BunniOracle.sol

// SPDX-License-Identifier: AGPL-v3
pragma solidity ^0.8.4;

import {IBunniToken} from "bunni/src/interfaces/IBunniToken.sol";

import {ERC20} from "solmate/tokens/ERC20.sol";
import {SafeCastLib} from "solmate/utils/SafeCastLib.sol";
import {FixedPointMathLib} from "solmate/utils/FixedPointMathLib.sol";

import {TickMath} from "@uniswap/v3-core/contracts/libraries/TickMath.sol";
import {IUniswapV3Pool} from "@uniswap/v3-core/contracts/interfaces/IUniswapV3Pool.sol";

import {OracleLibrary} from "@uniswap/v3-periphery/contracts/libraries/OracleLibrary.sol";
import {LiquidityAmounts} from "@uniswap/v3-periphery/contracts/libraries/LiquidityAmounts.sol";

import {Denominations} from "./external/Denominations.sol";
import {FeedRegistryInterface, AggregatorV2V3Interface} from "./external/FeedRegistryInterface.sol";

/// @title Price oracle for Bunni tokens and generalized Uniswap V3 positions
/// @author zefram.eth
/// @notice Uses a combination of Chainlink price oracles and Uniswap V3 built-in TWAP oracles
/// to compute the value of a Uniswap V3 liquidity position without being vulnerable to flashloan
/// manipulation attacks.
contract BunniOracle {
    /// -----------------------------------------------------------------------
    /// Libraries usage
    /// -----------------------------------------------------------------------

    using SafeCastLib for uint256;
    using FixedPointMathLib for uint256;

    /// -----------------------------------------------------------------------
    /// Constants
    /// -----------------------------------------------------------------------

    uint256 internal constant BASE = 1e18; // result of quoteUSD uses 18 decimals
    uint256 internal constant GRACE_PERIOD_TIME = 1 hours; // grace period after L2 sequencer downtime

    /// -----------------------------------------------------------------------
    /// Immutable args
    /// -----------------------------------------------------------------------

    /// @notice The Chainlink Feed Registry contract
    /// @dev Since the Feed Registry only exists on Ethereum, this value will be
    /// address(0) on non-Ethereum networks.
    FeedRegistryInterface public immutable chainlink;

    /// @notice The Chainlink uptime feed for deployment on L2s (e.g. Arbitrum, Optimism)
    /// @dev Is address(0) for non-L2 networks (e.g. Ethereum, Polygon)
    AggregatorV2V3Interface public immutable sequencerUptimeFeed;

    address internal immutable WETH;
    address internal immutable WBTC;
    address internal immutable USDC;
    address internal immutable USDT;
    address internal immutable DAI;
    address internal immutable FRAX;

    /// -----------------------------------------------------------------------
    /// Errors
    /// -----------------------------------------------------------------------

    error BunniOracle__SequencerDown();
    error BunniOracle__GracePeriodNotOver();
    error BunniOracle__ChainlinkPriceTooOld();
    error BunniOracle__NoChainlinkPriceAvailable();

    /// -----------------------------------------------------------------------
    /// Constructor
    /// -----------------------------------------------------------------------

    constructor(
        FeedRegistryInterface chainlink_,
        AggregatorV2V3Interface sequencerUptimeFeed_,
        address WETH_,
        address WBTC_,
        address USDC_,
        address USDT_,
        address DAI_,
        address FRAX_
    ) {
        chainlink = chainlink_;
        sequencerUptimeFeed = sequencerUptimeFeed_;
        WETH = WETH_;
        WBTC = WBTC_;
        USDC = USDC_;
        USDT = USDT_;
        DAI = DAI_;
        FRAX = FRAX_;
    }

    /// -----------------------------------------------------------------------
    /// External functions
    /// -----------------------------------------------------------------------

