// SPDX-License-Identifier: BSD-3-Clause
/// @title The Nouns DAO proxy contract
/*********************************
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// LICENSE
// NounsDAOProxy.sol is a modified version of Compound Lab's GovernorBravoDelegator.sol:
// https://github.com/compound-finance/compound-protocol/blob/b9b14038612d846b83f8a009a82c38974ff2dcfe/contracts/Governance/GovernorBravoDelegator.sol
//
// GovernorBravoDelegator.sol source code Copyright 2020 Compound Labs, Inc. licensed under the BSD-3-Clause license.
// With modifications by Nounders DAO.
//
// Additional conditions of BSD-3-Clause can be found here: https://opensource.org/licenses/BSD-3-Clause
//
//
// NounsDAOProxy.sol uses parts of Open Zeppelin's Proxy.sol:
// https://github.com/OpenZeppelin/openzeppelin-contracts/blob/5c8746f56b4bed8cc9e0e044f5f69ab2f9428ce1/contracts/proxy/Proxy.sol
//
// Proxy.sol source code licensed under MIT License.
//
// MODIFICATIONS
// The fallback() and receive() functions of Proxy.sol have been used to allow Solidity > 0.6.0 compatibility
pragma solidity ^0.8.6;
import './NounsDAOInterfaces.sol';
contract NounsDAOProxy is NounsDAOProxyStorage, NounsDAOEvents {
    constructor(
        address timelock_,
        address nouns_,
        address vetoer_,
        address admin_,
        address implementation_,
        uint256 votingPeriod_,
        uint256 votingDelay_,
        uint256 proposalThresholdBPS_,
        uint256 quorumVotesBPS_
    ) {
        // Admin set to msg.sender for initialization
        admin = msg.sender;
        delegateTo(
            implementation_,
            abi.encodeWithSignature(
                'initialize(address,address,address,uint256,uint256,uint256,uint256)',
                timelock_,
                nouns_,
                vetoer_,
                votingPeriod_,
                votingDelay_,
                proposalThresholdBPS_,
                quorumVotesBPS_
            )
        );
        _setImplementation(implementation_);
        admin = admin_;
    }
    /**
     * @notice Called by the admin to update the implementation of the delegator
     * @param implementation_ The address of the new implementation for delegation
     */
    function _setImplementation(address implementation_) public {
        require(msg.sender == admin, 'NounsDAOProxy::_setImplementation: admin only');
        require(implementation_ != address(0), 'NounsDAOProxy::_setImplementation: invalid implementation address');
        address oldImplementation = implementation;
        implementation = implementation_;
        emit NewImplementation(oldImplementation, implementation);
    }
    /**
     * @notice Internal method to delegate execution to another contract
     * @dev It returns to the external caller whatever the implementation returns or forwards reverts
     * @param callee The contract to delegatecall
     * @param data The raw data to delegatecall
     */
    function delegateTo(address callee, bytes memory data) internal {
        (bool success, bytes memory returnData) = callee.delegatecall(data);
        assembly {
            if eq(success, 0) {
                revert(add(returnData, 0x20), returndatasize())
            }
        }
    }
    /**
     * @dev Delegates execution to an implementation contract.
     * It returns to the external caller whatever the implementation returns
     * or forwards reverts.
     */
    function _fallback() internal {
        // delegate all other functions to current implementation
        (bool success, ) = implementation.delegatecall(msg.data);
        assembly {
            let free_mem_ptr := mload(0x40)
            returndatacopy(free_mem_ptr, 0, returndatasize())
            switch success
            case 0 {
                revert(free_mem_ptr, returndatasize())
            }
            default {
                return(free_mem_ptr, returndatasize())
            }
        }
    }
    /**
     * @dev Fallback function that delegates calls to the `implementation`. Will run if no other
     * function in the contract matches the call data.
     */
    fallback() external payable {
        _fallback();
    }
    /**
     * @dev Fallback function that delegates calls to `implementation`. Will run if call data
     * is empty.
     */
    receive() external payable {
        _fallback();
    }
}
// SPDX-License-Identifier: BSD-3-Clause
/// @title Nouns DAO Logic interfaces and events
/*********************************
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 *********************************/
// LICENSE
// NounsDAOInterfaces.sol is a modified version of Compound Lab's GovernorBravoInterfaces.sol:
// https://github.com/compound-finance/compound-protocol/blob/b9b14038612d846b83f8a009a82c38974ff2dcfe/contracts/Governance/GovernorBravoInterfaces.sol
//
// GovernorBravoInterfaces.sol source code Copyright 2020 Compound Labs, Inc. licensed under the BSD-3-Clause license.
// With modifications by Nounders DAO.
//
// Additional conditions of BSD-3-Clause can be found here: https://opensource.org/licenses/BSD-3-Clause
//
// MODIFICATIONS
// NounsDAOEvents, NounsDAOProxyStorage, NounsDAOStorageV1 adds support for changes made by Nouns DAO to GovernorBravo.sol
// See NounsDAOLogicV1.sol for more details.
pragma solidity ^0.8.6;
contract NounsDAOEvents {
    /// @notice An event emitted when a new proposal is created
    event ProposalCreated(
        uint256 id,
        address proposer,
        address[] targets,
        uint256[] values,
        string[] signatures,
        bytes[] calldatas,
        uint256 startBlock,
        uint256 endBlock,
        string description
    );
    event ProposalCreatedWithRequirements(
        uint256 id,
        address proposer,
        address[] targets,
        uint256[] values,
        string[] signatures,
        bytes[] calldatas,
        uint256 startBlock,
        uint256 endBlock,
        uint256 proposalThreshold,
        uint256 quorumVotes,
        string description
    );
    /// @notice An event emitted when a vote has been cast on a proposal
    /// @param voter The address which casted a vote
    /// @param proposalId The proposal id which was voted on
    /// @param support Support value for the vote. 0=against, 1=for, 2=abstain
    /// @param votes Number of votes which were cast by the voter
    /// @param reason The reason given for the vote by the voter
    event VoteCast(address indexed voter, uint256 proposalId, uint8 support, uint256 votes, string reason);
    /// @notice An event emitted when a proposal has been canceled
    event ProposalCanceled(uint256 id);
    /// @notice An event emitted when a proposal has been queued in the NounsDAOExecutor
    event ProposalQueued(uint256 id, uint256 eta);
    /// @notice An event emitted when a proposal has been executed in the NounsDAOExecutor
    event ProposalExecuted(uint256 id);
    /// @notice An event emitted when a proposal has been vetoed by vetoAddress
    event ProposalVetoed(uint256 id);
    /// @notice An event emitted when the voting delay is set
    event VotingDelaySet(uint256 oldVotingDelay, uint256 newVotingDelay);
    /// @notice An event emitted when the voting period is set
    event VotingPeriodSet(uint256 oldVotingPeriod, uint256 newVotingPeriod);
    /// @notice Emitted when implementation is changed
    event NewImplementation(address oldImplementation, address newImplementation);
    /// @notice Emitted when proposal threshold basis points is set
    event ProposalThresholdBPSSet(uint256 oldProposalThresholdBPS, uint256 newProposalThresholdBPS);
    /// @notice Emitted when quorum votes basis points is set
    event QuorumVotesBPSSet(uint256 oldQuorumVotesBPS, uint256 newQuorumVotesBPS);
    /// @notice Emitted when pendingAdmin is changed
    event NewPendingAdmin(address oldPendingAdmin, address newPendingAdmin);
    /// @notice Emitted when pendingAdmin is accepted, which means admin is updated
    event NewAdmin(address oldAdmin, address newAdmin);
    /// @notice Emitted when vetoer is changed
    event NewVetoer(address oldVetoer, address newVetoer);
}
contract NounsDAOProxyStorage {
    /// @notice Administrator for this contract
    address public admin;
    /// @notice Pending administrator for this contract
    address public pendingAdmin;
    /// @notice Active brains of Governor
    address public implementation;
}
/**
 * @title Storage for Governor Bravo Delegate
 * @notice For future upgrades, do not change NounsDAOStorageV1. Create a new
 * contract which implements NounsDAOStorageV1 and following the naming convention
 * NounsDAOStorageVX.
 */
contract NounsDAOStorageV1 is NounsDAOProxyStorage {
    /// @notice Vetoer who has the ability to veto any proposal
    address public vetoer;
    /// @notice The delay before voting on a proposal may take place, once proposed, in blocks
    uint256 public votingDelay;
    /// @notice The duration of voting on a proposal, in blocks
    uint256 public votingPeriod;
    /// @notice The basis point number of votes required in order for a voter to become a proposer. *DIFFERS from GovernerBravo
    uint256 public proposalThresholdBPS;
    /// @notice The basis point number of votes in support of a proposal required in order for a quorum to be reached and for a vote to succeed. *DIFFERS from GovernerBravo
    uint256 public quorumVotesBPS;
    /// @notice The total number of proposals
    uint256 public proposalCount;
    /// @notice The address of the Nouns DAO Executor NounsDAOExecutor
    INounsDAOExecutor public timelock;
    /// @notice The address of the Nouns tokens
    NounsTokenLike public nouns;
    /// @notice The official record of all proposals ever proposed
    mapping(uint256 => Proposal) public proposals;
    /// @notice The latest proposal for each proposer
    mapping(address => uint256) public latestProposalIds;
    struct Proposal {
        /// @notice Unique id for looking up a proposal
        uint256 id;
        /// @notice Creator of the proposal
        address proposer;
        /// @notice The number of votes needed to create a proposal at the time of proposal creation. *DIFFERS from GovernerBravo
        uint256 proposalThreshold;
        /// @notice The number of votes in support of a proposal required in order for a quorum to be reached and for a vote to succeed at the time of proposal creation. *DIFFERS from GovernerBravo
        uint256 quorumVotes;
        /// @notice The timestamp that the proposal will be available for execution, set once the vote succeeds
        uint256 eta;
        /// @notice the ordered list of target addresses for calls to be made
        address[] targets;
        /// @notice The ordered list of values (i.e. msg.value) to be passed to the calls to be made
        uint256[] values;
        /// @notice The ordered list of function signatures to be called
        string[] signatures;
        /// @notice The ordered list of calldata to be passed to each call
        bytes[] calldatas;
        /// @notice The block at which voting begins: holders must delegate their votes prior to this block
        uint256 startBlock;
        /// @notice The block at which voting ends: votes must be cast prior to this block
        uint256 endBlock;
        /// @notice Current number of votes in favor of this proposal
        uint256 forVotes;
        /// @notice Current number of votes in opposition to this proposal
        uint256 againstVotes;
        /// @notice Current number of votes for abstaining for this proposal
        uint256 abstainVotes;
        /// @notice Flag marking whether the proposal has been canceled
        bool canceled;
        /// @notice Flag marking whether the proposal has been vetoed
        bool vetoed;
        /// @notice Flag marking whether the proposal has been executed
        bool executed;
        /// @notice Receipts of ballots for the entire set of voters
        mapping(address => Receipt) receipts;
    }
    /// @notice Ballot receipt record for a voter
    struct Receipt {
        /// @notice Whether or not a vote has been cast
        bool hasVoted;
        /// @notice Whether or not the voter supports the proposal or abstains
        uint8 support;
        /// @notice The number of votes the voter had, which were cast
        uint96 votes;
    }
    /// @notice Possible states that a proposal may be in
    enum ProposalState {
        Pending,
        Active,
        Canceled,
        Defeated,
        Succeeded,
        Queued,
        Expired,
        Executed,
        Vetoed
    }
}
interface INounsDAOExecutor {
    function delay() external view returns (uint256);
    function GRACE_PERIOD() external view returns (uint256);
    function acceptAdmin() external;
    function queuedTransactions(bytes32 hash) external view returns (bool);
    function queueTransaction(
        address target,
        uint256 value,
        string calldata signature,
        bytes calldata data,
        uint256 eta
    ) external returns (bytes32);
    function cancelTransaction(
        address target,
        uint256 value,
        string calldata signature,
        bytes calldata data,
        uint256 eta
    ) external;
    function executeTransaction(
        address target,
        uint256 value,
        string calldata signature,
        bytes calldata data,
        uint256 eta
    ) external payable returns (bytes memory);
}
interface NounsTokenLike {
    function getPriorVotes(address account, uint256 blockNumber) external view returns (uint96);
    function totalSupply() external view returns (uint96);
}

// SPDX-License-Identifier: BSD-3-Clause
/// @title The Nouns DAO logic version 2
/*********************************
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 *********************************/
// LICENSE
// NounsDAOLogicV2.sol is a modified version of Compound Lab's GovernorBravoDelegate.sol:
// https://github.com/compound-finance/compound-protocol/blob/b9b14038612d846b83f8a009a82c38974ff2dcfe/contracts/Governance/GovernorBravoDelegate.sol
//
// GovernorBravoDelegate.sol source code Copyright 2020 Compound Labs, Inc. licensed under the BSD-3-Clause license.
// With modifications by Nounders DAO.
//
// Additional conditions of BSD-3-Clause can be found here: https://opensource.org/licenses/BSD-3-Clause
//
// MODIFICATIONS
// See NounsDAOLogicV1 for initial GovernorBravoDelegate modifications.
// NounsDAOLogicV2 adds:
// - `quorumParamsCheckpoints`, which store dynamic quorum parameters checkpoints
// to be used when calculating the dynamic quorum.
// - `_setDynamicQuorumParams(DynamicQuorumParams memory params)`, which allows the
// DAO to update the dynamic quorum parameters' values.
