// File: contracts/FlashLiquidator.sol



// SPDX-License-Identifier: GPL-2.0-or-later

pragma solidity >=0.8.6;

import "@yield-protocol/vault-interfaces/ICauldron.sol";
import "@yield-protocol/vault-interfaces/IWitch.sol";
import "uniswapv3-oracle/contracts/uniswapv0.8/IUniswapV3Pool.sol";
import "uniswapv3-oracle/contracts/uniswapv0.8/PoolAddress.sol";
import "./UniswapTransferHelper.sol";
import "./ISwapRouter.sol";


// @notice This is the standard Flash Liquidator used with Yield liquidator bots for most collateral types
contract FlashLiquidator {
    using UniswapTransferHelper for address;

    // DAI  official token -- "otherToken" for UniV3Pool flash loan
    address public constant DAI = 0x6B175474E89094C44Da98b954EedeAC495271d0F;
    // WETH official token -- alternate "otherToken"
    address public constant WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;


    ICauldron public immutable cauldron;      // Yield Cauldron
    IWitch public immutable witch;            // Yield Witch
    address public immutable factory;         // UniswapV3 pool factory
    ISwapRouter public immutable swapRouter;  // UniswapV3 swapRouter

    struct FlashCallbackData {
        bytes12 vaultId;
        address base;
        address collateral;
        uint256 baseLoan;
        address baseJoin;
        PoolAddress.PoolKey poolKey;
        address recipient;
    }

    // @dev Parameter order matters
    constructor(
        IWitch witch_,
        address factory_,
        ISwapRouter swapRouter_
    ) {
        witch = witch_;
        cauldron = witch_.cauldron();
        factory = factory_;
        swapRouter = swapRouter_;
    }

    // @notice This is used by the bot to determine the current collateral to debt ratio
    // @dev    Cauldron.level returns collateral * price(collateral, denominator=debt) - debt * ratio * accrual
    //         but the bot needs collateral * price(collateral, denominator=debt)/debt * accrual
    // @param  vaultId id of vault to check
    // @return adjusted collateralization level
    function collateralToDebtRatio(bytes12 vaultId) public
    returns (uint256) {
        DataTypes.Vault memory vault = cauldron.vaults(vaultId);
        DataTypes.Balances memory balances = cauldron.balances(vaultId);
        DataTypes.Series memory series = cauldron.series(vault.seriesId);

        if (balances.art == 0) {
            return 0;
        }
        (uint256 inkValue,)  = cauldron.spotOracles(series.baseId, vault.ilkId).oracle.get(vault.ilkId, series.baseId, balances.ink); // ink * spot
        uint128 accrued_debt = cauldron.debtToBase(vault.seriesId, balances.art);
        return inkValue * 1e18 / accrued_debt;
    }

    // @notice This is used by the bot to determine if the auction price has reached the final, minimum price yet
    // @param  vaultId id of vault to check
    // @return True if it has reached minimal price
    function isAtMinimalPrice(bytes12 vaultId) public returns (bool) {
        bytes6 ilkId = (cauldron.vaults(vaultId)).ilkId;
        (uint32 duration, ) = witch.ilks(ilkId);
        (, uint32 auctionStart) = witch.auctions(vaultId);
        uint256 elapsed = uint32(block.timestamp) - auctionStart;
        return elapsed >= duration;
    }

    // @notice Returns the address of a valid Uniswap V3 Pool
    // @dev from 'uniswap/v3-periphery/contracts/libraries/CallbackValidation.sol'
    // @param poolKey The identifying key of the V3 pool
    // @return pool The V3 pool contract address
    function _verifyCallback(PoolAddress.PoolKey memory poolKey)
        internal
        view
        returns (IUniswapV3Pool pool)
    {
        pool = IUniswapV3Pool(PoolAddress.computeAddress(factory, poolKey));
        require(msg.sender == address(pool), "Invalid caller");
    }

    // @param fee0 The fee from calling flash for token0
    // @param fee1 The fee from calling flash for token1
    // @param data The data needed in the callback passed as FlashCallbackData from `initFlash`
    // @notice implements the callback called from flash
    // @dev this fn should be overwritten by subclasses for non-standard collateral types
    function uniswapV3FlashCallback(
        uint256 fee0,
        uint256 fee1,
        bytes calldata data
    ) external virtual {
        // we only borrow 1 token
        require(fee0 == 0 || fee1 == 0, "Two tokens were borrowed");
        uint256 fee;
        unchecked {
            // Since one fee is always zero, this won't overflow
            fee = fee0 + fee1;
        }

        // decode and verify
        FlashCallbackData memory decoded = abi.decode(data, (FlashCallbackData));
        _verifyCallback(decoded.poolKey);

        // liquidate the vault
        decoded.base.safeApprove(decoded.baseJoin, decoded.baseLoan);
        uint256 collateralReceived = witch.payAll(decoded.vaultId, 0);

        // sell the collateral
        uint256 debtToReturn = decoded.baseLoan + fee;
        decoded.collateral.safeApprove(address(swapRouter), collateralReceived);
        uint256 debtRecovered = swapRouter.exactInputSingle(
            ISwapRouter.ExactInputSingleParams({
                tokenIn: decoded.collateral,
                tokenOut: decoded.base,
                fee: 3000,  // can't use the same fee as the flash loan
                           // because of reentrancy protection
                recipient: address(this),
                deadline: block.timestamp + 180,
                amountIn: collateralReceived,
                amountOutMinimum: debtToReturn, // bots will sandwich us and eat profits, we don't mind
                sqrtPriceLimitX96: 0
            })
        );

