// 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);
}