// - `getDynamicQuorumParamsAt(uint256 blockNumber_)`
// - Individual setters of the DynamicQuorumParams members:
//    - `_setMinQuorumVotesBPS(uint16 newMinQuorumVotesBPS)`
//    - `_setMaxQuorumVotesBPS(uint16 newMaxQuorumVotesBPS)`
//    - `_setQuorumCoefficient(uint32 newQuorumCoefficient)`
// - `minQuorumVotes` and `maxQuorumVotes`, which returns the current min and
// max quorum votes using the current Noun supply.
// - New `Proposal` struct member:
//    - `totalSupply` used in dynamic quorum calculation.
//    - `creationBlock` used for retrieving checkpoints of votes and dynamic quorum params. This now
// allows changing `votingDelay` without affecting the checkpoints lookup.
// - `quorumVotes(uint256 proposalId)`, which calculates and returns the dynamic
// quorum for a specific proposal.
// - `proposals(uint256 proposalId)` instead of the implicit getter, to avoid stack-too-deep error
//
// NounsDAOLogicV2 removes:
// - `quorumVotes()` has been replaced by `quorumVotes(uint256 proposalId)`.
pragma solidity ^0.8.6;
import './NounsDAOInterfaces.sol';
contract NounsDAOLogicV2 is NounsDAOStorageV2, NounsDAOEventsV2 {
    /// @notice The name of this contract
    string public constant name = 'Nouns DAO';
    /// @notice The minimum setable proposal threshold
    uint256 public constant MIN_PROPOSAL_THRESHOLD_BPS = 1; // 1 basis point or 0.01%
    /// @notice The maximum setable proposal threshold
    uint256 public constant MAX_PROPOSAL_THRESHOLD_BPS = 1_000; // 1,000 basis points or 10%
    /// @notice The minimum setable voting period
    uint256 public constant MIN_VOTING_PERIOD = 5_760; // About 24 hours
    /// @notice The max setable voting period
    uint256 public constant MAX_VOTING_PERIOD = 80_640; // About 2 weeks
    /// @notice The min setable voting delay
    uint256 public constant MIN_VOTING_DELAY = 1;
    /// @notice The max setable voting delay
    uint256 public constant MAX_VOTING_DELAY = 40_320; // About 1 week
    /// @notice The lower bound of minimum quorum votes basis points
    uint256 public constant MIN_QUORUM_VOTES_BPS_LOWER_BOUND = 200; // 200 basis points or 2%
    /// @notice The upper bound of minimum quorum votes basis points
    uint256 public constant MIN_QUORUM_VOTES_BPS_UPPER_BOUND = 2_000; // 2,000 basis points or 20%
    /// @notice The upper bound of maximum quorum votes basis points
    uint256 public constant MAX_QUORUM_VOTES_BPS_UPPER_BOUND = 6_000; // 4,000 basis points or 60%
    /// @notice The maximum setable quorum votes basis points
    uint256 public constant MAX_QUORUM_VOTES_BPS = 2_000; // 2,000 basis points or 20%
    /// @notice The maximum number of actions that can be included in a proposal
    uint256 public constant proposalMaxOperations = 10; // 10 actions
    /// @notice The maximum priority fee used to cap gas refunds in `castRefundableVote`
    uint256 public constant MAX_REFUND_PRIORITY_FEE = 2 gwei;
    /// @notice The vote refund gas overhead, including 7K for ETH transfer and 29K for general transaction overhead
    uint256 public constant REFUND_BASE_GAS = 36000;
    /// @notice The maximum gas units the DAO will refund voters on; supports about 9,190 characters
    uint256 public constant MAX_REFUND_GAS_USED = 200_000;
    /// @notice The maximum basefee the DAO will refund voters on
    uint256 public constant MAX_REFUND_BASE_FEE = 200 gwei;
    /// @notice The EIP-712 typehash for the contract's domain
    bytes32 public constant DOMAIN_TYPEHASH =
        keccak256('EIP712Domain(string name,uint256 chainId,address verifyingContract)');
    /// @notice The EIP-712 typehash for the ballot struct used by the contract
    bytes32 public constant BALLOT_TYPEHASH = keccak256('Ballot(uint256 proposalId,uint8 support)');
    /// @dev Introduced these errors to reduce contract size, to avoid deployment failure
    error AdminOnly();
    error InvalidMinQuorumVotesBPS();
    error InvalidMaxQuorumVotesBPS();
    error MinQuorumBPSGreaterThanMaxQuorumBPS();
    error UnsafeUint16Cast();
    error VetoerOnly();
    error PendingVetoerOnly();
    error VetoerBurned();
    error CantVetoExecutedProposal();
    error CantCancelExecutedProposal();
    /**
     * @notice Used to initialize the contract during delegator contructor
     * @param timelock_ The address of the NounsDAOExecutor
     * @param nouns_ The address of the NOUN tokens
     * @param vetoer_ The address allowed to unilaterally veto proposals
     * @param votingPeriod_ The initial voting period
     * @param votingDelay_ The initial voting delay
     * @param proposalThresholdBPS_ The initial proposal threshold in basis points
     * @param dynamicQuorumParams_ The initial dynamic quorum parameters
     */
    function initialize(
        address timelock_,
        address nouns_,
        address vetoer_,
        uint256 votingPeriod_,
        uint256 votingDelay_,
        uint256 proposalThresholdBPS_,
        DynamicQuorumParams calldata dynamicQuorumParams_
    ) public virtual {
        require(address(timelock) == address(0), 'NounsDAO::initialize: can only initialize once');
        if (msg.sender != admin) {
            revert AdminOnly();
        }
        require(timelock_ != address(0), 'NounsDAO::initialize: invalid timelock address');
        require(nouns_ != address(0), 'NounsDAO::initialize: invalid nouns address');
        require(
            votingPeriod_ >= MIN_VOTING_PERIOD && votingPeriod_ <= MAX_VOTING_PERIOD,
            'NounsDAO::initialize: invalid voting period'
        );
        require(
            votingDelay_ >= MIN_VOTING_DELAY && votingDelay_ <= MAX_VOTING_DELAY,
            'NounsDAO::initialize: invalid voting delay'
        );
        require(
            proposalThresholdBPS_ >= MIN_PROPOSAL_THRESHOLD_BPS && proposalThresholdBPS_ <= MAX_PROPOSAL_THRESHOLD_BPS,
            'NounsDAO::initialize: invalid proposal threshold bps'
        );
        emit VotingPeriodSet(votingPeriod, votingPeriod_);
        emit VotingDelaySet(votingDelay, votingDelay_);
        emit ProposalThresholdBPSSet(proposalThresholdBPS, proposalThresholdBPS_);
        timelock = INounsDAOExecutor(timelock_);
        nouns = NounsTokenLike(nouns_);
        vetoer = vetoer_;
        votingPeriod = votingPeriod_;
        votingDelay = votingDelay_;
        proposalThresholdBPS = proposalThresholdBPS_;
        _setDynamicQuorumParams(
            dynamicQuorumParams_.minQuorumVotesBPS,
            dynamicQuorumParams_.maxQuorumVotesBPS,
            dynamicQuorumParams_.quorumCoefficient
        );
    }
    struct ProposalTemp {
        uint256 totalSupply;
        uint256 proposalThreshold;
        uint256 latestProposalId;
        uint256 startBlock;
        uint256 endBlock;
    }
    /**
     * @notice Function used to propose a new proposal. Sender must have delegates above the proposal threshold
     * @param targets Target addresses for proposal calls
     * @param values Eth values for proposal calls
     * @param signatures Function signatures for proposal calls
     * @param calldatas Calldatas for proposal calls
     * @param description String description of the proposal
     * @return Proposal id of new proposal
     */
    function propose(
        address[] memory targets,
        uint256[] memory values,
        string[] memory signatures,
        bytes[] memory calldatas,
        string memory description
    ) public returns (uint256) {
        ProposalTemp memory temp;
        temp.totalSupply = nouns.totalSupply();
        temp.proposalThreshold = bps2Uint(proposalThresholdBPS, temp.totalSupply);
        require(
            nouns.getPriorVotes(msg.sender, block.number - 1) > temp.proposalThreshold,
            'NounsDAO::propose: proposer votes below proposal threshold'
        );
        require(
            targets.length == values.length &&
                targets.length == signatures.length &&
                targets.length == calldatas.length,
            'NounsDAO::propose: proposal function information arity mismatch'
        );
        require(targets.length != 0, 'NounsDAO::propose: must provide actions');
        require(targets.length <= proposalMaxOperations, 'NounsDAO::propose: too many actions');
        temp.latestProposalId = latestProposalIds[msg.sender];
        if (temp.latestProposalId != 0) {
            ProposalState proposersLatestProposalState = state(temp.latestProposalId);
            require(
                proposersLatestProposalState != ProposalState.Active,
                'NounsDAO::propose: one live proposal per proposer, found an already active proposal'
            );
            require(
                proposersLatestProposalState != ProposalState.Pending,
                'NounsDAO::propose: one live proposal per proposer, found an already pending proposal'
            );
        }
        temp.startBlock = block.number + votingDelay;
        temp.endBlock = temp.startBlock + votingPeriod;
        proposalCount++;
        Proposal storage newProposal = _proposals[proposalCount];
        newProposal.id = proposalCount;
        newProposal.proposer = msg.sender;
        newProposal.proposalThreshold = temp.proposalThreshold;
        newProposal.eta = 0;
        newProposal.targets = targets;
        newProposal.values = values;
        newProposal.signatures = signatures;
        newProposal.calldatas = calldatas;
        newProposal.startBlock = temp.startBlock;
        newProposal.endBlock = temp.endBlock;
        newProposal.forVotes = 0;
        newProposal.againstVotes = 0;
        newProposal.abstainVotes = 0;
        newProposal.canceled = false;
        newProposal.executed = false;
        newProposal.vetoed = false;
        newProposal.totalSupply = temp.totalSupply;
        newProposal.creationBlock = block.number;
        latestProposalIds[newProposal.proposer] = newProposal.id;
        /// @notice Maintains backwards compatibility with GovernorBravo events
        emit ProposalCreated(
            newProposal.id,
            msg.sender,
            targets,
            values,
            signatures,
            calldatas,
            newProposal.startBlock,
            newProposal.endBlock,
            description
        );
        /// @notice Updated event with `proposalThreshold` and `minQuorumVotes`
        /// @notice `minQuorumVotes` is always zero since V2 introduces dynamic quorum with checkpoints
        emit ProposalCreatedWithRequirements(
            newProposal.id,
            msg.sender,
            targets,
            values,
            signatures,
            calldatas,
            newProposal.startBlock,
            newProposal.endBlock,
            newProposal.proposalThreshold,
            minQuorumVotes(),
            description
        );
        return newProposal.id;
    }
    /**
     * @notice Queues a proposal of state succeeded
     * @param proposalId The id of the proposal to queue
     */
    function queue(uint256 proposalId) external {
        require(
            state(proposalId) == ProposalState.Succeeded,
            'NounsDAO::queue: proposal can only be queued if it is succeeded'
        );
        Proposal storage proposal = _proposals[proposalId];
        uint256 eta = block.timestamp + timelock.delay();
        for (uint256 i = 0; i < proposal.targets.length; i++) {
            queueOrRevertInternal(
                proposal.targets[i],
                proposal.values[i],
                proposal.signatures[i],
                proposal.calldatas[i],
                eta
            );
        }
        proposal.eta = eta;
        emit ProposalQueued(proposalId, eta);
    }
    function queueOrRevertInternal(
        address target,
        uint256 value,
        string memory signature,
        bytes memory data,
        uint256 eta
    ) internal {
        require(
            !timelock.queuedTransactions(keccak256(abi.encode(target, value, signature, data, eta))),
            'NounsDAO::queueOrRevertInternal: identical proposal action already queued at eta'
        );
        timelock.queueTransaction(target, value, signature, data, eta);
    }
    /**
     * @notice Executes a queued proposal if eta has passed
     * @param proposalId The id of the proposal to execute
     */
    function execute(uint256 proposalId) external {
        require(
            state(proposalId) == ProposalState.Queued,
            'NounsDAO::execute: proposal can only be executed if it is queued'
        );
        Proposal storage proposal = _proposals[proposalId];
        proposal.executed = true;
        for (uint256 i = 0; i < proposal.targets.length; i++) {
            timelock.executeTransaction(
                proposal.targets[i],
                proposal.values[i],
                proposal.signatures[i],
                proposal.calldatas[i],
                proposal.eta
            );
        }
        emit ProposalExecuted(proposalId);
    }
    /**
     * @notice Cancels a proposal only if sender is the proposer, or proposer delegates dropped below proposal threshold
     * @param proposalId The id of the proposal to cancel
     */
    function cancel(uint256 proposalId) external {
        if (state(proposalId) == ProposalState.Executed) {
            revert CantCancelExecutedProposal();
        }
        Proposal storage proposal = _proposals[proposalId];
        require(
            msg.sender == proposal.proposer ||
                nouns.getPriorVotes(proposal.proposer, block.number - 1) <= proposal.proposalThreshold,
            'NounsDAO::cancel: proposer above threshold'
        );
        proposal.canceled = true;
        for (uint256 i = 0; i < proposal.targets.length; i++) {
            timelock.cancelTransaction(
                proposal.targets[i],
                proposal.values[i],
                proposal.signatures[i],
                proposal.calldatas[i],
                proposal.eta
            );
        }
        emit ProposalCanceled(proposalId);
    }
    /**
     * @notice Vetoes a proposal only if sender is the vetoer and the proposal has not been executed.
