// Copyright 2021-2022, Offchain Labs, Inc.
// For license information, see https://github.com/OffchainLabs/nitro-contracts/blob/main/LICENSE
// SPDX-License-Identifier: BUSL-1.1

// solhint-disable-next-line compiler-version
pragma solidity >=0.6.9 <0.9.0;
pragma experimental ABIEncoderV2;

library Messages {
    struct Message {
        uint8 kind;
        address sender;
        uint64 blockNumber;
        uint64 timestamp;
        uint256 inboxSeqNum;
        uint256 baseFeeL1;
        bytes32 messageDataHash;
    }

    function messageHash(
        Message memory message
    ) internal pure returns (bytes32) {
        return messageHash(
            message.kind,
            message.sender,
            message.blockNumber,
            message.timestamp,
            message.inboxSeqNum,
            message.baseFeeL1,
            message.messageDataHash
        );
    }

    function messageHash(
        uint8 kind,
        address sender,
        uint64 blockNumber,
        uint64 timestamp,
        uint256 inboxSeqNum,
        uint256 baseFeeL1,
        bytes32 messageDataHash
    ) internal pure returns (bytes32) {
        return keccak256(
            abi.encodePacked(
                kind, sender, blockNumber, timestamp, inboxSeqNum, baseFeeL1, messageDataHash
            )
        );
    }

    function accumulateInboxMessage(
        bytes32 prevAcc,
        bytes32 message
    ) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked(prevAcc, message));
    }

    /// @dev   Validates a delayed accumulator preimage
    /// @param delayedAcc The delayed accumulator to validate against
    /// @param beforeDelayedAcc The previous delayed accumulator
    /// @param message The message to validate
    function isValidDelayedAccPreimage(
        bytes32 delayedAcc,
        bytes32 beforeDelayedAcc,
        Message memory message
    ) internal pure returns (bool) {
        return delayedAcc == accumulateInboxMessage(beforeDelayedAcc, messageHash(message));
    }
}