        // if profitable pay profits to recipient
        if (debtRecovered > debtToReturn) {
            uint256 profit;
            unchecked {
                profit = debtRecovered - debtToReturn;
            }
            decoded.base.safeTransfer(decoded.recipient, profit);
        }
        // repay flash loan
        decoded.base.safeTransfer(msg.sender, debtToReturn);
    }

    // @notice Liquidates a vault with help from a Uniswap v3 flash loan
    // @param vaultId The vault to liquidate
    function liquidate(bytes12 vaultId) external {
        (, uint32 start) = witch.auctions(vaultId);
        require(start > 0, "Vault not under auction");
        DataTypes.Vault memory vault = cauldron.vaults(vaultId);
        DataTypes.Balances memory balances = cauldron.balances(vaultId);
        DataTypes.Series memory series = cauldron.series(vault.seriesId);
        address baseToken = cauldron.assets(series.baseId);
        uint128 baseLoan = cauldron.debtToBase(vault.seriesId, balances.art);
        address collateral = cauldron.assets(vault.ilkId);

        // The flash loan only borrows one token, so the UniV3Pool that is selected only
        // needs to have the baseToken in it. For the otherToken we prefer WETH or DAI
        address otherToken = baseToken == WETH ? DAI : WETH;

        // tokens in PoolKey must be ordered
        bool ordered = (baseToken < otherToken);
        PoolAddress.PoolKey memory poolKey = PoolAddress.PoolKey({
            token0: ordered ? baseToken : otherToken,
            token1: ordered ? otherToken : baseToken,
            fee: 500 // 0.3%
        });
        IUniswapV3Pool pool = IUniswapV3Pool(PoolAddress.computeAddress(factory, poolKey));

        // data for the callback to know what to do
        FlashCallbackData memory args = FlashCallbackData({
            vaultId: vaultId,
            base: baseToken,
            collateral: collateral,
            baseLoan: baseLoan,
            baseJoin: address(witch.ladle().joins(series.baseId)),
            poolKey: poolKey,
            recipient: msg.sender   // We will get front-run by generalized front-runners, this is desired as it reduces our gas costs
        });

        // initiate flash loan, with the liquidation logic embedded in the flash loan callback
        pool.flash(
            address(this),
            ordered ? baseLoan : 0,
            ordered ? 0 : baseLoan,
            abi.encode(
                args
            )
        );
    }
}

// File: @yield-protocol/vault-interfaces/ICauldron.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./IFYToken.sol";
import "./IOracle.sol";
import "./DataTypes.sol";


interface ICauldron {

    /// @dev Variable rate lending oracle for an underlying
    function lendingOracles(bytes6 baseId) external view returns (IOracle);

    /// @dev An user can own one or more Vaults, with each vault being able to borrow from a single series.
    function vaults(bytes12 vault) external view returns (DataTypes.Vault memory);

    /// @dev Series available in Cauldron.
    function series(bytes6 seriesId) external view returns (DataTypes.Series memory);

    /// @dev Assets available in Cauldron.
    function assets(bytes6 assetsId) external view returns (address);

    /// @dev Each vault records debt and collateral balances_.
    function balances(bytes12 vault) external view returns (DataTypes.Balances memory);

    /// @dev Max, min and sum of debt per underlying and collateral.
    function debt(bytes6 baseId, bytes6 ilkId) external view returns (DataTypes.Debt memory);

    // @dev Spot price oracle addresses and collateralization ratios
    function spotOracles(bytes6 baseId, bytes6 ilkId) external returns (DataTypes.SpotOracle memory);

    /// @dev Create a new vault, linked to a series (and therefore underlying) and up to 5 collateral types
    function build(address owner, bytes12 vaultId, bytes6 seriesId, bytes6 ilkId) external returns (DataTypes.Vault memory);

    /// @dev Destroy an empty vault. Used to recover gas costs.
    function destroy(bytes12 vault) external;

    /// @dev Change a vault series and/or collateral types.
    function tweak(bytes12 vaultId, bytes6 seriesId, bytes6 ilkId) external returns (DataTypes.Vault memory);

    /// @dev Give a vault to another user.
    function give(bytes12 vaultId, address receiver) external returns (DataTypes.Vault memory);

    /// @dev Move collateral and debt between vaults.
    function stir(bytes12 from, bytes12 to, uint128 ink, uint128 art) external returns (DataTypes.Balances memory, DataTypes.Balances memory);

    /// @dev Manipulate a vault debt and collateral.
    function pour(bytes12 vaultId, int128 ink, int128 art) external returns (DataTypes.Balances memory);

    /// @dev Change series and debt of a vault.
    /// The module calling this function also needs to buy underlying in the pool for the new series, and sell it in pool for the old series.
    function roll(bytes12 vaultId, bytes6 seriesId, int128 art) external returns (DataTypes.Vault memory, DataTypes.Balances memory);

    /// @dev Reduce debt and collateral from a vault, ignoring collateralization checks.
    function slurp(bytes12 vaultId, uint128 ink, uint128 art) external returns (DataTypes.Balances memory);

    // ==== Helpers ====

    /// @dev Convert a debt amount for a series from base to fyToken terms.
    /// @notice Think about rounding if using, since we are dividing.
    function debtFromBase(bytes6 seriesId, uint128 base) external returns (uint128 art);

