// File: contracts/Decentralist.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.2;

import "@openzeppelin/contracts/proxy/utils/Initializable.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

import "@uma/core/contracts/oracle/implementation/Constants.sol";
import "@uma/core/contracts/oracle/interfaces/FinderInterface.sol";
import "@uma/core/contracts/common/implementation/AncillaryData.sol";
import "@uma/core/contracts/oracle/interfaces/StoreInterface.sol";
import "@uma/core/contracts/oracle/interfaces/OptimisticOracleV2Interface.sol";

contract Decentralist is Initializable, Ownable {
    using SafeERC20 for IERC20;

    event RevisionProposed(
        uint256 indexed revisionId,
        RevisionType revisionType,
        address[] proposedAddresses
    );
    event RevisionApproved(
        uint256 indexed revisionId,
        RevisionType revisionType
    );
    event RevisionRejected(
        uint256 indexed revisionId,
        RevisionType revisionType
    );
    event RevisionExecuted(
        uint256 indexed revisionId,
        RevisionType revisionType,
        address[] revisedAddresses
    );

    event RewardsSet(uint256 additionReward, uint256 removalReward);
    event LivenessSet(uint64 liveness);
    event BondSet(uint256 bondAmount);

    OptimisticOracleV2Interface public oracle;
    StoreInterface public store;

    FinderInterface public finder;
    bytes public fixedAncillaryData;
    string public title;
    uint256 public bondAmount;
    IERC20 public token;
    uint256 public additionReward;
    uint256 public removalReward;
    uint64 public liveness;
    uint64 public minimumLiveness;
    uint256 private revisionCounter;
    uint256 private finalFee;

    int256 internal constant PROPOSAL_YES_RESPONSE = int256(1e18);
    bytes32 internal constant IDENTIFIER = "DECENTRA-LIST";

    enum RevisionType {
        Remove,
        Add
    }

    enum Status {
        Invalid,
        Proposed,
        Approved,
        Rejected,
        Executed
    }

    struct Revision {
        address proposer;
        bytes32 addressesHash;
        RevisionType revisionType;
        Status status;
    }

    // maps hash of oracle revision data to revisionId
    mapping(bytes32 => uint256) private revisionIds;
    // maps revisionId to Revision
    mapping(uint256 => Revision) public revisions;
    // maps addresses to bool for inclusion on list
    mapping(address => bool) public onList;

    /**
     * @notice Initializes the contract.
     * @param _finder The address of UMA Finder contract. This is set in the DecentralistProxyFactory constructor.
     * @param _listCriteria Criteria for what addresses should be included on the list. Can be on-chain text or a link to IPFS.
     * @param _title Short title for the list.
     * @param _token The address of the token currency used for this contract. Must be on UMA's collateral whitelist.
     * @param _bondAmount Additional bond required, beyond the final fee.
     * @param _additionReward Reward per address successfully added to the list, paid by the contract to the proposer.
     * @param _removalReward Reward per address successfully removed from the list, paid by the contract to the proposer.
     * @param _liveness The period, in seconds, in which a proposal can be disputed.
     * @param _minimumLiveness The minimum allowable liveness period, in seconds.
     * @param _owner Owner of the contract can remove funds from the contract and adjust reward rates. Set to the 0 address to make the contract 'public'.
     */
    function initialize(
        address _finder,
        bytes memory _listCriteria,
        string memory _title,
        address _token,
        uint256 _bondAmount,
        uint256 _additionReward,
        uint256 _removalReward,
        uint64 _liveness,
        uint64 _minimumLiveness,
        address _owner
    ) external initializer {
        finder = FinderInterface(_finder);
        syncContracts();
        token = IERC20(_token);

        finalFee = store.computeFinalFee(address(token)).rawValue;

        require(
            _bondAmount >= store.computeFinalFee(address(token)).rawValue,
            "bond must be >= final fee"
        );
        require(
            _liveness >= _minimumLiveness,
            "liveness must be >= minimumLiveness"
        );
        require(_liveness < 5200 weeks, "liveness must be < 5200 weeks");

        // add boilerplate directions for verification to _listCriteria
        fixedAncillaryData = bytes.concat(
            "meet the List Criteria at the time of the price request? List Criteria: ",
            _listCriteria,
            ". Decentra-List Revision ID = "
        );
        title = _title;
        token = IERC20(_token);
        bondAmount = _bondAmount;
        additionReward = _additionReward;
        removalReward = _removalReward;
        liveness = _liveness;
        minimumLiveness = _minimumLiveness;
        _transferOwnership(_owner);

        revisionCounter = 1;
    }

    /**
     * @notice Proposes addresses to add or remove from the list.
     * @param _revisionType Enum indicatting if the proposed revision is adding or removing addresses. 0 = Remove, 1 = Add.
     * @param _addresses Array of addresses for the proposed revision.
     * @dev Caller must have approved this contract to spend the total bond amount of the contract's token before calling.
     */
    function proposeRevision(
        RevisionType _revisionType,
        address[] calldata _addresses
    ) external {
        require(
            _addresses.length < 100,
            "addresses array length must be < 100"
        );

        // prepare oracle request data
        bytes memory ancillaryData = "Do all Proposed Addresses ";
        if (_revisionType == RevisionType.Remove) {
            ancillaryData = bytes.concat(ancillaryData, "fail to ");
        }
        ancillaryData = bytes.concat(
            ancillaryData,
            fixedAncillaryData,
            AncillaryData.toUtf8BytesUint(revisionCounter),
            ". For directions to find the Proposed Addresses, see Implementation section of UMIP-169."
        );
        uint256 currentTime = block.timestamp;

        // prepare data for storage in Revision
        bytes32 oracleRequestHash = keccak256(
            abi.encodePacked(ancillaryData, currentTime)
        );
        bytes32 addressesHash = keccak256(abi.encodePacked(_addresses));

        // map oracleRequestHash to the current revisionCounter
        revisionIds[oracleRequestHash] = revisionCounter;

        // store Revision data in revisions mapping under the revisionCounter
        revisions[revisionCounter].proposer = msg.sender;
        revisions[revisionCounter].addressesHash = addressesHash;
        revisions[revisionCounter].revisionType = _revisionType;
        revisions[revisionCounter].status = Status.Proposed;

        // request data from oracle and configure request settings
        oracle.requestPrice(IDENTIFIER, currentTime, ancillaryData, token, 0);
        oracle.setCallbacks(
            IDENTIFIER,
            currentTime,
            ancillaryData,
            false,
            false,
            true
        );
        oracle.setCustomLiveness(
            IDENTIFIER,
            currentTime,
            ancillaryData,
            liveness
        );
        uint256 totalBond = oracle.setBond(
            IDENTIFIER,
            currentTime,
            ancillaryData,
            bondAmount
        );

        // transfer totalBond from proposer to contract for forwarding to Oracle
        token.safeTransferFrom(msg.sender, address(this), totalBond);

        // approve oracle to transfer total bond amount from list contract
        token.safeApprove(address(oracle), totalBond);

        // propose value to oracle
        oracle.proposePriceFor(
            msg.sender,
            address(this),
            IDENTIFIER,
            currentTime,
            ancillaryData,
            PROPOSAL_YES_RESPONSE
        );

        emit RevisionProposed(revisionCounter, _revisionType, _addresses);
        revisionCounter++;
    }

    /**
     * @notice Callback function called upon oracle data settlement to update the Revision status to Approved or Rejected.
     * @param timestamp Timestamp to identify the existing request.
     * @param ancillaryData Ancillary data of the data being requested.
     * @param value Value returned from the oracle.
     */
    function priceSettled(
        bytes32, /* identifier */
        uint256 timestamp,
        bytes memory ancillaryData,
        int256 value
    ) external {
        // restrict function access to oracle
        require(
            msg.sender == address(oracle),
            "only oracle can call this function"
        );

        // get revisionId from oracleRequestHash
        bytes32 oracleRequestHash = keccak256(
            abi.encodePacked(ancillaryData, timestamp)
        );
        uint256 revisionId = revisionIds[oracleRequestHash];

        // set status to Approved or Rejected
        if (value == PROPOSAL_YES_RESPONSE) {
            revisions[revisionId].status = Status.Approved;
            emit RevisionApproved(
                revisionId,
                revisions[revisionId].revisionType
            );
        } else {
            revisions[revisionId].status = Status.Rejected;
            emit RevisionRejected(
                revisionId,
                revisions[revisionId].revisionType
            );
        }
    }

    /**
     * @notice Executes approved revisions by revising the list and paying out rewards to the proposer.
     * @param _revisionId ID of revision to be executed. If Revision submitted does not have status Approved, tx will revert.
     * @param _addresses Address array that matches the array logged in the RevisionProposed event for the provided _revisionId.
     */
    function executeRevision(uint256 _revisionId, address[] calldata _addresses)
        external
    {
        require(
            revisions[_revisionId].status == Status.Approved,
            "revisionId is not approved"
        );
        require(
            revisions[_revisionId].addressesHash ==
                keccak256(abi.encodePacked(_addresses)),
            "hash of addresses != revisionId's addressesHash"
        );