     * @param proposalId The id of the proposal to veto
     */
    function veto(uint256 proposalId) external {
        if (vetoer == address(0)) {
            revert VetoerBurned();
        }
        if (msg.sender != vetoer) {
            revert VetoerOnly();
        }
        if (state(proposalId) == ProposalState.Executed) {
            revert CantVetoExecutedProposal();
        }
        Proposal storage proposal = _proposals[proposalId];
        proposal.vetoed = true;
        for (uint256 i = 0; i < proposal.targets.length; i++) {
            timelock.cancelTransaction(
                proposal.targets[i],
                proposal.values[i],
                proposal.signatures[i],
                proposal.calldatas[i],
                proposal.eta
            );
        }
        emit ProposalVetoed(proposalId);
    }
    /**
     * @notice Gets actions of a proposal
     * @param proposalId the id of the proposal
     * @return targets
     * @return values
     * @return signatures
     * @return calldatas
     */
    function getActions(uint256 proposalId)
        external
        view
        returns (
            address[] memory targets,
            uint256[] memory values,
            string[] memory signatures,
            bytes[] memory calldatas
        )
    {
        Proposal storage p = _proposals[proposalId];
        return (p.targets, p.values, p.signatures, p.calldatas);
    }
    /**
     * @notice Gets the receipt for a voter on a given proposal
     * @param proposalId the id of proposal
     * @param voter The address of the voter
     * @return The voting receipt
     */
    function getReceipt(uint256 proposalId, address voter) external view returns (Receipt memory) {
        return _proposals[proposalId].receipts[voter];
    }
    /**
     * @notice Gets the state of a proposal
     * @param proposalId The id of the proposal
     * @return Proposal state
     */
    function state(uint256 proposalId) public view returns (ProposalState) {
        require(proposalCount >= proposalId, 'NounsDAO::state: invalid proposal id');
        Proposal storage proposal = _proposals[proposalId];
        if (proposal.vetoed) {
            return ProposalState.Vetoed;
        } else if (proposal.canceled) {
            return ProposalState.Canceled;
        } else if (block.number <= proposal.startBlock) {
            return ProposalState.Pending;
        } else if (block.number <= proposal.endBlock) {
            return ProposalState.Active;
        } else if (proposal.forVotes <= proposal.againstVotes || proposal.forVotes < quorumVotes(proposal.id)) {
            return ProposalState.Defeated;
        } else if (proposal.eta == 0) {
            return ProposalState.Succeeded;
        } else if (proposal.executed) {
            return ProposalState.Executed;
        } else if (block.timestamp >= proposal.eta + timelock.GRACE_PERIOD()) {
            return ProposalState.Expired;
        } else {
            return ProposalState.Queued;
        }
    }
    /**
     * @notice Returns the proposal details given a proposal id.
     *     The `quorumVotes` member holds the *current* quorum, given the current votes.
     * @param proposalId the proposal id to get the data for
     * @return A `ProposalCondensed` struct with the proposal data
     */
    function proposals(uint256 proposalId) external view returns (ProposalCondensed memory) {
        Proposal storage proposal = _proposals[proposalId];
        return
            ProposalCondensed({
                id: proposal.id,
                proposer: proposal.proposer,
                proposalThreshold: proposal.proposalThreshold,
                quorumVotes: quorumVotes(proposal.id),
                eta: proposal.eta,
                startBlock: proposal.startBlock,
                endBlock: proposal.endBlock,
                forVotes: proposal.forVotes,
                againstVotes: proposal.againstVotes,
                abstainVotes: proposal.abstainVotes,
                canceled: proposal.canceled,
                vetoed: proposal.vetoed,
                executed: proposal.executed,
                totalSupply: proposal.totalSupply,
                creationBlock: proposal.creationBlock
            });
    }
    /**
     * @notice Cast a vote for a proposal
     * @param proposalId The id of the proposal to vote on
     * @param support The support value for the vote. 0=against, 1=for, 2=abstain
     */
    function castVote(uint256 proposalId, uint8 support) external {
        emit VoteCast(msg.sender, proposalId, support, castVoteInternal(msg.sender, proposalId, support), '');
    }
    /**
     * @notice Cast a vote for a proposal, asking the DAO to refund gas costs.
     * Users with > 0 votes receive refunds. Refunds are partial when using a gas priority fee higher than the DAO's cap.
     * Refunds are partial when the DAO's balance is insufficient.
     * No refund is sent when the DAO's balance is empty. No refund is sent to users with no votes.
     * Voting takes place regardless of refund success.
     * @param proposalId The id of the proposal to vote on
     * @param support The support value for the vote. 0=against, 1=for, 2=abstain
     * @dev Reentrancy is defended against in `castVoteInternal` at the `receipt.hasVoted == false` require statement.
     */
    function castRefundableVote(uint256 proposalId, uint8 support) external {
        castRefundableVoteInternal(proposalId, support, '');
    }
    /**
     * @notice Cast a vote for a proposal, asking the DAO to refund gas costs.
     * Users with > 0 votes receive refunds. Refunds are partial when using a gas priority fee higher than the DAO's cap.
     * Refunds are partial when the DAO's balance is insufficient.
     * No refund is sent when the DAO's balance is empty. No refund is sent to users with no votes.
     * Voting takes place regardless of refund success.
     * @param proposalId The id of the proposal to vote on
     * @param support The support value for the vote. 0=against, 1=for, 2=abstain
     * @param reason The reason given for the vote by the voter
     * @dev Reentrancy is defended against in `castVoteInternal` at the `receipt.hasVoted == false` require statement.
     */
    function castRefundableVoteWithReason(
        uint256 proposalId,
        uint8 support,
        string calldata reason
    ) external {
        castRefundableVoteInternal(proposalId, support, reason);
    }
    /**
     * @notice Internal function that carries out refundable voting logic
     * @param proposalId The id of the proposal to vote on
     * @param support The support value for the vote. 0=against, 1=for, 2=abstain
     * @param reason The reason given for the vote by the voter
     * @dev Reentrancy is defended against in `castVoteInternal` at the `receipt.hasVoted == false` require statement.
     */
    function castRefundableVoteInternal(
        uint256 proposalId,
        uint8 support,
        string memory reason
    ) internal {
        uint256 startGas = gasleft();
        uint96 votes = castVoteInternal(msg.sender, proposalId, support);
        emit VoteCast(msg.sender, proposalId, support, votes, reason);
        if (votes > 0) {
            _refundGas(startGas);
        }
    }
    /**
     * @notice Cast a vote for a proposal with a reason
     * @param proposalId The id of the proposal to vote on
     * @param support The support value for the vote. 0=against, 1=for, 2=abstain
     * @param reason The reason given for the vote by the voter
     */
    function castVoteWithReason(
        uint256 proposalId,
        uint8 support,
        string calldata reason
    ) external {
        emit VoteCast(msg.sender, proposalId, support, castVoteInternal(msg.sender, proposalId, support), reason);
    }
    /**
     * @notice Cast a vote for a proposal by signature
     * @dev External function that accepts EIP-712 signatures for voting on proposals.
     */
    function castVoteBySig(
        uint256 proposalId,
        uint8 support,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external {
        bytes32 domainSeparator = keccak256(
            abi.encode(DOMAIN_TYPEHASH, keccak256(bytes(name)), getChainIdInternal(), address(this))
        );
        bytes32 structHash = keccak256(abi.encode(BALLOT_TYPEHASH, proposalId, support));
        bytes32 digest = keccak256(abi.encodePacked('\\x19\\x01', domainSeparator, structHash));
        address signatory = ecrecover(digest, v, r, s);
        require(signatory != address(0), 'NounsDAO::castVoteBySig: invalid signature');
        emit VoteCast(signatory, proposalId, support, castVoteInternal(signatory, proposalId, support), '');
    }
    /**
     * @notice Internal function that caries out voting logic
     * @param voter The voter that is casting their vote
     * @param proposalId The id of the proposal to vote on
     * @param support The support value for the vote. 0=against, 1=for, 2=abstain
     * @return The number of votes cast
     */
    function castVoteInternal(
        address voter,
        uint256 proposalId,
        uint8 support
    ) internal returns (uint96) {
        require(state(proposalId) == ProposalState.Active, 'NounsDAO::castVoteInternal: voting is closed');
        require(support <= 2, 'NounsDAO::castVoteInternal: invalid vote type');
        Proposal storage proposal = _proposals[proposalId];
        Receipt storage receipt = proposal.receipts[voter];
        require(receipt.hasVoted == false, 'NounsDAO::castVoteInternal: voter already voted');
        /// @notice: Unlike GovernerBravo, votes are considered from the block the proposal was created in order to normalize quorumVotes and proposalThreshold metrics
        uint96 votes = nouns.getPriorVotes(voter, proposalCreationBlock(proposal));
        if (support == 0) {
            proposal.againstVotes = proposal.againstVotes + votes;
        } else if (support == 1) {
            proposal.forVotes = proposal.forVotes + votes;
        } else if (support == 2) {
            proposal.abstainVotes = proposal.abstainVotes + votes;
        }
        receipt.hasVoted = true;
        receipt.support = support;
        receipt.votes = votes;
        return votes;
    }
    /**
     * @notice Admin function for setting the voting delay
     * @param newVotingDelay new voting delay, in blocks
     */
    function _setVotingDelay(uint256 newVotingDelay) external {
        if (msg.sender != admin) {
            revert AdminOnly();
        }
        require(
            newVotingDelay >= MIN_VOTING_DELAY && newVotingDelay <= MAX_VOTING_DELAY,
            'NounsDAO::_setVotingDelay: invalid voting delay'
        );
        uint256 oldVotingDelay = votingDelay;
        votingDelay = newVotingDelay;
        emit VotingDelaySet(oldVotingDelay, votingDelay);
    }
    /**
     * @notice Admin function for setting the voting period
     * @param newVotingPeriod new voting period, in blocks
     */
    function _setVotingPeriod(uint256 newVotingPeriod) external {
        if (msg.sender != admin) {
            revert AdminOnly();
        }
        require(
            newVotingPeriod >= MIN_VOTING_PERIOD && newVotingPeriod <= MAX_VOTING_PERIOD,
            'NounsDAO::_setVotingPeriod: invalid voting period'
        );
        uint256 oldVotingPeriod = votingPeriod;
        votingPeriod = newVotingPeriod;
        emit VotingPeriodSet(oldVotingPeriod, votingPeriod);
    }
    /**
     * @notice Admin function for setting the proposal threshold basis points
     * @dev newProposalThresholdBPS must be greater than the hardcoded min
     * @param newProposalThresholdBPS new proposal threshold
     */
    function _setProposalThresholdBPS(uint256 newProposalThresholdBPS) external {
        if (msg.sender != admin) {
            revert AdminOnly();
        }
        require(
            newProposalThresholdBPS >= MIN_PROPOSAL_THRESHOLD_BPS &&
                newProposalThresholdBPS <= MAX_PROPOSAL_THRESHOLD_BPS,
            'NounsDAO::_setProposalThreshold: invalid proposal threshold bps'
        );
        uint256 oldProposalThresholdBPS = proposalThresholdBPS;
        proposalThresholdBPS = newProposalThresholdBPS;
        emit ProposalThresholdBPSSet(oldProposalThresholdBPS, proposalThresholdBPS);
    }
    /**
     * @notice Admin function for setting the minimum quorum votes bps
     * @param newMinQuorumVotesBPS minimum quorum votes bps
     *     Must be between `MIN_QUORUM_VOTES_BPS_LOWER_BOUND` and `MIN_QUORUM_VOTES_BPS_UPPER_BOUND`
     *     Must be lower than or equal to maxQuorumVotesBPS
     */
    function _setMinQuorumVotesBPS(uint16 newMinQuorumVotesBPS) external {
        if (msg.sender != admin) {
            revert AdminOnly();
        }
        DynamicQuorumParams memory params = getDynamicQuorumParamsAt(block.number);
        require(
            newMinQuorumVotesBPS >= MIN_QUORUM_VOTES_BPS_LOWER_BOUND &&
                newMinQuorumVotesBPS <= MIN_QUORUM_VOTES_BPS_UPPER_BOUND,
            'NounsDAO::_setMinQuorumVotesBPS: invalid min quorum votes bps'
        );
        require(
            newMinQuorumVotesBPS <= params.maxQuorumVotesBPS,
            'NounsDAO::_setMinQuorumVotesBPS: min quorum votes bps greater than max'
        );
        uint16 oldMinQuorumVotesBPS = params.minQuorumVotesBPS;
        params.minQuorumVotesBPS = newMinQuorumVotesBPS;
        _writeQuorumParamsCheckpoint(params);
        emit MinQuorumVotesBPSSet(oldMinQuorumVotesBPS, newMinQuorumVotesBPS);
    }
    /**
     * @notice Admin function for setting the maximum quorum votes bps
     * @param newMaxQuorumVotesBPS maximum quorum votes bps
     *     Must be lower than `MAX_QUORUM_VOTES_BPS_UPPER_BOUND`
     *     Must be higher than or equal to minQuorumVotesBPS
     */
    function _setMaxQuorumVotesBPS(uint16 newMaxQuorumVotesBPS) external {
        if (msg.sender != admin) {
            revert AdminOnly();
        }
        DynamicQuorumParams memory params = getDynamicQuorumParamsAt(block.number);
        require(
            newMaxQuorumVotesBPS <= MAX_QUORUM_VOTES_BPS_UPPER_BOUND,
            'NounsDAO::_setMaxQuorumVotesBPS: invalid max quorum votes bps'
        );
        require(
            params.minQuorumVotesBPS <= newMaxQuorumVotesBPS,
            'NounsDAO::_setMaxQuorumVotesBPS: min quorum votes bps greater than max'
        );
        uint16 oldMaxQuorumVotesBPS = params.maxQuorumVotesBPS;
        params.maxQuorumVotesBPS = newMaxQuorumVotesBPS;
        _writeQuorumParamsCheckpoint(params);
        emit MaxQuorumVotesBPSSet(oldMaxQuorumVotesBPS, newMaxQuorumVotesBPS);
    }
    /**
     * @notice Admin function for setting the dynamic quorum coefficient
     * @param newQuorumCoefficient the new coefficient, as a fixed point integer with 6 decimals
     */
    function _setQuorumCoefficient(uint32 newQuorumCoefficient) external {
        if (msg.sender != admin) {
            revert AdminOnly();
        }
        DynamicQuorumParams memory params = getDynamicQuorumParamsAt(block.number);
        uint32 oldQuorumCoefficient = params.quorumCoefficient;
        params.quorumCoefficient = newQuorumCoefficient;
        _writeQuorumParamsCheckpoint(params);
        emit QuorumCoefficientSet(oldQuorumCoefficient, newQuorumCoefficient);
    }
    /**
     * @notice Admin function for setting all the dynamic quorum parameters
     * @param newMinQuorumVotesBPS minimum quorum votes bps
     *     Must be between `MIN_QUORUM_VOTES_BPS_LOWER_BOUND` and `MIN_QUORUM_VOTES_BPS_UPPER_BOUND`
     *     Must be lower than or equal to maxQuorumVotesBPS
     * @param newMaxQuorumVotesBPS maximum quorum votes bps
     *     Must be lower than `MAX_QUORUM_VOTES_BPS_UPPER_BOUND`
     *     Must be higher than or equal to minQuorumVotesBPS
     * @param newQuorumCoefficient the new coefficient, as a fixed point integer with 6 decimals
     */
    function _setDynamicQuorumParams(
        uint16 newMinQuorumVotesBPS,
        uint16 newMaxQuorumVotesBPS,
        uint32 newQuorumCoefficient
    ) public {
        if (msg.sender != admin) {
            revert AdminOnly();
        }
        if (
            newMinQuorumVotesBPS < MIN_QUORUM_VOTES_BPS_LOWER_BOUND ||
            newMinQuorumVotesBPS > MIN_QUORUM_VOTES_BPS_UPPER_BOUND
        ) {
            revert InvalidMinQuorumVotesBPS();
        }
        if (newMaxQuorumVotesBPS > MAX_QUORUM_VOTES_BPS_UPPER_BOUND) {
            revert InvalidMaxQuorumVotesBPS();
        }
        if (newMinQuorumVotesBPS > newMaxQuorumVotesBPS) {
            revert MinQuorumBPSGreaterThanMaxQuorumBPS();
        }
        DynamicQuorumParams memory oldParams = getDynamicQuorumParamsAt(block.number);
        DynamicQuorumParams memory params = DynamicQuorumParams({
            minQuorumVotesBPS: newMinQuorumVotesBPS,
            maxQuorumVotesBPS: newMaxQuorumVotesBPS,
            quorumCoefficient: newQuorumCoefficient
        });
        _writeQuorumParamsCheckpoint(params);
        emit MinQuorumVotesBPSSet(oldParams.minQuorumVotesBPS, params.minQuorumVotesBPS);
        emit MaxQuorumVotesBPSSet(oldParams.maxQuorumVotesBPS, params.maxQuorumVotesBPS);
        emit QuorumCoefficientSet(oldParams.quorumCoefficient, params.quorumCoefficient);
    }
    function _withdraw() external returns (uint256, bool) {
        if (msg.sender != admin) {
            revert AdminOnly();
        }
        uint256 amount = address(this).balance;
        (bool sent, ) = msg.sender.call{ value: amount }('');
        emit Withdraw(amount, sent);
        return (amount, sent);
    }
    /**
     * @notice Begins transfer of admin rights. The newPendingAdmin must call `_acceptAdmin` to finalize the transfer.
