pragma solidity 0.7.5;

/*
    The MIT License (MIT)
    Copyright (c) 2018 Murray Software, LLC.
    Permission is hereby granted, free of charge, to any person obtaining
    a copy of this software and associated documentation files (the
    "Software"), to deal in the Software without restriction, including
    without limitation the rights to use, copy, modify, merge, publish,
    distribute, sublicense, and/or sell copies of the Software, and to
    permit persons to whom the Software is furnished to do so, subject to
    the following conditions:
    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
//solhint-disable max-line-length
//solhint-disable no-inline-assembly

contract CloneFactory {
  function createClone(address target, bytes32 salt)
    internal
    returns (address payable result)
  {
    bytes20 targetBytes = bytes20(target);
    assembly {
      // load the next free memory slot as a place to store the clone contract data
      let clone := mload(0x40)

      // The bytecode block below is responsible for contract initialization
      // during deployment, it is worth noting the proxied contract constructor will not be called during
      // the cloning procedure and that is why an initialization function needs to be called after the
      // clone is created
      mstore(
        clone,
        0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000
      )

      // This stores the address location of the implementation contract
      // so that the proxy knows where to delegate call logic to
      mstore(add(clone, 0x14), targetBytes)

      // The bytecode block is the actual code that is deployed for each clone created.
      // It forwards all calls to the already deployed implementation via a delegatecall
      mstore(
        add(clone, 0x28),
        0x5af43d82803e903d91602b57fd5bf30000000000000000000000000000000000
      )

      // deploy the contract using the CREATE2 opcode
      // this deploys the minimal proxy defined above, which will proxy all
      // calls to use the logic defined in the implementation contract `target`
      result := create2(0, clone, 0x37, salt)
    }
  }

  function isClone(address target, address query)
    internal
    view
    returns (bool result)
  {
    bytes20 targetBytes = bytes20(target);
    assembly {
      // load the next free memory slot as a place to store the comparison clone
      let clone := mload(0x40)

      // The next three lines store the expected bytecode for a miniml proxy
      // that targets `target` as its implementation contract
      mstore(
        clone,
        0x363d3d373d3d3d363d7300000000000000000000000000000000000000000000
      )
      mstore(add(clone, 0xa), targetBytes)
      mstore(
        add(clone, 0x1e),
        0x5af43d82803e903d91602b57fd5bf30000000000000000000000000000000000
      )

      // the next two lines store the bytecode of the contract that we are checking in memory
      let other := add(clone, 0x40)
      extcodecopy(query, other, 0, 0x2d)

      // Check if the expected bytecode equals the actual bytecode and return the result
      result := and(
        eq(mload(clone), mload(other)),
        eq(mload(add(clone, 0xd)), mload(add(other, 0xd)))
      )
    }
  }
}


/**
 * Contract that exposes the needed erc20 token functions
 */

abstract contract ERC20Interface {
  // Send _value amount of tokens to address _to
  function transfer(address _to, uint256 _value)
    public
    virtual
    returns (bool success);

  // Get the account balance of another account with address _owner
  function balanceOf(address _owner)
    public
    virtual
    view
    returns (uint256 balance);
}

// helper methods for interacting with ERC20 tokens and sending ETH that do not consistently return true/false
library TransferHelper {
    function safeApprove(
        address token,
        address to,
        uint256 value
    ) internal {
        // bytes4(keccak256(bytes('approve(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x095ea7b3, to, value));
        require(
            success && (data.length == 0 || abi.decode(data, (bool))),
            'TransferHelper::safeApprove: approve failed'
        );
    }

    function safeTransfer(
        address token,
        address to,
        uint256 value
    ) internal {
        // bytes4(keccak256(bytes('transfer(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0xa9059cbb, to, value));
        require(
            success && (data.length == 0 || abi.decode(data, (bool))),
            'TransferHelper::safeTransfer: transfer failed'
        );
    }

    function safeTransferFrom(
        address token,
        address from,
        address to,
        uint256 value
    ) internal {
        // bytes4(keccak256(bytes('transferFrom(address,address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x23b872dd, from, to, value));
        require(
            success && (data.length == 0 || abi.decode(data, (bool))),
            'TransferHelper::transferFrom: transferFrom failed'
        );
    }

    function safeTransferETH(address to, uint256 value) internal {
        (bool success, ) = to.call{value: value}(new bytes(0));
        require(success, 'TransferHelper::safeTransferETH: ETH transfer failed');
    }
}


