pragma solidity ^0.4.21;

// File: contracts/math/SafeMath.sol

/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
contract SafeMath {
    /**
    * @dev constructor
    */
    function SafeMath() public {
    }

    function safeMul(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a * b;
        assert(a == 0 || c / a == b);
        return c;
    }

    function safeDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a / b;
        return c;
    }

    function safeSub(uint256 a, uint256 b) internal pure returns (uint256) {
        assert(a >= b);
        return a - b;
    }

    function safeAdd(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        assert(c >= a);
        return c;
    }
}

// File: contracts/token/IERC20Token.sol

/**
 * @title IERC20Token - ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract IERC20Token {
    string public name;
    string public symbol;
    uint8 public decimals;
    uint256 public totalSupply;

    function balanceOf(address _owner) public constant returns (uint256 balance);
    function transfer(address _to, uint256 _value)  public returns (bool success);
    function transferFrom(address _from, address _to, uint256 _value)  public returns (bool success);
    function approve(address _spender, uint256 _value)  public returns (bool success);
    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);
}

// File: contracts/token/LockedTokens.sol

/**
 * @title LockedTokens
 * @dev Lock tokens for certain period of time
 */
contract LockedTokens is SafeMath {
    struct Tokens {
        uint256 amount;
        uint256 lockEndTime;
        bool released;
    }

    event TokensUnlocked(address _to, uint256 _value);

    IERC20Token public token;
    address public crowdsaleAddress;
    mapping(address => Tokens[]) public walletTokens;

    /**
     * @dev LockedTokens constructor
     * @param _token ERC20 compatible token contract
     * @param _crowdsaleAddress Crowdsale contract address
     */
    function LockedTokens(IERC20Token _token, address _crowdsaleAddress) public {
        token = _token;
        crowdsaleAddress = _crowdsaleAddress;
    }

    /**
     * @dev Functions locks tokens
     * @param _to Wallet address to transfer tokens after _lockEndTime
     * @param _amount Amount of tokens to lock
     * @param _lockEndTime End of lock period
     */
    function addTokens(address _to, uint256 _amount, uint256 _lockEndTime) external {
        require(msg.sender == crowdsaleAddress);
        walletTokens[_to].push(Tokens({amount: _amount, lockEndTime: _lockEndTime, released: false}));
    }

    /**
     * @dev Called by owner of locked tokens to release them
     */
    function releaseTokens() public {
        require(walletTokens[msg.sender].length > 0);

        for(uint256 i = 0; i < walletTokens[msg.sender].length; i++) {
            if(!walletTokens[msg.sender][i].released && now >= walletTokens[msg.sender][i].lockEndTime) {
                walletTokens[msg.sender][i].released = true;
                token.transfer(msg.sender, walletTokens[msg.sender][i].amount);
                TokensUnlocked(msg.sender, walletTokens[msg.sender][i].amount);
            }
        }
    }
}