// SPDX-License-Identifier: MIT
// Gearbox Protocol. Generalized leverage for DeFi protocols
// (c) Gearbox Holdings, 2022
pragma solidity ^0.8.10;
import { IVersion } from "./IVersion.sol";

interface IPriceOracleV2Events {
    /// @dev Emits when a new price feed is added
    event NewPriceFeed(address indexed token, address indexed priceFeed);
}

interface IPriceOracleV2Exceptions {
    /// @dev Thrown if a price feed returns 0
    error ZeroPriceException();

    /// @dev Thrown if the last recorded result was not updated in the last round
    error ChainPriceStaleException();

    /// @dev Thrown on attempting to get a result for a token that does not have a price feed
    error PriceOracleNotExistsException();
}

/// @title Price oracle interface
interface IPriceOracleV2 is
    IPriceOracleV2Events,
    IPriceOracleV2Exceptions,
    IVersion
{
    /// @dev Converts a quantity of an asset to USD (decimals = 8).
    /// @param amount Amount to convert
    /// @param token Address of the token to be converted
    function convertToUSD(uint256 amount, address token)
        external
        view
        returns (uint256);

    /// @dev Converts a quantity of USD (decimals = 8) to an equivalent amount of an asset
    /// @param amount Amount to convert
    /// @param token Address of the token converted to
    function convertFromUSD(uint256 amount, address token)
        external
        view
        returns (uint256);

    /// @dev Converts one asset into another
    ///
    /// @param amount Amount to convert
    /// @param tokenFrom Address of the token to convert from
    /// @param tokenTo Address of the token to convert to
    function convert(
        uint256 amount,
        address tokenFrom,
        address tokenTo
    ) external view returns (uint256);

    /// @dev Returns collateral values for two tokens, required for a fast check
    /// @param amountFrom Amount of the outbound token
    /// @param tokenFrom Address of the outbound token
    /// @param amountTo Amount of the inbound token
    /// @param tokenTo Address of the inbound token
    /// @return collateralFrom Value of the outbound token amount in USD
    /// @return collateralTo Value of the inbound token amount in USD
    function fastCheck(
        uint256 amountFrom,
        address tokenFrom,
        uint256 amountTo,
        address tokenTo
    ) external view returns (uint256 collateralFrom, uint256 collateralTo);

    /// @dev Returns token's price in USD (8 decimals)
    /// @param token The token to compute the price for
    function getPrice(address token) external view returns (uint256);

    /// @dev Returns the price feed address for the passed token
    /// @param token Token to get the price feed for
    function priceFeeds(address token)
        external
        view
        returns (address priceFeed);

    /// @dev Returns the price feed for the passed token,
    ///      with additional parameters
    /// @param token Token to get the price feed for
    function priceFeedsWithFlags(address token)
        external
        view
        returns (
            address priceFeed,
            bool skipCheck,
            uint256 decimals
        );
}

interface IPriceOracleV2Ext is IPriceOracleV2 {
    /// @dev Sets a price feed if it doesn't exist, or updates an existing one
    /// @param token Address of the token to set the price feed for
    /// @param priceFeed Address of a USD price feed adhering to Chainlink's interface
    function addPriceFeed(address token, address priceFeed) external;
}