// SPDX-License-Identifier: MIT
pragma solidity ^0.8.23;

// interfaces
import {IProxy} from "./IProxy.sol";

// libraries

// contracts

abstract contract Proxy is IProxy {
    fallback() external payable {
        _fallback();
    }

    function _fallback() internal {
        address facet = _getImplementation();

        if (facet.code.length == 0) revert Proxy__ImplementationIsNotContract();

        // solhint-disable-next-line no-inline-assembly
        assembly {
            calldatacopy(0, 0, calldatasize())
            let result := delegatecall(gas(), facet, 0, calldatasize(), 0, 0)
            returndatacopy(0, 0, returndatasize())

            switch result
            case 0 { revert(0, returndatasize()) }
            default { return(0, returndatasize()) }
        }
    }

    function _getImplementation() internal virtual returns (address);
}