddress)).transfer(_sentValue);
            }
            return;
        }

        
        for (uint8 stageId = 0; stageId <= stageCount; stageId++) {
            participantStats.stages[stageId].pendingETH = 0;
        }

        
        participantStats.pendingETH = 0;

        
        canceledETH = canceledETH.add(participantPendingEth);
        pendingETH = pendingETH.sub(participantPendingEth);

        
        emit PendingContributionsCanceled(_participantAddress, participantPendingEth, uint32(participantStats.contributions));
        emit TransferEvent(
            uint8(TransferTypes.CONTRIBUTION_CANCELED),
            _participantAddress,
            participantPendingEth
        );


        
        address(uint160(_participantAddress)).transfer(participantPendingEth.add(_sentValue));

        
        sanityCheckParticipant(_participantAddress);
        sanityCheckProject();
    }


    
    function acceptContributions(address _participantAddress)
    internal
    isInitialized
    isNotFrozen
    isRunning
    {
        Participant storage participantStats = participants[_participantAddress];

        
        if (participantStats.pendingETH == 0) {
            return;
        }

        uint8 currentStage = getCurrentStage();
        uint256 totalRefundedETH;
        uint256 totalNewReservedTokens;

        calcParticipantAllocation(_participantAddress);

        
        if(participantStats.committedETH == 0) {
            participantStats.firstContributionBlock = participantStats._lastBlock; 
        }

        
        for (uint8 stageId = 0; stageId <= stageCount; stageId++) {
            ParticipantStageDetails storage byStage = participantStats.stages[stageId];

            
            if (byStage.pendingETH == 0) {
                continue;
            }

            
            if(stageId < currentStage) {
                
                participantStats.stages[currentStage].pendingETH = participantStats.stages[currentStage].pendingETH.add(byStage.pendingETH);
                
                byStage.pendingETH = 0;
                continue;
            }

            

            uint256 maxCommittableEth = committableEthAtStage(stageId, currentStage);
            uint256 newlyCommittableEth = byStage.pendingETH;
            uint256 returnEth = 0;
            uint256 overflowEth = 0;

            
            
            if (newlyCommittableEth > maxCommittableEth) {
                overflowEth = newlyCommittableEth.sub(maxCommittableEth);
                newlyCommittableEth = maxCommittableEth;

                
                if (stageId == stageCount) {
                    returnEth = overflowEth;
                    totalRefundedETH = totalRefundedETH.add(returnEth);

                
                } else {
                    participantStats.stages[stageId + 1].pendingETH = participantStats.stages[stageId + 1].pendingETH.add(overflowEth);
                    byStage.pendingETH = byStage.pendingETH.sub(overflowEth);
                }
            }

            
            uint256 newTokenAmount = getTokenAmountForEthAtStage(
                newlyCommittableEth, stageId
            );

            totalNewReservedTokens = totalNewReservedTokens.add(newTokenAmount);

            
            participantStats._currentReservedTokens = participantStats._currentReservedTokens.add(newTokenAmount);
            participantStats.reservedTokens = participantStats.reservedTokens.add(newTokenAmount);
            participantStats.committedETH = participantStats.committedETH.add(newlyCommittableEth);
            participantStats.pendingETH = participantStats.pendingETH.sub(newlyCommittableEth).sub(returnEth);

            byStage.pendingETH = byStage.pendingETH.sub(newlyCommittableEth).sub(returnEth);

            
            tokenSupply = tokenSupply.sub(newTokenAmount);
            pendingETH = pendingETH.sub(newlyCommittableEth).sub(returnEth);
            committedETH = committedETH.add(newlyCommittableEth);
            _projectCurrentlyReservedETH = _projectCurrentlyReservedETH.add(newlyCommittableEth);

            
            emit ContributionsAccepted(_participantAddress, newlyCommittableEth, newTokenAmount, stageId);
        }

        
        if (totalRefundedETH > 0) {
            emit TransferEvent(uint8(TransferTypes.CONTRIBUTION_ACCEPTED_OVERFLOW), _participantAddress, totalRefundedETH);
            address(uint160(_participantAddress)).transfer(totalRefundedETH);
        }

        
        