    /// @dev Convert a debt amount for a series from fyToken to base terms
    function debtToBase(bytes6 seriesId, uint128 art) external returns (uint128 base);

    // ==== Accounting ====

    /// @dev Record the borrowing rate at maturity for a series
    function mature(bytes6 seriesId) external;
    
    /// @dev Retrieve the rate accrual since maturity, maturing if necessary.
    function accrual(bytes6 seriesId) external returns (uint256);

    /// @dev Return the collateralization level of a vault. It will be negative if undercollateralized.
    function level(bytes12 vaultId) external returns (int256);
}
// File: @yield-protocol/vault-interfaces/IWitch.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./ILadle.sol";


interface IWitch {
    /// @dev Link to the Cauldron in the Yield Protocol
    function cauldron() external returns (ICauldron);

    /// @dev Link to the Ladle in the Yield Protocol
    function ladle() external returns (ILadle);

    /// @dev Vaults up for liquidation
    function auctions(bytes12 vaultId) external returns (address owner, uint32 start);

    /// @dev Auction parameters per ilk
    function ilks(bytes6 ilkId) external returns (uint32 duration, uint64 initialOffer);

    /// @dev Pay all debt from a vault in liquidation, getting at least `min` collateral.
    function payAll(bytes12 vaultId, uint128 min) external returns (uint256 ink);
}
// File: uniswapv3-oracle/contracts/uniswapv0.8/IUniswapV3Pool.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

import './pool/IUniswapV3PoolImmutables.sol';
import './pool/IUniswapV3PoolState.sol';
import './pool/IUniswapV3PoolDerivedState.sol';
import './pool/IUniswapV3PoolActions.sol';
import './pool/IUniswapV3PoolOwnerActions.sol';
import './pool/IUniswapV3PoolEvents.sol';

/// @title The interface for a Uniswap V3 Pool
/// @notice A Uniswap pool facilitates swapping and automated market making between any two assets that strictly conform
/// to the ERC20 specification
/// @dev The pool interface is broken up into many smaller pieces
interface IUniswapV3Pool is
    IUniswapV3PoolImmutables,
    IUniswapV3PoolState,
    IUniswapV3PoolDerivedState,
    IUniswapV3PoolActions,
    IUniswapV3PoolOwnerActions,
    IUniswapV3PoolEvents
{

}

// File: uniswapv3-oracle/contracts/uniswapv0.8/PoolAddress.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Provides functions for deriving a pool address from the factory, tokens, and the fee
library PoolAddress {
    bytes32 internal constant POOL_INIT_CODE_HASH = 0xe34f199b19b2b4f47f68442619d555527d244f78a3297ea89325f843f87b8b54;

    /// @notice The identifying key of the pool
    struct PoolKey {
        address token0;
        address token1;
        uint24 fee;
    }

    /// @notice Returns PoolKey: the ordered tokens with the matched fee levels
    /// @param tokenA The first token of a pool, unsorted
    /// @param tokenB The second token of a pool, unsorted
    /// @param fee The fee level of the pool
    /// @return Poolkey The pool details with ordered token0 and token1 assignments
    function getPoolKey(
        address tokenA,
        address tokenB,
        uint24 fee
    ) internal pure returns (PoolKey memory) {
        if (tokenA > tokenB) (tokenA, tokenB) = (tokenB, tokenA);
        return PoolKey({token0: tokenA, token1: tokenB, fee: fee});
    }

    /// @notice Deterministically computes the pool address given the factory and PoolKey
    /// @param factory The Uniswap V3 factory contract address
    /// @param key The PoolKey
    /// @return pool The contract address of the V3 pool
    function computeAddress(address factory, PoolKey memory key) internal pure returns (address pool) {
        require(key.token0 < key.token1);
        pool = address(
            uint160(
                uint256(
                    keccak256(
                        abi.encodePacked(
                            hex'ff',
                            factory,
                            keccak256(abi.encode(key.token0, key.token1, key.fee)),
                            POOL_INIT_CODE_HASH
                        )
                    )
                )
            )
        );
    }
}
// File: contracts/UniswapTransferHelper.sol



// SPDX-License-Identifier: GPL-2.0-or-later

pragma solidity >=0.8.6;

import '@yield-protocol/utils-v2/contracts/interfaces/IWETH9.sol';

// File @uniswap/v3-periphery/contracts/libraries/TransferHelper.sol@v1.1.1
//
library UniswapTransferHelper {
    // @notice Transfers tokens from msg.sender to a recipient
    // @dev Errors with ST if transfer fails
    // @param token The contract address of the token which will be transferred
    // @param to The recipient of the transfer
    // @param value The value of the transfer
    function safeTransfer(
        address token,
        address to,
        uint256 value
    ) internal {
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(IERC20.transfer.selector, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'ST');
    }

    // @notice Approves the stipulated contract to spend the given allowance in the given token
    // @dev Errors with "SA" if transfer fails
    // @param token The contract address of the token to be approved
    // @param to The target of the approval
    // @param value The amount of the given token the target will be allowed to spend
    function safeApprove(
        address token,
        address to,
        uint256 value
    ) internal {
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(IERC20.approve.selector, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'SA');
    }
}

// File: contracts/ISwapRouter.sol



// SPDX-License-Identifier: GPL-2.0-or-later

pragma solidity >=0.8.6;

