pragma solidity ^0.4.24;

import "./ERC223.sol";
import "./ERC223ReceivingContract.sol";
import "zeppelin-solidity/contracts/token/ERC20/StandardToken.sol";

contract ERC223StandardToken is ERC223, StandardToken {

    using SafeMath for uint;

    // Function that is called when a user or another contract wants to transfer funds .
    function transfer(address _to, uint _value, bytes _data, string _custom_fallback) public returns (bool success) {

        if (isContract(_to)) {
            require(balanceOf(msg.sender) > _value);
            balances[msg.sender] = balanceOf(msg.sender).sub(_value);
            balances[_to] = balanceOf(_to).add(_value);
            assert(_to.call.value(0)(bytes4(keccak256(abi.encodePacked(_custom_fallback))), msg.sender, _value, _data));

            emit Transfer(msg.sender, _to, _value, _data);

            return true;
        }
        else {
            return transferToAddress(_to, _value, _data);
        }
    }


    // Function that is called when a user or another contract wants to transfer funds .
    function transfer(address _to, uint _value, bytes _data) public returns (bool success) {

        if (isContract(_to)) {
            return transferToContract(_to, _value, _data);
        }
        else {
            return transferToAddress(_to, _value, _data);
        }
    }


    // Standard function transfer similar to ERC20 transfer with no _data .
    // Added due to backwards compatibility reasons .
    function transfer(address _to, uint _value) public returns (bool success) {

        //standard function transfer similar to ERC20 transfer with no _data
        //added due to backwards compatibility reasons
        bytes memory empty;

        if (isContract(_to)) {
            return transferToContract(_to, _value, empty);
        }
        else {
            return transferToAddress(_to, _value, empty);
        }
    }


    //assemble the given address bytecode. If bytecode exists then the _addr is a contract.
    function isContract(address _addr) private view returns (bool is_contract) {

        uint length;

        assembly {
        //retrieve the size of the code on target address, this needs assembly
            length := extcodesize(_addr)
        }

        return (length > 0);
    }


    //function that is called when transaction target is an address
    function transferToAddress(address _to, uint _value, bytes _data) private returns (bool success) {

        require(balanceOf(msg.sender) > _value);
        balances[msg.sender] = balanceOf(msg.sender).sub(_value);
        balances[_to] = balanceOf(_to).add(_value);

        emit Transfer(msg.sender, _to, _value, _data);

        return true;
    }


    //function that is called when transaction target is a contract
    function transferToContract(address _to, uint _value, bytes _data) private returns (bool success) {

        require(balanceOf(msg.sender) > _value);
        balances[msg.sender] = balanceOf(msg.sender).sub(_value);
        balances[_to] = balanceOf(_to).add(_value);

        ERC223ReceivingContract receiver = ERC223ReceivingContract(_to);
        receiver.tokenFallback(msg.sender, _value, _data);

        emit Transfer(msg.sender, _to, _value, _data);

        return true;
    }
}