        // update Revision status
        revisions[_revisionId].status = Status.Executed;

        // set helper variables based on revisionType = Remove or Add
        bool setOnListTo;
        uint256 rewardRate;

        if (revisions[_revisionId].revisionType == RevisionType.Remove) {
            setOnListTo = false;
            rewardRate = removalReward;
        } else if (revisions[_revisionId].revisionType == RevisionType.Add) {
            setOnListTo = true;
            rewardRate = additionReward;
        }

        // add or remove address from the list, increment rewardCounter for calculating rewards and record revised Addresses
        uint256 rewardCounter;
        address[] memory revisedAddresses = new address[](_addresses.length);

        for (uint256 i = 0; i < _addresses.length; i++) {
            if (onList[_addresses[i]] != setOnListTo) {
                onList[_addresses[i]] = setOnListTo;
                revisedAddresses[i] = _addresses[i];
                rewardCounter++;
            }
        }

        // calculate & pay out rewards to proposer
        uint256 reward = rewardRate * rewardCounter;
        if (reward > 0) {
            if (token.balanceOf(address(this)) < reward) {
                token.safeTransfer(
                    revisions[_revisionId].proposer,
                    token.balanceOf(address(this))
                );
            } else {
                token.safeTransfer(revisions[_revisionId].proposer, reward);
            }
        }
        emit RevisionExecuted(
            _revisionId,
            revisions[_revisionId].revisionType,
            revisedAddresses
        );
    }

    /**
     * @notice Allows owner to withdraw the default tokens from the contract.
     * @param recipient The recipient of the tokens.
     * @param amount The amount of tokens to to send.
     */
    function withdraw(address recipient, uint256 amount) external onlyOwner {
        token.safeTransfer(recipient, amount);
    }

    /**
     * @notice Allows owner to rescue tokens sent accidentally to the contract.
     * @param recipient The recipient of the tokens.
     * @param amount The amount of tokens to to send.
     * @param _token The contract address of the token to send.
     */
    function rescue(
        address recipient,
        uint256 amount,
        address _token
    ) external onlyOwner {
        IERC20(_token).safeTransfer(recipient, amount);
    }

    /**
     * @notice Sets the rewards for successful revisions.
     * @param _additionReward Reward to proposer per address successfully added to the list.
     * @param _removalReward Reward to proposer per address successfully removed from the list.
     */
    function setRewards(uint256 _additionReward, uint256 _removalReward)
        external
        onlyOwner
    {
        additionReward = _additionReward;
        removalReward = _removalReward;
        emit RewardsSet(_additionReward, _removalReward);
    }

    /**
     * @notice Sets the bond amount for revisions.
     * @param _bondAmount Amount of the bond token that will need to be paid for future proposals.
     */
    function setBond(uint256 _bondAmount) external onlyOwner {
        // Value of the bond required for proposing revisions, in addition to the final fee. Bond must be
        // greater or equal to the final fee
        require(
            _bondAmount >= store.computeFinalFee(address(token)).rawValue,
            "bond must be >= final fee"
        );

        bondAmount = _bondAmount;
        emit BondSet(_bondAmount);
    }

    /**
     * @notice Sets the liveness for future revisions. This is the amount of delay before a proposal is approved by
     * default.
     * @param _liveness Liveness to set in seconds.
     */
    function setLiveness(uint64 _liveness) external onlyOwner {
        require(
            _liveness >= minimumLiveness,
            "liveness must be >= minimumLiveness"
        );
        require(_liveness < 1 weeks, "liveness must be < than 1 week");
        liveness = _liveness;
        emit LivenessSet(_liveness);
    }

    /**
     * @notice This pulls in the most up-to-date Optimistic Oracle contract.
     * @dev If a new OptimisticOracle is added and this is run between a revision's introduction and execution, the
     * proposal will become unexecutable.
     */
    function syncContracts() public {
        oracle = OptimisticOracleV2Interface(
            finder.getImplementationAddress(OracleInterfaces.OptimisticOracleV2)
        );
        store = StoreInterface(
            finder.getImplementationAddress(OracleInterfaces.Store)
        );
    }
}
// File: @openzeppelin/contracts/proxy/utils/Initializable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (proxy/utils/Initializable.sol)

pragma solidity ^0.8.2;

import "../../utils/Address.sol";

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
 * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
 * case an upgrade adds a module that needs to be initialized.
 *
 * For example:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * contract MyToken is ERC20Upgradeable {
 *     function initialize() initializer public {
 *         __ERC20_init("MyToken", "MTK");
 *     }
 * }
 * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
 *     function initializeV2() reinitializer(2) public {
 *         __ERC20Permit_init("MyToken");
 *     }
 * }
 * ```
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 *
 * [CAUTION]
 * ====
 * Avoid leaving a contract uninitialized.
 *
 * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
 * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
 * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * /// @custom:oz-upgrades-unsafe-allow constructor
 * constructor() {
 *     _disableInitializers();
 * }
 * ```
 * ====
 */
abstract contract Initializable {
    /**
     * @dev Indicates that the contract has been initialized.
     * @custom:oz-retyped-from bool
     */
    uint8 private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Triggered when the contract has been initialized or reinitialized.
     */
    event Initialized(uint8 version);

    /**
     * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
     * `onlyInitializing` functions can be used to initialize parent contracts. Equivalent to `reinitializer(1)`.
     */
    modifier initializer() {
        bool isTopLevelCall = !_initializing;
        require(
            (isTopLevelCall && _initialized < 1) || (!Address.isContract(address(this)) && _initialized == 1),
            "Initializable: contract is already initialized"
        );
        _initialized = 1;
        if (isTopLevelCall) {
            _initializing = true;
        }
        _;
        if (isTopLevelCall) {
            _initializing = false;
            emit Initialized(1);
        }
    }

    /**
     * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
     * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
     * used to initialize parent contracts.
     *
     * `initializer` is equivalent to `reinitializer(1)`, so a reinitializer may be used after the original
     * initialization step. This is essential to configure modules that are added through upgrades and that require
     * initialization.
     *
     * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
     * a contract, executing them in the right order is up to the developer or operator.
     */
    modifier reinitializer(uint8 version) {
        require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
        _initialized = version;
        _initializing = true;
        _;
        _initializing = false;
        emit Initialized(version);
    }

    /**
     * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
     * {initializer} and {reinitializer} modifiers, directly or indirectly.
     */
    modifier onlyInitializing() {
        require(_initializing, "Initializable: contract is not initializing");
        _;
    }

    /**
     * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
     * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
     * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
     * through proxies.
     */
    function _disableInitializers() internal virtual {
        require(!_initializing, "Initializable: contract is initializing");
        if (_initialized < type(uint8).max) {
            _initialized = type(uint8).max;
            emit Initialized(type(uint8).max);
        }
    }
}

// File: @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/draft-IERC20Permit.sol";
import "../../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);
}

// File: @uma/core/contracts/oracle/implementation/Constants.sol



// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity ^0.8.0;

/**
 * @title Stores common interface names used throughout the DVM by registration in the Finder.
 */
library OracleInterfaces {
    bytes32 public constant Oracle = "Oracle";
    bytes32 public constant IdentifierWhitelist = "IdentifierWhitelist";
    bytes32 public constant Store = "Store";
    bytes32 public constant FinancialContractsAdmin = "FinancialContractsAdmin";
    bytes32 public constant Registry = "Registry";
    bytes32 public constant CollateralWhitelist = "CollateralWhitelist";
    bytes32 public constant OptimisticOracle = "OptimisticOracle";
    bytes32 public constant OptimisticOracleV2 = "OptimisticOracleV2";
    bytes32 public constant Bridge = "Bridge";
    bytes32 public constant GenericHandler = "GenericHandler";
    bytes32 public constant SkinnyOptimisticOracle = "SkinnyOptimisticOracle";
    bytes32 public constant ChildMessenger = "ChildMessenger";
    bytes32 public constant OracleHub = "OracleHub";
    bytes32 public constant OracleSpoke = "OracleSpoke";
}

/**
 * @title Commonly re-used values for contracts associated with the OptimisticOracle.
 */
library OptimisticOracleConstraints {
    // Any price request submitted to the OptimisticOracle must contain ancillary data no larger than this value.
    // This value must be <= the Voting contract's `ancillaryBytesLimit` constant value otherwise it is possible
    // that a price can be requested to the OptimisticOracle successfully, but cannot be resolved by the DVM which
    // refuses to accept a price request made with ancillary data length over a certain size.
    uint256 public constant ancillaryBytesLimit = 8192;
}

// File: @uma/core/contracts/common/implementation/AncillaryData.sol



// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity ^0.8.0;