// File @uniswap/v3-periphery/contracts/interfaces/ISwapRouter.sol@v1.1.1

// @title Router token swapping functionality
// @notice Functions for swapping tokens via Uniswap V3
interface ISwapRouter {
    struct ExactInputSingleParams {
        address tokenIn;
        address tokenOut;
        uint24 fee;
        address recipient;
        uint256 deadline;
        uint256 amountIn;
        uint256 amountOutMinimum;
        uint160 sqrtPriceLimitX96;
    }

    // @notice Swaps `amountIn` of one token for as much as possible of another token
    // @param params The parameters necessary for the swap, encoded as `ExactInputSingleParams` in calldata
    // @return amountOut The amount of the received token
    function exactInputSingle(ExactInputSingleParams calldata params) external payable returns (uint256 amountOut);
}

// File: @yield-protocol/vault-interfaces/IFYToken.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "@yield-protocol/utils-v2/contracts/token/IERC20.sol";


interface IFYToken is IERC20 {
    /// @dev Asset that is returned on redemption.
    function underlying() external view returns (address);

    /// @dev Unix time at which redemption of fyToken for underlying are possible
    function maturity() external view returns (uint256);
    
    /// @dev Record price data at maturity
    function mature() external;

    /// @dev Mint fyToken providing an equal amount of underlying to the protocol
    function mintWithUnderlying(address to, uint256 amount) external;

    /// @dev Burn fyToken after maturity for an amount of underlying.
    function redeem(address to, uint256 amount) external returns (uint256);

    /// @dev Mint fyToken.
    /// This function can only be called by other Yield contracts, not users directly.
    /// @param to Wallet to mint the fyToken in.
    /// @param fyTokenAmount Amount of fyToken to mint.
    function mint(address to, uint256 fyTokenAmount) external;

    /// @dev Burn fyToken.
    /// This function can only be called by other Yield contracts, not users directly.
    /// @param from Wallet to burn the fyToken from.
    /// @param fyTokenAmount Amount of fyToken to burn.
    function burn(address from, uint256 fyTokenAmount) external;
}
// File: @yield-protocol/vault-interfaces/IOracle.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface IOracle {
    /**
     * @notice Doesn't refresh the price, but returns the latest value available without doing any transactional operations:
     * @return value in wei
     */
    function peek(bytes32 base, bytes32 quote, uint256 amount) external view returns (uint256 value, uint256 updateTime);

    /**
     * @notice Does whatever work or queries will yield the most up-to-date price, and returns it.
     * @return value in wei
     */
    function get(bytes32 base, bytes32 quote, uint256 amount) external returns (uint256 value, uint256 updateTime);
}

// File: @yield-protocol/vault-interfaces/DataTypes.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./IFYToken.sol";
import "./IOracle.sol";


library DataTypes {
    struct Series {
        IFYToken fyToken;                                               // Redeemable token for the series.
        bytes6  baseId;                                                 // Asset received on redemption.
        uint32  maturity;                                               // Unix time at which redemption becomes possible.
        // bytes2 free
    }

    struct Debt {
        uint96 max;                                                     // Maximum debt accepted for a given underlying, across all series
        uint24 min;                                                     // Minimum debt accepted for a given underlying, across all series
        uint8 dec;                                                      // Multiplying factor (10**dec) for max and min 
        uint128 sum;                                                    // Current debt for a given underlying, across all series
    }

    struct SpotOracle {
        IOracle oracle;                                                 // Address for the spot price oracle
        uint32  ratio;                                                  // Collateralization ratio to multiply the price for
        // bytes8 free
    }

    struct Vault {
        address owner;
        bytes6  seriesId;                                                // Each vault is related to only one series, which also determines the underlying.
        bytes6  ilkId;                                                   // Asset accepted as collateral
    }

    struct Balances {
        uint128 art;                                                     // Debt amount
        uint128 ink;                                                     // Collateral amount
    }
}
// File: @yield-protocol/utils-v2/contracts/token/IERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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 `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, 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 `sender` to `recipient` 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 sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @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);
}
// File: @yield-protocol/vault-interfaces/ILadle.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./IJoin.sol";
import "./ICauldron.sol";


interface ILadle {
    function joins(bytes6) external view returns (IJoin);
    function cauldron() external view returns (ICauldron);
    function build(bytes6 seriesId, bytes6 ilkId, uint8 salt) external returns (bytes12 vaultId, DataTypes.Vault memory vault);
    function destroy(bytes12 vaultId) external;
    function pour(bytes12 vaultId, address to, int128 ink, int128 art) external;
    function close(bytes12 vaultId, address to, int128 ink, int128 art) external;
}

// File: @yield-protocol/vault-interfaces/IJoin.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "@yield-protocol/utils-v2/contracts/token/IERC20.sol";


interface IJoin {
    /// @dev asset managed by this contract
    function asset() external view returns (address);

    /// @dev Add tokens to this contract.
    function join(address user, uint128 wad) external returns (uint128);

    /// @dev Remove tokens to this contract.
    function exit(address user, uint128 wad) external returns (uint128);
}
// File: uniswapv3-oracle/contracts/uniswapv0.8/pool/IUniswapV3PoolImmutables.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Pool state that never changes
/// @notice These parameters are fixed for a pool forever, i.e., the methods will always return the same values
interface IUniswapV3PoolImmutables {
    /// @notice The contract that deployed the pool, which must adhere to the IUniswapV3Factory interface
    /// @return The contract address
    function factory() external view returns (address);