     * @dev Admin function to begin change of admin. The newPendingAdmin must call `_acceptAdmin` to finalize the transfer.
     * @param newPendingAdmin New pending admin.
     */
    function _setPendingAdmin(address newPendingAdmin) external {
        // Check caller = admin
        require(msg.sender == admin, 'NounsDAO::_setPendingAdmin: admin only');
        // Save current value, if any, for inclusion in log
        address oldPendingAdmin = pendingAdmin;
        // Store pendingAdmin with value newPendingAdmin
        pendingAdmin = newPendingAdmin;
        // Emit NewPendingAdmin(oldPendingAdmin, newPendingAdmin)
        emit NewPendingAdmin(oldPendingAdmin, newPendingAdmin);
    }
    /**
     * @notice Accepts transfer of admin rights. msg.sender must be pendingAdmin
     * @dev Admin function for pending admin to accept role and update admin
     */
    function _acceptAdmin() external {
        // Check caller is pendingAdmin and pendingAdmin ≠ address(0)
        require(msg.sender == pendingAdmin && msg.sender != address(0), 'NounsDAO::_acceptAdmin: pending admin only');
        // Save current values for inclusion in log
        address oldAdmin = admin;
        address oldPendingAdmin = pendingAdmin;
        // Store admin with value pendingAdmin
        admin = pendingAdmin;
        // Clear the pending value
        pendingAdmin = address(0);
        emit NewAdmin(oldAdmin, admin);
        emit NewPendingAdmin(oldPendingAdmin, pendingAdmin);
    }
    /**
     * @notice Begins transition of vetoer. The newPendingVetoer must call _acceptVetoer to finalize the transfer.
     * @param newPendingVetoer New Pending Vetoer
     */
    function _setPendingVetoer(address newPendingVetoer) public {
        if (msg.sender != vetoer) {
            revert VetoerOnly();
        }
        emit NewPendingVetoer(pendingVetoer, newPendingVetoer);
        pendingVetoer = newPendingVetoer;
    }
    function _acceptVetoer() external {
        if (msg.sender != pendingVetoer) {
            revert PendingVetoerOnly();
        }
        // Update vetoer
        emit NewVetoer(vetoer, pendingVetoer);
        vetoer = pendingVetoer;
        // Clear the pending value
        emit NewPendingVetoer(pendingVetoer, address(0));
        pendingVetoer = address(0);
    }
    /**
     * @notice Burns veto priviledges
     * @dev Vetoer function destroying veto power forever
     */
    function _burnVetoPower() public {
        // Check caller is vetoer
        require(msg.sender == vetoer, 'NounsDAO::_burnVetoPower: vetoer only');
        // Update vetoer to 0x0
        emit NewVetoer(vetoer, address(0));
        vetoer = address(0);
        // Clear the pending value
        emit NewPendingVetoer(pendingVetoer, address(0));
        pendingVetoer = address(0);
    }
    /**
     * @notice Current proposal threshold using Noun Total Supply
     * Differs from `GovernerBravo` which uses fixed amount
     */
    function proposalThreshold() public view returns (uint256) {
        return bps2Uint(proposalThresholdBPS, nouns.totalSupply());
    }
    function proposalCreationBlock(Proposal storage proposal) internal view returns (uint256) {
        if (proposal.creationBlock == 0) {
            return proposal.startBlock - votingDelay;
        }
        return proposal.creationBlock;
    }
    /**
     * @notice Quorum votes required for a specific proposal to succeed
     * Differs from `GovernerBravo` which uses fixed amount
     */
    function quorumVotes(uint256 proposalId) public view returns (uint256) {
        Proposal storage proposal = _proposals[proposalId];
        if (proposal.totalSupply == 0) {
            return proposal.quorumVotes;
        }
        return
            dynamicQuorumVotes(
                proposal.againstVotes,
                proposal.totalSupply,
                getDynamicQuorumParamsAt(proposal.creationBlock)
            );
    }
    /**
     * @notice Calculates the required quorum of for-votes based on the amount of against-votes
     *     The more against-votes there are for a proposal, the higher the required quorum is.
     *     The quorum BPS is between `params.minQuorumVotesBPS` and params.maxQuorumVotesBPS.
     *     The additional quorum is calculated as:
     *       quorumCoefficient * againstVotesBPS
     * @dev Note the coefficient is a fixed point integer with 6 decimals
     * @param againstVotes Number of against-votes in the proposal
     * @param totalSupply The total supply of Nouns at the time of proposal creation
     * @param params Configurable parameters for calculating the quorum based on againstVotes. See `DynamicQuorumParams` definition for additional details.
     * @return quorumVotes The required quorum
     */
    function dynamicQuorumVotes(
        uint256 againstVotes,
        uint256 totalSupply,
        DynamicQuorumParams memory params
    ) public pure returns (uint256) {
        uint256 againstVotesBPS = (10000 * againstVotes) / totalSupply;
        uint256 quorumAdjustmentBPS = (params.quorumCoefficient * againstVotesBPS) / 1e6;
        uint256 adjustedQuorumBPS = params.minQuorumVotesBPS + quorumAdjustmentBPS;
        uint256 quorumBPS = min(params.maxQuorumVotesBPS, adjustedQuorumBPS);
        return bps2Uint(quorumBPS, totalSupply);
    }
    /**
     * @notice returns the dynamic quorum parameters values at a certain block number
     * @dev The checkpoints array must not be empty, and the block number must be higher than or equal to
     *     the block of the first checkpoint
     * @param blockNumber_ the block number to get the params at
     * @return The dynamic quorum parameters that were set at the given block number
     */
    function getDynamicQuorumParamsAt(uint256 blockNumber_) public view returns (DynamicQuorumParams memory) {
        uint32 blockNumber = safe32(blockNumber_, 'NounsDAO::getDynamicQuorumParamsAt: block number exceeds 32 bits');
        uint256 len = quorumParamsCheckpoints.length;
        if (len == 0) {
            return
                DynamicQuorumParams({
                    minQuorumVotesBPS: safe16(quorumVotesBPS),
                    maxQuorumVotesBPS: safe16(quorumVotesBPS),
                    quorumCoefficient: 0
                });
        }
        if (quorumParamsCheckpoints[len - 1].fromBlock <= blockNumber) {
            return quorumParamsCheckpoints[len - 1].params;
        }
        if (quorumParamsCheckpoints[0].fromBlock > blockNumber) {
            return
                DynamicQuorumParams({
                    minQuorumVotesBPS: safe16(quorumVotesBPS),
                    maxQuorumVotesBPS: safe16(quorumVotesBPS),
                    quorumCoefficient: 0
                });
        }
        uint256 lower = 0;
        uint256 upper = len - 1;
        while (upper > lower) {
            uint256 center = upper - (upper - lower) / 2;
            DynamicQuorumParamsCheckpoint memory cp = quorumParamsCheckpoints[center];
            if (cp.fromBlock == blockNumber) {
                return cp.params;
            } else if (cp.fromBlock < blockNumber) {
                lower = center;
            } else {
                upper = center - 1;
            }
        }
        return quorumParamsCheckpoints[lower].params;
    }
    function _writeQuorumParamsCheckpoint(DynamicQuorumParams memory params) internal {
        uint32 blockNumber = safe32(block.number, 'block number exceeds 32 bits');
        uint256 pos = quorumParamsCheckpoints.length;
        if (pos > 0 && quorumParamsCheckpoints[pos - 1].fromBlock == blockNumber) {
            quorumParamsCheckpoints[pos - 1].params = params;
        } else {
            quorumParamsCheckpoints.push(DynamicQuorumParamsCheckpoint({ fromBlock: blockNumber, params: params }));
        }
    }
    function _refundGas(uint256 startGas) internal {
        unchecked {
            uint256 balance = address(this).balance;
            if (balance == 0) {
                return;
            }
            uint256 basefee = min(block.basefee, MAX_REFUND_BASE_FEE);
            uint256 gasPrice = min(tx.gasprice, basefee + MAX_REFUND_PRIORITY_FEE);
            uint256 gasUsed = min(startGas - gasleft() + REFUND_BASE_GAS, MAX_REFUND_GAS_USED);
            uint256 refundAmount = min(gasPrice * gasUsed, balance);
            (bool refundSent, ) = tx.origin.call{ value: refundAmount }('');
            emit RefundableVote(tx.origin, refundAmount, refundSent);
        }
    }
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }
    /**
     * @notice Current min quorum votes using Noun total supply
     */
    function minQuorumVotes() public view returns (uint256) {
        return bps2Uint(getDynamicQuorumParamsAt(block.number).minQuorumVotesBPS, nouns.totalSupply());
    }
    /**
     * @notice Current max quorum votes using Noun total supply
     */
    function maxQuorumVotes() public view returns (uint256) {
        return bps2Uint(getDynamicQuorumParamsAt(block.number).maxQuorumVotesBPS, nouns.totalSupply());
    }
    function bps2Uint(uint256 bps, uint256 number) internal pure returns (uint256) {
        return (number * bps) / 10000;
    }
    function getChainIdInternal() internal view returns (uint256) {
        uint256 chainId;
        assembly {
            chainId := chainid()
        }
        return chainId;
    }
    function safe32(uint256 n, string memory errorMessage) internal pure returns (uint32) {
        require(n <= type(uint32).max, errorMessage);
        return uint32(n);
    }
    function safe16(uint256 n) internal pure returns (uint16) {
        if (n > type(uint16).max) {
            revert UnsafeUint16Cast();
        }
        return uint16(n);
    }
    receive() external payable {}
}
// SPDX-License-Identifier: BSD-3-Clause
/// @title Nouns DAO Logic interfaces and events
/*********************************
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░█████████░░█████████░░░ *
 * ░░░░░░██░░░████░░██░░░████░░░ *
 * ░░██████░░░████████░░░████░░░ *
 * ░░██░░██░░░████░░██░░░████░░░ *
 * ░░██░░██░░░████░░██░░░████░░░ *
 * ░░░░░░█████████░░█████████░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 *********************************/
// LICENSE
// NounsDAOInterfaces.sol is a modified version of Compound Lab's GovernorBravoInterfaces.sol:
// https://github.com/compound-finance/compound-protocol/blob/b9b14038612d846b83f8a009a82c38974ff2dcfe/contracts/Governance/GovernorBravoInterfaces.sol
//
// GovernorBravoInterfaces.sol source code Copyright 2020 Compound Labs, Inc. licensed under the BSD-3-Clause license.