    /// @notice Computes the USD value of a Uniswap V3 liquidity position.
    /// @dev This function is meant for ease of use: the number of input parameters is minimized
    /// and we make external contract calls to obtain the token & price feed addresses. Only works
    /// on Ethereum since the Feed Registry is only available there.
    /// @param pool The Uniswap V3 pool
    /// @param tickLower The lower tick of the liquidity position
    /// @param tickUpper The upper tick of the liquidity position
    /// @param liquidity The liquidity value of the position
    /// @param uniV3OracleSecondsAgo The size of the TWAP window used by the Uniswap V3 TWAP oracle in seconds.
    /// Ignored if both token0 and token1 have chainlink price feeds. The call reverts if the TWAP oracle
    /// doesn't have observations old enough in the past to support the window size.
    /// @param chainlinkPriceMaxAgeSecs The maximum age of the results returned by chainlink in seconds.
    /// The call reverts if the result is older than this value.
    /// @return valueUSD The value of the liquidity position in USD, 18 decimals
    function quoteUSD(
        IUniswapV3Pool pool,
        int24 tickLower,
        int24 tickUpper,
        uint128 liquidity,
        uint32 uniV3OracleSecondsAgo,
        uint256 chainlinkPriceMaxAgeSecs
    ) external view returns (uint256 valueUSD) {
        address token0 = pool.token0();
        address token1 = pool.token1();

        AggregatorV2V3Interface feed0;
        AggregatorV2V3Interface feed1;
        try chainlink.getFeed(_transformToken(token0), Denominations.USD) returns (AggregatorV2V3Interface f) {
            feed0 = f;
        } catch {}
        try chainlink.getFeed(_transformToken(token1), Denominations.USD) returns (AggregatorV2V3Interface f) {
            feed1 = f;
        } catch {}

        uint256 token0Base = _getTokenBase(token0);
        uint256 token1Base = _getTokenBase(token1);

        return _quoteUSD(
            pool,
            token0,
            token1,
            token0Base,
            token1Base,
            tickLower,
            tickUpper,
            liquidity,
            uniV3OracleSecondsAgo,
            chainlinkPriceMaxAgeSecs,
            feed0,
            feed1
        );
    }

    /// @notice Computes the USD value of a Uniswap V3 liquidity position.
    /// @dev This function is meant for ease of use: the number of input parameters is minimized
    /// and we make external contract calls to obtain the token & price feed addresses. Only works
    /// on Ethereum since the Feed Registry is only available there. Lets the user provide whether
    /// a chainlink price feed exists for each token to save gas (~5k) in the case where only one token
    /// has a feed
    /// @param pool The Uniswap V3 pool
    /// @param tickLower The lower tick of the liquidity position
    /// @param tickUpper The upper tick of the liquidity position
    /// @param liquidity The liquidity value of the position
    /// @param feed0Exists Whether a chainlink price feed exists for token0 of the pool
    /// @param feed1Exists Whether a chainlink price feed exists for token1 of the pool
    /// @param uniV3OracleSecondsAgo The size of the TWAP window used by the Uniswap V3 TWAP oracle in seconds.
    /// Ignored if both token0 and token1 have chainlink price feeds. The call reverts if the TWAP oracle
    /// doesn't have observations old enough in the past to support the window size.
    /// @param chainlinkPriceMaxAgeSecs The maximum age of the results returned by chainlink in seconds.
    /// The call reverts if the result is older than this value.
    /// @return valueUSD The value of the liquidity position in USD, 18 decimals
    function quoteUSD(
        IUniswapV3Pool pool,
        int24 tickLower,
        int24 tickUpper,
        uint128 liquidity,
        bool feed0Exists,
        bool feed1Exists,
        uint32 uniV3OracleSecondsAgo,
        uint256 chainlinkPriceMaxAgeSecs
    ) external view returns (uint256 valueUSD) {
        address token0 = pool.token0();
        address token1 = pool.token1();

        AggregatorV2V3Interface feed0 = feed0Exists
            ? chainlink.getFeed(_transformToken(token0), Denominations.USD)
            : AggregatorV2V3Interface(address(0));
        AggregatorV2V3Interface feed1 = feed1Exists
            ? chainlink.getFeed(_transformToken(token1), Denominations.USD)
            : AggregatorV2V3Interface(address(0));

        uint256 token0Base = _getTokenBase(token0);
        uint256 token1Base = _getTokenBase(token1);

        return _quoteUSD(
            pool,
            token0,
            token1,
            token0Base,
            token1Base,
            tickLower,
            tickUpper,
            liquidity,
            uniV3OracleSecondsAgo,
            chainlinkPriceMaxAgeSecs,
            feed0,
            feed1
        );
    }