    /// @notice The first of the two tokens of the pool, sorted by address
    /// @return The token contract address
    function token0() external view returns (address);

    /// @notice The second of the two tokens of the pool, sorted by address
    /// @return The token contract address
    function token1() external view returns (address);

    /// @notice The pool's fee in hundredths of a bip, i.e. 1e-6
    /// @return The fee
    function fee() external view returns (uint24);

    /// @notice The pool tick spacing
    /// @dev Ticks can only be used at multiples of this value, minimum of 1 and always positive
    /// e.g.: a tickSpacing of 3 means ticks can be initialized every 3rd tick, i.e., ..., -6, -3, 0, 3, 6, ...
    /// This value is an int24 to avoid casting even though it is always positive.
    /// @return The tick spacing
    function tickSpacing() external view returns (int24);

    /// @notice The maximum amount of position liquidity that can use any tick in the range
    /// @dev This parameter is enforced per tick to prevent liquidity from overflowing a uint128 at any point, and
    /// also prevents out-of-range liquidity from being used to prevent adding in-range liquidity to a pool
    /// @return The max amount of liquidity per tick
    function maxLiquidityPerTick() external view returns (uint128);
}

// File: uniswapv3-oracle/contracts/uniswapv0.8/pool/IUniswapV3PoolState.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Pool state that can change
/// @notice These methods compose the pool's state, and can change with any frequency including multiple times
/// per transaction
interface IUniswapV3PoolState {
    /// @notice The 0th storage slot in the pool stores many values, and is exposed as a single method to save gas
    /// when accessed externally.
    /// @return sqrtPriceX96 The current price of the pool as a sqrt(token1/token0) Q64.96 value
    /// tick The current tick of the pool, i.e. according to the last tick transition that was run.
    /// This value may not always be equal to SqrtTickMath.getTickAtSqrtRatio(sqrtPriceX96) if the price is on a tick
    /// boundary.
    /// observationIndex The index of the last oracle observation that was written,
    /// observationCardinality The current maximum number of observations stored in the pool,
    /// observationCardinalityNext The next maximum number of observations, to be updated when the observation.
    /// feeProtocol The protocol fee for both tokens of the pool.
    /// Encoded as two 4 bit values, where the protocol fee of token1 is shifted 4 bits and the protocol fee of token0
    /// is the lower 4 bits. Used as the denominator of a fraction of the swap fee, e.g. 4 means 1/4th of the swap fee.
    /// unlocked Whether the pool is currently locked to reentrancy
    function slot0()
        external
        view
        returns (
            uint160 sqrtPriceX96,
            int24 tick,
            uint16 observationIndex,
            uint16 observationCardinality,
            uint16 observationCardinalityNext,
            uint8 feeProtocol,
            bool unlocked
        );

    /// @notice The fee growth as a Q128.128 fees of token0 collected per unit of liquidity for the entire life of the pool
    /// @dev This value can overflow the uint256
    function feeGrowthGlobal0X128() external view returns (uint256);

    /// @notice The fee growth as a Q128.128 fees of token1 collected per unit of liquidity for the entire life of the pool
    /// @dev This value can overflow the uint256
    function feeGrowthGlobal1X128() external view returns (uint256);

    /// @notice The amounts of token0 and token1 that are owed to the protocol
    /// @dev Protocol fees will never exceed uint128 max in either token
    function protocolFees() external view returns (uint128 token0, uint128 token1);

    /// @notice The currently in range liquidity available to the pool
    /// @dev This value has no relationship to the total liquidity across all ticks
    function liquidity() external view returns (uint128);

    /// @notice Look up information about a specific tick in the pool
    /// @param tick The tick to look up
    /// @return liquidityGross the total amount of position liquidity that uses the pool either as tick lower or
    /// tick upper,
    /// liquidityNet how much liquidity changes when the pool price crosses the tick,
    /// feeGrowthOutside0X128 the fee growth on the other side of the tick from the current tick in token0,
    /// feeGrowthOutside1X128 the fee growth on the other side of the tick from the current tick in token1,
    /// tickCumulativeOutside the cumulative tick value on the other side of the tick from the current tick
    /// secondsPerLiquidityOutsideX128 the seconds spent per liquidity on the other side of the tick from the current tick,
    /// secondsOutside the seconds spent on the other side of the tick from the current tick,
    /// initialized Set to true if the tick is initialized, i.e. liquidityGross is greater than 0, otherwise equal to false.
    /// Outside values can only be used if the tick is initialized, i.e. if liquidityGross is greater than 0.
    /// In addition, these values are only relative and must be used only in comparison to previous snapshots for
    /// a specific position.
    function ticks(int24 tick)
        external
        view
        returns (
            uint128 liquidityGross,
            int128 liquidityNet,
            uint256 feeGrowthOutside0X128,
            uint256 feeGrowthOutside1X128,
            int56 tickCumulativeOutside,
            uint160 secondsPerLiquidityOutsideX128,
            uint32 secondsOutside,
            bool initialized
        );

    /// @notice Returns 256 packed tick initialized boolean values. See TickBitmap for more information
    function tickBitmap(int16 wordPosition) external view returns (uint256);