// With modifications by Nounders DAO.
//
// Additional conditions of BSD-3-Clause can be found here: https://opensource.org/licenses/BSD-3-Clause
//
// MODIFICATIONS
// NounsDAOEvents, NounsDAOProxyStorage, NounsDAOStorageV1 add support for changes made by Nouns DAO to GovernorBravo.sol
// See NounsDAOLogicV1.sol for more details.
// NounsDAOStorageV1Adjusted and NounsDAOStorageV2 add support for a dynamic vote quorum.
// See NounsDAOLogicV2.sol for more details.
pragma solidity ^0.8.6;
contract NounsDAOEvents {
    /// @notice An event emitted when a new proposal is created
    event ProposalCreated(
        uint256 id,
        address proposer,
        address[] targets,
        uint256[] values,
        string[] signatures,
        bytes[] calldatas,
        uint256 startBlock,
        uint256 endBlock,
        string description
    );
    /// @notice An event emitted when a new proposal is created, which includes additional information
    event ProposalCreatedWithRequirements(
        uint256 id,
        address proposer,
        address[] targets,
        uint256[] values,
        string[] signatures,
        bytes[] calldatas,
        uint256 startBlock,
        uint256 endBlock,
        uint256 proposalThreshold,
        uint256 quorumVotes,
        string description
    );
    /// @notice An event emitted when a vote has been cast on a proposal
    /// @param voter The address which casted a vote
    /// @param proposalId The proposal id which was voted on
    /// @param support Support value for the vote. 0=against, 1=for, 2=abstain
    /// @param votes Number of votes which were cast by the voter
    /// @param reason The reason given for the vote by the voter
    event VoteCast(address indexed voter, uint256 proposalId, uint8 support, uint256 votes, string reason);
    /// @notice An event emitted when a proposal has been canceled
    event ProposalCanceled(uint256 id);
    /// @notice An event emitted when a proposal has been queued in the NounsDAOExecutor
    event ProposalQueued(uint256 id, uint256 eta);
    /// @notice An event emitted when a proposal has been executed in the NounsDAOExecutor
    event ProposalExecuted(uint256 id);
    /// @notice An event emitted when a proposal has been vetoed by vetoAddress
    event ProposalVetoed(uint256 id);
    /// @notice An event emitted when the voting delay is set
    event VotingDelaySet(uint256 oldVotingDelay, uint256 newVotingDelay);
    /// @notice An event emitted when the voting period is set
    event VotingPeriodSet(uint256 oldVotingPeriod, uint256 newVotingPeriod);
    /// @notice Emitted when implementation is changed
    event NewImplementation(address oldImplementation, address newImplementation);
    /// @notice Emitted when proposal threshold basis points is set
    event ProposalThresholdBPSSet(uint256 oldProposalThresholdBPS, uint256 newProposalThresholdBPS);
    /// @notice Emitted when quorum votes basis points is set
    event QuorumVotesBPSSet(uint256 oldQuorumVotesBPS, uint256 newQuorumVotesBPS);
    /// @notice Emitted when pendingAdmin is changed
    event NewPendingAdmin(address oldPendingAdmin, address newPendingAdmin);
    /// @notice Emitted when pendingAdmin is accepted, which means admin is updated
    event NewAdmin(address oldAdmin, address newAdmin);
    /// @notice Emitted when vetoer is changed
    event NewVetoer(address oldVetoer, address newVetoer);
}
contract NounsDAOEventsV2 is NounsDAOEvents {
    /// @notice Emitted when minQuorumVotesBPS is set
    event MinQuorumVotesBPSSet(uint16 oldMinQuorumVotesBPS, uint16 newMinQuorumVotesBPS);
    /// @notice Emitted when maxQuorumVotesBPS is set
    event MaxQuorumVotesBPSSet(uint16 oldMaxQuorumVotesBPS, uint16 newMaxQuorumVotesBPS);
    /// @notice Emitted when quorumCoefficient is set
    event QuorumCoefficientSet(uint32 oldQuorumCoefficient, uint32 newQuorumCoefficient);
    /// @notice Emitted when a voter cast a vote requesting a gas refund.
    event RefundableVote(address indexed voter, uint256 refundAmount, bool refundSent);
    /// @notice Emitted when admin withdraws the DAO's balance.
    event Withdraw(uint256 amount, bool sent);
    /// @notice Emitted when pendingVetoer is changed
    event NewPendingVetoer(address oldPendingVetoer, address newPendingVetoer);
}
contract NounsDAOProxyStorage {
    /// @notice Administrator for this contract
    address public admin;
    /// @notice Pending administrator for this contract
    address public pendingAdmin;
    /// @notice Active brains of Governor
    address public implementation;
}
/**
 * @title Storage for Governor Bravo Delegate
 * @notice For future upgrades, do not change NounsDAOStorageV1. Create a new
 * contract which implements NounsDAOStorageV1 and following the naming convention
 * NounsDAOStorageVX.
 */
contract NounsDAOStorageV1 is NounsDAOProxyStorage {
    /// @notice Vetoer who has the ability to veto any proposal
    address public vetoer;
    /// @notice The delay before voting on a proposal may take place, once proposed, in blocks
    uint256 public votingDelay;
    /// @notice The duration of voting on a proposal, in blocks
    uint256 public votingPeriod;
    /// @notice The basis point number of votes required in order for a voter to become a proposer. *DIFFERS from GovernerBravo
    uint256 public proposalThresholdBPS;
    /// @notice The basis point number of votes in support of a proposal required in order for a quorum to be reached and for a vote to succeed. *DIFFERS from GovernerBravo
    uint256 public quorumVotesBPS;
    /// @notice The total number of proposals
    uint256 public proposalCount;
    /// @notice The address of the Nouns DAO Executor NounsDAOExecutor
    INounsDAOExecutor public timelock;
    /// @notice The address of the Nouns tokens
    NounsTokenLike public nouns;
    /// @notice The official record of all proposals ever proposed
    mapping(uint256 => Proposal) public proposals;
    /// @notice The latest proposal for each proposer
    mapping(address => uint256) public latestProposalIds;
    struct Proposal {
        /// @notice Unique id for looking up a proposal
        uint256 id;
        /// @notice Creator of the proposal
        address proposer;
        /// @notice The number of votes needed to create a proposal at the time of proposal creation. *DIFFERS from GovernerBravo
        uint256 proposalThreshold;
        /// @notice The number of votes in support of a proposal required in order for a quorum to be reached and for a vote to succeed at the time of proposal creation. *DIFFERS from GovernerBravo
        uint256 quorumVotes;
        /// @notice The timestamp that the proposal will be available for execution, set once the vote succeeds
        uint256 eta;
        /// @notice the ordered list of target addresses for calls to be made
        address[] targets;
        /// @notice The ordered list of values (i.e. msg.value) to be passed to the calls to be made
        uint256[] values;
        /// @notice The ordered list of function signatures to be called
        string[] signatures;
        /// @notice The ordered list of calldata to be passed to each call
        bytes[] calldatas;
        /// @notice The block at which voting begins: holders must delegate their votes prior to this block
        uint256 startBlock;
        /// @notice The block at which voting ends: votes must be cast prior to this block
        uint256 endBlock;
        /// @notice Current number of votes in favor of this proposal
        uint256 forVotes;
        /// @notice Current number of votes in opposition to this proposal
        uint256 againstVotes;
        /// @notice Current number of votes for abstaining for this proposal
        uint256 abstainVotes;
        /// @notice Flag marking whether the proposal has been canceled
        bool canceled;
        /// @notice Flag marking whether the proposal has been vetoed
        bool vetoed;
        /// @notice Flag marking whether the proposal has been executed
        bool executed;
        /// @notice Receipts of ballots for the entire set of voters
        mapping(address => Receipt) receipts;
    }
    /// @notice Ballot receipt record for a voter
    struct Receipt {
        /// @notice Whether or not a vote has been cast
        bool hasVoted;
        /// @notice Whether or not the voter supports the proposal or abstains
        uint8 support;
        /// @notice The number of votes the voter had, which were cast
        uint96 votes;
    }
    /// @notice Possible states that a proposal may be in
    enum ProposalState {
        Pending,
        Active,
        Canceled,
        Defeated,
        Succeeded,
        Queued,
        Expired,
        Executed,
        Vetoed
    }
}
/**
 * @title Extra fields added to the `Proposal` struct from NounsDAOStorageV1
 * @notice The following fields were added to the `Proposal` struct:
 * - `Proposal.totalSupply`
 * - `Proposal.creationBlock`
 */
contract NounsDAOStorageV1Adjusted is NounsDAOProxyStorage {
    /// @notice Vetoer who has the ability to veto any proposal
    address public vetoer;
    /// @notice The delay before voting on a proposal may take place, once proposed, in blocks
    uint256 public votingDelay;
    /// @notice The duration of voting on a proposal, in blocks
    uint256 public votingPeriod;
    /// @notice The basis point number of votes required in order for a voter to become a proposer. *DIFFERS from GovernerBravo
    uint256 public proposalThresholdBPS;
    /// @notice The basis point number of votes in support of a proposal required in order for a quorum to be reached and for a vote to succeed. *DIFFERS from GovernerBravo
    uint256 public quorumVotesBPS;
    /// @notice The total number of proposals
    uint256 public proposalCount;
    /// @notice The address of the Nouns DAO Executor NounsDAOExecutor
    INounsDAOExecutor public timelock;
    /// @notice The address of the Nouns tokens
    NounsTokenLike public nouns;
    /// @notice The official record of all proposals ever proposed
    mapping(uint256 => Proposal) internal _proposals;
    /// @notice The latest proposal for each proposer
    mapping(address => uint256) public latestProposalIds;
    struct Proposal {
        /// @notice Unique id for looking up a proposal
        uint256 id;
        /// @notice Creator of the proposal
        address proposer;
        /// @notice The number of votes needed to create a proposal at the time of proposal creation. *DIFFERS from GovernerBravo
        uint256 proposalThreshold;
        /// @notice The number of votes in support of a proposal required in order for a quorum to be reached and for a vote to succeed at the time of proposal creation. *DIFFERS from GovernerBravo
        uint256 quorumVotes;
        /// @notice The timestamp that the proposal will be available for execution, set once the vote succeeds
        uint256 eta;
        /// @notice the ordered list of target addresses for calls to be made
        address[] targets;
        /// @notice The ordered list of values (i.e. msg.value) to be passed to the calls to be made
        uint256[] values;
        /// @notice The ordered list of function signatures to be called
        string[] signatures;
        /// @notice The ordered list of calldata to be passed to each call
        bytes[] calldatas;
        /// @notice The block at which voting begins: holders must delegate their votes prior to this block
        uint256 startBlock;
        /// @notice The block at which voting ends: votes must be cast prior to this block
        uint256 endBlock;
        /// @notice Current number of votes in favor of this proposal
        uint256 forVotes;
        /// @notice Current number of votes in opposition to this proposal
        uint256 againstVotes;
        /// @notice Current number of votes for abstaining for this proposal
        uint256 abstainVotes;
        /// @notice Flag marking whether the proposal has been canceled
        bool canceled;
        /// @notice Flag marking whether the proposal has been vetoed
        bool vetoed;
        /// @notice Flag marking whether the proposal has been executed
        bool executed;
        /// @notice Receipts of ballots for the entire set of voters
        mapping(address => Receipt) receipts;
        /// @notice The total supply at the time of proposal creation
        uint256 totalSupply;
        /// @notice The block at which this proposal was created
        uint256 creationBlock;
    }
    /// @notice Ballot receipt record for a voter
    struct Receipt {
        /// @notice Whether or not a vote has been cast
        bool hasVoted;
        /// @notice Whether or not the voter supports the proposal or abstains
        uint8 support;
        /// @notice The number of votes the voter had, which were cast
        uint96 votes;
    }
    /// @notice Possible states that a proposal may be in
    enum ProposalState {
        Pending,
        Active,
        Canceled,
        Defeated,
        Succeeded,
        Queued,
        Expired,
        Executed,
        Vetoed
    }
}
/**
 * @title Storage for Governor Bravo Delegate
 * @notice For future upgrades, do not change NounsDAOStorageV2. Create a new
 * contract which implements NounsDAOStorageV2 and following the naming convention
 * NounsDAOStorageVX.
