/**
  *       .
  *      / \
  *     |.'.|
  *     |'.'|
  *   ,'|   |`.
  *  |,-'-|-'-.|
  *   __|_| |         _        _      _____           _
  *  | ___ \|        | |      | |    | ___ \         | |
  *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
  *  |    // _ \ / __| |/ / _ \ __|  |  __/ _ \ / _ \| |
  *  | |\ \ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
  *  \_| \_\___/ \___|_|\_\___|\__|  \_|  \___/ \___/|_|
  * +---------------------------------------------------+
  * |  DECENTRALISED STAKING PROTOCOL FOR ETHEREUM 2.0  |
  * +---------------------------------------------------+
  *
  *  Rocket Pool is a first-of-its-kind ETH2 Proof of Stake protocol, designed to be community owned,
  *  decentralised, trustless and compatible with staking in Ethereum 2.0.
  *
  *  For more information about Rocket Pool, visit https://rocketpool.net
  *
  *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
  *
  */

pragma solidity >0.5.0 <0.9.0;

// SPDX-License-Identifier: GPL-3.0-only

interface AddressQueueStorageInterface {
    function getLength(bytes32 _key) external view returns (uint);
    function getItem(bytes32 _key, uint _index) external view returns (address);
    function getIndexOf(bytes32 _key, address _value) external view returns (int);
    function enqueueItem(bytes32 _key, address _value) external;
    function dequeueItem(bytes32 _key) external returns (address);
    function removeItem(bytes32 _key, address _value) external;
}

/**
  *       .
  *      / \
  *     |.'.|
  *     |'.'|
  *   ,'|   |`.
  *  |,-'-|-'-.|
  *   __|_| |         _        _      _____           _
  *  | ___ \|        | |      | |    | ___ \         | |
  *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
  *  |    // _ \ / __| |/ / _ \ __|  |  __/ _ \ / _ \| |
  *  | |\ \ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
  *  \_| \_\___/ \___|_|\_\___|\__|  \_|  \___/ \___/|_|
  * +---------------------------------------------------+
  * |  DECENTRALISED STAKING PROTOCOL FOR ETHEREUM 2.0  |
  * +---------------------------------------------------+
  *
  *  Rocket Pool is a first-of-its-kind ETH2 Proof of Stake protocol, designed to be community owned,
  *  decentralised, trustless and compatible with staking in Ethereum 2.0.
  *
  *  For more information about Rocket Pool, visit https://rocketpool.net
  *
  *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
  *
  */

pragma solidity 0.7.6;

// SPDX-License-Identifier: GPL-3.0-only

// Represents the type of deposits required by a minipool

enum MinipoolDeposit {
    None,       // Marks an invalid deposit type
    Full,       // The minipool requires 32 ETH from the node operator, 16 ETH of which will be refinanced from user deposits
    Half,       // The minipool required 16 ETH from the node operator to be matched with 16 ETH from user deposits
    Empty,      // The minipool requires 0 ETH from the node operator to be matched with 32 ETH from user deposits (trusted nodes only)
    Variable    // Indicates this minipool is of the new generation that supports a variable deposit amount
}

/**
  *       .
  *      / \
  *     |.'.|
  *     |'.'|
  *   ,'|   |`.
  *  |,-'-|-'-.|
  *   __|_| |         _        _      _____           _
  *  | ___ \|        | |      | |    | ___ \         | |
  *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
  *  |    // _ \ / __| |/ / _ \ __|  |  __/ _ \ / _ \| |
  *  | |\ \ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
  *  \_| \_\___/ \___|_|\_\___|\__|  \_|  \___/ \___/|_|
  * +---------------------------------------------------+
  * |  DECENTRALISED STAKING PROTOCOL FOR ETHEREUM 2.0  |
  * +---------------------------------------------------+
  *
  *  Rocket Pool is a first-of-its-kind ETH2 Proof of Stake protocol, designed to be community owned,
  *  decentralised, trustless and compatible with staking in Ethereum 2.0.
  *
  *  For more information about Rocket Pool, visit https://rocketpool.net
  *
  *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
  *
  */

pragma solidity 0.7.6;

// SPDX-License-Identifier: GPL-3.0-only

// Represents a minipool's status within the network

enum MinipoolStatus {
    Initialised,    // The minipool has been initialised and is awaiting a deposit of user ETH
    Prelaunch,      // The minipool has enough ETH to begin staking and is awaiting launch by the node operator
    Staking,        // The minipool is currently staking
    Withdrawable,   // NO LONGER USED
    Dissolved       // The minipool has been dissolved and its user deposited ETH has been returned to the deposit pool
}

/**
  *       .
  *      / \
  *     |.'.|
  *     |'.'|
  *   ,'|   |`.
  *  |,-'-|-'-.|
  *   __|_| |         _        _      _____           _
  *  | ___ \|        | |      | |    | ___ \         | |
  *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
  *  |    // _ \ / __| |/ / _ \ __|  |  __/ _ \ / _ \| |
  *  | |\ \ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
  *  \_| \_\___/ \___|_|\_\___|\__|  \_|  \___/ \___/|_|
  * +---------------------------------------------------+
  * |  DECENTRALISED STAKING PROTOCOL FOR ETHEREUM 2.0  |
  * +---------------------------------------------------+
  *
  *  Rocket Pool is a first-of-its-kind ETH2 Proof of Stake protocol, designed to be community owned,
  *  decentralised, trustless and compatible with staking in Ethereum 2.0.
  *
  *  For more information about Rocket Pool, visit https://rocketpool.net
  *
  *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
  *
  */

pragma solidity 0.7.6;

