// SPDX-License-Identifier: MIT

pragma solidity ^0.8.20;

import { SafeERC20, IERC20 } from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import { MessagingParams, MessagingFee, MessagingReceipt } from "@layerzerolabs/lz-evm-protocol-v2/contracts/interfaces/ILayerZeroEndpointV2.sol";
import { OAppCore } from "./OAppCore.sol";

/**
 * @title OAppSender
 * @dev Abstract contract implementing the OAppSender functionality for sending messages to a LayerZero endpoint.
 */
abstract contract OAppSender is OAppCore {
    using SafeERC20 for IERC20;

    // Custom error messages
    error NotEnoughNative(uint256 msgValue);
    error LzTokenUnavailable();

    // @dev The version of the OAppSender implementation.
    // @dev Version is bumped when changes are made to this contract.
    uint64 internal constant SENDER_VERSION = 1;

    /**
     * @notice Retrieves the OApp version information.
     * @return senderVersion The version of the OAppSender.sol contract.
     * @return receiverVersion The version of the OAppReceiver.sol contract.
     *
     * @dev Providing 0 as the default for OAppReceiver version. Indicates that the OAppReceiver is not implemented.
     * ie. this is a SEND only OApp.
     * @dev If the OApp uses both OAppSender and OAppReceiver, then this needs to be override returning the correct versions
     */
    function oAppVersion() public view virtual returns (uint64 senderVersion, uint64 receiverVersion) {
        return (SENDER_VERSION, 0);
    }

    /**
     * @dev Internal function to interact with the LayerZero EndpointV2.quote() for fee calculation.
     * @param _dstEid The destination endpoint ID.
     * @param _message The message payload.
     * @param _options Additional options for the message.
     * @param _payInLzToken Flag indicating whether to pay the fee in LZ tokens.
     * @return fee The calculated MessagingFee for the message.
     *      - nativeFee: The native fee for the message.
     *      - lzTokenFee: The LZ token fee for the message.
     */
    function _quote(
        uint32 _dstEid,
        bytes memory _message,
        bytes memory _options,
        bool _payInLzToken
    ) internal view virtual returns (MessagingFee memory fee) {
        return
            endpoint.quote(
                MessagingParams(_dstEid, _getPeerOrRevert(_dstEid), _message, _options, _payInLzToken),
                address(this)
            );
    }

    /**
     * @dev Internal function to interact with the LayerZero EndpointV2.send() for sending a message.
     * @param _dstEid The destination endpoint ID.
     * @param _message The message payload.
     * @param _options Additional options for the message.
     * @param _fee The calculated LayerZero fee for the message.
     *      - nativeFee: The native fee.
     *      - lzTokenFee: The lzToken fee.
     * @param _refundAddress The address to receive any excess fee values sent to the endpoint.
     * @return receipt The receipt for the sent message.
     *      - guid: The unique identifier for the sent message.
     *      - nonce: The nonce of the sent message.
     *      - fee: The LayerZero fee incurred for the message.
     */
    function _lzSend(
        uint32 _dstEid,
        bytes memory _message,
        bytes memory _options,
        MessagingFee memory _fee,
        address _refundAddress
    ) internal virtual returns (MessagingReceipt memory receipt) {
        // @dev Push corresponding fees to the endpoint, any excess is sent back to the _refundAddress from the endpoint.
        uint256 messageValue = _payNative(_fee.nativeFee);
        if (_fee.lzTokenFee > 0) _payLzToken(_fee.lzTokenFee);

        return
            // solhint-disable-next-line check-send-result
            endpoint.send{ value: messageValue }(
                MessagingParams(_dstEid, _getPeerOrRevert(_dstEid), _message, _options, _fee.lzTokenFee > 0),
                _refundAddress
            );
    }

    /**
     * @dev Internal function to pay the native fee associated with the message.
     * @param _nativeFee The native fee to be paid.
     * @return nativeFee The amount of native currency paid.
     *
     * @dev If the OApp needs to initiate MULTIPLE LayerZero messages in a single transaction,
     * this will need to be overridden because msg.value would contain multiple lzFees.
     * @dev Should be overridden in the event the LayerZero endpoint requires a different native currency.
     * @dev Some EVMs use an ERC20 as a method for paying transactions/gasFees.
     * @dev The endpoint is EITHER/OR, ie. it will NOT support both types of native payment at a time.
     */
    function _payNative(uint256 _nativeFee) internal virtual returns (uint256 nativeFee) {
        if (msg.value != _nativeFee) revert NotEnoughNative(msg.value);
        return _nativeFee;
    }

    /**
     * @dev Internal function to pay the LZ token fee associated with the message.
     * @param _lzTokenFee The LZ token fee to be paid.
     *
     * @dev If the caller is trying to pay in the specified lzToken, then the lzTokenFee is passed to the endpoint.
     * @dev Any excess sent, is passed back to the specified _refundAddress in the _lzSend().
     */
    function _payLzToken(uint256 _lzTokenFee) internal virtual {
        // @dev Cannot cache the token because it is not immutable in the endpoint.
        address lzToken = endpoint.lzToken();
        if (lzToken == address(0)) revert LzTokenUnavailable();

        // Pay LZ token fee by sending tokens to the endpoint.
        IERC20(lzToken).safeTransferFrom(msg.sender, address(endpoint), _lzTokenFee);
    }
}