 */
contract NounsDAOStorageV2 is NounsDAOStorageV1Adjusted {
    DynamicQuorumParamsCheckpoint[] public quorumParamsCheckpoints;
    /// @notice Pending new vetoer
    address public pendingVetoer;
    struct DynamicQuorumParams {
        /// @notice The minimum basis point number of votes in support of a proposal required in order for a quorum to be reached and for a vote to succeed.
        uint16 minQuorumVotesBPS;
        /// @notice The maximum basis point number of votes in support of a proposal required in order for a quorum to be reached and for a vote to succeed.
        uint16 maxQuorumVotesBPS;
        /// @notice The dynamic quorum coefficient
        /// @dev Assumed to be fixed point integer with 6 decimals, i.e 0.2 is represented as 0.2 * 1e6 = 200000
        uint32 quorumCoefficient;
    }
    /// @notice A checkpoint for storing dynamic quorum params from a given block
    struct DynamicQuorumParamsCheckpoint {
        /// @notice The block at which the new values were set
        uint32 fromBlock;
        /// @notice The parameter values of this checkpoint
        DynamicQuorumParams params;
    }
    struct ProposalCondensed {
        /// @notice Unique id for looking up a proposal
        uint256 id;
        /// @notice Creator of the proposal
        address proposer;
        /// @notice The number of votes needed to create a proposal at the time of proposal creation. *DIFFERS from GovernerBravo
        uint256 proposalThreshold;
        /// @notice The minimum number of votes in support of a proposal required in order for a quorum to be reached and for a vote to succeed at the time of proposal creation. *DIFFERS from GovernerBravo
        uint256 quorumVotes;
        /// @notice The timestamp that the proposal will be available for execution, set once the vote succeeds
        uint256 eta;
        /// @notice The block at which voting begins: holders must delegate their votes prior to this block
        uint256 startBlock;
        /// @notice The block at which voting ends: votes must be cast prior to this block
        uint256 endBlock;
        /// @notice Current number of votes in favor of this proposal
        uint256 forVotes;
        /// @notice Current number of votes in opposition to this proposal
        uint256 againstVotes;
        /// @notice Current number of votes for abstaining for this proposal
        uint256 abstainVotes;
        /// @notice Flag marking whether the proposal has been canceled
        bool canceled;
        /// @notice Flag marking whether the proposal has been vetoed
        bool vetoed;
        /// @notice Flag marking whether the proposal has been executed
        bool executed;
        /// @notice The total supply at the time of proposal creation
        uint256 totalSupply;
        /// @notice The block at which this proposal was created
        uint256 creationBlock;
    }
}
interface INounsDAOExecutor {
    function delay() external view returns (uint256);
    function GRACE_PERIOD() external view returns (uint256);
    function acceptAdmin() external;
    function queuedTransactions(bytes32 hash) external view returns (bool);
    function queueTransaction(
        address target,
        uint256 value,
        string calldata signature,
        bytes calldata data,
        uint256 eta
    ) external returns (bytes32);
    function cancelTransaction(
        address target,
        uint256 value,
        string calldata signature,
        bytes calldata data,
        uint256 eta
    ) external;
    function executeTransaction(
        address target,
        uint256 value,
        string calldata signature,
        bytes calldata data,
        uint256 eta
    ) external payable returns (bytes memory);
}
interface NounsTokenLike {
    function getPriorVotes(address account, uint256 blockNumber) external view returns (uint96);
    function totalSupply() external view returns (uint256);
}

// SPDX-License-Identifier: GPL-3.0
/// @title The Nouns ERC-721 token
/*********************************
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░█████████░░█████████░░░ *
 * ░░░░░░██░░░████░░██░░░████░░░ *
 * ░░██████░░░████████░░░████░░░ *
 * ░░██░░██░░░████░░██░░░████░░░ *
 * ░░██░░██░░░████░░██░░░████░░░ *
 * ░░░░░░█████████░░█████████░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 *********************************/
pragma solidity ^0.8.6;
import { Ownable } from '@openzeppelin/contracts/access/Ownable.sol';
import { ERC721Checkpointable } from './base/ERC721Checkpointable.sol';
import { INounsDescriptor } from './interfaces/INounsDescriptor.sol';
import { INounsSeeder } from './interfaces/INounsSeeder.sol';
import { INounsToken } from './interfaces/INounsToken.sol';
import { ERC721 } from './base/ERC721.sol';
import { IERC721 } from '@openzeppelin/contracts/token/ERC721/IERC721.sol';
import { IProxyRegistry } from './external/opensea/IProxyRegistry.sol';
contract NounsToken is INounsToken, Ownable, ERC721Checkpointable {
    // The nounders DAO address (creators org)
    address public noundersDAO;
    // An address who has permissions to mint Nouns
    address public minter;
    // The Nouns token URI descriptor
    INounsDescriptor public descriptor;
    // The Nouns token seeder
    INounsSeeder public seeder;
    // Whether the minter can be updated
    bool public isMinterLocked;
    // Whether the descriptor can be updated
    bool public isDescriptorLocked;
    // Whether the seeder can be updated
    bool public isSeederLocked;
    // The noun seeds
    mapping(uint256 => INounsSeeder.Seed) public seeds;
    // The internal noun ID tracker
    uint256 private _currentNounId;
    // IPFS content hash of contract-level metadata
    string private _contractURIHash = 'QmZi1n79FqWt2tTLwCqiy6nLM6xLGRsEPQ5JmReJQKNNzX';
    // OpenSea's Proxy Registry
    IProxyRegistry public immutable proxyRegistry;
    /**
     * @notice Require that the minter has not been locked.
     */
    modifier whenMinterNotLocked() {
        require(!isMinterLocked, 'Minter is locked');
        _;
    }
    /**
     * @notice Require that the descriptor has not been locked.
     */
    modifier whenDescriptorNotLocked() {
        require(!isDescriptorLocked, 'Descriptor is locked');
        _;
    }
    /**
     * @notice Require that the seeder has not been locked.
     */
    modifier whenSeederNotLocked() {
        require(!isSeederLocked, 'Seeder is locked');
        _;
    }
    /**
     * @notice Require that the sender is the nounders DAO.
     */
    modifier onlyNoundersDAO() {
        require(msg.sender == noundersDAO, 'Sender is not the nounders DAO');
        _;
    }
    /**
     * @notice Require that the sender is the minter.
     */
    modifier onlyMinter() {
        require(msg.sender == minter, 'Sender is not the minter');
        _;
    }
    constructor(
        address _noundersDAO,
        address _minter,
        INounsDescriptor _descriptor,
        INounsSeeder _seeder,
        IProxyRegistry _proxyRegistry
    ) ERC721('Nouns', 'NOUN') {
        noundersDAO = _noundersDAO;
        minter = _minter;
        descriptor = _descriptor;
        seeder = _seeder;
        proxyRegistry = _proxyRegistry;
    }
    /**
     * @notice The IPFS URI of contract-level metadata.
     */
    function contractURI() public view returns (string memory) {
        return string(abi.encodePacked('ipfs://', _contractURIHash));
    }
    /**
     * @notice Set the _contractURIHash.
     * @dev Only callable by the owner.
     */
    function setContractURIHash(string memory newContractURIHash) external onlyOwner {
        _contractURIHash = newContractURIHash;
    }
    /**
     * @notice Override isApprovedForAll to whitelist user's OpenSea proxy accounts to enable gas-less listings.
     */
    function isApprovedForAll(address owner, address operator) public view override(IERC721, ERC721) returns (bool) {
        // Whitelist OpenSea proxy contract for easy trading.
        if (proxyRegistry.proxies(owner) == operator) {
            return true;
        }
        return super.isApprovedForAll(owner, operator);
    }
    /**
     * @notice Mint a Noun to the minter, along with a possible nounders reward
     * Noun. Nounders reward Nouns are minted every 10 Nouns, starting at 0,
     * until 183 nounder Nouns have been minted (5 years w/ 24 hour auctions).
     * @dev Call _mintTo with the to address(es).
     */
    function mint() public override onlyMinter returns (uint256) {
        if (_currentNounId <= 1820 && _currentNounId % 10 == 0) {
            _mintTo(noundersDAO, _currentNounId++);
        }
        return _mintTo(minter, _currentNounId++);
    }
    /**
     * @notice Burn a noun.
     */
    function burn(uint256 nounId) public override onlyMinter {
        _burn(nounId);
        emit NounBurned(nounId);
    }
    /**
     * @notice A distinct Uniform Resource Identifier (URI) for a given asset.
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view override returns (string memory) {
        require(_exists(tokenId), 'NounsToken: URI query for nonexistent token');
        return descriptor.tokenURI(tokenId, seeds[tokenId]);
    }
    /**
     * @notice Similar to `tokenURI`, but always serves a base64 encoded data URI
     * with the JSON contents directly inlined.
     */
    function dataURI(uint256 tokenId) public view override returns (string memory) {
        require(_exists(tokenId), 'NounsToken: URI query for nonexistent token');
        return descriptor.dataURI(tokenId, seeds[tokenId]);
    }
    /**
     * @notice Set the nounders DAO.
     * @dev Only callable by the nounders DAO when not locked.
     */
    function setNoundersDAO(address _noundersDAO) external override onlyNoundersDAO {
        noundersDAO = _noundersDAO;
        emit NoundersDAOUpdated(_noundersDAO);
    }
    /**
     * @notice Set the token minter.
     * @dev Only callable by the owner when not locked.
     */
    function setMinter(address _minter) external override onlyOwner whenMinterNotLocked {
        minter = _minter;
        emit MinterUpdated(_minter);
    }
    /**
     * @notice Lock the minter.
     * @dev This cannot be reversed and is only callable by the owner when not locked.
     */
    function lockMinter() external override onlyOwner whenMinterNotLocked {
        isMinterLocked = true;
        emit MinterLocked();
    }
    /**
     * @notice Set the token URI descriptor.
     * @dev Only callable by the owner when not locked.
     */
    function setDescriptor(INounsDescriptor _descriptor) external override onlyOwner whenDescriptorNotLocked {
        descriptor = _descriptor;
        emit DescriptorUpdated(_descriptor);
    }
    /**
     * @notice Lock the descriptor.
     * @dev This cannot be reversed and is only callable by the owner when not locked.
     */
    function lockDescriptor() external override onlyOwner whenDescriptorNotLocked {
        isDescriptorLocked = true;
        emit DescriptorLocked();
    }
    /**
     * @notice Set the token seeder.
     * @dev Only callable by the owner when not locked.
     */
    function setSeeder(INounsSeeder _seeder) external override onlyOwner whenSeederNotLocked {
        seeder = _seeder;
        emit SeederUpdated(_seeder);
    }
    /**
     * @notice Lock the seeder.
     * @dev This cannot be reversed and is only callable by the owner when not locked.
     */
    function lockSeeder() external override onlyOwner whenSeederNotLocked {
        isSeederLocked = true;
        emit SeederLocked();
    }
    /**
     * @notice Mint a Noun with `nounId` to the provided `to` address.
     */
    function _mintTo(address to, uint256 nounId) internal returns (uint256) {
        INounsSeeder.Seed memory seed = seeds[nounId] = seeder.generateSeed(nounId, descriptor);
        _mint(owner(), to, nounId);
        emit NounCreated(nounId, seed);
        return nounId;
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
 * @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() {
        _setOwner(_msgSender());
    }
    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }
    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        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 {
        _setOwner(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");
        _setOwner(newOwner);
    }
    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}
// SPDX-License-Identifier: BSD-3-Clause
/// @title Vote checkpointing for an ERC-721 token
/*********************************
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░█████████░░█████████░░░ *
 * ░░░░░░██░░░████░░██░░░████░░░ *
 * ░░██████░░░████████░░░████░░░ *
 * ░░██░░██░░░████░░██░░░████░░░ *
 * ░░██░░██░░░████░░██░░░████░░░ *
 * ░░░░░░█████████░░█████████░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 *********************************/
// LICENSE
// ERC721Checkpointable.sol uses and modifies part of Compound Lab's Comp.sol:
// https://github.com/compound-finance/compound-protocol/blob/ae4388e780a8d596d97619d9704a931a2752c2bc/contracts/Governance/Comp.sol
//
// Comp.sol source code Copyright 2020 Compound Labs, Inc. licensed under the BSD-3-Clause license.
// With modifications by Nounders DAO.
//
// Additional conditions of BSD-3-Clause can be found here: https://opensource.org/licenses/BSD-3-Clause
//
// MODIFICATIONS
// Checkpointing logic from Comp.sol has been used with the following modifications:
// - `delegates` is renamed to `_delegates` and is set to private
// - `delegates` is a public function that uses the `_delegates` mapping look-up, but unlike
//   Comp.sol, returns the delegator's own address if there is no delegate.
//   This avoids the delegator needing to "delegate to self" with an additional transaction
// - `_transferTokens()` is renamed `_beforeTokenTransfer()` and adapted to hook into OpenZeppelin's ERC721 hooks.
pragma solidity ^0.8.6;
import './ERC721Enumerable.sol';
abstract contract ERC721Checkpointable is ERC721Enumerable {
    /// @notice Defines decimals as per ERC-20 convention to make integrations with 3rd party governance platforms easier
    uint8 public constant decimals = 0;
    /// @notice A record of each accounts delegate
    mapping(address => address) private _delegates;
    /// @notice A checkpoint for marking number of votes from a given block
    struct Checkpoint {
        uint32 fromBlock;
        uint96 votes;
    }
    /// @notice A record of votes checkpoints for each account, by index
    mapping(address => mapping(uint32 => Checkpoint)) public checkpoints;
    /// @notice The number of checkpoints for each account
    mapping(address => uint32) public numCheckpoints;
    /// @notice The EIP-712 typehash for the contract's domain
    bytes32 public constant DOMAIN_TYPEHASH =
        keccak256('EIP712Domain(string name,uint256 chainId,address verifyingContract)');
    /// @notice The EIP-712 typehash for the delegation struct used by the contract
    bytes32 public constant DELEGATION_TYPEHASH =
        keccak256('Delegation(address delegatee,uint256 nonce,uint256 expiry)');
    /// @notice A record of states for signing / validating signatures
    mapping(address => uint256) public nonces;
    /// @notice An event thats emitted when an account changes its delegate
    event DelegateChanged(address indexed delegator, address indexed fromDelegate, address indexed toDelegate);
    /// @notice An event thats emitted when a delegate account's vote balance changes
    event DelegateVotesChanged(address indexed delegate, uint256 previousBalance, uint256 newBalance);
    /**
     * @notice The votes a delegator can delegate, which is the current balance of the delegator.