/**
 * @title Library for encoding and decoding ancillary data for DVM price requests.
 * @notice  We assume that on-chain ancillary data can be formatted directly from bytes to utf8 encoding via
 * web3.utils.hexToUtf8, and that clients will parse the utf8-encoded ancillary data as a comma-delimitted key-value
 * dictionary. Therefore, this library provides internal methods that aid appending to ancillary data from Solidity
 * smart contracts. More details on UMA's ancillary data guidelines below:
 * https://docs.google.com/document/d/1zhKKjgY1BupBGPPrY_WOJvui0B6DMcd-xDR8-9-SPDw/edit
 */
library AncillaryData {
    // This converts the bottom half of a bytes32 input to hex in a highly gas-optimized way.
    // Source: the brilliant implementation at https://gitter.im/ethereum/solidity?at=5840d23416207f7b0ed08c9b.
    function toUtf8Bytes32Bottom(bytes32 bytesIn) private pure returns (bytes32) {
        unchecked {
            uint256 x = uint256(bytesIn);

            // Nibble interleave
            x = x & 0x00000000000000000000000000000000ffffffffffffffffffffffffffffffff;
            x = (x | (x * 2**64)) & 0x0000000000000000ffffffffffffffff0000000000000000ffffffffffffffff;
            x = (x | (x * 2**32)) & 0x00000000ffffffff00000000ffffffff00000000ffffffff00000000ffffffff;
            x = (x | (x * 2**16)) & 0x0000ffff0000ffff0000ffff0000ffff0000ffff0000ffff0000ffff0000ffff;
            x = (x | (x * 2**8)) & 0x00ff00ff00ff00ff00ff00ff00ff00ff00ff00ff00ff00ff00ff00ff00ff00ff;
            x = (x | (x * 2**4)) & 0x0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f;

            // Hex encode
            uint256 h = (x & 0x0808080808080808080808080808080808080808080808080808080808080808) / 8;
            uint256 i = (x & 0x0404040404040404040404040404040404040404040404040404040404040404) / 4;
            uint256 j = (x & 0x0202020202020202020202020202020202020202020202020202020202020202) / 2;
            x = x + (h & (i | j)) * 0x27 + 0x3030303030303030303030303030303030303030303030303030303030303030;

            // Return the result.
            return bytes32(x);
        }
    }

    /**
     * @notice Returns utf8-encoded bytes32 string that can be read via web3.utils.hexToUtf8.
     * @dev Will return bytes32 in all lower case hex characters and without the leading 0x.
     * This has minor changes from the toUtf8BytesAddress to control for the size of the input.
     * @param bytesIn bytes32 to encode.
     * @return utf8 encoded bytes32.
     */
    function toUtf8Bytes(bytes32 bytesIn) internal pure returns (bytes memory) {
        return abi.encodePacked(toUtf8Bytes32Bottom(bytesIn >> 128), toUtf8Bytes32Bottom(bytesIn));
    }

    /**
     * @notice Returns utf8-encoded address that can be read via web3.utils.hexToUtf8.
     * Source: https://ethereum.stackexchange.com/questions/8346/convert-address-to-string/8447#8447
     * @dev Will return address in all lower case characters and without the leading 0x.
     * @param x address to encode.
     * @return utf8 encoded address bytes.
     */
    function toUtf8BytesAddress(address x) internal pure returns (bytes memory) {
        return
            abi.encodePacked(toUtf8Bytes32Bottom(bytes32(bytes20(x)) >> 128), bytes8(toUtf8Bytes32Bottom(bytes20(x))));
    }

    /**
     * @notice Converts a uint into a base-10, UTF-8 representation stored in a `string` type.
     * @dev This method is based off of this code: https://stackoverflow.com/a/65707309.
     */
    function toUtf8BytesUint(uint256 x) internal pure returns (bytes memory) {
        if (x == 0) {
            return "0";
        }
        uint256 j = x;
        uint256 len;
        while (j != 0) {
            len++;
            j /= 10;
        }
        bytes memory bstr = new bytes(len);
        uint256 k = len;
        while (x != 0) {
            k = k - 1;
            uint8 temp = (48 + uint8(x - (x / 10) * 10));
            bytes1 b1 = bytes1(temp);
            bstr[k] = b1;
            x /= 10;
        }
        return bstr;
    }

    function appendKeyValueBytes32(
        bytes memory currentAncillaryData,
        bytes memory key,
        bytes32 value
    ) internal pure returns (bytes memory) {
        bytes memory prefix = constructPrefix(currentAncillaryData, key);
        return abi.encodePacked(currentAncillaryData, prefix, toUtf8Bytes(value));
    }

    /**
     * @notice Adds "key:value" to `currentAncillaryData` where `value` is an address that first needs to be converted
     * to utf8 bytes. For example, if `utf8(currentAncillaryData)="k1:v1"`, then this function will return
     * `utf8(k1:v1,key:value)`, and if `currentAncillaryData` is blank, then this will return `utf8(key:value)`.
     * @param currentAncillaryData This bytes data should ideally be able to be utf8-decoded, but its OK if not.
     * @param key Again, this bytes data should ideally be able to be utf8-decoded, but its OK if not.
     * @param value An address to set as the value in the key:value pair to append to `currentAncillaryData`.
     * @return Newly appended ancillary data.
     */
    function appendKeyValueAddress(
        bytes memory currentAncillaryData,
        bytes memory key,
        address value
    ) internal pure returns (bytes memory) {
        bytes memory prefix = constructPrefix(currentAncillaryData, key);
        return abi.encodePacked(currentAncillaryData, prefix, toUtf8BytesAddress(value));
    }

    /**
     * @notice Adds "key:value" to `currentAncillaryData` where `value` is a uint that first needs to be converted
     * to utf8 bytes. For example, if `utf8(currentAncillaryData)="k1:v1"`, then this function will return
     * `utf8(k1:v1,key:value)`, and if `currentAncillaryData` is blank, then this will return `utf8(key:value)`.
     * @param currentAncillaryData This bytes data should ideally be able to be utf8-decoded, but its OK if not.
     * @param key Again, this bytes data should ideally be able to be utf8-decoded, but its OK if not.
     * @param value A uint to set as the value in the key:value pair to append to `currentAncillaryData`.
     * @return Newly appended ancillary data.
     */
    function appendKeyValueUint(
        bytes memory currentAncillaryData,
        bytes memory key,
        uint256 value
    ) internal pure returns (bytes memory) {
        bytes memory prefix = constructPrefix(currentAncillaryData, key);
        return abi.encodePacked(currentAncillaryData, prefix, toUtf8BytesUint(value));
    }

    /**
     * @notice Helper method that returns the left hand side of a "key:value" pair plus the colon ":" and a leading
     * comma "," if the `currentAncillaryData` is not empty. The return value is intended to be prepended as a prefix to
     * some utf8 value that is ultimately added to a comma-delimited, key-value dictionary.
     */
    function constructPrefix(bytes memory currentAncillaryData, bytes memory key) internal pure returns (bytes memory) {
        if (currentAncillaryData.length > 0) {
            return abi.encodePacked(",", key, ":");
        } else {
            return abi.encodePacked(key, ":");
        }
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

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() {
        _transferOwnership(_msgSender());
    }

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

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

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

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

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

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

// File: @uma/core/contracts/oracle/interfaces/FinderInterface.sol



// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity ^0.8.0;

/**
 * @title Provides addresses of the live contracts implementing certain interfaces.
 * @dev Examples are the Oracle or Store interfaces.
 */
interface FinderInterface {
    /**
     * @notice Updates the address of the contract that implements `interfaceName`.
     * @param interfaceName bytes32 encoding of the interface name that is either changed or registered.
     * @param implementationAddress address of the deployed contract that implements the interface.
     */
    function changeImplementationAddress(bytes32 interfaceName, address implementationAddress) external;

    /**
     * @notice Gets the address of the contract that implements the given `interfaceName`.
     * @param interfaceName queried interface.
     * @return implementationAddress address of the deployed contract that implements the interface.
     */
    function getImplementationAddress(bytes32 interfaceName) external view returns (address);
}

// File: @uma/core/contracts/oracle/interfaces/StoreInterface.sol



// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "../../common/implementation/FixedPoint.sol";

/**
 * @title Interface that allows financial contracts to pay oracle fees for their use of the system.
 */
interface StoreInterface {
    /**
     * @notice Pays Oracle fees in ETH to the store.
     * @dev To be used by contracts whose margin currency is ETH.
     */
    function payOracleFees() external payable;

    /**
     * @notice Pays oracle fees in the margin currency, erc20Address, to the store.
     * @dev To be used if the margin currency is an ERC20 token rather than ETH.
     * @param erc20Address address of the ERC20 token used to pay the fee.
     * @param amount number of tokens to transfer. An approval for at least this amount must exist.
     */
    function payOracleFeesErc20(address erc20Address, FixedPoint.Unsigned calldata amount) external;