/**
 * Contract that will forward any incoming Ether to the creator of the contract
 *
 */
contract Forwarder {
  // Address to which any funds sent to this contract will be forwarded
  address public parentAddress;
  event ForwarderDeposited(address from, uint256 value, bytes data);

  /**
   * Initialize the contract, and sets the destination address to that of the creator
   */
  function init(address _parentAddress) external onlyUninitialized {
    parentAddress = _parentAddress;
    uint256 value = address(this).balance;

    if (value == 0) {
      return;
    }

    (bool success, ) = parentAddress.call{ value: value }('');
    require(success, 'Flush failed');
    // NOTE: since we are forwarding on initialization,
    // we don't have the context of the original sender.
    // We still emit an event about the forwarding but set
    // the sender to the forwarder itself
    emit ForwarderDeposited(address(this), value, msg.data);
  }

  /**
   * Modifier that will execute internal code block only if the sender is the parent address
   */
  modifier onlyParent {
    require(msg.sender == parentAddress, 'Only Parent');
    _;
  }

  /**
   * Modifier that will execute internal code block only if the contract has not been initialized yet
   */
  modifier onlyUninitialized {
    require(parentAddress == address(0x0), 'Already initialized');
    _;
  }

  /**
   * Default function; Gets called when data is sent but does not match any other function
   */
  fallback() external payable {
    flush();
  }

  /**
   * Default function; Gets called when Ether is deposited with no data, and forwards it to the parent address
   */
  receive() external payable {
    flush();
  }

  /**
   * Execute a token transfer of the full balance from the forwarder token to the parent address
   * @param tokenContractAddress the address of the erc20 token contract
   */
  function flushTokens(address tokenContractAddress) external onlyParent {
    ERC20Interface instance = ERC20Interface(tokenContractAddress);
    address forwarderAddress = address(this);
    uint256 forwarderBalance = instance.balanceOf(forwarderAddress);
    if (forwarderBalance == 0) {
      return;
    }

    TransferHelper.safeTransfer(
      tokenContractAddress,
      parentAddress,
      forwarderBalance
    );
  }

  /**
   * Flush the entire balance of the contract to the parent address.
   */
  function flush() public {
    uint256 value = address(this).balance;

    if (value == 0) {
      return;
    }

    (bool success, ) = parentAddress.call{ value: value }('');
    require(success, 'Flush failed');
    emit ForwarderDeposited(msg.sender, value, msg.data);
  }
}

contract ForwarderFactory is CloneFactory {
  address public implementationAddress;

  event ForwarderCreated(address newForwarderAddress, address parentAddress);

  constructor(address _implementationAddress) {
    implementationAddress = _implementationAddress;
  }

  function createForwarder(address parent, bytes32 salt) external {
    // include the signers in the salt so any contract deployed to a given address must have the same signers
    bytes32 finalSalt = keccak256(abi.encodePacked(parent, salt));

    address payable clone = createClone(implementationAddress, finalSalt);
    Forwarder(clone).init(parent);
    emit ForwarderCreated(clone, parent);
  }
}

pragma solidity 0.7.5;

/*
    The MIT License (MIT)
    Copyright (c) 2018 Murray Software, LLC.
    Permission is hereby granted, free of charge, to any person obtaining
    a copy of this software and associated documentation files (the
    "Software"), to deal in the Software without restriction, including
    without limitation the rights to use, copy, modify, merge, publish,
    distribute, sublicense, and/or sell copies of the Software, and to
    permit persons to whom the Software is furnished to do so, subject to
    the following conditions:
    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.
    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
//solhint-disable max-line-length
//solhint-disable no-inline-assembly

contract CloneFactory {
  function createClone(address target, bytes32 salt)
    internal
    returns (address payable result)
  {
    bytes20 targetBytes = bytes20(target);
    assembly {
      // load the next free memory slot as a place to store the clone contract data
      let clone := mload(0x40)