// SPDX-License-Identifier: GPL-3.0-only

import "../interface/RocketStorageInterface.sol";

/// @title Base settings / modifiers for each contract in Rocket Pool
/// @author David Rugendyke

abstract contract RocketBase {

    // Calculate using this as the base
    uint256 constant calcBase = 1 ether;

    // Version of the contract
    uint8 public version;

    // The main storage contract where primary persistant storage is maintained
    RocketStorageInterface rocketStorage = RocketStorageInterface(0);


    /*** Modifiers **********************************************************/

    /**
    * @dev Throws if called by any sender that doesn't match a Rocket Pool network contract
    */
    modifier onlyLatestNetworkContract() {
        require(getBool(keccak256(abi.encodePacked("contract.exists", msg.sender))), "Invalid or outdated network contract");
        _;
    }

    /**
    * @dev Throws if called by any sender that doesn't match one of the supplied contract or is the latest version of that contract
    */
    modifier onlyLatestContract(string memory _contractName, address _contractAddress) {
        require(_contractAddress == getAddress(keccak256(abi.encodePacked("contract.address", _contractName))), "Invalid or outdated contract");
        _;
    }

    /**
    * @dev Throws if called by any sender that isn't a registered node
    */
    modifier onlyRegisteredNode(address _nodeAddress) {
        require(getBool(keccak256(abi.encodePacked("node.exists", _nodeAddress))), "Invalid node");
        _;
    }

    /**
    * @dev Throws if called by any sender that isn't a trusted node DAO member
    */
    modifier onlyTrustedNode(address _nodeAddress) {
        require(getBool(keccak256(abi.encodePacked("dao.trustednodes.", "member", _nodeAddress))), "Invalid trusted node");
        _;
    }

    /**
    * @dev Throws if called by any sender that isn't a registered minipool
    */
    modifier onlyRegisteredMinipool(address _minipoolAddress) {
        require(getBool(keccak256(abi.encodePacked("minipool.exists", _minipoolAddress))), "Invalid minipool");
        _;
    }
    

    /**
    * @dev Throws if called by any account other than a guardian account (temporary account allowed access to settings before DAO is fully enabled)
    */
    modifier onlyGuardian() {
        require(msg.sender == rocketStorage.getGuardian(), "Account is not a temporary guardian");
        _;
    }




    /*** Methods **********************************************************/

    /// @dev Set the main Rocket Storage address
    constructor(RocketStorageInterface _rocketStorageAddress) {
        // Update the contract address
        rocketStorage = RocketStorageInterface(_rocketStorageAddress);
    }


    /// @dev Get the address of a network contract by name
    function getContractAddress(string memory _contractName) internal view returns (address) {
        // Get the current contract address
        address contractAddress = getAddress(keccak256(abi.encodePacked("contract.address", _contractName)));
        // Check it
        require(contractAddress != address(0x0), "Contract not found");
        // Return
        return contractAddress;
    }


    /// @dev Get the address of a network contract by name (returns address(0x0) instead of reverting if contract does not exist)
    function getContractAddressUnsafe(string memory _contractName) internal view returns (address) {
        // Get the current contract address
        address contractAddress = getAddress(keccak256(abi.encodePacked("contract.address", _contractName)));
        // Return
        return contractAddress;
    }


    /// @dev Get the name of a network contract by address
    function getContractName(address _contractAddress) internal view returns (string memory) {
        // Get the contract name
        string memory contractName = getString(keccak256(abi.encodePacked("contract.name", _contractAddress)));
        // Check it
        require(bytes(contractName).length > 0, "Contract not found");
        // Return
        return contractName;
    }

    /// @dev Get revert error message from a .call method
    function getRevertMsg(bytes memory _returnData) internal pure returns (string memory) {
        // If the _res length is less than 68, then the transaction failed silently (without a revert message)
        if (_returnData.length < 68) return "Transaction reverted silently";
        assembly {
            // Slice the sighash.
            _returnData := add(_returnData, 0x04)
        }
        return abi.decode(_returnData, (string)); // All that remains is the revert string
    }



    /*** Rocket Storage Methods ****************************************/

    // Note: Unused helpers have been removed to keep contract sizes down

    /// @dev Storage get methods
    function getAddress(bytes32 _key) internal view returns (address) { return rocketStorage.getAddress(_key); }
    function getUint(bytes32 _key) internal view returns (uint) { return rocketStorage.getUint(_key); }
    function getString(bytes32 _key) internal view returns (string memory) { return rocketStorage.getString(_key); }
    function getBytes(bytes32 _key) internal view returns (bytes memory) { return rocketStorage.getBytes(_key); }
    function getBool(bytes32 _key) internal view returns (bool) { return rocketStorage.getBool(_key); }
    function getInt(bytes32 _key) internal view returns (int) { return rocketStorage.getInt(_key); }
    function getBytes32(bytes32 _key) internal view returns (bytes32) { return rocketStorage.getBytes32(_key); }

    /// @dev Storage set methods
    function setAddress(bytes32 _key, address _value) internal { rocketStorage.setAddress(_key, _value); }
    function setUint(bytes32 _key, uint _value) internal { rocketStorage.setUint(_key, _value); }
    function setString(bytes32 _key, string memory _value) internal { rocketStorage.setString(_key, _value); }
    function setBytes(bytes32 _key, bytes memory _value) internal { rocketStorage.setBytes(_key, _value); }
    function setBool(bytes32 _key, bool _value) internal { rocketStorage.setBool(_key, _value); }
    function setInt(bytes32 _key, int _value) internal { rocketStorage.setInt(_key, _value); }
    function setBytes32(bytes32 _key, bytes32 _value) internal { rocketStorage.setBytes32(_key, _value); }