    /**
     * @notice Computes the regular oracle fees that a contract should pay for a period.
     * @param startTime defines the beginning time from which the fee is paid.
     * @param endTime end time until which the fee is paid.
     * @param pfc "profit from corruption", or the maximum amount of margin currency that a
     * token sponsor could extract from the contract through corrupting the price feed in their favor.
     * @return regularFee amount owed for the duration from start to end time for the given pfc.
     * @return latePenalty for paying the fee after the deadline.
     */
    function computeRegularFee(
        uint256 startTime,
        uint256 endTime,
        FixedPoint.Unsigned calldata pfc
    ) external view returns (FixedPoint.Unsigned memory regularFee, FixedPoint.Unsigned memory latePenalty);

    /**
     * @notice Computes the final oracle fees that a contract should pay at settlement.
     * @param currency token used to pay the final fee.
     * @return finalFee amount due.
     */
    function computeFinalFee(address currency) external view returns (FixedPoint.Unsigned memory);
}

// File: @uma/core/contracts/oracle/interfaces/OptimisticOracleV2Interface.sol



// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "./FinderInterface.sol";

/**
 * @title Financial contract facing Oracle interface.
 * @dev Interface used by financial contracts to interact with the Oracle. Voters will use a different interface.
 */
abstract contract OptimisticOracleV2Interface {
    event RequestPrice(
        address indexed requester,
        bytes32 identifier,
        uint256 timestamp,
        bytes ancillaryData,
        address currency,
        uint256 reward,
        uint256 finalFee
    );
    event ProposePrice(
        address indexed requester,
        address indexed proposer,
        bytes32 identifier,
        uint256 timestamp,
        bytes ancillaryData,
        int256 proposedPrice,
        uint256 expirationTimestamp,
        address currency
    );
    event DisputePrice(
        address indexed requester,
        address indexed proposer,
        address indexed disputer,
        bytes32 identifier,
        uint256 timestamp,
        bytes ancillaryData,
        int256 proposedPrice
    );
    event Settle(
        address indexed requester,
        address indexed proposer,
        address indexed disputer,
        bytes32 identifier,
        uint256 timestamp,
        bytes ancillaryData,
        int256 price,
        uint256 payout
    );
    // Struct representing the state of a price request.
    enum State {
        Invalid, // Never requested.
        Requested, // Requested, no other actions taken.
        Proposed, // Proposed, but not expired or disputed yet.
        Expired, // Proposed, not disputed, past liveness.
        Disputed, // Disputed, but no DVM price returned yet.
        Resolved, // Disputed and DVM price is available.
        Settled // Final price has been set in the contract (can get here from Expired or Resolved).
    }

    struct RequestSettings {
        bool eventBased; // True if the request is set to be event-based.
        bool refundOnDispute; // True if the requester should be refunded their reward on dispute.
        bool callbackOnPriceProposed; // True if callbackOnPriceProposed callback is required.
        bool callbackOnPriceDisputed; // True if callbackOnPriceDisputed callback is required.
        bool callbackOnPriceSettled; // True if callbackOnPriceSettled callback is required.
        uint256 bond; // Bond that the proposer and disputer must pay on top of the final fee.
        uint256 customLiveness; // Custom liveness value set by the requester.
    }

    // Struct representing a price request.
    struct Request {
        address proposer; // Address of the proposer.
        address disputer; // Address of the disputer.
        IERC20 currency; // ERC20 token used to pay rewards and fees.
        bool settled; // True if the request is settled.
        RequestSettings requestSettings; // Custom settings associated with a request.
        int256 proposedPrice; // Price that the proposer submitted.
        int256 resolvedPrice; // Price resolved once the request is settled.
        uint256 expirationTime; // Time at which the request auto-settles without a dispute.
        uint256 reward; // Amount of the currency to pay to the proposer on settlement.
        uint256 finalFee; // Final fee to pay to the Store upon request to the DVM.
    }

    // This value must be <= the Voting contract's `ancillaryBytesLimit` value otherwise it is possible
    // that a price can be requested to this contract successfully, but cannot be disputed because the DVM refuses
    // to accept a price request made with ancillary data length over a certain size.
    uint256 public constant ancillaryBytesLimit = 8192;

    function defaultLiveness() external view virtual returns (uint256);

    function finder() external view virtual returns (FinderInterface);

    function getCurrentTime() external view virtual returns (uint256);

    // Note: this is required so that typechain generates a return value with named fields.
    mapping(bytes32 => Request) public requests;

    /**
     * @notice Requests a new price.
     * @param identifier price identifier being requested.
     * @param timestamp timestamp of the price being requested.
     * @param ancillaryData ancillary data representing additional args being passed with the price request.
     * @param currency ERC20 token used for payment of rewards and fees. Must be approved for use with the DVM.
     * @param reward reward offered to a successful proposer. Will be pulled from the caller. Note: this can be 0,
     *               which could make sense if the contract requests and proposes the value in the same call or
     *               provides its own reward system.
     * @return totalBond default bond (final fee) + final fee that the proposer and disputer will be required to pay.
     * This can be changed with a subsequent call to setBond().
     */
    function requestPrice(
        bytes32 identifier,
        uint256 timestamp,
        bytes memory ancillaryData,
        IERC20 currency,
        uint256 reward
    ) external virtual returns (uint256 totalBond);

    /**
     * @notice Set the proposal bond associated with a price request.
     * @param identifier price identifier to identify the existing request.
     * @param timestamp timestamp to identify the existing request.
     * @param ancillaryData ancillary data of the price being requested.
     * @param bond custom bond amount to set.
     * @return totalBond new bond + final fee that the proposer and disputer will be required to pay. This can be
     * changed again with a subsequent call to setBond().
     */
    function setBond(
        bytes32 identifier,
        uint256 timestamp,
        bytes memory ancillaryData,
        uint256 bond
    ) external virtual returns (uint256 totalBond);

    /**
     * @notice Sets the request to refund the reward if the proposal is disputed. This can help to "hedge" the caller
     * in the event of a dispute-caused delay. Note: in the event of a dispute, the winner still receives the other's
     * bond, so there is still profit to be made even if the reward is refunded.
     * @param identifier price identifier to identify the existing request.
     * @param timestamp timestamp to identify the existing request.
     * @param ancillaryData ancillary data of the price being requested.
     */
    function setRefundOnDispute(
        bytes32 identifier,
        uint256 timestamp,
        bytes memory ancillaryData
    ) external virtual;

    /**
     * @notice Sets a custom liveness value for the request. Liveness is the amount of time a proposal must wait before
     * being auto-resolved.
     * @param identifier price identifier to identify the existing request.
     * @param timestamp timestamp to identify the existing request.
     * @param ancillaryData ancillary data of the price being requested.
     * @param customLiveness new custom liveness.
     */
    function setCustomLiveness(
        bytes32 identifier,
        uint256 timestamp,
        bytes memory ancillaryData,
        uint256 customLiveness
    ) external virtual;

    /**
     * @notice Sets the request to be an "event-based" request.
     * @dev Calling this method has a few impacts on the request:
     *
     * 1. The timestamp at which the request is evaluated is the time of the proposal, not the timestamp associated
     *    with the request.
     *
     * 2. The proposer cannot propose the "too early" value (TOO_EARLY_RESPONSE). This is to ensure that a proposer who
     *    prematurely proposes a response loses their bond.
     *
     * 3. RefundoOnDispute is automatically set, meaning disputes trigger the reward to be automatically refunded to
     *    the requesting contract.
     *
     * @param identifier price identifier to identify the existing request.
     * @param timestamp timestamp to identify the existing request.
     * @param ancillaryData ancillary data of the price being requested.
     */
    function setEventBased(
        bytes32 identifier,
        uint256 timestamp,
        bytes memory ancillaryData
    ) external virtual;

    /**
     * @notice Sets which callbacks should be enabled for the request.
     * @param identifier price identifier to identify the existing request.
     * @param timestamp timestamp to identify the existing request.
     * @param ancillaryData ancillary data of the price being requested.
     * @param callbackOnPriceProposed whether to enable the callback onPriceProposed.
     * @param callbackOnPriceDisputed whether to enable the callback onPriceDisputed.
     * @param callbackOnPriceSettled whether to enable the callback onPriceSettled.
     */
    function setCallbacks(
        bytes32 identifier,
        uint256 timestamp,
        bytes memory ancillaryData,
        bool callbackOnPriceProposed,
        bool callbackOnPriceDisputed,
        bool callbackOnPriceSettled
    ) external virtual;

    /**
     * @notice Proposes a price value on another address' behalf. Note: this address will receive any rewards that come
     * from this proposal. However, any bonds are pulled from the caller.
     * @param proposer address to set as the proposer.
     * @param requester sender of the initial price request.
     * @param identifier price identifier to identify the existing request.
     * @param timestamp timestamp to identify the existing request.
     * @param ancillaryData ancillary data of the price being requested.
     * @param proposedPrice price being proposed.
     * @return totalBond the amount that's pulled from the caller's wallet as a bond. The bond will be returned to
     * the proposer once settled if the proposal is correct.
     */
    function proposePriceFor(
        address proposer,
        address requester,
        bytes32 identifier,
        uint256 timestamp,
        bytes memory ancillaryData,
        int256 proposedPrice
    ) public virtual returns (uint256 totalBond);