    /// @notice Computes the USD value of a Uniswap V3 liquidity position.
    /// @dev This function is meant for ease of use: the number of input parameters is minimized
    /// and we make external contract calls to obtain the token & price feed addresses. Used on non-Ethereum
    /// chains since there's no Feed Registry available.
    /// If the Feed Registry is available and has a valid feed for a token, the feed from the registry will be used
    /// instead of feed0/feed1.
    /// @param pool The Uniswap V3 pool
    /// @param tickLower The lower tick of the liquidity position
    /// @param tickUpper The upper tick of the liquidity position
    /// @param liquidity The liquidity value of the position
    /// @param uniV3OracleSecondsAgo The size of the TWAP window used by the Uniswap V3 TWAP oracle in seconds.
    /// Ignored if both token0 and token1 have chainlink price feeds. The call reverts if the TWAP oracle
    /// doesn't have observations old enough in the past to support the window size.
    /// @param chainlinkPriceMaxAgeSecs The maximum age of the results returned by chainlink in seconds.
    /// The call reverts if the result is older than this value.
    /// @param feed0 The Chainlink price feed for token0. Use address(0) if not available.
    /// @param feed1 The Chainlink price feed for token1. Use address(0) if not available.
    /// @return valueUSD The value of the liquidity position in USD, 18 decimals
    function quoteUSD(
        IUniswapV3Pool pool,
        int24 tickLower,
        int24 tickUpper,
        uint128 liquidity,
        uint32 uniV3OracleSecondsAgo,
        uint256 chainlinkPriceMaxAgeSecs,
        AggregatorV2V3Interface feed0,
        AggregatorV2V3Interface feed1
    ) external view returns (uint256 valueUSD) {
        address token0 = pool.token0();
        address token1 = pool.token1();

        uint256 token0Base = _getTokenBase(token0);
        uint256 token1Base = _getTokenBase(token1);

        return _quoteUSD(
            pool,
            token0,
            token1,
            token0Base,
            token1Base,
            tickLower,
            tickUpper,
            liquidity,
            uniV3OracleSecondsAgo,
            chainlinkPriceMaxAgeSecs,
            feed0,
            feed1
        );
    }

    /// @notice Computes the USD value of a Uniswap V3 liquidity position.
    /// @dev This function is meant for maximum gas efficiency: many parameters that could've been fetched
    /// via external calls are instead input arguments. Used on non-Ethereum
    /// chains since there's no Feed Registry available. If the wrong values are given for input arguments, the result
    /// is undefined.
    /// If the Feed Registry is available and has a valid feed for a token, the feed from the registry will be used
    /// instead of feed0/feed1.
    /// @param pool The Uniswap V3 pool
    /// @param token0 token0 of the Uniswap pool
    /// @param token1 token1 of the Uniswap pool
    /// @param token0Base 10 ** token0Decimals
    /// @param token1Base 10 ** token1Decimals
    /// @param tickLower The lower tick of the liquidity position
    /// @param tickUpper The upper tick of the liquidity position
    /// @param liquidity The liquidity value of the position
    /// @param uniV3OracleSecondsAgo The size of the TWAP window used by the Uniswap V3 TWAP oracle in seconds.
    /// Ignored if both token0 and token1 have chainlink price feeds. The call reverts if the TWAP oracle
    /// doesn't have observations old enough in the past to support the window size.
    /// @param chainlinkPriceMaxAgeSecs The maximum age of the results returned by chainlink in seconds.
    /// The call reverts if the result is older than this value.
    /// @param feed0 The Chainlink price feed for token0. Use address(0) if not available.
    /// @param feed1 The Chainlink price feed for token1. Use address(0) if not available.
    /// @return valueUSD The value of the liquidity position in USD, 18 decimals
    function quoteUSD(
        IUniswapV3Pool pool,
        address token0,
        address token1,
        uint256 token0Base,
        uint256 token1Base,
        int24 tickLower,
        int24 tickUpper,
        uint128 liquidity,
        uint32 uniV3OracleSecondsAgo,
        uint256 chainlinkPriceMaxAgeSecs,
        AggregatorV2V3Interface feed0,
        AggregatorV2V3Interface feed1
    ) external view returns (uint256 valueUSD) {
        return _quoteUSD(
            pool,
            token0,
            token1,
            token0Base,
            token1Base,
            tickLower,
            tickUpper,
            liquidity,
            uniV3OracleSecondsAgo,
            chainlinkPriceMaxAgeSecs,
            feed0,
            feed1
        );
    }