      // The bytecode block below is responsible for contract initialization
      // during deployment, it is worth noting the proxied contract constructor will not be called during
      // the cloning procedure and that is why an initialization function needs to be called after the
      // clone is created
      mstore(
        clone,
        0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000
      )

      // This stores the address location of the implementation contract
      // so that the proxy knows where to delegate call logic to
      mstore(add(clone, 0x14), targetBytes)

      // The bytecode block is the actual code that is deployed for each clone created.
      // It forwards all calls to the already deployed implementation via a delegatecall
      mstore(
        add(clone, 0x28),
        0x5af43d82803e903d91602b57fd5bf30000000000000000000000000000000000
      )

      // deploy the contract using the CREATE2 opcode
      // this deploys the minimal proxy defined above, which will proxy all
      // calls to use the logic defined in the implementation contract `target`
      result := create2(0, clone, 0x37, salt)
    }
  }

  function isClone(address target, address query)
    internal
    view
    returns (bool result)
  {
    bytes20 targetBytes = bytes20(target);
    assembly {
      // load the next free memory slot as a place to store the comparison clone
      let clone := mload(0x40)

      // The next three lines store the expected bytecode for a miniml proxy
      // that targets `target` as its implementation contract
      mstore(
        clone,
        0x363d3d373d3d3d363d7300000000000000000000000000000000000000000000
      )
      mstore(add(clone, 0xa), targetBytes)
      mstore(
        add(clone, 0x1e),
        0x5af43d82803e903d91602b57fd5bf30000000000000000000000000000000000
      )

      // the next two lines store the bytecode of the contract that we are checking in memory
      let other := add(clone, 0x40)
      extcodecopy(query, other, 0, 0x2d)

      // Check if the expected bytecode equals the actual bytecode and return the result
      result := and(
        eq(mload(clone), mload(other)),
        eq(mload(add(clone, 0xd)), mload(add(other, 0xd)))
      )
    }
  }
}


/**
 * Contract that exposes the needed erc20 token functions
 */

abstract contract ERC20Interface {
  // Send _value amount of tokens to address _to
  function transfer(address _to, uint256 _value)
    public
    virtual
    returns (bool success);

  // Get the account balance of another account with address _owner
  function balanceOf(address _owner)
    public
    virtual
    view
    returns (uint256 balance);
}

// helper methods for interacting with ERC20 tokens and sending ETH that do not consistently return true/false
library TransferHelper {
    function safeApprove(
        address token,
        address to,
        uint256 value
    ) internal {
        // bytes4(keccak256(bytes('approve(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x095ea7b3, to, value));
        require(
            success && (data.length == 0 || abi.decode(data, (bool))),
            'TransferHelper::safeApprove: approve failed'
        );
    }

    function safeTransfer(
        address token,
        address to,
        uint256 value
    ) internal {
        // bytes4(keccak256(bytes('transfer(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0xa9059cbb, to, value));
        require(
            success && (data.length == 0 || abi.decode(data, (bool))),
            'TransferHelper::safeTransfer: transfer failed'
        );
    }

    function safeTransferFrom(
        address token,
        address from,
        address to,
        uint256 value
    ) internal {
        // bytes4(keccak256(bytes('transferFrom(address,address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x23b872dd, from, to, value));
        require(
            success && (data.length == 0 || abi.decode(data, (bool))),
            'TransferHelper::transferFrom: transferFrom failed'
        );
    }

    function safeTransferETH(address to, uint256 value) internal {
        (bool success, ) = to.call{value: value}(new bytes(0));
        require(success, 'TransferHelper::safeTransferETH: ETH transfer failed');
    }
}