    /// @dev Storage delete methods
    function deleteAddress(bytes32 _key) internal { rocketStorage.deleteAddress(_key); }
    function deleteUint(bytes32 _key) internal { rocketStorage.deleteUint(_key); }
    function deleteString(bytes32 _key) internal { rocketStorage.deleteString(_key); }
    function deleteBytes(bytes32 _key) internal { rocketStorage.deleteBytes(_key); }
    function deleteBool(bytes32 _key) internal { rocketStorage.deleteBool(_key); }
    function deleteInt(bytes32 _key) internal { rocketStorage.deleteInt(_key); }
    function deleteBytes32(bytes32 _key) internal { rocketStorage.deleteBytes32(_key); }

    /// @dev Storage arithmetic methods
    function addUint(bytes32 _key, uint256 _amount) internal { rocketStorage.addUint(_key, _amount); }
    function subUint(bytes32 _key, uint256 _amount) internal { rocketStorage.subUint(_key, _amount); }
}

/**
  *       .
  *      / \
  *     |.'.|
  *     |'.'|
  *   ,'|   |`.
  *  |,-'-|-'-.|
  *   __|_| |         _        _      _____           _
  *  | ___ \|        | |      | |    | ___ \         | |
  *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
  *  |    // _ \ / __| |/ / _ \ __|  |  __/ _ \ / _ \| |
  *  | |\ \ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
  *  \_| \_\___/ \___|_|\_\___|\__|  \_|  \___/ \___/|_|
  * +---------------------------------------------------+
  * |  DECENTRALISED STAKING PROTOCOL FOR ETHEREUM 2.0  |
  * +---------------------------------------------------+
  *
  *  Rocket Pool is a first-of-its-kind ETH2 Proof of Stake protocol, designed to be community owned,
  *  decentralised, trustless and compatible with staking in Ethereum 2.0.
  *
  *  For more information about Rocket Pool, visit https://rocketpool.net
  *
  *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
  *
  */

pragma solidity >0.5.0 <0.9.0;

// SPDX-License-Identifier: GPL-3.0-only

import "../../../../types/MinipoolDeposit.sol";

interface RocketDAOProtocolSettingsMinipoolInterface {
    function getLaunchBalance() external view returns (uint256);
    function getPreLaunchValue() external pure returns (uint256);
    function getDepositUserAmount(MinipoolDeposit _depositType) external view returns (uint256);
    function getFullDepositUserAmount() external view returns (uint256);
    function getHalfDepositUserAmount() external view returns (uint256);
    function getVariableDepositAmount() external view returns (uint256);
    function getSubmitWithdrawableEnabled() external view returns (bool);
    function getBondReductionEnabled() external view returns (bool);
    function getLaunchTimeout() external view returns (uint256);
    function getMaximumCount() external view returns (uint256);
    function isWithinUserDistributeWindow(uint256 _time) external view returns (bool);
    function hasUserDistributeWindowPassed(uint256 _time) external view returns (bool);
    function getUserDistributeWindowStart() external view returns (uint256);
    function getUserDistributeWindowLength() external view returns (uint256);
}

/**
  *       .
  *      / \
  *     |.'.|
  *     |'.'|
  *   ,'|   |`.
  *  |,-'-|-'-.|
  *   __|_| |         _        _      _____           _
  *  | ___ \|        | |      | |    | ___ \         | |
  *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
  *  |    // _ \ / __| |/ / _ \ __|  |  __/ _ \ / _ \| |
  *  | |\ \ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
  *  \_| \_\___/ \___|_|\_\___|\__|  \_|  \___/ \___/|_|
  * +---------------------------------------------------+
  * |  DECENTRALISED STAKING PROTOCOL FOR ETHEREUM 2.0  |
  * +---------------------------------------------------+
  *
  *  Rocket Pool is a first-of-its-kind ETH2 Proof of Stake protocol, designed to be community owned,
  *  decentralised, trustless and compatible with staking in Ethereum 2.0.
  *
  *  For more information about Rocket Pool, visit https://rocketpool.net
  *
  *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
  *
  */

pragma solidity >0.5.0 <0.9.0;

// SPDX-License-Identifier: GPL-3.0-only

import "../../types/MinipoolDeposit.sol";
import "../../types/MinipoolStatus.sol";
import "../RocketStorageInterface.sol";

interface RocketMinipoolInterface {
    function version() external view returns (uint8);
    function initialise(address _nodeAddress) external;
    function getStatus() external view returns (MinipoolStatus);
    function getFinalised() external view returns (bool);
    function getStatusBlock() external view returns (uint256);
    function getStatusTime() external view returns (uint256);
    function getScrubVoted(address _member) external view returns (bool);
    function getDepositType() external view returns (MinipoolDeposit);
    function getNodeAddress() external view returns (address);
    function getNodeFee() external view returns (uint256);
    function getNodeDepositBalance() external view returns (uint256);
    function getNodeRefundBalance() external view returns (uint256);
    function getNodeDepositAssigned() external view returns (bool);
    function getPreLaunchValue() external view returns (uint256);
    function getNodeTopUpValue() external view returns (uint256);
    function getVacant() external view returns (bool);
    function getPreMigrationBalance() external view returns (uint256);
    function getUserDistributed() external view returns (bool);
    function getUserDepositBalance() external view returns (uint256);
    function getUserDepositAssigned() external view returns (bool);
    function getUserDepositAssignedTime() external view returns (uint256);
    function getTotalScrubVotes() external view returns (uint256);
    function calculateNodeShare(uint256 _balance) external view returns (uint256);
    function calculateUserShare(uint256 _balance) external view returns (uint256);
    function preDeposit(uint256 _bondingValue, bytes calldata _validatorPubkey, bytes calldata _validatorSignature, bytes32 _depositDataRoot) external payable;
    function deposit() external payable;
    function userDeposit() external payable;
    function distributeBalance(bool _rewardsOnly) external;
    function beginUserDistribute() external;
    function userDistributeAllowed() external view returns (bool);
    function refund() external;
    function slash() external;
    function finalise() external;
    function canStake() external view returns (bool);
    function canPromote() external view returns (bool);
    function stake(bytes calldata _validatorSignature, bytes32 _depositDataRoot) external;
    function prepareVacancy(uint256 _bondAmount, uint256 _currentBalance) external;
    function promote() external;
    function dissolve() external;
    function close() external;
    function voteScrub() external;
    function reduceBondAmount() external;
}