    /// @notice Computes the USD price of a Bunni LP token.
    /// @dev This function is meant for ease of use: the number of input parameters is minimized
    /// and we make external contract calls to obtain the token & price feed addresses. Only works
    /// on Ethereum since the Feed Registry is only available there.
    /// @param bunniToken The Bunni LP token
    /// @param uniV3OracleSecondsAgo The size of the TWAP window used by the Uniswap V3 TWAP oracle in seconds.
    /// Ignored if both token0 and token1 have chainlink price feeds. The call reverts if the TWAP oracle
    /// doesn't have observations old enough in the past to support the window size.
    /// @param chainlinkPriceMaxAgeSecs The maximum age of the results returned by chainlink in seconds.
    /// The call reverts if the result is older than this value.
    /// @return priceUSD The price of the Bunni LP token in USD, 18 decimals
    function bunniTokenPriceUSD(IBunniToken bunniToken, uint32 uniV3OracleSecondsAgo, uint256 chainlinkPriceMaxAgeSecs)
        external
        view
        returns (uint256 priceUSD)
    {
        IUniswapV3Pool pool = bunniToken.pool();
        address token0 = pool.token0();
        address token1 = pool.token1();

        AggregatorV2V3Interface feed0;
        AggregatorV2V3Interface feed1;
        try chainlink.getFeed(_transformToken(token0), Denominations.USD) returns (AggregatorV2V3Interface f) {
            feed0 = f;
        } catch {}
        try chainlink.getFeed(_transformToken(token1), Denominations.USD) returns (AggregatorV2V3Interface f) {
            feed1 = f;
        } catch {}

        int24 tickLower = bunniToken.tickLower();
        int24 tickUpper = bunniToken.tickUpper();
        uint256 token0Base = _getTokenBase(token0);
        uint256 token1Base = _getTokenBase(token1);

        return _bunniTokenPriceUSD(
            bunniToken,
            pool,
            token0,
            token1,
            token0Base,
            token1Base,
            tickLower,
            tickUpper,
            uniV3OracleSecondsAgo,
            chainlinkPriceMaxAgeSecs,
            feed0,
            feed1
        );
    }

    /// @notice Computes the USD price of a Bunni LP token.
    /// @dev This function is meant for ease of use: the number of input parameters is minimized
    /// and we make external contract calls to obtain the token & price feed addresses. Only works
    /// on Ethereum since the Feed Registry is only available there. Lets the user provide whether
    /// a chainlink price feed exists for each token to save gas (~5k) in the case where only one token
    /// has a feed
    /// @param bunniToken The Bunni LP token
    /// @param feed0Exists Whether a chainlink price feed exists for token0 of the pool
    /// @param feed1Exists Whether a chainlink price feed exists for token1 of the pool
    /// @param uniV3OracleSecondsAgo The size of the TWAP window used by the Uniswap V3 TWAP oracle in seconds.
    /// Ignored if both token0 and token1 have chainlink price feeds. The call reverts if the TWAP oracle
    /// doesn't have observations old enough in the past to support the window size.
    /// @param chainlinkPriceMaxAgeSecs The maximum age of the results returned by chainlink in seconds.
    /// The call reverts if the result is older than this value.
    /// @return priceUSD The price of the Bunni LP token in USD, 18 decimals
    function bunniTokenPriceUSD(
        IBunniToken bunniToken,
        bool feed0Exists,
        bool feed1Exists,
        uint32 uniV3OracleSecondsAgo,
        uint256 chainlinkPriceMaxAgeSecs
    ) external view returns (uint256 priceUSD) {
        IUniswapV3Pool pool = bunniToken.pool();
        address token0 = pool.token0();
        address token1 = pool.token1();

        AggregatorV2V3Interface feed0 = feed0Exists
            ? chainlink.getFeed(_transformToken(token0), Denominations.USD)
            : AggregatorV2V3Interface(address(0));
        AggregatorV2V3Interface feed1 = feed1Exists
            ? chainlink.getFeed(_transformToken(token1), Denominations.USD)
            : AggregatorV2V3Interface(address(0));

        int24 tickLower = bunniToken.tickLower();
        int24 tickUpper = bunniToken.tickUpper();
        uint256 token0Base = _getTokenBase(token0);
        uint256 token1Base = _getTokenBase(token1);

        return _bunniTokenPriceUSD(
            bunniToken,
            pool,
            token0,
            token1,
            token0Base,
            token1Base,
            tickLower,
            tickUpper,
            uniV3OracleSecondsAgo,
            chainlinkPriceMaxAgeSecs,
            feed0,
            feed1
        );
    }