/**
 * Contract that will forward any incoming Ether to the creator of the contract
 *
 */
contract Forwarder {
  // Address to which any funds sent to this contract will be forwarded
  address public parentAddress;
  event ForwarderDeposited(address from, uint256 value, bytes data);

  /**
   * Initialize the contract, and sets the destination address to that of the creator
   */
  function init(address _parentAddress) external onlyUninitialized {
    parentAddress = _parentAddress;
    uint256 value = address(this).balance;

    if (value == 0) {
      return;
    }

    (bool success, ) = parentAddress.call{ value: value }('');
    require(success, 'Flush failed');
    // NOTE: since we are forwarding on initialization,
    // we don't have the context of the original sender.
    // We still emit an event about the forwarding but set
    // the sender to the forwarder itself
    emit ForwarderDeposited(address(this), value, msg.data);
  }

  /**
   * Modifier that will execute internal code block only if the sender is the parent address
   */
  modifier onlyParent {
    require(msg.sender == parentAddress, 'Only Parent');
    _;
  }

  /**
   * Modifier that will execute internal code block only if the contract has not been initialized yet
   */
  modifier onlyUninitialized {
    require(parentAddress == address(0x0), 'Already initialized');
    _;
  }

  /**
   * Default function; Gets called when data is sent but does not match any other function
   */
  fallback() external payable {
    flush();
  }

  /**
   * Default function; Gets called when Ether is deposited with no data, and forwards it to the parent address
   */
  receive() external payable {
    flush();
  }

  /**
   * Execute a token transfer of the full balance from the forwarder token to the parent address
   * @param tokenContractAddress the address of the erc20 token contract
   */
  function flushTokens(address tokenContractAddress) external onlyParent {
    ERC20Interface instance = ERC20Interface(tokenContractAddress);
    address forwarderAddress = address(this);
    uint256 forwarderBalance = instance.balanceOf(forwarderAddress);
    if (forwarderBalance == 0) {
      return;
    }

    TransferHelper.safeTransfer(
      tokenContractAddress,
      parentAddress,
      forwarderBalance
    );
  }

  /**
   * Flush the entire balance of the contract to the parent address.
   */
  function flush() public {
    uint256 value = address(this).balance;

    if (value == 0) {
      return;
    }

    (bool success, ) = parentAddress.call{ value: value }('');
    require(success, 'Flush failed');
    emit ForwarderDeposited(msg.sender, value, msg.data);
  }
}

contract ForwarderFactory is CloneFactory {
  address public implementationAddress;

  event ForwarderCreated(address newForwarderAddress, address parentAddress);

  constructor(address _implementationAddress) {
    implementationAddress = _implementationAddress;
  }

  function createForwarder(address parent, bytes32 salt) external {
    // include the signers in the salt so any contract deployed to a given address must have the same signers
    bytes32 finalSalt = keccak256(abi.encodePacked(parent, salt));

    address payable clone = createClone(implementationAddress, finalSalt);
    Forwarder(clone).init(parent);
    emit ForwarderCreated(clone, parent);
  }
}

pragma solidity ^0.4.14;

/**
 * Contract that exposes the needed erc20 token functions
 */

contract ERC20Interface {
  // Send _value amount of tokens to address _to
  function transfer(address _to, uint256 _value) returns (bool success);
  // Get the account balance of another account with address _owner
  function balanceOf(address _owner) constant returns (uint256 balance);
}

/**
 * Contract that will forward any incoming Ether to its creator
 */
contract Forwarder {
  // Address to which any funds sent to this contract will be forwarded
  address public parentAddress;
  event ForwarderDeposited(address from, uint value, bytes data);

  event TokensFlushed(
    address tokenContractAddress, // The contract address of the token
    uint value // Amount of token sent
  );

  /**
   * Create the contract, and set the destination address to that of the creator
   */
  function Forwarder() {
    parentAddress = msg.sender;
  }

  /**
   * Modifier that will execute internal code block only if the sender is a parent of the forwarder contract
   */
  modifier onlyParent {
    if (msg.sender != parentAddress) {
      throw;
    }
    _;
  }

