Contract Source Code:

// SPDX-License-Identifier: GPL-3.0-or-later

// Hydrometer combines powerful liquidity incentives, low slippage, and a vote-locked governance model using $HYDRO and $veHYDRO tokens, ensuring an innovative and decentralized experience for all users.

//https://x.com/Hydrometer_Fi

pragma solidity 0.8.19;

// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

interface IFactoryRegistry {
    error FallbackFactory();
    error InvalidFactoriesToPoolFactory();
    error PathAlreadyApproved();
    error PathNotApproved();
    error SameAddress();
    error ZeroAddress();

    event Approve(address indexed poolFactory, address indexed votingRewardsFactory, address indexed gaugeFactory);
    event Unapprove(address indexed poolFactory, address indexed votingRewardsFactory, address indexed gaugeFactory);
    event SetManagedRewardsFactory(address indexed _newRewardsFactory);

    /// @notice Approve a set of factories used in the Protocol.
    ///         Router.sol is able to swap any poolFactories currently approved.
    ///         Cannot approve address(0) factories.
    ///         Cannot aprove path that is already approved.
    ///         Each poolFactory has one unique set and maintains state.  In the case a poolFactory is unapproved
    ///             and then re-approved, the same set of factories must be used.  In other words, you cannot overwrite
    ///             the factories tied to a poolFactory address.
    ///         VotingRewardsFactories and GaugeFactories may use the same address across multiple poolFactories.
    /// @dev Callable by onlyOwner
    /// @param poolFactory .
    /// @param votingRewardsFactory .
    /// @param gaugeFactory .
    function approve(address poolFactory, address votingRewardsFactory, address gaugeFactory) external;

    /// @notice Unapprove a set of factories used in the Protocol.
    ///         While a poolFactory is unapproved, Router.sol cannot swap with pools made from the corresponding factory
    ///         Can only unapprove an approved path.
    ///         Cannot unapprove the fallback path (core v2 factories).
    /// @dev Callable by onlyOwner
    /// @param poolFactory .
    function unapprove(address poolFactory) external;

    /// @notice Factory to create free and locked rewards for a managed veNFT
    function managedRewardsFactory() external view returns (address);

    /// @notice Set the rewards factory address
    /// @dev Callable by onlyOwner
    /// @param _newManagedRewardsFactory address of new managedRewardsFactory
    function setManagedRewardsFactory(address _newManagedRewardsFactory) external;

    /// @notice Get the factories correlated to a poolFactory.
    ///         Once set, this can never be modified.
    ///         Returns the correlated factories even after an approved poolFactory is unapproved.
    function factoriesToPoolFactory(
        address poolFactory
    ) external view returns (address votingRewardsFactory, address gaugeFactory);

    /// @notice Get all PoolFactories approved by the registry
    /// @dev The same PoolFactory address cannot be used twice
    /// @return Array of PoolFactory addresses
    function poolFactories() external view returns (address[] memory);

    /// @notice Check if a PoolFactory is approved within the factory registry.  Router uses this method to
    ///         ensure a pool swapped from is approved.
    /// @param poolFactory .
    /// @return True if PoolFactory is approved, else false
    function isPoolFactoryApproved(address poolFactory) external view returns (bool);

    /// @notice Get the length of the poolFactories array
    function poolFactoriesLength() external view returns (uint256);
}

// OpenZeppelin Contracts (last updated v4.8.0) (utils/structs/EnumerableSet.sol)
// This file was procedurally generated from scripts/generate/templates/EnumerableSet.js.

/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```solidity
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
 * and `uint256` (`UintSet`) are supported.
 *
 * [WARNING]
 * ====
 * Trying to delete such a structure from storage will likely result in data corruption, rendering the structure
 * unusable.
 * See https://github.com/ethereum/solidity/pull/11843[ethereum/solidity#11843] for more info.
 *
 * In order to clean an EnumerableSet, you can either remove all elements one by one or create a fresh instance using an
 * array of EnumerableSet.
 * ====
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;
        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping(bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) {
            // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            if (lastIndex != toDeleteIndex) {
                bytes32 lastValue = set._values[lastIndex];

                // Move the last value to the index where the value to delete is
                set._values[toDeleteIndex] = lastValue;
                // Update the index for the moved value
                set._indexes[lastValue] = valueIndex; // Replace lastValue's index to valueIndex
            }

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        return set._values[index];
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function _values(Set storage set) private view returns (bytes32[] memory) {
        return set._values;
    }

    // Bytes32Set

    struct Bytes32Set {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(Bytes32Set storage set) internal view returns (bytes32[] memory) {
        bytes32[] memory store = _values(set._inner);
        bytes32[] memory result;

        /// @solidity memory-safe-assembly
        assembly {
            result := store
        }

        return result;
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint160(uint256(_at(set._inner, index))));
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(AddressSet storage set) internal view returns (address[] memory) {
        bytes32[] memory store = _values(set._inner);
        address[] memory result;

