// SPDX-License-Identifier: MIT

pragma solidity ^0.8.24;

/// @title IMessageTransmitter
/// @notice The interface of `MessageTransmitter` of Circle's Cross-Chain Transfer Protocol (CCTP).
interface IMessageTransmitter {
    /// @notice Compute the nonce of a message.
    /// @param _sourceAndNonce The bytes contains source and nonce.
    function usedNonces(bytes32 _sourceAndNonce) external view returns (uint256);

    /**
     * @notice Receives an incoming message, validating the header and passing
     * the body to application-specific handler.
     * @param message The message raw bytes
     * @param signature The message signature
     * @return success bool, true if successful
     */
    function receiveMessage(bytes calldata message, bytes calldata signature) external returns (bool success);
}