    /// @notice Returns the information about a position by the position's key
    /// @param key The position's key is a hash of a preimage composed by the owner, tickLower and tickUpper
    /// @return _liquidity The amount of liquidity in the position,
    /// Returns feeGrowthInside0LastX128 fee growth of token0 inside the tick range as of the last mint/burn/poke,
    /// Returns feeGrowthInside1LastX128 fee growth of token1 inside the tick range as of the last mint/burn/poke,
    /// Returns tokensOwed0 the computed amount of token0 owed to the position as of the last mint/burn/poke,
    /// Returns tokensOwed1 the computed amount of token1 owed to the position as of the last mint/burn/poke
    function positions(bytes32 key)
        external
        view
        returns (
            uint128 _liquidity,
            uint256 feeGrowthInside0LastX128,
            uint256 feeGrowthInside1LastX128,
            uint128 tokensOwed0,
            uint128 tokensOwed1
        );

    /// @notice Returns data about a specific observation index
    /// @param index The element of the observations array to fetch
    /// @dev You most likely want to use #observe() instead of this method to get an observation as of some amount of time
    /// ago, rather than at a specific index in the array.
    /// @return blockTimestamp The timestamp of the observation,
    /// Returns tickCumulative the tick multiplied by seconds elapsed for the life of the pool as of the observation timestamp,
    /// Returns secondsPerLiquidityCumulativeX128 the seconds per in range liquidity for the life of the pool as of the observation timestamp,
    /// Returns initialized whether the observation has been initialized and the values are safe to use
    function observations(uint256 index)
        external
        view
        returns (
            uint32 blockTimestamp,
            int56 tickCumulative,
            uint160 secondsPerLiquidityCumulativeX128,
            bool initialized
        );
}

// File: uniswapv3-oracle/contracts/uniswapv0.8/pool/IUniswapV3PoolDerivedState.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Pool state that is not stored
/// @notice Contains view functions to provide information about the pool that is computed rather than stored on the
/// blockchain. The functions here may have variable gas costs.
interface IUniswapV3PoolDerivedState {
    /// @notice Returns the cumulative tick and liquidity as of each timestamp `secondsAgo` from the current block timestamp
    /// @dev To get a time weighted average tick or liquidity-in-range, you must call this with two values, one representing
    /// the beginning of the period and another for the end of the period. E.g., to get the last hour time-weighted average tick,
    /// you must call it with secondsAgos = [3600, 0].
    /// @dev The time weighted average tick represents the geometric time weighted average price of the pool, in
    /// log base sqrt(1.0001) of token1 / token0. The TickMath library can be used to go from a tick value to a ratio.
    /// @param secondsAgos From how long ago each cumulative tick and liquidity value should be returned
    /// @return tickCumulatives Cumulative tick values as of each `secondsAgos` from the current block timestamp
    /// @return secondsPerLiquidityCumulativeX128s Cumulative seconds per liquidity-in-range value as of each `secondsAgos` from the current block
    /// timestamp
    function observe(uint32[] calldata secondsAgos)
        external
        view
        returns (int56[] memory tickCumulatives, uint160[] memory secondsPerLiquidityCumulativeX128s);

    /// @notice Returns a snapshot of the tick cumulative, seconds per liquidity and seconds inside a tick range
    /// @dev Snapshots must only be compared to other snapshots, taken over a period for which a position existed.
    /// I.e., snapshots cannot be compared if a position is not held for the entire period between when the first
    /// snapshot is taken and the second snapshot is taken.
    /// @param tickLower The lower tick of the range
    /// @param tickUpper The upper tick of the range
    /// @return tickCumulativeInside The snapshot of the tick accumulator for the range
    /// @return secondsPerLiquidityInsideX128 The snapshot of seconds per liquidity for the range
    /// @return secondsInside The snapshot of seconds per liquidity for the range
    function snapshotCumulativesInside(int24 tickLower, int24 tickUpper)
        external
        view
        returns (
            int56 tickCumulativeInside,
            uint160 secondsPerLiquidityInsideX128,
            uint32 secondsInside
        );
}

// File: uniswapv3-oracle/contracts/uniswapv0.8/pool/IUniswapV3PoolActions.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Permissionless pool actions
/// @notice Contains pool methods that can be called by anyone
interface IUniswapV3PoolActions {
    /// @notice Sets the initial price for the pool
    /// @dev Price is represented as a sqrt(amountToken1/amountToken0) Q64.96 value
    /// @param sqrtPriceX96 the initial sqrt price of the pool as a Q64.96
    function initialize(uint160 sqrtPriceX96) external;

    /// @notice Adds liquidity for the given recipient/tickLower/tickUpper position
    /// @dev The caller of this method receives a callback in the form of IUniswapV3MintCallback#uniswapV3MintCallback
    /// in which they must pay any token0 or token1 owed for the liquidity. The amount of token0/token1 due depends
    /// on tickLower, tickUpper, the amount of liquidity, and the current price.
    /// @param recipient The address for which the liquidity will be created
    /// @param tickLower The lower tick of the position in which to add liquidity
    /// @param tickUpper The upper tick of the position in which to add liquidity
    /// @param amount The amount of liquidity to mint
    /// @param data Any data that should be passed through to the callback
    /// @return amount0 The amount of token0 that was paid to mint the given amount of liquidity. Matches the value in the callback
    /// @return amount1 The amount of token1 that was paid to mint the given amount of liquidity. Matches the value in the callback
    function mint(
        address recipient,
        int24 tickLower,
        int24 tickUpper,
        uint128 amount,
        bytes calldata data
    ) external returns (uint256 amount0, uint256 amount1);

