pragma solidity 0.4.20;

// No deps verison.

/**
 * @title ERC20
 * @dev A standard interface for tokens.
 * @dev https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20-token-standard.md
 */
contract ERC20 {
  
    /// @dev Returns the total token supply
    function totalSupply() public constant returns (uint256 supply);

    /// @dev Returns the account balance of the account with address _owner
    function balanceOf(address _owner) public constant returns (uint256 balance);

    /// @dev Transfers _value number of tokens to address _to
    function transfer(address _to, uint256 _value) public returns (bool success);

    /// @dev Transfers _value number of tokens from address _from to address _to
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);

    /// @dev Allows _spender to withdraw from the msg.sender's account up to the _value amount
    function approve(address _spender, uint256 _value) public returns (bool success);

    /// @dev Returns the amount which _spender is still allowed to withdraw from _owner
    function allowance(address _owner, address _spender) public constant returns (uint256 remaining);

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);

}

/// @title Owned
/// @author Adrià Massanet <adria@codecontext.io>
/// @notice The Owned contract has an owner address, and provides basic 
///  authorization control functions, this simplifies & the implementation of
///  user permissions; this contract has three work flows for a change in
///  ownership, the first requires the new owner to validate that they have the
///  ability to accept ownership, the second allows the ownership to be
///  directly transfered without requiring acceptance, and the third allows for
///  the ownership to be removed to allow for decentralization 
contract Owned {

    address public owner;
    address public newOwnerCandidate;

    event OwnershipRequested(address indexed by, address indexed to);
    event OwnershipTransferred(address indexed from, address indexed to);
    event OwnershipRemoved();

    /// @dev The constructor sets the `msg.sender` as the`owner` of the contract
    function Owned() public {
        owner = msg.sender;
    }

    /// @dev `owner` is the only address that can call a function with this
    /// modifier
    modifier onlyOwner() {
        require (msg.sender == owner);
        _;
    }
    
    /// @dev In this 1st option for ownership transfer `proposeOwnership()` must
    ///  be called first by the current `owner` then `acceptOwnership()` must be
    ///  called by the `newOwnerCandidate`
    /// @notice `onlyOwner` Proposes to transfer control of the contract to a
    ///  new owner
    /// @param _newOwnerCandidate The address being proposed as the new owner
    function proposeOwnership(address _newOwnerCandidate) public onlyOwner {
        newOwnerCandidate = _newOwnerCandidate;
        OwnershipRequested(msg.sender, newOwnerCandidate);
    }

    /// @notice Can only be called by the `newOwnerCandidate`, accepts the
    ///  transfer of ownership
    function acceptOwnership() public {
        require(msg.sender == newOwnerCandidate);

        address oldOwner = owner;
        owner = newOwnerCandidate;
        newOwnerCandidate = 0x0;

        OwnershipTransferred(oldOwner, owner);
    }

    /// @dev In this 2nd option for ownership transfer `changeOwnership()` can
    ///  be called and it will immediately assign ownership to the `newOwner`
    /// @notice `owner` can step down and assign some other address to this role
    /// @param _newOwner The address of the new owner
    function changeOwnership(address _newOwner) public onlyOwner {
        require(_newOwner != 0x0);

        address oldOwner = owner;
        owner = _newOwner;
        newOwnerCandidate = 0x0;

        OwnershipTransferred(oldOwner, owner);
    }

    /// @dev In this 3rd option for ownership transfer `removeOwnership()` can
    ///  be called and it will immediately assign ownership to the 0x0 address;
    ///  it requires a 0xdece be input as a parameter to prevent accidental use
    /// @notice Decentralizes the contract, this operation cannot be undone 
    /// @param _dac `0xdac` has to be entered for this function to work
    function removeOwnership(address _dac) public onlyOwner {
        require(_dac == 0xdac);
        owner = 0x0;
        newOwnerCandidate = 0x0;
        OwnershipRemoved();     
    }
} 

/// @dev `Escapable` is a base level contract built off of the `Owned`
///  contract; it creates an escape hatch function that can be called in an
///  emergency that will allow designated addresses to send any ether or tokens
///  held in the contract to an `escapeHatchDestination` as long as they were
///  not blacklisted
contract Escapable is Owned {
    address public escapeHatchCaller;
    address public escapeHatchDestination;
    mapping (address=>bool) private escapeBlacklist; // Token contract addresses

    /// @notice The Constructor assigns the `escapeHatchDestination` and the
    ///  `escapeHatchCaller`
    /// @param _escapeHatchCaller The address of a trusted account or contract
    ///  to call `escapeHatch()` to send the ether in this contract to the
    ///  `escapeHatchDestination` it would be ideal that `escapeHatchCaller`
    ///  cannot move funds out of `escapeHatchDestination`
    /// @param _escapeHatchDestination The address of a safe location (usu a
    ///  Multisig) to send the ether held in this contract; if a neutral address
    ///  is required, the WHG Multisig is an option:
    ///  0x8Ff920020c8AD673661c8117f2855C384758C572 
    function Escapable(address _escapeHatchCaller, address _escapeHatchDestination) public {
        escapeHatchCaller = _escapeHatchCaller;
        escapeHatchDestination = _escapeHatchDestination;
    }

