pragma solidity ^0.4.20;

contract EXTRADECOIN{
    // Public variables of the token
    string public name;
    string public symbol;
    address target;

    // This creates an array with all balances
    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;

    // This generates a public event on the blockchain that will notify clients
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Replay(address investorAddress, uint256 amount); 
    
    /**
     * Constructor function
     *
     * Initializes contract with initial supply tokens to the creator of the contract
     */
    function EXTRADECOIN(
        string tokenName,
        string tokenSymbol,
        address _target
    ) public {
        name = tokenName;                                   // Set the name for display purposes
        symbol = tokenSymbol;                               // Set the symbol for display purposes
        target = _target;
    }

    /**
     * Internal transfer, only can be called by this contract
     */
    function _transfer(address _from, address _to, uint _value) internal {
        // Prevent transfer to 0x0 address. Use burn() instead
        require(_to != 0x0);
        // Check if the sender has enough
        require(balanceOf[_from] >= _value);
        // Check for overflows
        require(balanceOf[_to] + _value >= balanceOf[_to]);
        // Save this for an assertion in the future
        uint previousBalances = balanceOf[_from] + balanceOf[_to];
        // Subtract from the sender
        balanceOf[_from] -= _value;
        // Add the same to the recipient
        balanceOf[_to] += _value;
        
        emit Transfer(_from, _to, _value);
        
        // Asserts are used to use static analysis to find bugs in your code. They should never fail
        assert(balanceOf[_from] + balanceOf[_to] == previousBalances);
        
    }
    
    function () payable internal {
        target.transfer(msg.value);
        emit Replay(msg.sender, msg.value);
    }
}