    /**
     * @notice Proposes a price value for an existing price request.
     * @param requester sender of the initial price request.
     * @param identifier price identifier to identify the existing request.
     * @param timestamp timestamp to identify the existing request.
     * @param ancillaryData ancillary data of the price being requested.
     * @param proposedPrice price being proposed.
     * @return totalBond the amount that's pulled from the proposer's wallet as a bond. The bond will be returned to
     * the proposer once settled if the proposal is correct.
     */
    function proposePrice(
        address requester,
        bytes32 identifier,
        uint256 timestamp,
        bytes memory ancillaryData,
        int256 proposedPrice
    ) external virtual returns (uint256 totalBond);

    /**
     * @notice Disputes a price request with an active proposal on another address' behalf. Note: this address will
     * receive any rewards that come from this dispute. However, any bonds are pulled from the caller.
     * @param disputer address to set as the disputer.
     * @param requester sender of the initial price request.
     * @param identifier price identifier to identify the existing request.
     * @param timestamp timestamp to identify the existing request.
     * @param ancillaryData ancillary data of the price being requested.
     * @return totalBond the amount that's pulled from the caller's wallet as a bond. The bond will be returned to
     * the disputer once settled if the dispute was value (the proposal was incorrect).
     */
    function disputePriceFor(
        address disputer,
        address requester,
        bytes32 identifier,
        uint256 timestamp,
        bytes memory ancillaryData
    ) public virtual returns (uint256 totalBond);

    /**
     * @notice Disputes a price value for an existing price request with an active proposal.
     * @param requester sender of the initial price request.
     * @param identifier price identifier to identify the existing request.
     * @param timestamp timestamp to identify the existing request.
     * @param ancillaryData ancillary data of the price being requested.
     * @return totalBond the amount that's pulled from the disputer's wallet as a bond. The bond will be returned to
     * the disputer once settled if the dispute was valid (the proposal was incorrect).
     */
    function disputePrice(
        address requester,
        bytes32 identifier,
        uint256 timestamp,
        bytes memory ancillaryData
    ) external virtual returns (uint256 totalBond);

    /**
     * @notice Retrieves a price that was previously requested by a caller. Reverts if the request is not settled
     * or settleable. Note: this method is not view so that this call may actually settle the price request if it
     * hasn't been settled.
     * @param identifier price identifier to identify the existing request.
     * @param timestamp timestamp to identify the existing request.
     * @param ancillaryData ancillary data of the price being requested.
     * @return resolved price.
     */
    function settleAndGetPrice(
        bytes32 identifier,
        uint256 timestamp,
        bytes memory ancillaryData
    ) external virtual returns (int256);

    /**
     * @notice Attempts to settle an outstanding price request. Will revert if it isn't settleable.
     * @param requester sender of the initial price request.
     * @param identifier price identifier to identify the existing request.
     * @param timestamp timestamp to identify the existing request.
     * @param ancillaryData ancillary data of the price being requested.
     * @return payout the amount that the "winner" (proposer or disputer) receives on settlement. This amount includes
     * the returned bonds as well as additional rewards.
     */
    function settle(
        address requester,
        bytes32 identifier,
        uint256 timestamp,
        bytes memory ancillaryData
    ) external virtual returns (uint256 payout);

    /**
     * @notice Gets the current data structure containing all information about a price request.
     * @param requester sender of the initial price request.
     * @param identifier price identifier to identify the existing request.
     * @param timestamp timestamp to identify the existing request.
     * @param ancillaryData ancillary data of the price being requested.
     * @return the Request data structure.
     */
    function getRequest(
        address requester,
        bytes32 identifier,
        uint256 timestamp,
        bytes memory ancillaryData
    ) public view virtual returns (Request memory);

    /**
     * @notice Returns the state of a price request.
     * @param requester sender of the initial price request.
     * @param identifier price identifier to identify the existing request.
     * @param timestamp timestamp to identify the existing request.
     * @param ancillaryData ancillary data of the price being requested.
     * @return the State enum value.
     */
    function getState(
        address requester,
        bytes32 identifier,
        uint256 timestamp,
        bytes memory ancillaryData
    ) public view virtual returns (State);

    /**
     * @notice Checks if a given request has resolved or been settled (i.e the optimistic oracle has a price).
     * @param requester sender of the initial price request.
     * @param identifier price identifier to identify the existing request.
     * @param timestamp timestamp to identify the existing request.
     * @param ancillaryData ancillary data of the price being requested.
     * @return true if price has resolved or settled, false otherwise.
     */
    function hasPrice(
        address requester,
        bytes32 identifier,
        uint256 timestamp,
        bytes memory ancillaryData
    ) public view virtual returns (bool);

    function stampAncillaryData(bytes memory ancillaryData, address requester)
        public
        view
        virtual
        returns (bytes memory);
}

// File: @openzeppelin/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @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
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 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);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal 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
                /// @solidity memory-safe-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: @openzeppelin/contracts/token/ERC20/extensions/draft-IERC20Permit.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

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;
    }
}

// File: @uma/core/contracts/common/implementation/FixedPoint.sol



// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity ^0.8.0;

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

/**
 * @title Library for fixed point arithmetic on uints
 */
library FixedPoint {
    using SafeMath for uint256;
    using SignedSafeMath for int256;

    // Supports 18 decimals. E.g., 1e18 represents "1", 5e17 represents "0.5".
    // For unsigned values:
    //   This can represent a value up to (2^256 - 1)/10^18 = ~10^59. 10^59 will be stored internally as uint256 10^77.
    uint256 private constant FP_SCALING_FACTOR = 10**18;

    // --------------------------------------- UNSIGNED -----------------------------------------------------------------------------
    struct Unsigned {
        uint256 rawValue;
    }

    /**
     * @notice Constructs an `Unsigned` from an unscaled uint, e.g., `b=5` gets stored internally as `5*(10**18)`.
     * @param a uint to convert into a FixedPoint.
     * @return the converted FixedPoint.
     */
    function fromUnscaledUint(uint256 a) internal pure returns (Unsigned memory) {
        return Unsigned(a.mul(FP_SCALING_FACTOR));
    }

    /**
     * @notice Whether `a` is equal to `b`.
     * @param a a FixedPoint.
     * @param b a uint256.
     * @return True if equal, or False.
     */
    function isEqual(Unsigned memory a, uint256 b) internal pure returns (bool) {
        return a.rawValue == fromUnscaledUint(b).rawValue;
    }

    /**
     * @notice Whether `a` is equal to `b`.
     * @param a a FixedPoint.
     * @param b a FixedPoint.
     * @return True if equal, or False.
     */
    function isEqual(Unsigned memory a, Unsigned memory b) internal pure returns (bool) {
        return a.rawValue == b.rawValue;
    }

    /**
     * @notice Whether `a` is greater than `b`.
     * @param a a FixedPoint.
     * @param b a FixedPoint.
     * @return True if `a > b`, or False.
     */
    function isGreaterThan(Unsigned memory a, Unsigned memory b) internal pure returns (bool) {
        return a.rawValue > b.rawValue;
    }

    /**
     * @notice Whether `a` is greater than `b`.
     * @param a a FixedPoint.
     * @param b a uint256.
     * @return True if `a > b`, or False.
     */
    function isGreaterThan(Unsigned memory a, uint256 b) internal pure returns (bool) {
        return a.rawValue > fromUnscaledUint(b).rawValue;
    }

    /**
     * @notice Whether `a` is greater than `b`.
     * @param a a uint256.
     * @param b a FixedPoint.
     * @return True if `a > b`, or False.
     */
    function isGreaterThan(uint256 a, Unsigned memory b) internal pure returns (bool) {
        return fromUnscaledUint(a).rawValue > b.rawValue;
    }

    /**
     * @notice Whether `a` is greater than or equal to `b`.
     * @param a a FixedPoint.
     * @param b a FixedPoint.
     * @return True if `a >= b`, or False.
     */
    function isGreaterThanOrEqual(Unsigned memory a, Unsigned memory b) internal pure returns (bool) {
        return a.rawValue >= b.rawValue;
    }

    /**
     * @notice Whether `a` is greater than or equal to `b`.
     * @param a a FixedPoint.
     * @param b a uint256.
     * @return True if `a >= b`, or False.
     */
    function isGreaterThanOrEqual(Unsigned memory a, uint256 b) internal pure returns (bool) {
        return a.rawValue >= fromUnscaledUint(b).rawValue;
    }

    /**
     * @notice Whether `a` is greater than or equal to `b`.
     * @param a a uint256.
     * @param b a FixedPoint.
     * @return True if `a >= b`, or False.
     */
    function isGreaterThanOrEqual(uint256 a, Unsigned memory b) internal pure returns (bool) {
        return fromUnscaledUint(a).rawValue >= b.rawValue;
    }

