// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.8.18;

import "@openzeppelin/contracts/utils/Context.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

/**
 * @title MutableERC2771Context
 * @notice Context variant with ERC2771 support (with mutable `_trustedForwarder`).
 * @dev Based on OpenZeppelin ERC2771Context contract.
 */
abstract contract MutableERC2771Context is Context, Ownable {
    address private _trustedForwarder;

    event TrustedForwarderSet(address indexed previousForwarder, address indexed newForwarder);

    constructor(address trustedForwarder_) {
        _setTrustedForwarder(trustedForwarder_);
    }

    function setTrustedForwarder(address trustedForwarder) external virtual onlyOwner {
        _setTrustedForwarder(trustedForwarder);
    }

    function _setTrustedForwarder(address trustedForwarder) internal virtual {
        address previousForwarder = _trustedForwarder;
        _trustedForwarder = trustedForwarder;
        emit TrustedForwarderSet(previousForwarder, trustedForwarder);
    }

    function isTrustedForwarder(address forwarder) public view virtual returns (bool) {
        return forwarder == _trustedForwarder;
    }

    function _msgSender() internal view virtual override returns (address sender) {
        if (isTrustedForwarder(msg.sender)) {
            // The assembly code is more direct than the Solidity version using `abi.decode`.
            /// @solidity memory-safe-assembly
            assembly {
                sender := shr(96, calldataload(sub(calldatasize(), 20)))
            }
        } else {
            return super._msgSender();
        }
    }

    function _msgData() internal view virtual override returns (bytes calldata) {
        if (isTrustedForwarder(msg.sender)) {
            return msg.data[:msg.data.length - 20];
        } else {
            return super._msgData();
        }
    }
}