    /// @notice Collects tokens owed to a position
    /// @dev Does not recompute fees earned, which must be done either via mint or burn of any amount of liquidity.
    /// Collect must be called by the position owner. To withdraw only token0 or only token1, amount0Requested or
    /// amount1Requested may be set to zero. To withdraw all tokens owed, caller may pass any value greater than the
    /// actual tokens owed, e.g. type(uint128).max. Tokens owed may be from accumulated swap fees or burned liquidity.
    /// @param recipient The address which should receive the fees collected
    /// @param tickLower The lower tick of the position for which to collect fees
    /// @param tickUpper The upper tick of the position for which to collect fees
    /// @param amount0Requested How much token0 should be withdrawn from the fees owed
    /// @param amount1Requested How much token1 should be withdrawn from the fees owed
    /// @return amount0 The amount of fees collected in token0
    /// @return amount1 The amount of fees collected in token1
    function collect(
        address recipient,
        int24 tickLower,
        int24 tickUpper,
        uint128 amount0Requested,
        uint128 amount1Requested
    ) external returns (uint128 amount0, uint128 amount1);

    /// @notice Burn liquidity from the sender and account tokens owed for the liquidity to the position
    /// @dev Can be used to trigger a recalculation of fees owed to a position by calling with an amount of 0
    /// @dev Fees must be collected separately via a call to #collect
    /// @param tickLower The lower tick of the position for which to burn liquidity
    /// @param tickUpper The upper tick of the position for which to burn liquidity
    /// @param amount How much liquidity to burn
    /// @return amount0 The amount of token0 sent to the recipient
    /// @return amount1 The amount of token1 sent to the recipient
    function burn(
        int24 tickLower,
        int24 tickUpper,
        uint128 amount
    ) external returns (uint256 amount0, uint256 amount1);

    /// @notice Swap token0 for token1, or token1 for token0
    /// @dev The caller of this method receives a callback in the form of IUniswapV3SwapCallback#uniswapV3SwapCallback
    /// @param recipient The address to receive the output of the swap
    /// @param zeroForOne The direction of the swap, true for token0 to token1, false for token1 to token0
    /// @param amountSpecified The amount of the swap, which implicitly configures the swap as exact input (positive), or exact output (negative)
    /// @param sqrtPriceLimitX96 The Q64.96 sqrt price limit. If zero for one, the price cannot be less than this
    /// value after the swap. If one for zero, the price cannot be greater than this value after the swap
    /// @param data Any data to be passed through to the callback
    /// @return amount0 The delta of the balance of token0 of the pool, exact when negative, minimum when positive
    /// @return amount1 The delta of the balance of token1 of the pool, exact when negative, minimum when positive
    function swap(
        address recipient,
        bool zeroForOne,
        int256 amountSpecified,
        uint160 sqrtPriceLimitX96,
        bytes calldata data
    ) external returns (int256 amount0, int256 amount1);

    /// @notice Receive token0 and/or token1 and pay it back, plus a fee, in the callback
    /// @dev The caller of this method receives a callback in the form of IUniswapV3FlashCallback#uniswapV3FlashCallback
    /// @dev Can be used to donate underlying tokens pro-rata to currently in-range liquidity providers by calling
    /// with 0 amount{0,1} and sending the donation amount(s) from the callback
    /// @param recipient The address which will receive the token0 and token1 amounts
    /// @param amount0 The amount of token0 to send
    /// @param amount1 The amount of token1 to send
    /// @param data Any data to be passed through to the callback
    function flash(
        address recipient,
        uint256 amount0,
        uint256 amount1,
        bytes calldata data
    ) external;

    /// @notice Increase the maximum number of price and liquidity observations that this pool will store
    /// @dev This method is no-op if the pool already has an observationCardinalityNext greater than or equal to
    /// the input observationCardinalityNext.
    /// @param observationCardinalityNext The desired minimum number of observations for the pool to store
    function increaseObservationCardinalityNext(uint16 observationCardinalityNext) external;
}

// File: uniswapv3-oracle/contracts/uniswapv0.8/pool/IUniswapV3PoolOwnerActions.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Permissioned pool actions
/// @notice Contains pool methods that may only be called by the factory owner
interface IUniswapV3PoolOwnerActions {
    /// @notice Set the denominator of the protocol's % share of the fees
    /// @param feeProtocol0 new protocol fee for token0 of the pool
    /// @param feeProtocol1 new protocol fee for token1 of the pool
    function setFeeProtocol(uint8 feeProtocol0, uint8 feeProtocol1) external;

    /// @notice Collect the protocol fee accrued to the pool
    /// @param recipient The address to which collected protocol fees should be sent
    /// @param amount0Requested The maximum amount of token0 to send, can be 0 to collect fees in only token1
    /// @param amount1Requested The maximum amount of token1 to send, can be 0 to collect fees in only token0
    /// @return amount0 The protocol fee collected in token0
    /// @return amount1 The protocol fee collected in token1
    function collectProtocol(
        address recipient,
        uint128 amount0Requested,
        uint128 amount1Requested
    ) external returns (uint128 amount0, uint128 amount1);
}

// File: uniswapv3-oracle/contracts/uniswapv0.8/pool/IUniswapV3PoolEvents.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Events emitted by a pool
/// @notice Contains all events emitted by the pool
interface IUniswapV3PoolEvents {
    /// @notice Emitted exactly once by a pool when #initialize is first called on the pool
    /// @dev Mint/Burn/Swap cannot be emitted by the pool before Initialize
    /// @param sqrtPriceX96 The initial sqrt price of the pool, as a Q64.96
    /// @param tick The initial tick of the pool, i.e. log base 1.0001 of the starting price of the pool
    event Initialize(uint160 sqrtPriceX96, int24 tick);