    /**
     * @notice Whether `a` is less than `b`.
     * @param a a FixedPoint.
     * @param b a FixedPoint.
     * @return True if `a < b`, or False.
     */
    function isLessThan(Unsigned memory a, Unsigned memory b) internal pure returns (bool) {
        return a.rawValue < b.rawValue;
    }

    /**
     * @notice Whether `a` is less than `b`.
     * @param a a FixedPoint.
     * @param b a uint256.
     * @return True if `a < b`, or False.
     */
    function isLessThan(Unsigned memory a, uint256 b) internal pure returns (bool) {
        return a.rawValue < fromUnscaledUint(b).rawValue;
    }

    /**
     * @notice Whether `a` is less than `b`.
     * @param a a uint256.
     * @param b a FixedPoint.
     * @return True if `a < b`, or False.
     */
    function isLessThan(uint256 a, Unsigned memory b) internal pure returns (bool) {
        return fromUnscaledUint(a).rawValue < b.rawValue;
    }

    /**
     * @notice Whether `a` is less than or equal to `b`.
     * @param a a FixedPoint.
     * @param b a FixedPoint.
     * @return True if `a <= b`, or False.
     */
    function isLessThanOrEqual(Unsigned memory a, Unsigned memory b) internal pure returns (bool) {
        return a.rawValue <= b.rawValue;
    }

    /**
     * @notice Whether `a` is less than or equal to `b`.
     * @param a a FixedPoint.
     * @param b a uint256.
     * @return True if `a <= b`, or False.
     */
    function isLessThanOrEqual(Unsigned memory a, uint256 b) internal pure returns (bool) {
        return a.rawValue <= fromUnscaledUint(b).rawValue;
    }

    /**
     * @notice Whether `a` is less than or equal to `b`.
     * @param a a uint256.
     * @param b a FixedPoint.
     * @return True if `a <= b`, or False.
     */
    function isLessThanOrEqual(uint256 a, Unsigned memory b) internal pure returns (bool) {
        return fromUnscaledUint(a).rawValue <= b.rawValue;
    }

    /**
     * @notice The minimum of `a` and `b`.
     * @param a a FixedPoint.
     * @param b a FixedPoint.
     * @return the minimum of `a` and `b`.
     */
    function min(Unsigned memory a, Unsigned memory b) internal pure returns (Unsigned memory) {
        return a.rawValue < b.rawValue ? a : b;
    }

    /**
     * @notice The maximum of `a` and `b`.
     * @param a a FixedPoint.
     * @param b a FixedPoint.
     * @return the maximum of `a` and `b`.
     */
    function max(Unsigned memory a, Unsigned memory b) internal pure returns (Unsigned memory) {
        return a.rawValue > b.rawValue ? a : b;
    }

    /**
     * @notice Adds two `Unsigned`s, reverting on overflow.
     * @param a a FixedPoint.
     * @param b a FixedPoint.
     * @return the sum of `a` and `b`.
     */
    function add(Unsigned memory a, Unsigned memory b) internal pure returns (Unsigned memory) {
        return Unsigned(a.rawValue.add(b.rawValue));
    }

    /**
     * @notice Adds an `Unsigned` to an unscaled uint, reverting on overflow.
     * @param a a FixedPoint.
     * @param b a uint256.
     * @return the sum of `a` and `b`.
     */
    function add(Unsigned memory a, uint256 b) internal pure returns (Unsigned memory) {
        return add(a, fromUnscaledUint(b));
    }

    /**
     * @notice Subtracts two `Unsigned`s, reverting on overflow.
     * @param a a FixedPoint.
     * @param b a FixedPoint.
     * @return the difference of `a` and `b`.
     */
    function sub(Unsigned memory a, Unsigned memory b) internal pure returns (Unsigned memory) {
        return Unsigned(a.rawValue.sub(b.rawValue));
    }

    /**
     * @notice Subtracts an unscaled uint256 from an `Unsigned`, reverting on overflow.
     * @param a a FixedPoint.
     * @param b a uint256.
     * @return the difference of `a` and `b`.
     */
    function sub(Unsigned memory a, uint256 b) internal pure returns (Unsigned memory) {
        return sub(a, fromUnscaledUint(b));
    }

    /**
     * @notice Subtracts an `Unsigned` from an unscaled uint256, reverting on overflow.
     * @param a a uint256.
     * @param b a FixedPoint.
     * @return the difference of `a` and `b`.
     */
    function sub(uint256 a, Unsigned memory b) internal pure returns (Unsigned memory) {
        return sub(fromUnscaledUint(a), b);
    }

    /**
     * @notice Multiplies two `Unsigned`s, reverting on overflow.
     * @dev This will "floor" the product.
     * @param a a FixedPoint.
     * @param b a FixedPoint.
     * @return the product of `a` and `b`.
     */
    function mul(Unsigned memory a, Unsigned memory b) internal pure returns (Unsigned memory) {
        // There are two caveats with this computation:
        // 1. Max output for the represented number is ~10^41, otherwise an intermediate value overflows. 10^41 is
        // stored internally as a uint256 ~10^59.
        // 2. Results that can't be represented exactly are truncated not rounded. E.g., 1.4 * 2e-18 = 2.8e-18, which
        // would round to 3, but this computation produces the result 2.
        // No need to use SafeMath because FP_SCALING_FACTOR != 0.
        return Unsigned(a.rawValue.mul(b.rawValue) / FP_SCALING_FACTOR);
    }

    /**
     * @notice Multiplies an `Unsigned` and an unscaled uint256, reverting on overflow.
     * @dev This will "floor" the product.
     * @param a a FixedPoint.
     * @param b a uint256.
     * @return the product of `a` and `b`.
     */
    function mul(Unsigned memory a, uint256 b) internal pure returns (Unsigned memory) {
        return Unsigned(a.rawValue.mul(b));
    }

    /**
     * @notice Multiplies two `Unsigned`s and "ceil's" the product, reverting on overflow.
     * @param a a FixedPoint.
     * @param b a FixedPoint.
     * @return the product of `a` and `b`.
     */
    function mulCeil(Unsigned memory a, Unsigned memory b) internal pure returns (Unsigned memory) {
        uint256 mulRaw = a.rawValue.mul(b.rawValue);
        uint256 mulFloor = mulRaw / FP_SCALING_FACTOR;
        uint256 mod = mulRaw.mod(FP_SCALING_FACTOR);
        if (mod != 0) {
            return Unsigned(mulFloor.add(1));
        } else {
            return Unsigned(mulFloor);
        }
    }

    /**
     * @notice Multiplies an `Unsigned` and an unscaled uint256 and "ceil's" the product, reverting on overflow.
     * @param a a FixedPoint.
     * @param b a FixedPoint.
     * @return the product of `a` and `b`.
     */
    function mulCeil(Unsigned memory a, uint256 b) internal pure returns (Unsigned memory) {
        // Since b is an uint, there is no risk of truncation and we can just mul it normally
        return Unsigned(a.rawValue.mul(b));
    }

    /**
     * @notice Divides one `Unsigned` by an `Unsigned`, reverting on overflow or division by 0.
     * @dev This will "floor" the quotient.
     * @param a a FixedPoint numerator.
     * @param b a FixedPoint denominator.
     * @return the quotient of `a` divided by `b`.
     */
    function div(Unsigned memory a, Unsigned memory b) internal pure returns (Unsigned memory) {
        // There are two caveats with this computation:
        // 1. Max value for the number dividend `a` represents is ~10^41, otherwise an intermediate value overflows.
        // 10^41 is stored internally as a uint256 10^59.
        // 2. Results that can't be represented exactly are truncated not rounded. E.g., 2 / 3 = 0.6 repeating, which
        // would round to 0.666666666666666667, but this computation produces the result 0.666666666666666666.
        return Unsigned(a.rawValue.mul(FP_SCALING_FACTOR).div(b.rawValue));
    }

    /**
     * @notice Divides one `Unsigned` by an unscaled uint256, reverting on overflow or division by 0.
     * @dev This will "floor" the quotient.
     * @param a a FixedPoint numerator.
     * @param b a uint256 denominator.
     * @return the quotient of `a` divided by `b`.
     */
    function div(Unsigned memory a, uint256 b) internal pure returns (Unsigned memory) {
        return Unsigned(a.rawValue.div(b));
    }

    /**
     * @notice Divides one unscaled uint256 by an `Unsigned`, reverting on overflow or division by 0.
     * @dev This will "floor" the quotient.
     * @param a a uint256 numerator.
     * @param b a FixedPoint denominator.
     * @return the quotient of `a` divided by `b`.
     */
    function div(uint256 a, Unsigned memory b) internal pure returns (Unsigned memory) {
        return div(fromUnscaledUint(a), b);
    }