/**
  *       .
  *      / \
  *     |.'.|
  *     |'.'|
  *   ,'|   |`.
  *  |,-'-|-'-.|
  *   __|_| |         _        _      _____           _
  *  | ___ \|        | |      | |    | ___ \         | |
  *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
  *  |    // _ \ / __| |/ / _ \ __|  |  __/ _ \ / _ \| |
  *  | |\ \ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
  *  \_| \_\___/ \___|_|\_\___|\__|  \_|  \___/ \___/|_|
  * +---------------------------------------------------+
  * |  DECENTRALISED STAKING PROTOCOL FOR ETHEREUM 2.0  |
  * +---------------------------------------------------+
  *
  *  Rocket Pool is a first-of-its-kind ETH2 Proof of Stake protocol, designed to be community owned,
  *  decentralised, trustless and compatible with staking in Ethereum 2.0.
  *
  *  For more information about Rocket Pool, visit https://rocketpool.net
  *
  *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
  *
  */

// SPDX-License-Identifier: GPL-3.0-only
pragma solidity 0.7.6;

import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/math/SignedSafeMath.sol";
import "@openzeppelin/contracts/utils/SafeCast.sol";

import "../RocketBase.sol";
import "../../interface/minipool/RocketMinipoolInterface.sol";
import "../../interface/minipool/RocketMinipoolQueueInterface.sol";
import "../../interface/dao/protocol/settings/RocketDAOProtocolSettingsMinipoolInterface.sol";
import "../../interface/util/AddressQueueStorageInterface.sol";
import "../../types/MinipoolDeposit.sol";

/// @notice Minipool queueing for deposit assignment
contract RocketMinipoolQueue is RocketBase, RocketMinipoolQueueInterface {

    // Libs
    using SafeMath for uint;
    using SignedSafeMath for int;

    // Constants
    bytes32 private constant queueKeyFull = keccak256("minipools.available.full");
    bytes32 private constant queueKeyHalf = keccak256("minipools.available.half");
    bytes32 private constant queueKeyVariable = keccak256("minipools.available.variable");

    // Events
    event MinipoolEnqueued(address indexed minipool, bytes32 indexed queueId, uint256 time);
    event MinipoolDequeued(address indexed minipool, bytes32 indexed queueId, uint256 time);
    event MinipoolRemoved(address indexed minipool, bytes32 indexed queueId, uint256 time);

    constructor(RocketStorageInterface _rocketStorageAddress) RocketBase(_rocketStorageAddress) {
        version = 2;
    }

    /// @notice Get the total combined length of the queues
    function getTotalLength() override external view returns (uint256) {
        return (
            getLengthLegacy(queueKeyFull)
        ).add(
            getLengthLegacy(queueKeyHalf)
        ).add(
            getLength()
        );
    }

    /// @notice Returns true if there are any legacy minipools in the queue
    function getContainsLegacy() override external view returns (bool) {
        return getLengthLegacy(queueKeyFull).add(getLengthLegacy(queueKeyHalf)) > 0;
    }

    /// @notice Get the length of a given queue. Returns 0 for invalid queues
    /// @param _depositType Which queue to query the length of
    function getLengthLegacy(MinipoolDeposit _depositType) override external view returns (uint256) {
        if (_depositType == MinipoolDeposit.Full) { return getLengthLegacy(queueKeyFull); }
        if (_depositType == MinipoolDeposit.Half) { return getLengthLegacy(queueKeyHalf); }
        return 0;
    }

    /// @dev Returns a queue length by internal key representation
    /// @param _key The internal key representation of the queue to query the length of
    function getLengthLegacy(bytes32 _key) private view returns (uint256) {
        AddressQueueStorageInterface addressQueueStorage = AddressQueueStorageInterface(getContractAddress("addressQueueStorage"));
        return addressQueueStorage.getLength(_key);
    }

    /// @notice Gets the length of the variable (global) queue
    function getLength() override public view returns (uint256) {
        AddressQueueStorageInterface addressQueueStorage = AddressQueueStorageInterface(getContractAddress("addressQueueStorage"));
        return addressQueueStorage.getLength(queueKeyVariable);
    }

    /// @notice Get the total combined capacity of the queues
    function getTotalCapacity() override external view returns (uint256) {
        RocketDAOProtocolSettingsMinipoolInterface rocketDAOProtocolSettingsMinipool = RocketDAOProtocolSettingsMinipoolInterface(getContractAddress("rocketDAOProtocolSettingsMinipool"));
        return (
            getLengthLegacy(queueKeyFull).mul(rocketDAOProtocolSettingsMinipool.getFullDepositUserAmount())
        ).add(
            getLengthLegacy(queueKeyHalf).mul(rocketDAOProtocolSettingsMinipool.getHalfDepositUserAmount())
        ).add(
            getVariableCapacity()
        );
    }

