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

/// @title IOracle
/// @author Morpho Labs
/// @custom:contact [email protected]
/// @notice Interface that oracles used by Morpho must implement.
/// @dev It is the user's responsibility to select markets with safe oracles.
interface IOracle {
    /// @notice Returns the price of 1 asset of collateral token quoted in 1 asset of loan token, scaled by 1e36.
    /// @dev It corresponds to the price of 10**(collateral token decimals) assets of collateral token quoted in
    /// 10**(loan token decimals) assets of loan token with `36 + loan token decimals - collateral token decimals`
    /// decimals of precision.
    function price() external view returns (uint256);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/math/Math.sol)

pragma solidity ^0.8.20;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    /**
     * @dev Muldiv operation overflow.
     */
    error MathOverflowedMulDiv();

    enum Rounding {
        Floor, // Toward negative infinity
        Ceil, // Toward positive infinity
        Trunc, // Toward zero
        Expand // Away from zero
    }

    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     */
    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.
     */
    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.
     */
    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.
     */
    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.
     */
    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 largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds towards infinity instead
     * of rounding towards zero.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        if (b == 0) {
            // Guarantee the same behavior as in a regular Solidity division.
            return a / b;
        }

        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }

    /**
     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or
     * denominator == 0.
     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv) with further edits by
     * Uniswap Labs also under MIT license.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
        unchecked {
            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
            // variables such that product = prod1 * 2^256 + prod0.
            uint256 prod0 = x * y; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }

            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                // Solidity will revert if denominator == 0, unlike the div opcode on its own.
                // The surrounding unchecked block does not change this fact.
                // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
                return prod0 / denominator;
            }

            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            if (denominator <= prod1) {
                revert MathOverflowedMulDiv();
            }

            ///////////////////////////////////////////////
            // 512 by 256 division.
            ///////////////////////////////////////////////

            // Make division exact by subtracting the remainder from [prod1 prod0].
            uint256 remainder;
            assembly {
                // Compute remainder using mulmod.
                remainder := mulmod(x, y, denominator)

                // Subtract 256 bit number from 512 bit number.
                prod1 := sub(prod1, gt(remainder, prod0))
                prod0 := sub(prod0, remainder)
            }

            // Factor powers of two out of denominator and compute largest power of two divisor of denominator.
            // Always >= 1. See https://cs.stackexchange.com/q/138556/92363.

            uint256 twos = denominator & (0 - denominator);
            assembly {
                // Divide denominator by twos.
                denominator := div(denominator, twos)

                // Divide [prod1 prod0] by twos.
                prod0 := div(prod0, twos)

                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                twos := add(div(sub(0, twos), twos), 1)
            }

            // Shift in bits from prod1 into prod0.
            prod0 |= prod1 * twos;

            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
            // four bits. That is, denominator * inv = 1 mod 2^4.
            uint256 inverse = (3 * denominator) ^ 2;

            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also
            // works in modular arithmetic, doubling the correct bits in each step.
            inverse *= 2 - denominator * inverse; // inverse mod 2^8
            inverse *= 2 - denominator * inverse; // inverse mod 2^16
            inverse *= 2 - denominator * inverse; // inverse mod 2^32
            inverse *= 2 - denominator * inverse; // inverse mod 2^64
            inverse *= 2 - denominator * inverse; // inverse mod 2^128
            inverse *= 2 - denominator * inverse; // inverse mod 2^256

            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
            // is no longer required.
            result = prod0 * inverse;
            return result;
        }
    }

    /**
     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
        uint256 result = mulDiv(x, y, denominator);
        if (unsignedRoundsUp(rounding) && mulmod(x, y, denominator) > 0) {
            result += 1;
        }
        return result;
    }

    /**
     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded
     * towards zero.
     *
     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
     */
    function sqrt(uint256 a) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
        //
        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
        //
        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
        //
        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
        uint256 result = 1 << (log2(a) >> 1);

        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
        // into the expected uint128 result.
        unchecked {
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            return min(result, a / result);
        }
    }

