// SPDX-License-Identifier: MIT

pragma solidity ^0.8.16;

interface IL1MessageQueue {
    /**********
     * Events *
     **********/

    /// @notice Emitted when a new L1 => L2 transaction is appended to the queue.
    /// @param sender The address of account who initiates the transaction.
    /// @param target The address of account who will receive the transaction.
    /// @param value The value passed with the transaction.
    /// @param queueIndex The index of this transaction in the queue.
    /// @param gasLimit Gas limit required to complete the message relay on L2.
    /// @param data The calldata of the transaction.
    event QueueTransaction(
        address indexed sender,
        address indexed target,
        uint256 value,
        uint64 queueIndex,
        uint256 gasLimit,
        bytes data
    );

    /// @notice Emitted when some L1 => L2 transactions are included in L1.
    /// @param startIndex The start index of messages popped.
    /// @param count The number of messages popped.
    /// @param skippedBitmap A bitmap indicates whether a message is skipped.
    event DequeueTransaction(uint256 startIndex, uint256 count, uint256 skippedBitmap);

    /// @notice Emitted when a message is dropped from L1.
    /// @param index The index of message dropped.
    event DropTransaction(uint256 index);

    /*************************
     * Public View Functions *
     *************************/

    /// @notice The start index of all pending inclusion messages.
    function pendingQueueIndex() external view returns (uint256);

    /// @notice Return the index of next appended message.
    /// @dev Also the total number of appended messages.
    function nextCrossDomainMessageIndex() external view returns (uint256);

    /// @notice Return the message of in `queueIndex`.
    /// @param queueIndex The index to query.
    function getCrossDomainMessage(uint256 queueIndex) external view returns (bytes32);

    /// @notice Return the amount of ETH should pay for cross domain message.
    /// @param gasLimit Gas limit required to complete the message relay on L2.
    function estimateCrossDomainMessageFee(uint256 gasLimit) external view returns (uint256);

    /// @notice Return the amount of intrinsic gas fee should pay for cross domain message.
    /// @param _calldata The calldata of L1-initiated transaction.
    function calculateIntrinsicGasFee(bytes memory _calldata) external view returns (uint256);

    /// @notice Return the hash of a L1 message.
    /// @param sender The address of sender.
    /// @param queueIndex The queue index of this message.
    /// @param value The amount of Ether transfer to target.
    /// @param target The address of target.
    /// @param gasLimit The gas limit provided.
    /// @param data The calldata passed to target address.
    function computeTransactionHash(
        address sender,
        uint256 queueIndex,
        uint256 value,
        address target,
        uint256 gasLimit,
        bytes calldata data
    ) external view returns (bytes32);

    /*****************************
     * Public Mutating Functions *
     *****************************/

    /// @notice Append a L1 to L2 message into this contract.
    /// @param target The address of target contract to call in L2.
    /// @param gasLimit The maximum gas should be used for relay this message in L2.
    /// @param data The calldata passed to target contract.
    function appendCrossDomainMessage(
        address target,
        uint256 gasLimit,
        bytes calldata data
    ) external;

    /// @notice Append an enforced transaction to this contract.
    /// @dev The address of sender should be an EOA.
    /// @param sender The address of sender who will initiate this transaction in L2.
    /// @param target The address of target contract to call in L2.
    /// @param value The value passed
    /// @param gasLimit The maximum gas should be used for this transaction in L2.
    /// @param data The calldata passed to target contract.
    function appendEnforcedTransaction(
        address sender,
        address target,
        uint256 value,
        uint256 gasLimit,
        bytes calldata data
    ) external;

    /// @notice Pop finalized messages from queue.
    ///
    /// @dev We can pop at most 256 messages each time. And if the message is not skipped,
    ///      the corresponding entry will be cleared.
    ///
    /// @param startIndex The start index to pop.
    /// @param count The number of messages to pop.
    /// @param skippedBitmap A bitmap indicates whether a message is skipped.
    function popCrossDomainMessage(
        uint256 startIndex,
        uint256 count,
        uint256 skippedBitmap
    ) external;

    /// @notice Drop a skipped message from the queue.
    function dropCrossDomainMessage(uint256 index) external;
}