  /**
   * Default function; Gets called when Ether is deposited, and forwards it to the destination address
   */
  function() payable {
    if (!parentAddress.call.value(msg.value)(msg.data))
      throw;
    // Fire off the deposited event if we can forward it  
    ForwarderDeposited(msg.sender, msg.value, msg.data);
  }

  /**
   * Execute a token transfer of the full balance from the forwarder token to the main wallet contract
   * @param tokenContractAddress the address of the erc20 token contract
   */
  function flushTokens(address tokenContractAddress) onlyParent {
    ERC20Interface instance = ERC20Interface(tokenContractAddress);
    var forwarderAddress = address(this);
    var forwarderBalance = instance.balanceOf(forwarderAddress);
    if (forwarderBalance == 0) {
      return;
    }
    if (!instance.transfer(parentAddress, forwarderBalance)) {
      throw;
    }
    TokensFlushed(tokenContractAddress, forwarderBalance);
  }

  /**
   * It is possible that funds were sent to this address before the contract was deployed.
   * We can flush those funds to the destination address.
   */
  function flush() {
    if (!parentAddress.call.value(this.balance)())
      throw;
  }
}

/**
 * Basic multi-signer wallet designed for use in a co-signing environment where 2 signatures are required to move funds.
 * Typically used in a 2-of-3 signing configuration. Uses ecrecover to allow for 2 signatures in a single transaction.
 */
contract WalletSimple {
  // Events
  event Deposited(address from, uint value, bytes data);
  event SafeModeActivated(address msgSender);
  event Transacted(
    address msgSender, // Address of the sender of the message initiating the transaction
    address otherSigner, // Address of the signer (second signature) used to initiate the transaction
    bytes32 operation, // Operation hash (sha3 of toAddress, value, data, expireTime, sequenceId)
    address toAddress, // The address the transaction was sent to
    uint value, // Amount of Wei sent to the address
    bytes data // Data sent when invoking the transaction
  );
  event TokenTransacted(
    address msgSender, // Address of the sender of the message initiating the transaction
    address otherSigner, // Address of the signer (second signature) used to initiate the transaction
    bytes32 operation, // Operation hash (sha3 of toAddress, value, tokenContractAddress, expireTime, sequenceId)
    address toAddress, // The address the transaction was sent to
    uint value, // Amount of token sent
    address tokenContractAddress // The contract address of the token
  );

  // Public fields
  address[] public signers; // The addresses that can co-sign transactions on the wallet
  bool public safeMode = false; // When active, wallet may only send to signer addresses

  // Internal fields
  uint constant SEQUENCE_ID_WINDOW_SIZE = 10;
  uint[10] recentSequenceIds;

  /**
   * Modifier that will execute internal code block only if the sender is an authorized signer on this wallet
   */
  modifier onlysigner {
    if (!isSigner(msg.sender)) {
      throw;
    }
    _;
  }

  /**
   * Set up a simple multi-sig wallet by specifying the signers allowed to be used on this wallet.
   * 2 signers will be required to send a transaction from this wallet.
   * Note: The sender is NOT automatically added to the list of signers.
   * Signers CANNOT be changed once they are set
   *
   * @param allowedSigners An array of signers on the wallet
   */
  function WalletSimple(address[] allowedSigners) {
    if (allowedSigners.length != 3) {
      // Invalid number of signers
      throw;
    }
    signers = allowedSigners;
  }

  /**
   * Gets called when a transaction is received without calling a method
   */
  function() payable {
    if (msg.value > 0) {
      // Fire deposited event if we are receiving funds
      Deposited(msg.sender, msg.value, msg.data);
    }
  }

  /**
   * Create a new contract (and also address) that forwards funds to this contract
   * returns address of newly created forwarder address
   */
  function createForwarder() onlysigner returns (address) {
    return new Forwarder();
  }