    /**
     * @notice Calculates sqrt(a), following the selected rounding direction.
     */
    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = sqrt(a);
            return result + (unsignedRoundsUp(rounding) && result * result < a ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 2 of a positive value rounded towards zero.
     * Returns 0 if given 0.
     */
    function log2(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 128;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 64;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 32;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 16;
            }
            if (value >> 8 > 0) {
                value >>= 8;
                result += 8;
            }
            if (value >> 4 > 0) {
                value >>= 4;
                result += 4;
            }
            if (value >> 2 > 0) {
                value >>= 2;
                result += 2;
            }
            if (value >> 1 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log2(value);
            return result + (unsignedRoundsUp(rounding) && 1 << result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 10 of a positive value rounded towards zero.
     * Returns 0 if given 0.
     */
    function log10(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >= 10 ** 64) {
                value /= 10 ** 64;
                result += 64;
            }
            if (value >= 10 ** 32) {
                value /= 10 ** 32;
                result += 32;
            }
            if (value >= 10 ** 16) {
                value /= 10 ** 16;
                result += 16;
            }
            if (value >= 10 ** 8) {
                value /= 10 ** 8;
                result += 8;
            }
            if (value >= 10 ** 4) {
                value /= 10 ** 4;
                result += 4;
            }
            if (value >= 10 ** 2) {
                value /= 10 ** 2;
                result += 2;
            }
            if (value >= 10 ** 1) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log10(value);
            return result + (unsignedRoundsUp(rounding) && 10 ** result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 256 of a positive value rounded towards zero.
     * Returns 0 if given 0.
     *
     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
     */
    function log256(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 16;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 8;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 4;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 2;
            }
            if (value >> 8 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 256, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log256(value);
            return result + (unsignedRoundsUp(rounding) && 1 << (result << 3) < value ? 1 : 0);
        }
    }

    /**
     * @dev Returns whether a provided rounding mode is considered rounding up for unsigned integers.
     */
    function unsignedRoundsUp(Rounding rounding) internal pure returns (bool) {
        return uint8(rounding) % 2 == 1;
    }
}

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity 0.8.21;

import {IChainlinkOracle} from "./interfaces/IChainlinkOracle.sol";
import {IOracle} from "../lib/morpho-blue/src/interfaces/IOracle.sol";

import {AggregatorV3Interface, ChainlinkDataFeedLib} from "./libraries/ChainlinkDataFeedLib.sol";
import {IERC4626, VaultLib} from "./libraries/VaultLib.sol";
import {ErrorsLib} from "./libraries/ErrorsLib.sol";
import {Math} from "../lib/openzeppelin-contracts/contracts/utils/math/Math.sol";

/// @title ChainlinkOracle
/// @author Morpho Labs
/// @custom:contact [email protected]
/// @notice Morpho Blue oracle using Chainlink-compliant feeds.
contract ChainlinkOracle is IChainlinkOracle {
    using Math for uint256;
    using VaultLib for IERC4626;
    using ChainlinkDataFeedLib for AggregatorV3Interface;

    /* IMMUTABLES */

    /// @inheritdoc IChainlinkOracle
    IERC4626 public immutable VAULT;

    /// @inheritdoc IChainlinkOracle
    uint256 public immutable VAULT_CONVERSION_SAMPLE;

    /// @inheritdoc IChainlinkOracle
    AggregatorV3Interface public immutable BASE_FEED_1;

    /// @inheritdoc IChainlinkOracle
    AggregatorV3Interface public immutable BASE_FEED_2;

    /// @inheritdoc IChainlinkOracle
    AggregatorV3Interface public immutable QUOTE_FEED_1;

    /// @inheritdoc IChainlinkOracle
    AggregatorV3Interface public immutable QUOTE_FEED_2;

    /// @inheritdoc IChainlinkOracle
    uint256 public immutable SCALE_FACTOR;

    /* CONSTRUCTOR */

    /// @dev Here is the list of assumptions that guarantees the oracle behaves as expected:
    /// - Feeds are either Chainlink-compliant or the address zero.
    /// - Feeds have the same behavioral assumptions as Chainlink's.
    /// - Feeds are set in the correct order.
    /// - Decimals passed as argument are correct.
    /// - The vault's sample shares quoted as assets and the base feed prices don't overflow when multiplied.
    /// - The quote feed prices don't overflow when multiplied.
    /// - The vault, if set, is ERC4626-compliant.
    /// @param vault Vault. Pass address zero to omit this parameter.
    /// @param baseFeed1 First base feed. Pass address zero if the price = 1.
    /// @param baseFeed2 Second base feed. Pass address zero if the price = 1.
    /// @param quoteFeed1 First quote feed. Pass address zero if the price = 1.
    /// @param quoteFeed2 Second quote feed. Pass address zero if the price = 1.
    /// @param vaultConversionSample The sample amount of vault shares used to convert to the underlying asset.
    /// Pass 1 if the oracle does not use a vault. Should be chosen such that converting `vaultConversionSample` to
    /// assets has enough precision.
    /// @param baseTokenDecimals Base token decimals.
    /// @param quoteTokenDecimals Quote token decimals.
    constructor(
        IERC4626 vault,
        AggregatorV3Interface baseFeed1,
        AggregatorV3Interface baseFeed2,
        AggregatorV3Interface quoteFeed1,
        AggregatorV3Interface quoteFeed2,
        uint256 vaultConversionSample,
        uint256 baseTokenDecimals,
        uint256 quoteTokenDecimals
    ) {
        // The ERC4626 vault parameter is used to price `VAULT_CONVERSION_SAMPLE` of its shares, so it requires dividing
        // by that number, hence the division by `VAULT_CONVERSION_SAMPLE` in the `SCALE_FACTOR` definition.
        // Verify that vault = address(0) => vaultConversionSample = 1.
        require(
            address(vault) != address(0) || vaultConversionSample == 1, ErrorsLib.VAULT_CONVERSION_SAMPLE_IS_NOT_ONE
        );
        require(vaultConversionSample != 0, ErrorsLib.VAULT_CONVERSION_SAMPLE_IS_ZERO);