    /// @notice Computes the USD price of a Bunni LP token.
    /// @dev This function is meant for ease of use: the number of input parameters is minimized
    /// and we make external contract calls to obtain the token & price feed addresses. Used on non-Ethereum
    /// chains since there's no Feed Registry available.
    /// If the Feed Registry is available and has a valid feed for a token, the feed from the registry will be used
    /// instead of feed0/feed1.
    /// @param bunniToken The Bunni LP token
    /// @param uniV3OracleSecondsAgo The size of the TWAP window used by the Uniswap V3 TWAP oracle in seconds.
    /// Ignored if both token0 and token1 have chainlink price feeds. The call reverts if the TWAP oracle
    /// doesn't have observations old enough in the past to support the window size.
    /// @param chainlinkPriceMaxAgeSecs The maximum age of the results returned by chainlink in seconds.
    /// The call reverts if the result is older than this value.
    /// @param feed0 The Chainlink price feed for token0. Use address(0) if not available.
    /// @param feed1 The Chainlink price feed for token1. Use address(0) if not available.
    /// @return priceUSD The price of the Bunni LP token in USD, 18 decimals
    function bunniTokenPriceUSD(
        IBunniToken bunniToken,
        uint32 uniV3OracleSecondsAgo,
        uint256 chainlinkPriceMaxAgeSecs,
        AggregatorV2V3Interface feed0,
        AggregatorV2V3Interface feed1
    ) external view returns (uint256 priceUSD) {
        IUniswapV3Pool pool = bunniToken.pool();
        address token0 = pool.token0();
        address token1 = pool.token1();

        int24 tickLower = bunniToken.tickLower();
        int24 tickUpper = bunniToken.tickUpper();
        uint256 token0Base = _getTokenBase(token0);
        uint256 token1Base = _getTokenBase(token1);

        return _bunniTokenPriceUSD(
            bunniToken,
            pool,
            token0,
            token1,
            token0Base,
            token1Base,
            tickLower,
            tickUpper,
            uniV3OracleSecondsAgo,
            chainlinkPriceMaxAgeSecs,
            feed0,
            feed1
        );
    }

    /// @notice Computes the USD price of a Bunni LP token.
    /// @dev This function is meant for maximum gas efficiency: many parameters that could've been fetched
    /// via external calls are instead input arguments. Used on non-Ethereum
    /// chains since there's no Feed Registry available. If the wrong values are given for input arguments, the result
    /// is undefined.
    /// If the Feed Registry is available and has a valid feed for a token, the feed from the registry will be used
    /// instead of feed0/feed1.
    /// @param bunniToken The Bunni LP token
    /// @param uniV3OracleSecondsAgo The size of the TWAP window used by the Uniswap V3 TWAP oracle in seconds.
    /// Ignored if both token0 and token1 have chainlink price feeds. The call reverts if the TWAP oracle
    /// doesn't have observations old enough in the past to support the window size.
    /// @param chainlinkPriceMaxAgeSecs The maximum age of the results returned by chainlink in seconds.
    /// The call reverts if the result is older than this value.
    /// @param feed0 The Chainlink price feed for token0. Use address(0) if not available.
    /// @param feed1 The Chainlink price feed for token1. Use address(0) if not available.
    /// @return priceUSD The price of the Bunni LP token in USD, 18 decimals
    function bunniTokenPriceUSD(
        IBunniToken bunniToken,
        IUniswapV3Pool pool,
        address token0,
        address token1,
        uint256 token0Base,
        uint256 token1Base,
        int24 tickLower,
        int24 tickUpper,
        uint32 uniV3OracleSecondsAgo,
        uint256 chainlinkPriceMaxAgeSecs,
        AggregatorV2V3Interface feed0,
        AggregatorV2V3Interface feed1
    ) external view returns (uint256 priceUSD) {
        return _bunniTokenPriceUSD(
            bunniToken,
            pool,
            token0,
            token1,
            token0Base,
            token1Base,
            tickLower,
            tickUpper,
            uniV3OracleSecondsAgo,
            chainlinkPriceMaxAgeSecs,
            feed0,
            feed1
        );
    }