        IERC777(tokenAddress).send(_participantAddress, totalNewReservedTokens, "");

        
        sanityCheckParticipant(_participantAddress);
        sanityCheckProject();
    }


    
    function withdraw(address _participantAddress, uint256 _returnedTokenAmount)
    internal
    isInitialized
    isNotFrozen
    isRunning
    {
        Participant storage participantStats = participants[_participantAddress];

        calcParticipantAllocation(_participantAddress);

        require(_returnedTokenAmount > 0, 'You can not withdraw without sending tokens.');
        require(participantStats._currentReservedTokens > 0 && participantStats.reservedTokens > 0, 'You can not withdraw, you have no locked tokens.');

        uint256 returnedTokenAmount = _returnedTokenAmount;
        uint256 overflowingTokenAmount;
        uint256 returnEthAmount;

        
        if (returnedTokenAmount > participantStats._currentReservedTokens) {
            overflowingTokenAmount = returnedTokenAmount.sub(participantStats._currentReservedTokens);
            returnedTokenAmount = participantStats._currentReservedTokens;
        }

        
        returnEthAmount = participantStats.committedETH.mul(
            returnedTokenAmount.sub(1).mul(10 ** 20) 
            .div(participantStats.reservedTokens)
        ).div(10 ** 20);


        
        participantStats.withdraws++;
        participantStats._currentReservedTokens = participantStats._currentReservedTokens.sub(returnedTokenAmount);
        participantStats.reservedTokens = participantStats.reservedTokens.sub(returnedTokenAmount);
        participantStats.committedETH = participantStats.committedETH.sub(returnEthAmount);

        
        tokenSupply = tokenSupply.add(returnedTokenAmount);
        withdrawnETH = withdrawnETH.add(returnEthAmount);
        committedETH = committedETH.sub(returnEthAmount);

        _projectCurrentlyReservedETH = _projectCurrentlyReservedETH.sub(returnEthAmount);


        
        if (overflowingTokenAmount > 0) {
            
            bytes memory data;

            
            emit TransferEvent(uint8(TransferTypes.PARTICIPANT_WITHDRAW_OVERFLOW), _participantAddress, overflowingTokenAmount);

            
            IERC777(tokenAddress).send(_participantAddress, overflowingTokenAmount, data);
        }

        
        emit ParticipantWithdraw(_participantAddress, returnEthAmount, returnedTokenAmount, uint32(participantStats.withdraws));
        emit TransferEvent(uint8(TransferTypes.PARTICIPANT_WITHDRAW), _participantAddress, returnEthAmount);

        
        address(uint160(_participantAddress)).transfer(returnEthAmount);

        
        sanityCheckParticipant(_participantAddress);
        sanityCheckProject();
    }

    

    
    modifier onlyProjectAddress() {
        require(msg.sender == projectAddress, "Only the project can call this method.");
        _;
    }

    
    modifier onlyDeployingAddress() {
        require(msg.sender == deployingAddress, "Only the deployer can call this method.");
        _;
    }

    
    modifier onlyWhitelistingAddress() {
        require(msg.sender == whitelistingAddress, "Only the whitelist controller can call this method.");
        _;
    }

    
    modifier onlyFreezerAddress() {
        require(msg.sender == freezerAddress, "Only the freezer address can call this method.");
        _;
    }

    
    modifier onlyRescuerAddress() {
        require(msg.sender == rescuerAddress, "Only the rescuer address can call this method.");
        _;
    }

    
    modifier isInitialized() {
        require(initialized == true, "Contract must be initialized.");
        _;
    }

    
    modifier isNotInitialized() {
        require(initialized == false, "Contract can not be initialized.");
        _;
    }

    
    modifier isFrozen() {
        require(frozen == true, "rICO has to be frozen!");
        _;
    }

    
    modifier isNotFrozen() {
        require(frozen == false, "rICO is frozen!");
        _;
    }

    
    modifier isRunning() {
        uint256 blockNumber = getCurrentEffectiveBlockNumber();
        require(blockNumber >= commitPhaseStartBlock && blockNumber <= buyPhaseEndBlock, "Current block is outside the rICO period.");
        _;
    }
}