contract BagholderERC20 is Ownable {
    using SafeMath for uint256;

    mapping (address => uint256) held;
    mapping (address => uint256) balances;
    mapping (address => mapping (address => uint256)) internal allowed;

    uint256 public constant blockEndICO = 1525197600;

    /* Public variables for the ERC20 token */
    string public constant standard = "ERC20 Bagholder";
    uint8 public constant decimals = 8; // hardcoded to be a constant
    uint256 public totalSupply;
    string public name;
    string public symbol;

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

    function heldOf(address _owner) public view returns (uint256 balance) {
        return held[_owner];
    }

    function balanceOf(address _owner) public view returns (uint256 balance) {
        return balances[_owner];
    }

    function transfer(address _to, uint256 _value) public returns (bool) {
        require(block.timestamp > blockEndICO || msg.sender == owner);
        require(_to != address(0));
        require(_value <= balances[msg.sender]);

        // SafeMath.sub will throw if there is not enough balance.
        balances[msg.sender] = balances[msg.sender].sub(_value);
        held[_to] = block.number;
        balances[_to] = balances[_to].add(_value);

        Transfer(msg.sender, _to, _value);
        return true;
    }

    function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
        require(_to != address(0));
        require(_value <= balances[_from]);
        require(_value <= allowed[_from][msg.sender]);
        balances[_from] = balances[_from].sub(_value);
        held[_to] = block.number;
        balances[_to] = balances[_to].add(_value);
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);

        Transfer(_from, _to, _value);
        return true;
    }


    function approve(address _spender, uint256 _value) public onlyOwner returns (bool) {
        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        return true;
    }

    function allowance(address _owner, address _spender) public view returns (uint256) {
        return allowed[_owner][_spender];
    }

    function increaseApproval(address _spender, uint _addedValue) public onlyOwner returns (bool) {
        allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
        Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
    }

    function decreaseApproval(address _spender, uint _subtractedValue) public onlyOwner returns (bool) {
        uint oldValue = allowed[msg.sender][_spender];
        if (_subtractedValue > oldValue) {
            allowed[msg.sender][_spender] = 0;
        } else {
            allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
        }
        Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
    }

    /* Approve and then communicate the approved contract in a single tx */
    function approveAndCall(address _spender, uint256 _value, bytes _extraData) public onlyOwner returns (bool success) {    
        tokenRecipient spender = tokenRecipient(_spender);

        if (approve(_spender, _value)) {
            spender.receiveApproval(msg.sender, _value, this, _extraData);
            return true;
        }
    }
}
//////////////////////////////////////////////////////////////
function approveAndCall(address _spender, uint256 _value, bytes _extraData) public onlyOwner returns (bool success) {    
    tokenRecipient spender = tokenRecipient(_spender);

    if (approve(_spender, _value)) {
        spender.receiveApproval(msg.sender, _value, this, _extraData);
        return true;
    }
}

/* Approve and then communicate the approved contract in a single tx */