    /// @notice Emitted when liquidity is minted for a given position
    /// @param sender The address that minted the liquidity
    /// @param owner The owner of the position and recipient of any minted liquidity
    /// @param tickLower The lower tick of the position
    /// @param tickUpper The upper tick of the position
    /// @param amount The amount of liquidity minted to the position range
    /// @param amount0 How much token0 was required for the minted liquidity
    /// @param amount1 How much token1 was required for the minted liquidity
    event Mint(
        address sender,
        address indexed owner,
        int24 indexed tickLower,
        int24 indexed tickUpper,
        uint128 amount,
        uint256 amount0,
        uint256 amount1
    );

    /// @notice Emitted when fees are collected by the owner of a position
    /// @dev Collect events may be emitted with zero amount0 and amount1 when the caller chooses not to collect fees
    /// @param owner The owner of the position for which fees are collected
    /// @param tickLower The lower tick of the position
    /// @param tickUpper The upper tick of the position
    /// @param amount0 The amount of token0 fees collected
    /// @param amount1 The amount of token1 fees collected
    event Collect(
        address indexed owner,
        address recipient,
        int24 indexed tickLower,
        int24 indexed tickUpper,
        uint128 amount0,
        uint128 amount1
    );

    /// @notice Emitted when a position's liquidity is removed
    /// @dev Does not withdraw any fees earned by the liquidity position, which must be withdrawn via #collect
    /// @param owner The owner of the position for which liquidity is removed
    /// @param tickLower The lower tick of the position
    /// @param tickUpper The upper tick of the position
    /// @param amount The amount of liquidity to remove
    /// @param amount0 The amount of token0 withdrawn
    /// @param amount1 The amount of token1 withdrawn
    event Burn(
        address indexed owner,
        int24 indexed tickLower,
        int24 indexed tickUpper,
        uint128 amount,
        uint256 amount0,
        uint256 amount1
    );

    /// @notice Emitted by the pool for any swaps between token0 and token1
    /// @param sender The address that initiated the swap call, and that received the callback
    /// @param recipient The address that received the output of the swap
    /// @param amount0 The delta of the token0 balance of the pool
    /// @param amount1 The delta of the token1 balance of the pool
    /// @param sqrtPriceX96 The sqrt(price) of the pool after the swap, as a Q64.96
    /// @param liquidity The liquidity of the pool after the swap
    /// @param tick The log base 1.0001 of price of the pool after the swap
    event Swap(
        address indexed sender,
        address indexed recipient,
        int256 amount0,
        int256 amount1,
        uint160 sqrtPriceX96,
        uint128 liquidity,
        int24 tick
    );

    /// @notice Emitted by the pool for any flashes of token0/token1
    /// @param sender The address that initiated the swap call, and that received the callback
    /// @param recipient The address that received the tokens from flash
    /// @param amount0 The amount of token0 that was flashed
    /// @param amount1 The amount of token1 that was flashed
    /// @param paid0 The amount of token0 paid for the flash, which can exceed the amount0 plus the fee
    /// @param paid1 The amount of token1 paid for the flash, which can exceed the amount1 plus the fee
    event Flash(
        address indexed sender,
        address indexed recipient,
        uint256 amount0,
        uint256 amount1,
        uint256 paid0,
        uint256 paid1
    );

    /// @notice Emitted by the pool for increases to the number of observations that can be stored
    /// @dev observationCardinalityNext is not the observation cardinality until an observation is written at the index
    /// just before a mint/swap/burn.
    /// @param observationCardinalityNextOld The previous value of the next observation cardinality
    /// @param observationCardinalityNextNew The updated value of the next observation cardinality
    event IncreaseObservationCardinalityNext(
        uint16 observationCardinalityNextOld,
        uint16 observationCardinalityNextNew
    );

    /// @notice Emitted when the protocol fee is changed by the pool
    /// @param feeProtocol0Old The previous value of the token0 protocol fee
    /// @param feeProtocol1Old The previous value of the token1 protocol fee
    /// @param feeProtocol0New The updated value of the token0 protocol fee
    /// @param feeProtocol1New The updated value of the token1 protocol fee
    event SetFeeProtocol(uint8 feeProtocol0Old, uint8 feeProtocol1Old, uint8 feeProtocol0New, uint8 feeProtocol1New);

    /// @notice Emitted when the collected protocol fees are withdrawn by the factory owner
    /// @param sender The address that collects the protocol fees
    /// @param recipient The address that receives the collected protocol fees
    /// @param amount0 The amount of token0 protocol fees that is withdrawn
    /// @param amount0 The amount of token1 protocol fees that is withdrawn
    event CollectProtocol(address indexed sender, address indexed recipient, uint128 amount0, uint128 amount1);
}

// File: @yield-protocol/utils-v2/contracts/interfaces/IWETH9.sol



// SPDX-License-Identifier: MIT
import "../token/IERC20.sol";

pragma solidity ^0.8.0;


interface IWETH9 is IERC20 {
    event  Deposit(address indexed dst, uint wad);
    event  Withdrawal(address indexed src, uint wad);

    function deposit() external payable;
    function withdraw(uint wad) external;
}