    /// @notice Get the total effective capacity of the queues (used in node demand calculation)
    function getEffectiveCapacity() override external view returns (uint256) {
        RocketDAOProtocolSettingsMinipoolInterface rocketDAOProtocolSettingsMinipool = RocketDAOProtocolSettingsMinipoolInterface(getContractAddress("rocketDAOProtocolSettingsMinipool"));
        return (
            getLengthLegacy(queueKeyFull).mul(rocketDAOProtocolSettingsMinipool.getFullDepositUserAmount())
        ).add(
            getLengthLegacy(queueKeyHalf).mul(rocketDAOProtocolSettingsMinipool.getHalfDepositUserAmount())
        ).add(
            getVariableCapacity()
        );
    }

    /// @dev Get the ETH capacity of the variable queue
    function getVariableCapacity() internal view returns (uint256) {
        RocketDAOProtocolSettingsMinipoolInterface rocketDAOProtocolSettingsMinipool = RocketDAOProtocolSettingsMinipoolInterface(getContractAddress("rocketDAOProtocolSettingsMinipool"));
        return getLength().mul(rocketDAOProtocolSettingsMinipool.getVariableDepositAmount());
    }

    /// @notice Get the capacity of the next available minipool. Returns 0 if no minipools are available
    function getNextCapacityLegacy() override external view returns (uint256) {
        RocketDAOProtocolSettingsMinipoolInterface rocketDAOProtocolSettingsMinipool = RocketDAOProtocolSettingsMinipoolInterface(getContractAddress("rocketDAOProtocolSettingsMinipool"));
        if (getLengthLegacy(queueKeyHalf) > 0) { return rocketDAOProtocolSettingsMinipool.getHalfDepositUserAmount(); }
        if (getLengthLegacy(queueKeyFull) > 0) { return rocketDAOProtocolSettingsMinipool.getFullDepositUserAmount(); }
        return 0;
    }

    /// @notice Get the deposit type of the next available minipool and the number of deposits in that queue.
    ///         Returns None if no minipools are available
    function getNextDepositLegacy() override external view returns (MinipoolDeposit, uint256) {
        uint256 length = getLengthLegacy(queueKeyHalf);
        if (length > 0) { return (MinipoolDeposit.Half, length); }
        length = getLengthLegacy(queueKeyFull);
        if (length > 0) { return (MinipoolDeposit.Full, length); }
        return (MinipoolDeposit.None, 0);
    }

    /// @dev Add a minipool to the end of the appropriate queue. Only accepts calls from the RocketMinipoolManager contract
    /// @param _minipool Address of the minipool to add to the queue
    function enqueueMinipool(address _minipool) override external onlyLatestContract("rocketMinipoolQueue", address(this)) onlyLatestContract("rocketNodeDeposit", msg.sender) {
        // Enqueue
        AddressQueueStorageInterface addressQueueStorage = AddressQueueStorageInterface(getContractAddress("addressQueueStorage"));
        addressQueueStorage.enqueueItem(queueKeyVariable, _minipool);
        // Emit enqueued event
        emit MinipoolEnqueued(_minipool, queueKeyVariable, block.timestamp);
    }

    /// @dev Dequeues a minipool from a legacy queue
    /// @param _depositType The queue to dequeue a minipool from
    function dequeueMinipoolByDepositLegacy(MinipoolDeposit _depositType) override external onlyLatestContract("rocketMinipoolQueue", address(this)) onlyLatestContract("rocketDepositPool", msg.sender) returns (address minipoolAddress) {
        if (_depositType == MinipoolDeposit.Half) { return dequeueMinipool(queueKeyHalf); }
        if (_depositType == MinipoolDeposit.Full) { return dequeueMinipool(queueKeyFull); }
        require(false, "No minipools are available");
    }

    /// @dev Dequeues multiple minipools from the variable queue and returns them all
    /// @param _maxToDequeue The maximum number of items to dequeue
    function dequeueMinipools(uint256 _maxToDequeue) override external onlyLatestContract("rocketMinipoolQueue", address(this)) onlyLatestContract("rocketDepositPool", msg.sender) returns (address[] memory minipoolAddress) {
        uint256 queueLength = getLength();
        uint256 count = _maxToDequeue;
        if (count > queueLength) {
            count = queueLength;
        }
        address[] memory minipoolAddresses = new address[](count);
        for (uint256 i = 0; i < count; i++) {
            RocketMinipoolInterface minipool = RocketMinipoolInterface(dequeueMinipool(queueKeyVariable));
            minipoolAddresses[i] = address(minipool);
        }
        return minipoolAddresses;
    }

    /// @dev Dequeues a minipool from a queue given an internal key
    /// @param _key The internal key representation of the queue from which to dequeue a minipool from
    function dequeueMinipool(bytes32 _key) private returns (address) {
        // Dequeue
        AddressQueueStorageInterface addressQueueStorage = AddressQueueStorageInterface(getContractAddress("addressQueueStorage"));
        address minipool = addressQueueStorage.dequeueItem(_key);
        // Emit dequeued event
        emit MinipoolDequeued(minipool, _key, block.timestamp);
        // Return
        return minipool;
    }