        VAULT = vault;
        VAULT_CONVERSION_SAMPLE = vaultConversionSample;
        BASE_FEED_1 = baseFeed1;
        BASE_FEED_2 = baseFeed2;
        QUOTE_FEED_1 = quoteFeed1;
        QUOTE_FEED_2 = quoteFeed2;

        // In the following comment, we explain the general case (where we assume that no feed is the address zero)
        // how to scale the output price as Morpho Blue expects, given the input feed prices.
        // Similar explanations would hold in the case where some of the feeds are the address zero.

        // Let B1, B2, Q1, Q2, C be 5 assets, each respectively having dB1, dB2, dQ1, dQ2, dC decimals.
        // Let pB1 and pB2 be the base prices, and pQ1 and pQ2 the quote prices, so that:
        // - pB1 is the quantity of 1e(dB2) assets B2 that can be exchanged for 1e(dB1) assets B1.
        // - pB2 is the quantity of 1e(dC) assets C that can be exchanged for 1e(dB2) assets B2.
        // - pQ1 is the quantity of 1e(dQ2) assets Q2 that can be exchanged for 1e(dQ1) assets Q1.
        // - pQ2 is the quantity of 1e(dC) assets C that can be exchanged for 1e(dQ2) assets B2.

        // Morpho Blue expects `price()` to be the quantity of 1 asset Q1 that can be exchanged for 1 asset B1,
        // scaled by 1e36:
        // 1e36 * (pB1 * 1e(dB2 - dB1)) * (pB2 * 1e(dC - dB2)) / ((pQ1 * 1e(dQ2 - dQ1)) * (pQ2 * 1e(dC - dQ2)))
        // = 1e36 * (pB1 * 1e(-dB1) * pB2) / (pQ1 * 1e(-dQ1) * pQ2)

        // Let fpB1, fpB2, fpQ1, fpQ2 be the feed precision of the respective prices pB1, pB2, pQ1, pQ2.
        // Chainlink feeds return pB1 * 1e(fpB1), pB2 * 1e(fpB2), pQ1 * 1e(fpQ1) and pQ2 * 1e(fpQ2).

        // Based on the implementation of `price()` below, the value of `SCALE_FACTOR` should thus satisfy:
        // (pB1 * 1e(fpB1)) * (pB2 * 1e(fpB2)) * SCALE_FACTOR / ((pQ1 * 1e(fpQ1)) * (pQ2 * 1e(fpQ2)))
        // = 1e36 * (pB1 * 1e(-dB1) * pB2) / (pQ1 * 1e(-dQ1) * pQ2)

        // So SCALE_FACTOR = 1e36 * 1e(-dB1) * 1e(dQ1) * 1e(-fpB1) * 1e(-fpB2) * 1e(fpQ1) * 1e(fpQ2)
        //                 = 1e(36 + dQ1 + fpQ1 + fpQ2 - dB1 - fpB1 - fpB2)
        SCALE_FACTOR = 10
            ** (
                36 + quoteTokenDecimals + quoteFeed1.getDecimals() + quoteFeed2.getDecimals() - baseTokenDecimals
                    - baseFeed1.getDecimals() - baseFeed2.getDecimals()
            ) / vaultConversionSample;
    }

    /* PRICE */

    /// @inheritdoc IOracle
    function price() external view returns (uint256) {
        return SCALE_FACTOR.mulDiv(
            VAULT.getAssets(VAULT_CONVERSION_SAMPLE) * BASE_FEED_1.getPrice() * BASE_FEED_2.getPrice(),
            QUOTE_FEED_1.getPrice() * QUOTE_FEED_2.getPrice()
        );
    }
}

// SPDX-License-Identifier: MIT
pragma solidity >=0.5.0;