    /// @dev The addresses preassigned as `escapeHatchCaller` or `owner`
    ///  are the only addresses that can call a function with this modifier
    modifier onlyEscapeHatchCallerOrOwner {
        require ((msg.sender == escapeHatchCaller)||(msg.sender == owner));
        _;
    }

    /// @notice Creates the blacklist of tokens that are not able to be taken
    ///  out of the contract; can only be done at the deployment, and the logic
    ///  to add to the blacklist will be in the constructor of a child contract
    /// @param _token the token contract address that is to be blacklisted 
    function blacklistEscapeToken(address _token) internal {
        escapeBlacklist[_token] = true;
        EscapeHatchBlackistedToken(_token);
    }

    /// @notice Checks to see if `_token` is in the blacklist of tokens
    /// @param _token the token address being queried
    /// @return False if `_token` is in the blacklist and can't be taken out of
    ///  the contract via the `escapeHatch()`
    function isTokenEscapable(address _token) view public returns (bool) {
        return !escapeBlacklist[_token];
    }

    /// @notice The `escapeHatch()` should only be called as a last resort if a
    /// security issue is uncovered or something unexpected happened
    /// @param _token to transfer, use 0x0 for ether
    function escapeHatch(address _token) public onlyEscapeHatchCallerOrOwner {   
        require(escapeBlacklist[_token]==false);

        uint256 balance;

        /// @dev Logic for ether
        if (_token == 0x0) {
            balance = this.balance;
            escapeHatchDestination.transfer(balance);
            EscapeHatchCalled(_token, balance);
            return;
        }
        /// @dev Logic for tokens
        ERC20 token = ERC20(_token);
        balance = token.balanceOf(this);
        require(token.transfer(escapeHatchDestination, balance));
        EscapeHatchCalled(_token, balance);
    }

    /// @notice Changes the address assigned to call `escapeHatch()`
    /// @param _newEscapeHatchCaller The address of a trusted account or
    ///  contract to call `escapeHatch()` to send the value in this contract to
    ///  the `escapeHatchDestination`; it would be ideal that `escapeHatchCaller`
    ///  cannot move funds out of `escapeHatchDestination`
    function changeHatchEscapeCaller(address _newEscapeHatchCaller) public onlyEscapeHatchCallerOrOwner {
        escapeHatchCaller = _newEscapeHatchCaller;
    }

    event EscapeHatchBlackistedToken(address token);
    event EscapeHatchCalled(address token, uint amount);
}

// TightlyPacked is cheaper if you need to store input data and if amount is less than 12 bytes.
// Normal is cheaper if you don't need to store input data or if amounts are greater than 12 bytes.
contract UnsafeMultiplexor is Escapable(0, 0) {
    function init(address _escapeHatchCaller, address _escapeHatchDestination) public {
        require(escapeHatchCaller == 0);
        require(_escapeHatchCaller != 0);
        require(_escapeHatchDestination != 0);
        escapeHatchCaller = _escapeHatchCaller;
        escapeHatchDestination = _escapeHatchDestination;
    }
    
    modifier sendBackLeftEther() {
        uint balanceBefore = this.balance - msg.value;
        _;
        uint leftovers = this.balance - balanceBefore;
        if (leftovers > 0) {
            msg.sender.transfer(leftovers);
        }
    }
    
    function multiTransferTightlyPacked(bytes32[] _addressAndAmount) sendBackLeftEther() payable public returns(bool) {
        for (uint i = 0; i < _addressAndAmount.length; i++) {
            _unsafeTransfer(address(_addressAndAmount[i] >> 96), uint(uint96(_addressAndAmount[i])));
        }
        return true;
    }

    function multiTransfer(address[] _address, uint[] _amount) sendBackLeftEther() payable public returns(bool) {
        for (uint i = 0; i < _address.length; i++) {
            _unsafeTransfer(_address[i], _amount[i]);
        }
        return true;
    }

    function multiCallTightlyPacked(bytes32[] _addressAndAmount) sendBackLeftEther() payable public returns(bool) {
        for (uint i = 0; i < _addressAndAmount.length; i++) {
            _unsafeCall(address(_addressAndAmount[i] >> 96), uint(uint96(_addressAndAmount[i])));
        }
        return true;
    }

    function multiCall(address[] _address, uint[] _amount) sendBackLeftEther() payable public returns(bool) {
        for (uint i = 0; i < _address.length; i++) {
            _unsafeCall(_address[i], _amount[i]);
        }
        return true;
    }

    function _unsafeTransfer(address _to, uint _amount) internal {
        require(_to != 0);
        _to.send(_amount);
    }

    function _unsafeCall(address _to, uint _amount) internal {
        require(_to != 0);
        _to.call.value(_amount)();
    }
}