    /// @dev Remove a minipool from a queue. Only accepts calls from registered minipools
    function removeMinipool(MinipoolDeposit _depositType) override external onlyLatestContract("rocketMinipoolQueue", address(this)) onlyRegisteredMinipool(msg.sender) {
        // Remove minipool from queue
        if (_depositType == MinipoolDeposit.Half) { return removeMinipool(queueKeyHalf, msg.sender); }
        if (_depositType == MinipoolDeposit.Full) { return removeMinipool(queueKeyFull, msg.sender); }
        if (_depositType == MinipoolDeposit.Variable) { return removeMinipool(queueKeyVariable, msg.sender); }
        require(false, "Invalid minipool deposit type");
    }

    /// @dev Removes a minipool from a queue given an internal key
    /// @param _key The internal key representation of the queue from which to remove a minipool from
    /// @param _minipool The address of a minipool to remove from the specified queue
    function removeMinipool(bytes32 _key, address _minipool) private {
        // Remove
        AddressQueueStorageInterface addressQueueStorage = AddressQueueStorageInterface(getContractAddress("addressQueueStorage"));
        addressQueueStorage.removeItem(_key, _minipool);
        // Emit removed event
        emit MinipoolRemoved(_minipool, _key, block.timestamp);
    }

    /// @notice Returns the minipool address of the minipool in the global queue at a given index
    /// @param _index The index into the queue to retrieve
    function getMinipoolAt(uint256 _index) override external view returns(address) {
        AddressQueueStorageInterface addressQueueStorage = AddressQueueStorageInterface(getContractAddress("addressQueueStorage"));

        // Check if index is in the half queue
        uint256 halfLength = addressQueueStorage.getLength(queueKeyHalf);
        if (_index < halfLength) {
            return addressQueueStorage.getItem(queueKeyHalf, _index);
        }
        _index = _index.sub(halfLength);

        // Check if index is in the full queue
        uint256 fullLength = addressQueueStorage.getLength(queueKeyFull);
        if (_index < fullLength) {
            return addressQueueStorage.getItem(queueKeyFull, _index);
        }
        _index = _index.sub(fullLength);

        // Check if index is in the full queue
        uint256 variableLength = addressQueueStorage.getLength(queueKeyVariable);
        if (_index < variableLength) {
            return addressQueueStorage.getItem(queueKeyVariable, _index);
        }

        // Index is out of bounds
        return address(0);
    }

    /// @notice Returns the position a given minipool is in the queue
    /// @param _minipool The minipool to query the position of
    function getMinipoolPosition(address _minipool) override external view returns (int256) {
        AddressQueueStorageInterface addressQueueStorage = AddressQueueStorageInterface(getContractAddress("addressQueueStorage"));
        int256 position;

        // Check in half queue
        position = addressQueueStorage.getIndexOf(queueKeyHalf, _minipool);
        if (position != -1) {
            return position;
        }
        int256 offset = SafeCast.toInt256(addressQueueStorage.getLength(queueKeyHalf));

        // Check in full queue
        position = addressQueueStorage.getIndexOf(queueKeyFull, _minipool);
        if (position != -1) {
            return offset.add(position);
        }
        offset = offset.add(SafeCast.toInt256(addressQueueStorage.getLength(queueKeyFull)));

        // Check in variable queue
        position = addressQueueStorage.getIndexOf(queueKeyVariable, _minipool);
        if (position != -1) {
            return offset.add(position);
        }

        // Isn't in the queue
        return -1;
    }
}

/**
  *       .
  *      / \
  *     |.'.|
  *     |'.'|
  *   ,'|   |`.
  *  |,-'-|-'-.|
  *   __|_| |         _        _      _____           _
  *  | ___ \|        | |      | |    | ___ \         | |
  *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
  *  |    // _ \ / __| |/ / _ \ __|  |  __/ _ \ / _ \| |
  *  | |\ \ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
  *  \_| \_\___/ \___|_|\_\___|\__|  \_|  \___/ \___/|_|
  * +---------------------------------------------------+
  * |  DECENTRALISED STAKING PROTOCOL FOR ETHEREUM 2.0  |
  * +---------------------------------------------------+
  *
  *  Rocket Pool is a first-of-its-kind ETH2 Proof of Stake protocol, designed to be community owned,
  *  decentralised, trustless and compatible with staking in Ethereum 2.0.
  *
  *  For more information about Rocket Pool, visit https://rocketpool.net
  *
  *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
  *
  */

pragma solidity >0.5.0 <0.9.0;

// SPDX-License-Identifier: GPL-3.0-only

import "../../types/MinipoolDeposit.sol";

interface RocketMinipoolQueueInterface {
    function getTotalLength() external view returns (uint256);
    function getContainsLegacy() external view returns (bool);
    function getLengthLegacy(MinipoolDeposit _depositType) external view returns (uint256);
    function getLength() external view returns (uint256);
    function getTotalCapacity() external view returns (uint256);
    function getEffectiveCapacity() external view returns (uint256);
    function getNextCapacityLegacy() external view returns (uint256);
    function getNextDepositLegacy() external view returns (MinipoolDeposit, uint256);
    function enqueueMinipool(address _minipool) external;
    function dequeueMinipoolByDepositLegacy(MinipoolDeposit _depositType) external returns (address minipoolAddress);
    function dequeueMinipools(uint256 _maxToDequeue) external returns (address[] memory minipoolAddress);
    function removeMinipool(MinipoolDeposit _depositType) external;
    function getMinipoolAt(uint256 _index) external view returns(address);
    function getMinipoolPosition(address _minipool) external view returns (int256);
}