    /// -----------------------------------------------------------------------
    /// Internal functions
    /// -----------------------------------------------------------------------

    function _quoteUSD(
        IUniswapV3Pool pool,
        address token0,
        address token1,
        uint256 token0Base,
        uint256 token1Base,
        int24 tickLower,
        int24 tickUpper,
        uint128 liquidity,
        uint32 uniV3OracleSecondsAgo,
        uint256 chainlinkPriceMaxAgeSecs,
        AggregatorV2V3Interface feed0,
        AggregatorV2V3Interface feed1
    ) internal view returns (uint256 valueUSD) {
        uint256 price0USD;
        uint256 price1USD;
        uint256 decimals0; // num of decimals used by price0USD
        uint256 decimals1; // num of decimals used by price1USD

        // handle different cases based on availability of chainlink price feed
        {
            if (address(feed0) != address(0) && address(feed1) != address(0)) {
                // both tokens have chainlink price

                // fetch prices from chainlink
                (price0USD, decimals0) = _getPriceUSDFromFeed(feed0, token0, chainlinkPriceMaxAgeSecs);
                (price1USD, decimals1) = _getPriceUSDFromFeed(feed1, token1, chainlinkPriceMaxAgeSecs);
            } else if (address(feed0) != address(0)) {
                // feed0 != 0, feed1 == 0
                // token0 has chainlink price

                // fetch prices from chainlink
                (price0USD, decimals0) = _getPriceUSDFromFeed(feed0, token0, chainlinkPriceMaxAgeSecs);

                // compute price1USD using Uniswap v3 TWAP oracle
                (int24 arithmeticMeanTick,) = OracleLibrary.consult(address(pool), uniV3OracleSecondsAgo);
                uint256 quoteAmount =
                    OracleLibrary.getQuoteAtTick(arithmeticMeanTick, token1Base.safeCastTo128(), token1, token0); // price of token1 in token0
                (price1USD, decimals1) = (quoteAmount.mulDivDown(price0USD, token0Base), decimals0);
            } else if (address(feed1) != address(0)) {
                // feed0 == 0, feed1 != 0
                // token1 has chainlink price

                // fetch prices from chainlink
                (price1USD, decimals1) = _getPriceUSDFromFeed(feed1, token1, chainlinkPriceMaxAgeSecs);

                // compute price0USD using Uniswap v3 TWAP oracle
                (int24 arithmeticMeanTick,) = OracleLibrary.consult(address(pool), uniV3OracleSecondsAgo);
                uint256 quoteAmount =
                    OracleLibrary.getQuoteAtTick(arithmeticMeanTick, token0Base.safeCastTo128(), token0, token1); // price of token0 in token1
                (price0USD, decimals0) = (quoteAmount.mulDivDown(price1USD, token1Base), decimals1);
            } else {
                // neither token has chainlink price
                // cannot compute USD price in this case
                revert BunniOracle__NoChainlinkPriceAvailable();
            }
        }

        // use token prices to compute sqrtRatioX96 and then compute token amounts for liquidity
        (uint256 amount0, uint256 amount1) = LiquidityAmounts.getAmountsForLiquidity(
            _getSqrtRatioX96(price0USD, price1USD, decimals0, decimals1, token0Base, token1Base),
            TickMath.getSqrtRatioAtTick(tickLower),
            TickMath.getSqrtRatioAtTick(tickUpper),
            liquidity
        );

        // add up position value of both tokens
        valueUSD = amount0.mulDivDown(price0USD, 10 ** decimals0).mulDivDown(BASE, token0Base)
            + amount1.mulDivDown(price1USD, 10 ** decimals1).mulDivDown(BASE, token1Base);
    }

    function _bunniTokenPriceUSD(
        IBunniToken bunniToken,
        IUniswapV3Pool pool,
        address token0,
        address token1,
        uint256 token0Base,
        uint256 token1Base,
        int24 tickLower,
        int24 tickUpper,
        uint32 uniV3OracleSecondsAgo,
        uint256 chainlinkPriceMaxAgeSecs,
        AggregatorV2V3Interface feed0,
        AggregatorV2V3Interface feed1
    ) internal view returns (uint256 priceUSD) {
        uint128 liquidity;
        {
            uint256 existingShareSupply = bunniToken.totalSupply();
            if (existingShareSupply == 0) {
                return 0;
            } else {
                // fetch total liquidity of Bunni token's position
                (liquidity,,,,) = pool.positions(keccak256(abi.encodePacked(bunniToken.hub(), tickLower, tickUpper)));