/// @dev From
/// https://github.com/smartcontractkit/chainlink/blob/master/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol
interface AggregatorV3Interface {
    function decimals() external view returns (uint8);

    function description() external view returns (string memory);

    function version() external view returns (uint256);

    function getRoundData(uint80 _roundId)
        external
        view
        returns (uint80 roundId, int256 answer, uint256 startedAt, uint256 updatedAt, uint80 answeredInRound);

    function latestRoundData()
        external
        view
        returns (uint80 roundId, int256 answer, uint256 startedAt, uint256 updatedAt, uint80 answeredInRound);
}

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

import {IERC4626} from "./IERC4626.sol";
import {AggregatorV3Interface} from "./AggregatorV3Interface.sol";
import {IOracle} from "../../lib/morpho-blue/src/interfaces/IOracle.sol";

/// @title IChainlinkOracle
/// @author Morpho Labs
/// @custom:contact [email protected]
/// @notice Interface of ChainlinkOracle.
interface IChainlinkOracle is IOracle {
    /// @notice Returns the address of the ERC4626 vault.
    function VAULT() external view returns (IERC4626);

    /// @notice Returns the vault conversion sample.
    function VAULT_CONVERSION_SAMPLE() external view returns (uint256);

    /// @notice Returns the address of the first Chainlink base feed.
    function BASE_FEED_1() external view returns (AggregatorV3Interface);

    /// @notice Returns the address of the second Chainlink base feed.
    function BASE_FEED_2() external view returns (AggregatorV3Interface);

    /// @notice Returns the address of the first Chainlink quote feed.
    function QUOTE_FEED_1() external view returns (AggregatorV3Interface);

    /// @notice Returns the address of the second Chainlink quote feed.
    function QUOTE_FEED_2() external view returns (AggregatorV3Interface);

    /// @notice Returns the price scale factor, calculated at contract creation.
    function SCALE_FACTOR() external view returns (uint256);
}

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

interface IERC4626 {
    function convertToAssets(uint256) external view returns (uint256);
}

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity ^0.8.0;

import {AggregatorV3Interface} from "../interfaces/AggregatorV3Interface.sol";

import {ErrorsLib} from "./ErrorsLib.sol";

/// @title ChainlinkDataFeedLib
/// @author Morpho Labs
/// @custom:contact [email protected]
/// @notice Library exposing functions to interact with a Chainlink-compliant feed.
library ChainlinkDataFeedLib {
    /// @dev Performs safety checks and returns the latest price of a `feed`.
    /// @dev When `feed` is the address zero, returns 1.
    /// @dev Notes on safety checks:
    /// - L2s are not supported.
    /// - Staleness is not checked because it's assumed that the Chainlink feed keeps its promises on this.
    /// - The price is not checked to be in the min/max bounds because it's assumed that the Chainlink feed keeps its
    /// promises on this.
    function getPrice(AggregatorV3Interface feed) internal view returns (uint256) {
        if (address(feed) == address(0)) return 1;

        (, int256 answer,,,) = feed.latestRoundData();
        require(answer >= 0, ErrorsLib.NEGATIVE_ANSWER);

        return uint256(answer);
    }

    /// @dev Returns the number of decimals of a `feed`.
    /// @dev When `feed` is the address zero, returns 0.
    function getDecimals(AggregatorV3Interface feed) internal view returns (uint256) {
        if (address(feed) == address(0)) return 0;

        return feed.decimals();
    }
}

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity ^0.8.0;

/// @title ErrorsLib
/// @author Morpho Labs
/// @custom:contact [email protected]
/// @notice Library exposing error messages.
library ErrorsLib {
    /// @notice Thrown when the answer returned by a Chainlink feed is negative.
    string constant NEGATIVE_ANSWER = "negative answer";

    /// @notice Thrown when the vault conversion sample is 0.
    string constant VAULT_CONVERSION_SAMPLE_IS_ZERO = "vault conversion sample is zero";

    /// @notice Thrown when the vault conversion sample is not 1 while vault = address(0).
    string constant VAULT_CONVERSION_SAMPLE_IS_NOT_ONE = "vault conversion sample is not one";
}

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity ^0.8.0;

import {IERC4626} from "../interfaces/IERC4626.sol";

/// @title VaultLib
/// @author Morpho Labs
/// @custom:contact [email protected]
/// @notice Library exposing functions to price shares of an ERC4626 vault.
library VaultLib {
    /// @dev Converts `shares` into the corresponding assets on the `vault`.
    /// @dev When `vault` is the address zero, returns 1.
    function getAssets(IERC4626 vault, uint256 shares) internal view returns (uint256) {
        if (address(vault) == address(0)) return 1;

        return vault.convertToAssets(shares);
    }
}