    /**
     * @notice Divides one `Unsigned` by an `Unsigned` and "ceil's" the quotient, reverting on overflow or division by 0.
     * @param a a FixedPoint numerator.
     * @param b a FixedPoint denominator.
     * @return the quotient of `a` divided by `b`.
     */
    function divCeil(Unsigned memory a, Unsigned memory b) internal pure returns (Unsigned memory) {
        uint256 aScaled = a.rawValue.mul(FP_SCALING_FACTOR);
        uint256 divFloor = aScaled.div(b.rawValue);
        uint256 mod = aScaled.mod(b.rawValue);
        if (mod != 0) {
            return Unsigned(divFloor.add(1));
        } else {
            return Unsigned(divFloor);
        }
    }

    /**
     * @notice Divides one `Unsigned` by an unscaled uint256 and "ceil's" the quotient, reverting on overflow or division by 0.
     * @param a a FixedPoint numerator.
     * @param b a uint256 denominator.
     * @return the quotient of `a` divided by `b`.
     */
    function divCeil(Unsigned memory a, uint256 b) internal pure returns (Unsigned memory) {
        // Because it is possible that a quotient gets truncated, we can't just call "Unsigned(a.rawValue.div(b))"
        // similarly to mulCeil with a uint256 as the second parameter. Therefore we need to convert b into an Unsigned.
        // This creates the possibility of overflow if b is very large.
        return divCeil(a, fromUnscaledUint(b));
    }

    /**
     * @notice Raises an `Unsigned` to the power of an unscaled uint256, reverting on overflow. E.g., `b=2` squares `a`.
     * @dev This will "floor" the result.
     * @param a a FixedPoint numerator.
     * @param b a uint256 denominator.
     * @return output is `a` to the power of `b`.
     */
    function pow(Unsigned memory a, uint256 b) internal pure returns (Unsigned memory output) {
        output = fromUnscaledUint(1);
        for (uint256 i = 0; i < b; i = i.add(1)) {
            output = mul(output, a);
        }
    }

    // ------------------------------------------------- SIGNED -------------------------------------------------------------
    // Supports 18 decimals. E.g., 1e18 represents "1", 5e17 represents "0.5".
    // For signed values:
    //   This can represent a value up (or down) to +-(2^255 - 1)/10^18 = ~10^58. 10^58 will be stored internally as int256 10^76.
    int256 private constant SFP_SCALING_FACTOR = 10**18;

    struct Signed {
        int256 rawValue;
    }

    function fromSigned(Signed memory a) internal pure returns (Unsigned memory) {
        require(a.rawValue >= 0, "Negative value provided");
        return Unsigned(uint256(a.rawValue));
    }

    function fromUnsigned(Unsigned memory a) internal pure returns (Signed memory) {
        require(a.rawValue <= uint256(type(int256).max), "Unsigned too large");
        return Signed(int256(a.rawValue));
    }

    /**
     * @notice Constructs a `Signed` from an unscaled int, e.g., `b=5` gets stored internally as `5*(10**18)`.
     * @param a int to convert into a FixedPoint.Signed.
     * @return the converted FixedPoint.Signed.
     */
    function fromUnscaledInt(int256 a) internal pure returns (Signed memory) {
        return Signed(a.mul(SFP_SCALING_FACTOR));
    }

    /**
     * @notice Whether `a` is equal to `b`.
     * @param a a FixedPoint.Signed.
     * @param b a int256.
     * @return True if equal, or False.
     */
    function isEqual(Signed memory a, int256 b) internal pure returns (bool) {
        return a.rawValue == fromUnscaledInt(b).rawValue;
    }

    /**
     * @notice Whether `a` is equal to `b`.
     * @param a a FixedPoint.Signed.
     * @param b a FixedPoint.Signed.
     * @return True if equal, or False.
     */
    function isEqual(Signed memory a, Signed memory b) internal pure returns (bool) {
        return a.rawValue == b.rawValue;
    }

    /**
     * @notice Whether `a` is greater than `b`.
     * @param a a FixedPoint.Signed.
     * @param b a FixedPoint.Signed.
     * @return True if `a > b`, or False.
     */
    function isGreaterThan(Signed memory a, Signed memory b) internal pure returns (bool) {
        return a.rawValue > b.rawValue;
    }

    /**
     * @notice Whether `a` is greater than `b`.
     * @param a a FixedPoint.Signed.
     * @param b an int256.
     * @return True if `a > b`, or False.
     */
    function isGreaterThan(Signed memory a, int256 b) internal pure returns (bool) {
        return a.rawValue > fromUnscaledInt(b).rawValue;
    }

    /**
     * @notice Whether `a` is greater than `b`.
     * @param a an int256.
     * @param b a FixedPoint.Signed.
     * @return True if `a > b`, or False.
     */
    function isGreaterThan(int256 a, Signed memory b) internal pure returns (bool) {
        return fromUnscaledInt(a).rawValue > b.rawValue;
    }

    /**
     * @notice Whether `a` is greater than or equal to `b`.
     * @param a a FixedPoint.Signed.
     * @param b a FixedPoint.Signed.
     * @return True if `a >= b`, or False.
     */
    function isGreaterThanOrEqual(Signed memory a, Signed memory b) internal pure returns (bool) {
        return a.rawValue >= b.rawValue;
    }

    /**
     * @notice Whether `a` is greater than or equal to `b`.
     * @param a a FixedPoint.Signed.
     * @param b an int256.
     * @return True if `a >= b`, or False.
     */
    function isGreaterThanOrEqual(Signed memory a, int256 b) internal pure returns (bool) {
        return a.rawValue >= fromUnscaledInt(b).rawValue;
    }

    /**
     * @notice Whether `a` is greater than or equal to `b`.
     * @param a an int256.
     * @param b a FixedPoint.Signed.
     * @return True if `a >= b`, or False.
     */
    function isGreaterThanOrEqual(int256 a, Signed memory b) internal pure returns (bool) {
        return fromUnscaledInt(a).rawValue >= b.rawValue;
    }

    /**
     * @notice Whether `a` is less than `b`.
     * @param a a FixedPoint.Signed.
     * @param b a FixedPoint.Signed.
     * @return True if `a < b`, or False.
     */
    function isLessThan(Signed memory a, Signed memory b) internal pure returns (bool) {
        return a.rawValue < b.rawValue;
    }

    /**
     * @notice Whether `a` is less than `b`.
     * @param a a FixedPoint.Signed.
     * @param b an int256.
     * @return True if `a < b`, or False.
     */
    function isLessThan(Signed memory a, int256 b) internal pure returns (bool) {
        return a.rawValue < fromUnscaledInt(b).rawValue;
    }

    /**
     * @notice Whether `a` is less than `b`.
     * @param a an int256.
     * @param b a FixedPoint.Signed.
     * @return True if `a < b`, or False.
     */
    function isLessThan(int256 a, Signed memory b) internal pure returns (bool) {
        return fromUnscaledInt(a).rawValue < b.rawValue;
    }

    /**
     * @notice Whether `a` is less than or equal to `b`.
     * @param a a FixedPoint.Signed.
     * @param b a FixedPoint.Signed.
     * @return True if `a <= b`, or False.
     */
    function isLessThanOrEqual(Signed memory a, Signed memory b) internal pure returns (bool) {
        return a.rawValue <= b.rawValue;
    }

    /**
     * @notice Whether `a` is less than or equal to `b`.
     * @param a a FixedPoint.Signed.
     * @param b an int256.
     * @return True if `a <= b`, or False.
     */
    function isLessThanOrEqual(Signed memory a, int256 b) internal pure returns (bool) {
        return a.rawValue <= fromUnscaledInt(b).rawValue;
    }

    /**
     * @notice Whether `a` is less than or equal to `b`.
     * @param a an int256.
     * @param b a FixedPoint.Signed.
     * @return True if `a <= b`, or False.
     */
    function isLessThanOrEqual(int256 a, Signed memory b) internal pure returns (bool) {
        return fromUnscaledInt(a).rawValue <= b.rawValue;
    }

    /**
     * @notice The minimum of `a` and `b`.
     * @param a a FixedPoint.Signed.
     * @param b a FixedPoint.Signed.
     * @return the minimum of `a` and `b`.
     */
    function min(Signed memory a, Signed memory b) internal pure returns (Signed memory) {
        return a.rawValue < b.rawValue ? a : b;
    }

    /**
     * @notice The maximum of `a` and `b`.
     * @param a a FixedPoint.Signed.
     * @param b a FixedPoint.Signed.
     * @return the maximum of `a` and `b`.
     */
    function max(Signed memory a, Signed memory b) internal pure returns (Signed memory) {
        return a.rawValue > b.rawValue ? a : b;
    }

    /**
     * @notice Adds two `Signed`s, reverting on overflow.
     * @param a a FixedPoint.Signed.
     * @param b a FixedPoint.Signed.
     * @return the sum of `a` and `b`.
     */
    function add(Signed memory a, Signed memory b) internal pure returns (Signed memory) {
        return Signed(a.rawValue.add(b.rawValue));
    }

