pragma solidity 0.4.21;

contract owned {
    address public owner;

    function owned() public {
        owner = msg.sender;
    }

    modifier onlyOwner {
        require(msg.sender == owner);
        _;
    }

    function transferOwnership(address newOwner) onlyOwner public {
        owner = newOwner;
    }
}

contract TokenERC20 is owned {
    address public deployer;

    string public name ="Universe-TWD";
    string public symbol = "UTWD";
    uint8 public decimals = 18;

    uint256 public totalSupply;


    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;

    event Approval(address indexed owner, address indexed spender, uint value);

    event Transfer(address indexed from, address indexed to, uint256 value);

    event Burn(address indexed from, uint256 value);

    function TokenERC20() public {
        deployer = msg.sender;
    }

    function _transfer(address _from, address _to, uint _value) internal {
        require(_to != 0x0);
        require(balanceOf[_from] >= _value);
        require(balanceOf[_to] + _value >= balanceOf[_to]);
        uint previousBalances = balanceOf[_from] + balanceOf[_to];
        balanceOf[_from] -= _value;
        balanceOf[_to] += _value;
        emit Transfer(_from, _to, _value);
        assert(balanceOf[_from] + balanceOf[_to] == previousBalances);
    }

    function transfer(address _to, uint256 _value) public {
        _transfer(msg.sender, _to, _value);
    }
	
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
        require(allowance[_from][msg.sender] >= _value);
        allowance[_from][msg.sender] -= _value;
        _transfer(_from, _to, _value);
        return true;
    }

    function approve(address _spender, uint256 _value) public returns (bool success) {
        allowance[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

    function burn(uint256 _value) onlyOwner public returns (bool success) {
        require(balanceOf[msg.sender] >= _value);
        balanceOf[msg.sender] -= _value;
        totalSupply -= _value;
        emit Burn(msg.sender, _value);
        return true;
    }

}

contract MyAdvancedToken is TokenERC20 {
    mapping (address => bool) public frozenAccount;

    event FrozenFunds(address target, bool frozen);

    function MyAdvancedToken() TokenERC20() public {}

     function _transfer(address _from, address _to, uint _value) internal {
        require(_to != 0x0);
        require(balanceOf[_from] >= _value);
        require(balanceOf[_to] + _value > balanceOf[_to]);
        require(!frozenAccount[_from]);
        require(!frozenAccount[_to]);
        balanceOf[_from] -= _value;
        balanceOf[_to] += _value;
        Transfer(_from, _to, _value);
    }

    function mintToken(address target, uint256 mintedAmount) onlyOwner public {
        uint tempSupply = totalSupply;
        balanceOf[target] += mintedAmount;
        totalSupply += mintedAmount;
        require(totalSupply >= tempSupply);
        Transfer(0, this, mintedAmount);
        Transfer(this, target, mintedAmount);
    }


    function freezeAccount(address target, bool freeze) onlyOwner public {
        frozenAccount[target] = freeze;
        emit FrozenFunds(target, freeze);
    }

    function () payable public {
        require(false);
    }

}

contract UTWD is MyAdvancedToken {
    mapping(address => uint) public lockdate;
    mapping(address => uint) public lockTokenBalance;

    event LockToken(address account, uint amount, uint unixtime);

    function UTWD() MyAdvancedToken() public {}
    function getLockBalance(address account) internal returns(uint) {
        if(now >= lockdate[account]) {
            lockdate[account] = 0;
            lockTokenBalance[account] = 0;
        }
        return lockTokenBalance[account];
    }

    function _transfer(address _from, address _to, uint _value) internal {
        uint usableBalance = balanceOf[_from] - getLockBalance(_from);
        require(balanceOf[_from] >= usableBalance);
        require(_to != 0x0);
        require(usableBalance >= _value);
        require(balanceOf[_to] + _value > balanceOf[_to]);
        require(!frozenAccount[_from]);
        require(!frozenAccount[_to]);
        balanceOf[_from] -= _value;
        balanceOf[_to] += _value;
        emit Transfer(_from, _to, _value);
    }


    function lockTokenToDate(address account, uint amount, uint unixtime) onlyOwner public {
        require(unixtime >= lockdate[account]);
        require(unixtime >= now);
        if(balanceOf[account] >= amount) {
            lockdate[account] = unixtime;
            lockTokenBalance[account] = amount;
            emit LockToken(account, amount, unixtime);
        }
    }

    function lockTokenDays(address account, uint amount, uint _days) public {
        uint unixtime = _days * 1 days + now;
        lockTokenToDate(account, amount, unixtime);
    }

    function burn(uint256 _value) onlyOwner public returns (bool success) {
        uint usableBalance = balanceOf[msg.sender] - getLockBalance(msg.sender);
        require(balanceOf[msg.sender] >= usableBalance);
        require(usableBalance >= _value);
        balanceOf[msg.sender] -= _value;
        totalSupply -= _value; 
        emit Burn(msg.sender, _value);
        return true;
    }
}