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hgateway.sol

pragma solidity >=0.4.22 <0.6.0;

contract owned {
    address public owner = msg.sender;
    uint public creationTime = now;

    modifier onlyOwner {
        require(
            msg.sender == owner,
            "Access restricted."
        );
        _;
    }
}

contract Paybox is owned {
    
    struct Transaction {
        bytes id; //payment id
        bool paid; //is paidback to acceptor
        address addr; //payment address
        uint amount; //amount in wei
        uint balance; //balance in wei
        uint created; //created date
    }
    
    mapping(address => Transaction) public transactions;

    
    function () external payable {
        receive('accidental_payment',msg.sender, now);
    }
    
    function receive(bytes memory _id, address _addr, uint _created) onlyOwner public payable {
        uint amount = msg.value;
        
        require(msg.value > 0, "No value was sent with transaction");
        require(_id.length != 0, "Id is required");
        require(_addr != address(0), "Address is required");
        
        Transaction memory trx = Transaction({
                id: _id,
                paid: false,
                addr: _addr,
                amount: amount,
                balance: amount,
                created: _created
            });
        transactions[_addr] = trx;
    }
    
    function send(address _from, address payable _to, uint _amount) onlyOwner public {
        require(_amount > 0, "No value was sent with transaction");
        require(_from != address(0), "FromAddress is required");
        require(_to != address(0), "ToAddress is required");
        
        Transaction storage txr = transactions[_from];
        
        require(txr.balance >= _amount, "Transaction balance is not sufficient");
        if (_amount == txr.amount)
            txr.paid = true;
        txr.balance -= _amount;
        
        address(_to).transfer(_amount);
    }
    
}