// SPDX-License-Identifier: MIT
pragma solidity 0.8.30;

/// @title TizmoRegistry
/// @notice An append-only record of hashes submitted by a wallet, never a token.
/// @dev A record is evidence of submission, not proof of authorship or ownership.
contract TizmoRegistry {
    uint256 public constant MAX_METADATA_URI_BYTES = 512;

    struct Record {
        bytes32 fileHash;
        bytes32 recipeHash;
        address registrant;
        uint64 timestamp;
        bytes32 previousId;
        string metadataURI;
    }

    mapping(bytes32 => Record) private records;
    mapping(address => mapping(bytes32 => bytes32)) public recordFor;

    error ZeroHash();
    error DuplicateRecord(bytes32 existingId);
    error UnknownRecord(bytes32 recordId);
    error DifferentRegistrant(bytes32 previousId);
    error MetadataTooLong(uint256 byteLength);

    event WorkRegistered(
        bytes32 indexed recordId,
        address indexed registrant,
        bytes32 indexed fileHash,
        bytes32 recipeHash,
        bytes32 previousId,
        uint64 timestamp,
        string metadataURI
    );

    /// @param fileHash SHA256 digest of the exact exported file bytes.
    /// @param recipeHash SHA256 digest of the canonical renderer recipe bytes.
    /// @param previousId Earlier record by this wallet, or zero for a first version.
    /// @param metadataURI Optional public metadata reference, limited to 512 UTF8 bytes.
    function register(
        bytes32 fileHash,
        bytes32 recipeHash,
        bytes32 previousId,
        string calldata metadataURI
    ) external returns (bytes32 recordId) {
        if (fileHash == bytes32(0) || recipeHash == bytes32(0)) revert ZeroHash();
        bytes32 existingId = recordFor[msg.sender][fileHash];
        if (existingId != bytes32(0)) revert DuplicateRecord(existingId);
        uint256 uriLength = bytes(metadataURI).length;
        if (uriLength > MAX_METADATA_URI_BYTES) revert MetadataTooLong(uriLength);

        if (previousId != bytes32(0)) {
            address previousRegistrant = records[previousId].registrant;
            if (previousRegistrant == address(0)) revert UnknownRecord(previousId);
            if (previousRegistrant != msg.sender) revert DifferentRegistrant(previousId);
        }

        recordId = keccak256(abi.encode(msg.sender, fileHash, block.chainid, address(this)));
        uint64 submittedAt = uint64(block.timestamp);
        records[recordId] = Record({
            fileHash: fileHash,
            recipeHash: recipeHash,
            registrant: msg.sender,
            timestamp: submittedAt,
            previousId: previousId,
            metadataURI: metadataURI
        });
        recordFor[msg.sender][fileHash] = recordId;
        emit WorkRegistered(recordId, msg.sender, fileHash, recipeHash, previousId, submittedAt, metadataURI);
    }

    function getRecord(bytes32 recordId) external view returns (Record memory record) {
        record = records[recordId];
        if (record.registrant == address(0)) revert UnknownRecord(recordId);
    }
}