                // compute liquidity per Bunni token
                // liquidity is uint128, BASE uses 60 bits
                // so liquidity * BASE can't overflow 256 bits
                liquidity = uint128((liquidity * BASE) / existingShareSupply);
            }
        }

        return _quoteUSD(
            pool,
            token0,
            token1,
            token0Base,
            token1Base,
            tickLower,
            tickUpper,
            liquidity,
            uniV3OracleSecondsAgo,
            chainlinkPriceMaxAgeSecs,
            feed0,
            feed1
        );
    }

    function _getPriceUSDFromFeed(AggregatorV2V3Interface feed, address token, uint256 chainlinkPriceMaxAgeSecs)
        internal
        view
        returns (uint256 priceUSD, uint256 decimals)
    {
        // ensure the L2 sequencer is up if this is an L2 deployment
        if (address(sequencerUptimeFeed) != address(0)) {
            (, int256 answer, uint256 startedAt,,) = sequencerUptimeFeed.latestRoundData();

            // Answer == 0: Sequencer is up
            // Answer == 1: Sequencer is down
            if (answer != 0) {
                revert BunniOracle__SequencerDown();
            }

            // Make sure the grace period has passed after the
            // sequencer is back up.
            uint256 timeSinceUp = block.timestamp - startedAt;
            if (timeSinceUp <= GRACE_PERIOD_TIME) {
                revert BunniOracle__GracePeriodNotOver();
            }
        }

        // fetch USD price of tokens from chainlink
        // prices use 8 decimals
        int256 priceUSDInt;
        uint256 updatedAt;
        if (address(chainlink) != address(0)) {
            // FeedRegistry is available
            (, priceUSDInt,, updatedAt,) = chainlink.latestRoundData(_transformToken(token), Denominations.USD);
            if (token == WETH || token == USDC || token == WBTC || token == USDT || token == DAI || token == FRAX) {
                decimals = 8;
            } else {
                decimals = chainlink.decimals(_transformToken(token), Denominations.USD);
            }
        } else {
            // FeedRegistry is not available
            (, priceUSDInt,, updatedAt,) = feed.latestRoundData();
            if (token == WETH || token == USDC || token == WBTC || token == USDT || token == DAI || token == FRAX) {
                decimals = 8;
            } else {
                decimals = feed.decimals();
            }
        }

        // revert if the result is stale
        if (block.timestamp - updatedAt > chainlinkPriceMaxAgeSecs) revert BunniOracle__ChainlinkPriceTooOld();

        // set return priceUSD value
        priceUSD = uint256(priceUSDInt);
    }

    function _getSqrtRatioX96(
        uint256 price0USD,
        uint256 price1USD,
        uint256 decimals0,
        uint256 decimals1,
        uint256 token0Base,
        uint256 token1Base
    ) internal pure returns (uint160) {
        // Note: amount1 and amount0 may have different decimals which needs to be accounted for via token0Base and token1Base
        // sqrtRatioX96 = sqrt(amount1 / amount0) * 2**96
        //              = sqrt((price0USD * 10**decimals1 * token1Base) / (price1USD * 10**decimals0 * token0Base)) * 2**96
        //              = sqrt((price0USD * 10**decimals1 * token1Base * 2**96) / (price1USD * 10**decimals0 * token0Base)) * 2**48
        return (
            (((price0USD * 10 ** decimals1 * token1Base) << 96) / (price1USD * 10 ** decimals0 * token0Base)).sqrt()
                << 48
        ).safeCastTo160();
    }

    function _transformToken(address token) internal view returns (address) {
        // transforms WETH and WBTC to addresses accepted by chainlink
        if (token == WETH) {
            return Denominations.ETH;
        } else if (token == WBTC) {
            return Denominations.BTC;
        } else {
            return token;
        }
    }

    function _getTokenBase(address token) internal view returns (uint256) {
        // use hardcoded values for common tokens
        // to save gas
        if (token == WETH) {
            return BASE;
        } else if (token == USDC) {
            return 1e6;
        } else if (token == WBTC) {
            return 1e8;
        } else if (token == USDT) {
            return 1e6;
        } else if (token == DAI) {
            return BASE;
        } else if (token == FRAX) {
            return BASE;
        } else {
            return 10 ** uint256(ERC20(token).decimals());
        }
    }
}