  /**
   * Execute a multi-signature transaction from this wallet using 2 signers: one from msg.sender and the other from ecrecover.
   * The signature is a signed form (using eth.sign) of tightly packed toAddress, value, data, expireTime and sequenceId
   * Sequence IDs are numbers starting from 1. They are used to prevent replay attacks and may not be repeated.
   *
   * @param toAddress the destination address to send an outgoing transaction
   * @param value the amount in Wei to be sent
   * @param data the data to send to the toAddress when invoking the transaction
   * @param expireTime the number of seconds since 1970 for which this transaction is valid
   * @param sequenceId the unique sequence id obtainable from getNextSequenceId
   * @param signature the result of eth.sign on the operationHash sha3(toAddress, value, data, expireTime, sequenceId)
   */
  function sendMultiSig(address toAddress, uint value, bytes data, uint expireTime, uint sequenceId, bytes signature) onlysigner {
    // Verify the other signer
    var operationHash = sha3("ETHER", toAddress, value, data, expireTime, sequenceId);
    
    var otherSigner = verifyMultiSig(toAddress, operationHash, signature, expireTime, sequenceId);

    // Success, send the transaction
    if (!(toAddress.call.value(value)(data))) {
      // Failed executing transaction
      throw;
    }
    Transacted(msg.sender, otherSigner, operationHash, toAddress, value, data);
  }
  
  /**
   * Execute a multi-signature token transfer from this wallet using 2 signers: one from msg.sender and the other from ecrecover.
   * The signature is a signed form (using eth.sign) of tightly packed toAddress, value, tokenContractAddress, expireTime and sequenceId
   * Sequence IDs are numbers starting from 1. They are used to prevent replay attacks and may not be repeated.
   *
   * @param toAddress the destination address to send an outgoing transaction
   * @param value the amount in tokens to be sent
   * @param tokenContractAddress the address of the erc20 token contract
   * @param expireTime the number of seconds since 1970 for which this transaction is valid
   * @param sequenceId the unique sequence id obtainable from getNextSequenceId
   * @param signature the result of eth.sign on the operationHash sha3(toAddress, value, tokenContractAddress, expireTime, sequenceId)
   */
  function sendMultiSigToken(address toAddress, uint value, address tokenContractAddress, uint expireTime, uint sequenceId, bytes signature) onlysigner {
    // Verify the other signer
    var operationHash = sha3("ERC20", toAddress, value, tokenContractAddress, expireTime, sequenceId);
    
    var otherSigner = verifyMultiSig(toAddress, operationHash, signature, expireTime, sequenceId);
    
    ERC20Interface instance = ERC20Interface(tokenContractAddress);
    if (!instance.transfer(toAddress, value)) {
        throw;
    }
    TokenTransacted(msg.sender, otherSigner, operationHash, toAddress, value, tokenContractAddress);
  }

  /**
   * Execute a token flush from one of the forwarder addresses. This transfer needs only a single signature and can be done by any signer
   *
   * @param forwarderAddress the address of the forwarder address to flush the tokens from
   * @param tokenContractAddress the address of the erc20 token contract
   */
  function flushForwarderTokens(address forwarderAddress, address tokenContractAddress) onlysigner {    
    Forwarder forwarder = Forwarder(forwarderAddress);
    forwarder.flushTokens(tokenContractAddress);
  }  
  
  /**
   * Do common multisig verification for both eth sends and erc20token transfers
   *
   * @param toAddress the destination address to send an outgoing transaction
   * @param operationHash the sha3 of the toAddress, value, data/tokenContractAddress and expireTime
   * @param signature the tightly packed signature of r, s, and v as an array of 65 bytes (returned by eth.sign)
   * @param expireTime the number of seconds since 1970 for which this transaction is valid
   * @param sequenceId the unique sequence id obtainable from getNextSequenceId
   * returns address of the address to send tokens or eth to
   */
  function verifyMultiSig(address toAddress, bytes32 operationHash, bytes signature, uint expireTime, uint sequenceId) private returns (address) {

    var otherSigner = recoverAddressFromSignature(operationHash, signature);

