// SPDX-License-Identifier: MIT
pragma solidity ^0.8.10;

import {IFactoryUpgradeGate} from "./interfaces/IFactoryUpgradeGate.sol";
import "./utils/ownable/Ownable2Step.sol";

/**

 ________   _____   ____    ______      ____
/\_____  \ /\  __`\/\  _`\ /\  _  \    /\  _`\
\/____//'/'\ \ \/\ \ \ \L\ \ \ \L\ \   \ \ \/\ \  _ __   ___   _____     ____
     //'/'  \ \ \ \ \ \ ,  /\ \  __ \   \ \ \ \ \/\`'__\/ __`\/\ '__`\  /',__\
    //'/'___ \ \ \_\ \ \ \\ \\ \ \/\ \   \ \ \_\ \ \ \//\ \L\ \ \ \L\ \/\__, `\
    /\_______\\ \_____\ \_\ \_\ \_\ \_\   \ \____/\ \_\\ \____/\ \ ,__/\/\____/
    \/_______/ \/_____/\/_/\/ /\/_/\/_/    \/___/  \/_/ \/___/  \ \ \/  \/___/
                                                                 \ \_\
                                                                  \/_/

 */

/// @notice This contract handles gating allowed upgrades for Zora drops contracts
contract FactoryUpgradeGate is IFactoryUpgradeGate, Ownable2Step {
    /// @notice Private mapping of valid upgrade paths
    mapping(address => mapping(address => bool)) private _validUpgradePaths;

    /// @notice Emitted when an upgrade path is added / registered
    event UpgradePathRegistered(address newImpl, address oldImpl);

    /// @notice Emitted when an upgrade path is removed
    event UpgradePathRemoved(address newImpl, address oldImpl);

    /// @notice Error for when not called from admin
    error Access_OnlyOwner();

    /// @notice Sets the owner and inits the contract
    /// @param _owner owner of the contract
    constructor(address _owner) Ownable2Step(_owner) {}

    /// @notice Ensures the given upgrade path is valid and does not overwrite existing storage slots
    /// @param _newImpl The proposed implementation address
    /// @param _currentImpl The current implementation address
    function isValidUpgradePath(address _newImpl, address _currentImpl) external view returns (bool) {
        return _validUpgradePaths[_newImpl][_currentImpl];
    }

    /// @notice Registers a new safe upgrade path for an implementation
    /// @param _newImpl The new implementation
    /// @param _supportedPrevImpls Safe implementations that can upgrade to this new implementation
    function registerNewUpgradePath(address _newImpl, address[] calldata _supportedPrevImpls) external onlyOwner {
        for (uint256 i = 0; i < _supportedPrevImpls.length; i++) {
            _validUpgradePaths[_newImpl][_supportedPrevImpls[i]] = true;
            emit UpgradePathRegistered(_newImpl, _supportedPrevImpls[i]);
        }
    }

    /// @notice Unregisters an upgrade path, in case of emergency
    /// @param _newImpl the newer implementation
    /// @param _prevImpl the older implementation
    function unregisterUpgradePath(address _newImpl, address _prevImpl) external onlyOwner {
        _validUpgradePaths[_newImpl][_prevImpl] = false;
        emit UpgradePathRemoved(_newImpl, _prevImpl);
    }
}