     * @dev Used when calling `_delegate()`
     */
    function votesToDelegate(address delegator) public view returns (uint96) {
        return safe96(balanceOf(delegator), 'ERC721Checkpointable::votesToDelegate: amount exceeds 96 bits');
    }
    /**
     * @notice Overrides the standard `Comp.sol` delegates mapping to return
     * the delegator's own address if they haven't delegated.
     * This avoids having to delegate to oneself.
     */
    function delegates(address delegator) public view returns (address) {
        address current = _delegates[delegator];
        return current == address(0) ? delegator : current;
    }
    /**
     * @notice Adapted from `_transferTokens()` in `Comp.sol` to update delegate votes.
     * @dev hooks into OpenZeppelin's `ERC721._transfer`
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal override {
        super._beforeTokenTransfer(from, to, tokenId);
        /// @notice Differs from `_transferTokens()` to use `delegates` override method to simulate auto-delegation
        _moveDelegates(delegates(from), delegates(to), 1);
    }
    /**
     * @notice Delegate votes from `msg.sender` to `delegatee`
     * @param delegatee The address to delegate votes to
     */
    function delegate(address delegatee) public {
        if (delegatee == address(0)) delegatee = msg.sender;
        return _delegate(msg.sender, delegatee);
    }
    /**
     * @notice Delegates votes from signatory to `delegatee`
     * @param delegatee The address to delegate votes to
     * @param nonce The contract state required to match the signature
     * @param expiry The time at which to expire the signature
     * @param v The recovery byte of the signature
     * @param r Half of the ECDSA signature pair
     * @param s Half of the ECDSA signature pair
     */
    function delegateBySig(
        address delegatee,
        uint256 nonce,
        uint256 expiry,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) public {
        bytes32 domainSeparator = keccak256(
            abi.encode(DOMAIN_TYPEHASH, keccak256(bytes(name())), getChainId(), address(this))
        );
        bytes32 structHash = keccak256(abi.encode(DELEGATION_TYPEHASH, delegatee, nonce, expiry));
        bytes32 digest = keccak256(abi.encodePacked('\\x19\\x01', domainSeparator, structHash));
        address signatory = ecrecover(digest, v, r, s);
        require(signatory != address(0), 'ERC721Checkpointable::delegateBySig: invalid signature');
        require(nonce == nonces[signatory]++, 'ERC721Checkpointable::delegateBySig: invalid nonce');
        require(block.timestamp <= expiry, 'ERC721Checkpointable::delegateBySig: signature expired');
        return _delegate(signatory, delegatee);
    }
    /**
     * @notice Gets the current votes balance for `account`
     * @param account The address to get votes balance
     * @return The number of current votes for `account`
     */
    function getCurrentVotes(address account) external view returns (uint96) {
        uint32 nCheckpoints = numCheckpoints[account];
        return nCheckpoints > 0 ? checkpoints[account][nCheckpoints - 1].votes : 0;
    }
    /**
     * @notice Determine the prior number of votes for an account as of a block number
     * @dev Block number must be a finalized block or else this function will revert to prevent misinformation.
     * @param account The address of the account to check
     * @param blockNumber The block number to get the vote balance at
     * @return The number of votes the account had as of the given block
     */
    function getPriorVotes(address account, uint256 blockNumber) public view returns (uint96) {
        require(blockNumber < block.number, 'ERC721Checkpointable::getPriorVotes: not yet determined');
        uint32 nCheckpoints = numCheckpoints[account];
        if (nCheckpoints == 0) {
            return 0;
        }
        // First check most recent balance
        if (checkpoints[account][nCheckpoints - 1].fromBlock <= blockNumber) {
            return checkpoints[account][nCheckpoints - 1].votes;
        }
        // Next check implicit zero balance
        if (checkpoints[account][0].fromBlock > blockNumber) {
            return 0;
        }
        uint32 lower = 0;
        uint32 upper = nCheckpoints - 1;
        while (upper > lower) {
            uint32 center = upper - (upper - lower) / 2; // ceil, avoiding overflow
            Checkpoint memory cp = checkpoints[account][center];
            if (cp.fromBlock == blockNumber) {
                return cp.votes;
            } else if (cp.fromBlock < blockNumber) {
                lower = center;
            } else {
                upper = center - 1;
            }
        }
        return checkpoints[account][lower].votes;
    }
    function _delegate(address delegator, address delegatee) internal {
        /// @notice differs from `_delegate()` in `Comp.sol` to use `delegates` override method to simulate auto-delegation
        address currentDelegate = delegates(delegator);
        _delegates[delegator] = delegatee;
        emit DelegateChanged(delegator, currentDelegate, delegatee);
        uint96 amount = votesToDelegate(delegator);
        _moveDelegates(currentDelegate, delegatee, amount);
    }
    function _moveDelegates(
        address srcRep,
        address dstRep,
        uint96 amount
    ) internal {
        if (srcRep != dstRep && amount > 0) {
            if (srcRep != address(0)) {
                uint32 srcRepNum = numCheckpoints[srcRep];
                uint96 srcRepOld = srcRepNum > 0 ? checkpoints[srcRep][srcRepNum - 1].votes : 0;
                uint96 srcRepNew = sub96(srcRepOld, amount, 'ERC721Checkpointable::_moveDelegates: amount underflows');
                _writeCheckpoint(srcRep, srcRepNum, srcRepOld, srcRepNew);
            }
            if (dstRep != address(0)) {
                uint32 dstRepNum = numCheckpoints[dstRep];
                uint96 dstRepOld = dstRepNum > 0 ? checkpoints[dstRep][dstRepNum - 1].votes : 0;
                uint96 dstRepNew = add96(dstRepOld, amount, 'ERC721Checkpointable::_moveDelegates: amount overflows');
                _writeCheckpoint(dstRep, dstRepNum, dstRepOld, dstRepNew);
            }
        }
    }
    function _writeCheckpoint(
        address delegatee,
        uint32 nCheckpoints,
        uint96 oldVotes,
        uint96 newVotes
    ) internal {
        uint32 blockNumber = safe32(
            block.number,
            'ERC721Checkpointable::_writeCheckpoint: block number exceeds 32 bits'
        );
        if (nCheckpoints > 0 && checkpoints[delegatee][nCheckpoints - 1].fromBlock == blockNumber) {
            checkpoints[delegatee][nCheckpoints - 1].votes = newVotes;
        } else {
            checkpoints[delegatee][nCheckpoints] = Checkpoint(blockNumber, newVotes);
            numCheckpoints[delegatee] = nCheckpoints + 1;
        }
        emit DelegateVotesChanged(delegatee, oldVotes, newVotes);
    }
    function safe32(uint256 n, string memory errorMessage) internal pure returns (uint32) {
        require(n < 2**32, errorMessage);
        return uint32(n);
    }
    function safe96(uint256 n, string memory errorMessage) internal pure returns (uint96) {
        require(n < 2**96, errorMessage);
        return uint96(n);
    }
    function add96(
        uint96 a,
        uint96 b,
        string memory errorMessage
    ) internal pure returns (uint96) {
        uint96 c = a + b;
        require(c >= a, errorMessage);
        return c;
    }
    function sub96(
        uint96 a,
        uint96 b,
        string memory errorMessage
    ) internal pure returns (uint96) {
        require(b <= a, errorMessage);
        return a - b;
    }
    function getChainId() internal view returns (uint256) {
        uint256 chainId;
        assembly {
            chainId := chainid()
        }
        return chainId;
    }
}
// SPDX-License-Identifier: GPL-3.0
/// @title Interface for NounsDescriptor
/*********************************
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░█████████░░█████████░░░ *
 * ░░░░░░██░░░████░░██░░░████░░░ *
 * ░░██████░░░████████░░░████░░░ *
 * ░░██░░██░░░████░░██░░░████░░░ *
 * ░░██░░██░░░████░░██░░░████░░░ *
 * ░░░░░░█████████░░█████████░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 *********************************/
pragma solidity ^0.8.6;
import { INounsSeeder } from './INounsSeeder.sol';
interface INounsDescriptor {
    event PartsLocked();
    event DataURIToggled(bool enabled);
    event BaseURIUpdated(string baseURI);
    function arePartsLocked() external returns (bool);
    function isDataURIEnabled() external returns (bool);
    function baseURI() external returns (string memory);
    function palettes(uint8 paletteIndex, uint256 colorIndex) external view returns (string memory);
    function backgrounds(uint256 index) external view returns (string memory);
    function bodies(uint256 index) external view returns (bytes memory);
    function accessories(uint256 index) external view returns (bytes memory);
    function heads(uint256 index) external view returns (bytes memory);
    function glasses(uint256 index) external view returns (bytes memory);
    function backgroundCount() external view returns (uint256);
    function bodyCount() external view returns (uint256);
    function accessoryCount() external view returns (uint256);
    function headCount() external view returns (uint256);
    function glassesCount() external view returns (uint256);
    function addManyColorsToPalette(uint8 paletteIndex, string[] calldata newColors) external;
    function addManyBackgrounds(string[] calldata backgrounds) external;
    function addManyBodies(bytes[] calldata bodies) external;
    function addManyAccessories(bytes[] calldata accessories) external;
    function addManyHeads(bytes[] calldata heads) external;
    function addManyGlasses(bytes[] calldata glasses) external;
    function addColorToPalette(uint8 paletteIndex, string calldata color) external;
    function addBackground(string calldata background) external;
    function addBody(bytes calldata body) external;
    function addAccessory(bytes calldata accessory) external;
    function addHead(bytes calldata head) external;
    function addGlasses(bytes calldata glasses) external;
    function lockParts() external;
    function toggleDataURIEnabled() external;
    function setBaseURI(string calldata baseURI) external;
    function tokenURI(uint256 tokenId, INounsSeeder.Seed memory seed) external view returns (string memory);
    function dataURI(uint256 tokenId, INounsSeeder.Seed memory seed) external view returns (string memory);
    function genericDataURI(
        string calldata name,
        string calldata description,
        INounsSeeder.Seed memory seed
    ) external view returns (string memory);
    function generateSVGImage(INounsSeeder.Seed memory seed) external view returns (string memory);
}
// SPDX-License-Identifier: GPL-3.0
/// @title Interface for NounsSeeder
/*********************************
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░█████████░░█████████░░░ *
 * ░░░░░░██░░░████░░██░░░████░░░ *
 * ░░██████░░░████████░░░████░░░ *
 * ░░██░░██░░░████░░██░░░████░░░ *
 * ░░██░░██░░░████░░██░░░████░░░ *
 * ░░░░░░█████████░░█████████░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 *********************************/
pragma solidity ^0.8.6;
import { INounsDescriptor } from './INounsDescriptor.sol';
interface INounsSeeder {
    struct Seed {
        uint48 background;
        uint48 body;
        uint48 accessory;
        uint48 head;
        uint48 glasses;
    }
    function generateSeed(uint256 nounId, INounsDescriptor descriptor) external view returns (Seed memory);
}
// SPDX-License-Identifier: GPL-3.0
/// @title Interface for NounsToken
/*********************************
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
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 *********************************/
pragma solidity ^0.8.6;
import { IERC721 } from '@openzeppelin/contracts/token/ERC721/IERC721.sol';
import { INounsDescriptor } from './INounsDescriptor.sol';
import { INounsSeeder } from './INounsSeeder.sol';
interface INounsToken is IERC721 {
    event NounCreated(uint256 indexed tokenId, INounsSeeder.Seed seed);
    event NounBurned(uint256 indexed tokenId);
    event NoundersDAOUpdated(address noundersDAO);
    event MinterUpdated(address minter);
    event MinterLocked();
    event DescriptorUpdated(INounsDescriptor descriptor);
    event DescriptorLocked();
    event SeederUpdated(INounsSeeder seeder);
    event SeederLocked();
    function mint() external returns (uint256);
    function burn(uint256 tokenId) external;
    function dataURI(uint256 tokenId) external returns (string memory);
    function setNoundersDAO(address noundersDAO) external;
    function setMinter(address minter) external;
    function lockMinter() external;
    function setDescriptor(INounsDescriptor descriptor) external;
    function lockDescriptor() external;
    function setSeeder(INounsSeeder seeder) external;
    function lockSeeder() external;
}
// SPDX-License-Identifier: MIT
/// @title ERC721 Token Implementation
/*********************************
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 *********************************/
// LICENSE
// ERC721.sol modifies OpenZeppelin's ERC721.sol:
// https://github.com/OpenZeppelin/openzeppelin-contracts/blob/6618f9f18424ade44116d0221719f4c93be6a078/contracts/token/ERC721/ERC721.sol
//
// ERC721.sol source code copyright OpenZeppelin licensed under the MIT License.
// With modifications by Nounders DAO.
