pragma solidity ^0.8.13;

contract AckOrTimeoutReceipt {
    struct Receipt {
        address recipient;
        uint48 deadline;
        bool acked;
        bool finalized;
        bytes32 ackHash;
    }

    mapping(bytes32 => Receipt) private receipts;

    event ReceiptCreated(bytes32 indexed id, address indexed recipient, uint256 deadline);
    event Acked(bytes32 indexed id, bytes32 ackHash, address indexed recipient);
    event MissFinalized(bytes32 indexed id);

    function create(bytes32 id, address recipient, uint256 deadline) external {
        require(recipient != address(0));
        require(deadline > block.timestamp);
        require(deadline <= type(uint48).max);

        Receipt storage r = receipts[id];
        require(r.recipient == address(0));

        r.recipient = recipient;
        r.deadline = uint48(deadline);

        emit ReceiptCreated(id, recipient, deadline);
    }

    function ack(bytes32 id, bytes32 ackHash) external {
        Receipt storage r = receipts[id];
        require(r.recipient == msg.sender);
        require(!r.acked);
        require(block.timestamp < uint256(r.deadline));

        r.acked = true;
        r.ackHash = ackHash;

        emit Acked(id, ackHash, msg.sender);
    }

    function finalizeMiss(bytes32 id) external {
        Receipt storage r = receipts[id];
        require(r.recipient != address(0));
        require(!r.acked);
        require(block.timestamp >= uint256(r.deadline));
        require(!r.finalized);

        r.finalized = true;

        emit MissFinalized(id);
    }
}