/**
  *       .
  *      / \
  *     |.'.|
  *     |'.'|
  *   ,'|   |`.
  *  |,-'-|-'-.|
  *   __|_| |         _        _      _____           _
  *  | ___ \|        | |      | |    | ___ \         | |
  *  | |_/ /|__   ___| | _____| |_   | |_/ /__   ___ | |
  *  |    // _ \ / __| |/ / _ \ __|  |  __/ _ \ / _ \| |
  *  | |\ \ (_) | (__|   <  __/ |_   | | | (_) | (_) | |
  *  \_| \_\___/ \___|_|\_\___|\__|  \_|  \___/ \___/|_|
  * +---------------------------------------------------+
  * |  DECENTRALISED STAKING PROTOCOL FOR ETHEREUM 2.0  |
  * +---------------------------------------------------+
  *
  *  Rocket Pool is a first-of-its-kind ETH2 Proof of Stake protocol, designed to be community owned,
  *  decentralised, trustless and compatible with staking in Ethereum 2.0.
  *
  *  For more information about Rocket Pool, visit https://rocketpool.net
  *
  *  Authors: David Rugendyke, Jake Pospischil, Kane Wallmann, Darren Langley, Joe Clapis, Nick Doherty
  *
  */

pragma solidity >0.5.0 <0.9.0;

// SPDX-License-Identifier: GPL-3.0-only

interface RocketStorageInterface {

    // Deploy status
    function getDeployedStatus() external view returns (bool);

    // Guardian
    function getGuardian() external view returns(address);
    function setGuardian(address _newAddress) external;
    function confirmGuardian() external;

    // Getters
    function getAddress(bytes32 _key) external view returns (address);
    function getUint(bytes32 _key) external view returns (uint);
    function getString(bytes32 _key) external view returns (string memory);
    function getBytes(bytes32 _key) external view returns (bytes memory);
    function getBool(bytes32 _key) external view returns (bool);
    function getInt(bytes32 _key) external view returns (int);
    function getBytes32(bytes32 _key) external view returns (bytes32);

    // Setters
    function setAddress(bytes32 _key, address _value) external;
    function setUint(bytes32 _key, uint _value) external;
    function setString(bytes32 _key, string calldata _value) external;
    function setBytes(bytes32 _key, bytes calldata _value) external;
    function setBool(bytes32 _key, bool _value) external;
    function setInt(bytes32 _key, int _value) external;
    function setBytes32(bytes32 _key, bytes32 _value) external;

    // Deleters
    function deleteAddress(bytes32 _key) external;
    function deleteUint(bytes32 _key) external;
    function deleteString(bytes32 _key) external;
    function deleteBytes(bytes32 _key) external;
    function deleteBool(bytes32 _key) external;
    function deleteInt(bytes32 _key) external;
    function deleteBytes32(bytes32 _key) external;

    // Arithmetic
    function addUint(bytes32 _key, uint256 _amount) external;
    function subUint(bytes32 _key, uint256 _amount) external;

    // Protected storage
    function getNodeWithdrawalAddress(address _nodeAddress) external view returns (address);
    function getNodePendingWithdrawalAddress(address _nodeAddress) external view returns (address);
    function setWithdrawalAddress(address _nodeAddress, address _newWithdrawalAddress, bool _confirm) external;
    function confirmWithdrawalAddress(address _nodeAddress) external;
}

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;


/**
 * @dev Wrappers over Solidity's uintXX/intXX casting operators with added overflow
 * checks.
 *
 * Downcasting from uint256/int256 in Solidity does not revert on overflow. This can
 * easily result in undesired exploitation or bugs, since developers usually
 * assume that overflows raise errors. `SafeCast` restores this intuition by
 * reverting the transaction when such an operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 *
 * Can be combined with {SafeMath} and {SignedSafeMath} to extend it to smaller types, by performing
 * all math on `uint256` and `int256` and then downcasting.
 */
library SafeCast {

    /**
     * @dev Returns the downcasted uint128 from uint256, reverting on
     * overflow (when the input is greater than largest uint128).
     *
     * Counterpart to Solidity's `uint128` operator.
     *
     * Requirements:
     *
     * - input must fit into 128 bits
     */
    function toUint128(uint256 value) internal pure returns (uint128) {
        require(value < 2**128, "SafeCast: value doesn\'t fit in 128 bits");
        return uint128(value);
    }

    /**
     * @dev Returns the downcasted uint64 from uint256, reverting on
     * overflow (when the input is greater than largest uint64).
     *
     * Counterpart to Solidity's `uint64` operator.
     *
     * Requirements:
     *
     * - input must fit into 64 bits
     */
    function toUint64(uint256 value) internal pure returns (uint64) {
        require(value < 2**64, "SafeCast: value doesn\'t fit in 64 bits");
        return uint64(value);
    }

    /**
     * @dev Returns the downcasted uint32 from uint256, reverting on
     * overflow (when the input is greater than largest uint32).
     *
     * Counterpart to Solidity's `uint32` operator.
     *
     * Requirements:
     *
     * - input must fit into 32 bits
     */
    function toUint32(uint256 value) internal pure returns (uint32) {
        require(value < 2**32, "SafeCast: value doesn\'t fit in 32 bits");
        return uint32(value);
    }

    /**
     * @dev Returns the downcasted uint16 from uint256, reverting on
     * overflow (when the input is greater than largest uint16).
     *
     * Counterpart to Solidity's `uint16` operator.
     *
     * Requirements:
     *
     * - input must fit into 16 bits
     */
    function toUint16(uint256 value) internal pure returns (uint16) {
        require(value < 2**16, "SafeCast: value doesn\'t fit in 16 bits");
        return uint16(value);
    }