//
//
// MODIFICATIONS:
// `_safeMint` and `_mint` contain an additional `creator` argument and
// emit two `Transfer` logs, rather than one. The first log displays the
// transfer (mint) from `address(0)` to the `creator`. The second displays the
// transfer from the `creator` to the `to` address. This enables correct
// attribution on various NFT marketplaces.
pragma solidity ^0.8.6;
import '@openzeppelin/contracts/token/ERC721/IERC721.sol';
import '@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol';
import '@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol';
import '@openzeppelin/contracts/utils/Address.sol';
import '@openzeppelin/contracts/utils/Context.sol';
import '@openzeppelin/contracts/utils/Strings.sol';
import '@openzeppelin/contracts/utils/introspection/ERC165.sol';
/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension, but not including the Enumerable extension, which is available separately as
 * {ERC721Enumerable}.
 */
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
    using Address for address;
    using Strings for uint256;
    // Token name
    string private _name;
    // Token symbol
    string private _symbol;
    // Mapping from token ID to owner address
    mapping(uint256 => address) private _owners;
    // Mapping owner address to token count
    mapping(address => uint256) private _balances;
    // Mapping from token ID to approved address
    mapping(uint256 => address) private _tokenApprovals;
    // Mapping from owner to operator approvals
    mapping(address => mapping(address => bool)) private _operatorApprovals;
    /**
     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            super.supportsInterface(interfaceId);
    }
    /**
     * @dev See {IERC721-balanceOf}.
     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), 'ERC721: balance query for the zero address');
        return _balances[owner];
    }
    /**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        address owner = _owners[tokenId];
        require(owner != address(0), 'ERC721: owner query for nonexistent token');
        return owner;
    }
    /**
     * @dev See {IERC721Metadata-name}.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }
    /**
     * @dev See {IERC721Metadata-symbol}.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }
    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        require(_exists(tokenId), 'ERC721Metadata: URI query for nonexistent token');
        string memory baseURI = _baseURI();
        return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : '';
    }
    /**
     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
     * by default, can be overriden in child contracts.
     */
    function _baseURI() internal view virtual returns (string memory) {
        return '';
    }
    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public virtual override {
        address owner = ERC721.ownerOf(tokenId);
        require(to != owner, 'ERC721: approval to current owner');
        require(
            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
            'ERC721: approve caller is not owner nor approved for all'
        );
        _approve(to, tokenId);
    }
    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        require(_exists(tokenId), 'ERC721: approved query for nonexistent token');
        return _tokenApprovals[tokenId];
    }
    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        require(operator != _msgSender(), 'ERC721: approve to caller');
        _operatorApprovals[_msgSender()][operator] = approved;
        emit ApprovalForAll(_msgSender(), operator, approved);
    }
    /**
     * @dev See {IERC721-isApprovedForAll}.
     */
    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[owner][operator];
    }
    /**
     * @dev See {IERC721-transferFrom}.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), 'ERC721: transfer caller is not owner nor approved');
        _transfer(from, to, tokenId);
    }
    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        safeTransferFrom(from, to, tokenId, '');
    }
    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), 'ERC721: transfer caller is not owner nor approved');
        _safeTransfer(from, to, tokenId, _data);
    }
    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * `_data` is additional data, it has no specified format and it is sent in call to `to`.
     *
     * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
     * implement alternative mechanisms to perform token transfer, such as signature-based.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeTransfer(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) internal virtual {
        _transfer(from, to, tokenId);
        require(_checkOnERC721Received(from, to, tokenId, _data), 'ERC721: transfer to non ERC721Receiver implementer');
    }
    /**
     * @dev Returns whether `tokenId` exists.
     *
     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
     *
     * Tokens start existing when they are minted (`_mint`),
     * and stop existing when they are burned (`_burn`).
     */
    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return _owners[tokenId] != address(0);
    }
    /**
     * @dev Returns whether `spender` is allowed to manage `tokenId`.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
        require(_exists(tokenId), 'ERC721: operator query for nonexistent token');
        address owner = ERC721.ownerOf(tokenId);
        return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
    }
    /**
     * @dev Safely mints `tokenId`, transfers it to `to`, and emits two log events -
     * 1. Credits the `minter` with the mint.
     * 2. Shows transfer from the `minter` to `to`.
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeMint(
        address creator,
        address to,
        uint256 tokenId
    ) internal virtual {
        _safeMint(creator, to, tokenId, '');
    }
    /**
     * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
     * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
     */
    function _safeMint(
        address creator,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) internal virtual {
        _mint(creator, to, tokenId);
        require(
            _checkOnERC721Received(address(0), to, tokenId, _data),
            'ERC721: transfer to non ERC721Receiver implementer'
        );
    }
    /**
     * @dev Mints `tokenId`, transfers it to `to`, and emits two log events -
     * 1. Credits the `creator` with the mint.
     * 2. Shows transfer from the `creator` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - `to` cannot be the zero address.
     *
     * Emits a {Transfer} event.
     */
    function _mint(
        address creator,
        address to,
        uint256 tokenId
    ) internal virtual {
        require(to != address(0), 'ERC721: mint to the zero address');
        require(!_exists(tokenId), 'ERC721: token already minted');
        _beforeTokenTransfer(address(0), to, tokenId);
        _balances[to] += 1;
        _owners[tokenId] = to;
        emit Transfer(address(0), creator, tokenId);
        emit Transfer(creator, to, tokenId);
    }
    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId) internal virtual {
        address owner = ERC721.ownerOf(tokenId);
        _beforeTokenTransfer(owner, address(0), tokenId);
        // Clear approvals
        _approve(address(0), tokenId);
        _balances[owner] -= 1;
        delete _owners[tokenId];
        emit Transfer(owner, address(0), tokenId);
    }
    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     *
     * Emits a {Transfer} event.
     */
    function _transfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {
        require(ERC721.ownerOf(tokenId) == from, 'ERC721: transfer of token that is not own');
        require(to != address(0), 'ERC721: transfer to the zero address');
        _beforeTokenTransfer(from, to, tokenId);
        // Clear approvals from the previous owner
        _approve(address(0), tokenId);
        _balances[from] -= 1;
        _balances[to] += 1;
        _owners[tokenId] = to;
        emit Transfer(from, to, tokenId);
    }
    /**
     * @dev Approve `to` to operate on `tokenId`
     *
     * Emits a {Approval} event.
     */
    function _approve(address to, uint256 tokenId) internal virtual {
        _tokenApprovals[tokenId] = to;
        emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
    }
    /**
     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
     * The call is not executed if the target address is not a contract.
     *
     * @param from address representing the previous owner of the given token ID
     * @param to target address that will receive the tokens
     * @param tokenId uint256 ID of the token to be transferred
     * @param _data bytes optional data to send along with the call
     * @return bool whether the call correctly returned the expected magic value
     */
    function _checkOnERC721Received(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) private returns (bool) {
        if (to.isContract()) {
            try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
                return retval == IERC721Receiver(to).onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert('ERC721: transfer to non ERC721Receiver implementer');
                } else {
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }
    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../../utils/introspection/IERC165.sol";
/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);
    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);
    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;
    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;
    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;
    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);
    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;
    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.6;
interface IProxyRegistry {
    function proxies(address) external view returns (address);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/*
 * @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;
    }
}
// SPDX-License-Identifier: MIT
/// @title ERC721 Enumerable Extension
/*********************************
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░█████████░░█████████░░░ *
 * ░░░░░░██░░░████░░██░░░████░░░ *
 * ░░██████░░░████████░░░████░░░ *
 * ░░██░░██░░░████░░██░░░████░░░ *
 * ░░██░░██░░░████░░██░░░████░░░ *
 * ░░░░░░█████████░░█████████░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 * ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ *
 *********************************/
// LICENSE
// ERC721.sol modifies OpenZeppelin's ERC721Enumerable.sol:
// https://github.com/OpenZeppelin/openzeppelin-contracts/blob/6618f9f18424ade44116d0221719f4c93be6a078/contracts/token/ERC721/extensions/ERC721Enumerable.sol
//
// ERC721Enumerable.sol source code copyright OpenZeppelin licensed under the MIT License.
// With modifications by Nounders DAO.
//
// MODIFICATIONS:
// Consumes modified `ERC721` contract. See notes in `ERC721.sol`.
pragma solidity ^0.8.0;
import './ERC721.sol';
import '@openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol';
/**
 * @dev This implements an optional extension of {ERC721} defined in the EIP that adds
 * enumerability of all the token ids in the contract as well as all token ids owned by each
 * account.
 */
abstract contract ERC721Enumerable is ERC721, IERC721Enumerable {
    // Mapping from owner to list of owned token IDs
    mapping(address => mapping(uint256 => uint256)) private _ownedTokens;
    // Mapping from token ID to index of the owner tokens list
    mapping(uint256 => uint256) private _ownedTokensIndex;
    // Array with all token ids, used for enumeration
    uint256[] private _allTokens;
    // Mapping from token id to position in the allTokens array
    mapping(uint256 => uint256) private _allTokensIndex;
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC721) returns (bool) {
        return interfaceId == type(IERC721Enumerable).interfaceId || super.supportsInterface(interfaceId);
    }
    /**
     * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721.balanceOf(owner), 'ERC721Enumerable: owner index out of bounds');
        return _ownedTokens[owner][index];
    }
    /**
     * @dev See {IERC721Enumerable-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _allTokens.length;
    }
    /**
     * @dev See {IERC721Enumerable-tokenByIndex}.
     */
    function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721Enumerable.totalSupply(), 'ERC721Enumerable: global index out of bounds');
        return _allTokens[index];
    }
    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` will be burned.
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual override {
        super._beforeTokenTransfer(from, to, tokenId);
        if (from == address(0)) {
            _addTokenToAllTokensEnumeration(tokenId);
        } else if (from != to) {
            _removeTokenFromOwnerEnumeration(from, tokenId);
        }
        if (to == address(0)) {
            _removeTokenFromAllTokensEnumeration(tokenId);
        } else if (to != from) {
            _addTokenToOwnerEnumeration(to, tokenId);
        }
    }
    /**
     * @dev Private function to add a token to this extension's ownership-tracking data structures.
     * @param to address representing the new owner of the given token ID
     * @param tokenId uint256 ID of the token to be added to the tokens list of the given address
     */
    function _addTokenToOwnerEnumeration(address to, uint256 tokenId) private {
        uint256 length = ERC721.balanceOf(to);
        _ownedTokens[to][length] = tokenId;
        _ownedTokensIndex[tokenId] = length;
    }
    /**
     * @dev Private function to add a token to this extension's token tracking data structures.
     * @param tokenId uint256 ID of the token to be added to the tokens list
     */
    function _addTokenToAllTokensEnumeration(uint256 tokenId) private {
        _allTokensIndex[tokenId] = _allTokens.length;
        _allTokens.push(tokenId);
    }
    /**
     * @dev Private function to remove a token from this extension's ownership-tracking data structures. Note that
     * while the token is not assigned a new owner, the `_ownedTokensIndex` mapping is _not_ updated: this allows for
     * gas optimizations e.g. when performing a transfer operation (avoiding double writes).
     * This has O(1) time complexity, but alters the order of the _ownedTokens array.
     * @param from address representing the previous owner of the given token ID
     * @param tokenId uint256 ID of the token to be removed from the tokens list of the given address
     */
    function _removeTokenFromOwnerEnumeration(address from, uint256 tokenId) private {
        // To prevent a gap in from's tokens array, we store the last token in the index of the token to delete, and
        // then delete the last slot (swap and pop).
        uint256 lastTokenIndex = ERC721.balanceOf(from) - 1;
        uint256 tokenIndex = _ownedTokensIndex[tokenId];
        // When the token to delete is the last token, the swap operation is unnecessary
        if (tokenIndex != lastTokenIndex) {
            uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];
            _ownedTokens[from][tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
            _ownedTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
        }
        // This also deletes the contents at the last position of the array
        delete _ownedTokensIndex[tokenId];
        delete _ownedTokens[from][lastTokenIndex];
    }
    /**
     * @dev Private function to remove a token from this extension's token tracking data structures.
     * This has O(1) time complexity, but alters the order of the _allTokens array.
     * @param tokenId uint256 ID of the token to be removed from the tokens list
     */
    function _removeTokenFromAllTokensEnumeration(uint256 tokenId) private {
        // To prevent a gap in the tokens array, we store the last token in the index of the token to delete, and
        // then delete the last slot (swap and pop).
        uint256 lastTokenIndex = _allTokens.length - 1;
        uint256 tokenIndex = _allTokensIndex[tokenId];
        // When the token to delete is the last token, the swap operation is unnecessary. However, since this occurs so
        // rarely (when the last minted token is burnt) that we still do the swap here to avoid the gas cost of adding
        // an 'if' statement (like in _removeTokenFromOwnerEnumeration)
        uint256 lastTokenId = _allTokens[lastTokenIndex];
        _allTokens[tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
        _allTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
        // This also deletes the contents at the last position of the array
        delete _allTokensIndex[tokenId];
        _allTokens.pop();
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../IERC721.sol";
/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Enumerable is IERC721 {
    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() external view returns (uint256);
    /**
     * @dev Returns a token ID owned by `owner` at a given `index` of its token list.
     * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId);
    /**
     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
     * Use along with {totalSupply} to enumerate all tokens.
     */
    function tokenByIndex(uint256 index) external view returns (uint256);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../IERC721.sol";
/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Metadata is IERC721 {
    /**
     * @dev Returns the token collection name.
     */
    function name() external view returns (string memory);
    /**
     * @dev Returns the token collection symbol.
     */
    function symbol() external view returns (string memory);
    /**
     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.
        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }
    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");
        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }
    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }
    function _verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) private pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }
    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }
    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./IERC165.sol";
/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}