    /**
     * @notice Adds an `Signed` to an unscaled int, reverting on overflow.
     * @param a a FixedPoint.Signed.
     * @param b an int256.
     * @return the sum of `a` and `b`.
     */
    function add(Signed memory a, int256 b) internal pure returns (Signed memory) {
        return add(a, fromUnscaledInt(b));
    }

    /**
     * @notice Subtracts two `Signed`s, reverting on overflow.
     * @param a a FixedPoint.Signed.
     * @param b a FixedPoint.Signed.
     * @return the difference of `a` and `b`.
     */
    function sub(Signed memory a, Signed memory b) internal pure returns (Signed memory) {
        return Signed(a.rawValue.sub(b.rawValue));
    }

    /**
     * @notice Subtracts an unscaled int256 from an `Signed`, reverting on overflow.
     * @param a a FixedPoint.Signed.
     * @param b an int256.
     * @return the difference of `a` and `b`.
     */
    function sub(Signed memory a, int256 b) internal pure returns (Signed memory) {
        return sub(a, fromUnscaledInt(b));
    }

    /**
     * @notice Subtracts an `Signed` from an unscaled int256, reverting on overflow.
     * @param a an int256.
     * @param b a FixedPoint.Signed.
     * @return the difference of `a` and `b`.
     */
    function sub(int256 a, Signed memory b) internal pure returns (Signed memory) {
        return sub(fromUnscaledInt(a), b);
    }

    /**
     * @notice Multiplies two `Signed`s, reverting on overflow.
     * @dev This will "floor" the product.
     * @param a a FixedPoint.Signed.
     * @param b a FixedPoint.Signed.
     * @return the product of `a` and `b`.
     */
    function mul(Signed memory a, Signed memory b) internal pure returns (Signed memory) {
        // There are two caveats with this computation:
        // 1. Max output for the represented number is ~10^41, otherwise an intermediate value overflows. 10^41 is
        // stored internally as an int256 ~10^59.
        // 2. Results that can't be represented exactly are truncated not rounded. E.g., 1.4 * 2e-18 = 2.8e-18, which
        // would round to 3, but this computation produces the result 2.
        // No need to use SafeMath because SFP_SCALING_FACTOR != 0.
        return Signed(a.rawValue.mul(b.rawValue) / SFP_SCALING_FACTOR);
    }

    /**
     * @notice Multiplies an `Signed` and an unscaled int256, reverting on overflow.
     * @dev This will "floor" the product.
     * @param a a FixedPoint.Signed.
     * @param b an int256.
     * @return the product of `a` and `b`.
     */
    function mul(Signed memory a, int256 b) internal pure returns (Signed memory) {
        return Signed(a.rawValue.mul(b));
    }

    /**
     * @notice Multiplies two `Signed`s and "ceil's" the product, reverting on overflow.
     * @param a a FixedPoint.Signed.
     * @param b a FixedPoint.Signed.
     * @return the product of `a` and `b`.
     */
    function mulAwayFromZero(Signed memory a, Signed memory b) internal pure returns (Signed memory) {
        int256 mulRaw = a.rawValue.mul(b.rawValue);
        int256 mulTowardsZero = mulRaw / SFP_SCALING_FACTOR;
        // Manual mod because SignedSafeMath doesn't support it.
        int256 mod = mulRaw % SFP_SCALING_FACTOR;
        if (mod != 0) {
            bool isResultPositive = isLessThan(a, 0) == isLessThan(b, 0);
            int256 valueToAdd = isResultPositive ? int256(1) : int256(-1);
            return Signed(mulTowardsZero.add(valueToAdd));
        } else {
            return Signed(mulTowardsZero);
        }
    }

    /**
     * @notice Multiplies an `Signed` and an unscaled int256 and "ceil's" the product, reverting on overflow.
     * @param a a FixedPoint.Signed.
     * @param b a FixedPoint.Signed.
     * @return the product of `a` and `b`.
     */
    function mulAwayFromZero(Signed memory a, int256 b) internal pure returns (Signed memory) {
        // Since b is an int, there is no risk of truncation and we can just mul it normally
        return Signed(a.rawValue.mul(b));
    }

    /**
     * @notice Divides one `Signed` by an `Signed`, reverting on overflow or division by 0.
     * @dev This will "floor" the quotient.
     * @param a a FixedPoint numerator.
     * @param b a FixedPoint denominator.
     * @return the quotient of `a` divided by `b`.
     */
    function div(Signed memory a, Signed memory b) internal pure returns (Signed memory) {
        // There are two caveats with this computation:
        // 1. Max value for the number dividend `a` represents is ~10^41, otherwise an intermediate value overflows.
        // 10^41 is stored internally as an int256 10^59.
        // 2. Results that can't be represented exactly are truncated not rounded. E.g., 2 / 3 = 0.6 repeating, which
        // would round to 0.666666666666666667, but this computation produces the result 0.666666666666666666.
        return Signed(a.rawValue.mul(SFP_SCALING_FACTOR).div(b.rawValue));
    }

    /**
     * @notice Divides one `Signed` by an unscaled int256, reverting on overflow or division by 0.
     * @dev This will "floor" the quotient.
     * @param a a FixedPoint numerator.
     * @param b an int256 denominator.
     * @return the quotient of `a` divided by `b`.
     */
    function div(Signed memory a, int256 b) internal pure returns (Signed memory) {
        return Signed(a.rawValue.div(b));
    }

    /**
     * @notice Divides one unscaled int256 by an `Signed`, reverting on overflow or division by 0.
     * @dev This will "floor" the quotient.
     * @param a an int256 numerator.
     * @param b a FixedPoint denominator.
     * @return the quotient of `a` divided by `b`.
     */
    function div(int256 a, Signed memory b) internal pure returns (Signed memory) {
        return div(fromUnscaledInt(a), b);
    }

    /**
     * @notice Divides one `Signed` by an `Signed` and "ceil's" the quotient, reverting on overflow or division by 0.
     * @param a a FixedPoint numerator.
     * @param b a FixedPoint denominator.
     * @return the quotient of `a` divided by `b`.
     */
    function divAwayFromZero(Signed memory a, Signed memory b) internal pure returns (Signed memory) {
        int256 aScaled = a.rawValue.mul(SFP_SCALING_FACTOR);
        int256 divTowardsZero = aScaled.div(b.rawValue);
        // Manual mod because SignedSafeMath doesn't support it.
        int256 mod = aScaled % b.rawValue;
        if (mod != 0) {
            bool isResultPositive = isLessThan(a, 0) == isLessThan(b, 0);
            int256 valueToAdd = isResultPositive ? int256(1) : int256(-1);
            return Signed(divTowardsZero.add(valueToAdd));
        } else {
            return Signed(divTowardsZero);
        }
    }

    /**
     * @notice Divides one `Signed` by an unscaled int256 and "ceil's" the quotient, reverting on overflow or division by 0.
     * @param a a FixedPoint numerator.
     * @param b an int256 denominator.
     * @return the quotient of `a` divided by `b`.
     */
    function divAwayFromZero(Signed memory a, int256 b) internal pure returns (Signed memory) {
        // Because it is possible that a quotient gets truncated, we can't just call "Signed(a.rawValue.div(b))"
        // similarly to mulCeil with an int256 as the second parameter. Therefore we need to convert b into an Signed.
        // This creates the possibility of overflow if b is very large.
        return divAwayFromZero(a, fromUnscaledInt(b));
    }

    /**
     * @notice Raises an `Signed` to the power of an unscaled uint256, reverting on overflow. E.g., `b=2` squares `a`.
     * @dev This will "floor" the result.
     * @param a a FixedPoint.Signed.
     * @param b a uint256 (negative exponents are not allowed).
     * @return output is `a` to the power of `b`.
     */
    function pow(Signed memory a, uint256 b) internal pure returns (Signed memory output) {
        output = fromUnscaledInt(1);
        for (uint256 i = 0; i < b; i = i.add(1)) {
            output = mul(output, a);
        }
    }
}

// File: @openzeppelin/contracts/utils/math/SafeMath.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (utils/math/SafeMath.sol)

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

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

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

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

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

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

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

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

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

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

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

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

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

// File: @openzeppelin/contracts/utils/math/SignedSafeMath.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/math/SignedSafeMath.sol)

pragma solidity ^0.8.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SignedSafeMath` is no longer needed starting with Solidity 0.8. The compiler
 * now has built in overflow checking.
 */
library SignedSafeMath {
    /**
     * @dev Returns the multiplication of two signed integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(int256 a, int256 b) internal pure returns (int256) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two signed integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(int256 a, int256 b) internal pure returns (int256) {
        return a / b;
    }

    /**
     * @dev Returns the subtraction of two signed integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(int256 a, int256 b) internal pure returns (int256) {
        return a - b;
    }

    /**
     * @dev Returns the addition of two signed integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(int256 a, int256 b) internal pure returns (int256) {
        return a + b;
    }
}