    /**
     * @dev Returns the downcasted uint8 from uint256, reverting on
     * overflow (when the input is greater than largest uint8).
     *
     * Counterpart to Solidity's `uint8` operator.
     *
     * Requirements:
     *
     * - input must fit into 8 bits.
     */
    function toUint8(uint256 value) internal pure returns (uint8) {
        require(value < 2**8, "SafeCast: value doesn\'t fit in 8 bits");
        return uint8(value);
    }

    /**
     * @dev Converts a signed int256 into an unsigned uint256.
     *
     * Requirements:
     *
     * - input must be greater than or equal to 0.
     */
    function toUint256(int256 value) internal pure returns (uint256) {
        require(value >= 0, "SafeCast: value must be positive");
        return uint256(value);
    }

    /**
     * @dev Returns the downcasted int128 from int256, reverting on
     * overflow (when the input is less than smallest int128 or
     * greater than largest int128).
     *
     * Counterpart to Solidity's `int128` operator.
     *
     * Requirements:
     *
     * - input must fit into 128 bits
     *
     * _Available since v3.1._
     */
    function toInt128(int256 value) internal pure returns (int128) {
        require(value >= -2**127 && value < 2**127, "SafeCast: value doesn\'t fit in 128 bits");
        return int128(value);
    }

    /**
     * @dev Returns the downcasted int64 from int256, reverting on
     * overflow (when the input is less than smallest int64 or
     * greater than largest int64).
     *
     * Counterpart to Solidity's `int64` operator.
     *
     * Requirements:
     *
     * - input must fit into 64 bits
     *
     * _Available since v3.1._
     */
    function toInt64(int256 value) internal pure returns (int64) {
        require(value >= -2**63 && value < 2**63, "SafeCast: value doesn\'t fit in 64 bits");
        return int64(value);
    }

    /**
     * @dev Returns the downcasted int32 from int256, reverting on
     * overflow (when the input is less than smallest int32 or
     * greater than largest int32).
     *
     * Counterpart to Solidity's `int32` operator.
     *
     * Requirements:
     *
     * - input must fit into 32 bits
     *
     * _Available since v3.1._
     */
    function toInt32(int256 value) internal pure returns (int32) {
        require(value >= -2**31 && value < 2**31, "SafeCast: value doesn\'t fit in 32 bits");
        return int32(value);
    }

    /**
     * @dev Returns the downcasted int16 from int256, reverting on
     * overflow (when the input is less than smallest int16 or
     * greater than largest int16).
     *
     * Counterpart to Solidity's `int16` operator.
     *
     * Requirements:
     *
     * - input must fit into 16 bits
     *
     * _Available since v3.1._
     */
    function toInt16(int256 value) internal pure returns (int16) {
        require(value >= -2**15 && value < 2**15, "SafeCast: value doesn\'t fit in 16 bits");
        return int16(value);
    }

    /**
     * @dev Returns the downcasted int8 from int256, reverting on
     * overflow (when the input is less than smallest int8 or
     * greater than largest int8).
     *
     * Counterpart to Solidity's `int8` operator.
     *
     * Requirements:
     *
     * - input must fit into 8 bits.
     *
     * _Available since v3.1._
     */
    function toInt8(int256 value) internal pure returns (int8) {
        require(value >= -2**7 && value < 2**7, "SafeCast: value doesn\'t fit in 8 bits");
        return int8(value);
    }

    /**
     * @dev Converts an unsigned uint256 into a signed int256.
     *
     * Requirements:
     *
     * - input must be less than or equal to maxInt256.
     */
    function toInt256(uint256 value) internal pure returns (int256) {
        require(value < 2**255, "SafeCast: value doesn't fit in an int256");
        return int256(value);
    }
}

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        uint256 c = a + b;
        if (c < a) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b > a) return (false, 0);
        return (true, a - b);
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) return (true, 0);
        uint256 c = a * b;
        if (c / a != b) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a / b);
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a % b);
    }

    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SafeMath: subtraction overflow");
        return a - b;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) return 0;
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: division by zero");
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: modulo by zero");
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        return a - b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryDiv}.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        return a % b;
    }
}

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @title SignedSafeMath
 * @dev Signed math operations with safety checks that revert on error.
 */
library SignedSafeMath {
    int256 constant private _INT256_MIN = -2**255;

    /**
     * @dev Returns the multiplication of two signed integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(int256 a, int256 b) internal pure returns (int256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        require(!(a == -1 && b == _INT256_MIN), "SignedSafeMath: multiplication overflow");

        int256 c = a * b;
        require(c / a == b, "SignedSafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two signed integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(int256 a, int256 b) internal pure returns (int256) {
        require(b != 0, "SignedSafeMath: division by zero");
        require(!(b == -1 && a == _INT256_MIN), "SignedSafeMath: division overflow");

        int256 c = a / b;

        return c;
    }

    /**
     * @dev Returns the subtraction of two signed integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(int256 a, int256 b) internal pure returns (int256) {
        int256 c = a - b;
        require((b >= 0 && c <= a) || (b < 0 && c > a), "SignedSafeMath: subtraction overflow");

        return c;
    }

    /**
     * @dev Returns the addition of two signed integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(int256 a, int256 b) internal pure returns (int256) {
        int256 c = a + b;
        require((b >= 0 && c >= a) || (b < 0 && c < a), "SignedSafeMath: addition overflow");

        return c;
    }
}

{
  "compilationTarget": {
    "contracts/contract/minipool/RocketMinipoolQueue.sol": "RocketMinipoolQueue"
  },
  "evmVersion": "istanbul",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 15000
  },
  "remappings": []
}