        /// @solidity memory-safe-assembly
        assembly {
            result := store
        }

        return result;
    }

    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(UintSet storage set) internal view returns (uint256[] memory) {
        bytes32[] memory store = _values(set._inner);
        uint256[] memory result;

        /// @solidity memory-safe-assembly
        assembly {
            result := store
        }

        return result;
    }
}

/// @title Protocol Factory Registry
/// @author Carter Carlson (@pegahcarter)
/// @notice Protocol Factory Registry to swap and create gauges
contract FactoryRegistry is IFactoryRegistry, Ownable {
    using EnumerableSet for EnumerableSet.AddressSet;

    /// @dev factory to create free and locked rewards for a managed veNFT
    address private _managedRewardsFactory;

    /// @dev The protocol will always have a usable poolFactory, votingRewardsFactory, and gaugeFactory.  The votingRewardsFactory
    // and gaugeFactory are defined to the poolFactory which can never be removed
    address public immutable fallbackPoolFactory;

    /// @dev Array of poolFactories used to create a gauge and votingRewards
    EnumerableSet.AddressSet private _poolFactories;

    struct FactoriesToPoolFactory {
        address votingRewardsFactory;
        address gaugeFactory;
    }
    /// @dev the factories linked to the poolFactory
    mapping(address => FactoriesToPoolFactory) private _factoriesToPoolsFactory;

    constructor(
        address _fallbackPoolFactory,
        address _fallbackVotingRewardsFactory,
        address _fallbackGaugeFactory,
        address _newManagedRewardsFactory
    ) {
        fallbackPoolFactory = _fallbackPoolFactory;

        approve(_fallbackPoolFactory, _fallbackVotingRewardsFactory, _fallbackGaugeFactory);
        setManagedRewardsFactory(_newManagedRewardsFactory);
    }

    /// @inheritdoc IFactoryRegistry
    function approve(address poolFactory, address votingRewardsFactory, address gaugeFactory) public onlyOwner {
        if (poolFactory == address(0) || votingRewardsFactory == address(0) || gaugeFactory == address(0))
            revert ZeroAddress();
        if (_poolFactories.contains(poolFactory)) revert PathAlreadyApproved();

        FactoriesToPoolFactory memory usedFactories = _factoriesToPoolsFactory[poolFactory];

        // If the poolFactory *has not* been approved before, can approve any gauge/votingRewards factory
        // Only one check is sufficient
        if (usedFactories.votingRewardsFactory == address(0)) {
            _factoriesToPoolsFactory[poolFactory] = FactoriesToPoolFactory(votingRewardsFactory, gaugeFactory);
        } else {
            // If the poolFactory *has* been approved before, can only approve the same used gauge/votingRewards factory to
            //     to maintain state within Voter
            if (
                votingRewardsFactory != usedFactories.votingRewardsFactory || gaugeFactory != usedFactories.gaugeFactory
            ) revert InvalidFactoriesToPoolFactory();
        }

        _poolFactories.add(poolFactory);
        emit Approve(poolFactory, votingRewardsFactory, gaugeFactory);
    }

    /// @inheritdoc IFactoryRegistry
    function unapprove(address poolFactory) external onlyOwner {
        if (poolFactory == fallbackPoolFactory) revert FallbackFactory();
        if (!_poolFactories.contains(poolFactory)) revert PathNotApproved();
        _poolFactories.remove(poolFactory);
        (address votingRewardsFactory, address gaugeFactory) = factoriesToPoolFactory(poolFactory);
        emit Unapprove(poolFactory, votingRewardsFactory, gaugeFactory);
    }

    /// @inheritdoc IFactoryRegistry
    function setManagedRewardsFactory(address _newManagedRewardsFactory) public onlyOwner {
        if (_newManagedRewardsFactory == _managedRewardsFactory) revert SameAddress();
        if (_newManagedRewardsFactory == address(0)) revert ZeroAddress();
        _managedRewardsFactory = _newManagedRewardsFactory;
        emit SetManagedRewardsFactory(_newManagedRewardsFactory);
    }

    /// @inheritdoc IFactoryRegistry
    function managedRewardsFactory() external view returns (address) {
        return _managedRewardsFactory;
    }

    /// @inheritdoc IFactoryRegistry
    function factoriesToPoolFactory(
        address poolFactory
    ) public view returns (address votingRewardsFactory, address gaugeFactory) {
        FactoriesToPoolFactory memory f = _factoriesToPoolsFactory[poolFactory];
        votingRewardsFactory = f.votingRewardsFactory;
        gaugeFactory = f.gaugeFactory;
    }

    /// @inheritdoc IFactoryRegistry
    function poolFactories() external view returns (address[] memory) {
        return _poolFactories.values();
    }

    /// @inheritdoc IFactoryRegistry
    function isPoolFactoryApproved(address poolFactory) external view returns (bool) {
        return _poolFactories.contains(poolFactory);
    }

    /// @inheritdoc IFactoryRegistry
    function poolFactoriesLength() external view returns (uint256) {
        return _poolFactories.length();
    }
}