    // Verify if we are in safe mode. In safe mode, the wallet can only send to signers
    if (safeMode && !isSigner(toAddress)) {
      // We are in safe mode and the toAddress is not a signer. Disallow!
      throw;
    }
    // Verify that the transaction has not expired
    if (expireTime < block.timestamp) {
      // Transaction expired
      throw;
    }

    // Try to insert the sequence ID. Will throw if the sequence id was invalid
    tryInsertSequenceId(sequenceId);

    if (!isSigner(otherSigner)) {
      // Other signer not on this wallet or operation does not match arguments
      throw;
    }
    if (otherSigner == msg.sender) {
      // Cannot approve own transaction
      throw;
    }

    return otherSigner;
  }

  /**
   * Irrevocably puts contract into safe mode. When in this mode, transactions may only be sent to signing addresses.
   */
  function activateSafeMode() onlysigner {
    safeMode = true;
    SafeModeActivated(msg.sender);
  }

  /**
   * Determine if an address is a signer on this wallet
   * @param signer address to check
   * returns boolean indicating whether address is signer or not
   */
  function isSigner(address signer) returns (bool) {
    // Iterate through all signers on the wallet and
    for (uint i = 0; i < signers.length; i++) {
      if (signers[i] == signer) {
        return true;
      }
    }
    return false;
  }

  /**
   * Gets the second signer's address using ecrecover
   * @param operationHash the sha3 of the toAddress, value, data/tokenContractAddress and expireTime
   * @param signature the tightly packed signature of r, s, and v as an array of 65 bytes (returned by eth.sign)
   * returns address recovered from the signature
   */
  function recoverAddressFromSignature(bytes32 operationHash, bytes signature) private returns (address) {
    if (signature.length != 65) {
      throw;
    }
    // We need to unpack the signature, which is given as an array of 65 bytes (from eth.sign)
    bytes32 r;
    bytes32 s;
    uint8 v;
    assembly {
      r := mload(add(signature, 32))
      s := mload(add(signature, 64))
      v := and(mload(add(signature, 65)), 255)
    }
    if (v < 27) {
      v += 27; // Ethereum versions are 27 or 28 as opposed to 0 or 1 which is submitted by some signing libs
    }
    return ecrecover(operationHash, v, r, s);
  }

  /**
   * Verify that the sequence id has not been used before and inserts it. Throws if the sequence ID was not accepted.
   * We collect a window of up to 10 recent sequence ids, and allow any sequence id that is not in the window and
   * greater than the minimum element in the window.
   * @param sequenceId to insert into array of stored ids
   */
  function tryInsertSequenceId(uint sequenceId) onlysigner private {
    // Keep a pointer to the lowest value element in the window
    uint lowestValueIndex = 0;
    for (uint i = 0; i < SEQUENCE_ID_WINDOW_SIZE; i++) {
      if (recentSequenceIds[i] == sequenceId) {
        // This sequence ID has been used before. Disallow!
        throw;
      }
      if (recentSequenceIds[i] < recentSequenceIds[lowestValueIndex]) {
        lowestValueIndex = i;
      }
    }
    if (sequenceId < recentSequenceIds[lowestValueIndex]) {
      // The sequence ID being used is lower than the lowest value in the window
      // so we cannot accept it as it may have been used before
      throw;
    }
    if (sequenceId > (recentSequenceIds[lowestValueIndex] + 10000)) {
      // Block sequence IDs which are much higher than the lowest value
      // This prevents people blocking the contract by using very large sequence IDs quickly
      throw;
    }
    recentSequenceIds[lowestValueIndex] = sequenceId;
  }

  /**
   * Gets the next available sequence ID for signing when using executeAndConfirm
   * returns the sequenceId one higher than the highest currently stored
   */
  function getNextSequenceId() returns (uint) {
    uint highestSequenceId = 0;
    for (uint i = 0; i < SEQUENCE_ID_WINDOW_SIZE; i++) {
      if (recentSequenceIds[i] > highestSequenceId) {
        highestSequenceId = recentSequenceIds[i];
      }
    }
    return highestSequenceId + 1;
  }
}