// File: contracts/price-oracle/ChainlinkPriceOracle.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.7.6;

import "@openzeppelin/contracts/access/Ownable.sol";

import "./interfaces/AggregatorV3Interface.sol";
import "./interfaces/IPriceOracle.sol";

contract ChainlinkPriceOracle is Ownable, IPriceOracle {
  /***********
   * Structs *
   ***********/

  struct FeedInfo {
    // The address of chainlink price feed.
    address feed;
    // The decimal used by the feed.
    uint8 decimal;
  }

  /*************
   * Variables *
   *************/

  /// @notice Mapping from token address to chainlink feed information.
  mapping(address => FeedInfo) public feeds;

  /*************************
   * Public View Functions *
   *************************/

  /// @inheritdoc IPriceOracle
  function price(address _token) external view override returns (uint256) {
    FeedInfo memory _info = feeds[_token];
    require(_info.feed != address(0), "token not registered");

    (, int256 _answer, , , ) = AggregatorV3Interface(_info.feed).latestRoundData();
    if (_answer <= 0) return 0;
    if (_info.decimal < 18) _answer *= int256(10)**(18 - _info.decimal);
    else _answer /= int256(10)**(_info.decimal - 18);

    return uint256(_answer);
  }

  /*******************************
   * Public Restricted Functions *
   *******************************/

  /// @notice Set the chainlink price feeds.
  /// @param _tokens The address list of tokens to set.
  /// @param _feeds The corresponding address list of feeds.
  function setFeeds(address[] memory _tokens, address[] memory _feeds) external onlyOwner {
    require(_tokens.length == _feeds.length, "length mismatch");
    for (uint256 i = 0; i < _tokens.length; i++) {
      uint8 _decimal = AggregatorV3Interface(_feeds[i]).decimals();
      feeds[_tokens[i]] = FeedInfo(_feeds[i], _decimal);
    }
  }
}

// File: contracts/price-oracle/interfaces/IPriceOracle.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.7.6;

interface IPriceOracle {
  /*************************
   * Public View Functions *
   *************************/

  /// @notice Return the price in USD of `token`, with precision 1e18.
  /// @param token The address of token to query.
  function price(address token) external view returns (uint256);
}

// File: contracts/price-oracle/interfaces/AggregatorV3Interface.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.7.6;

interface AggregatorV3Interface {
  function decimals() external view returns (uint8);

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

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.7.0;

import "../utils/Context.sol";
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

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

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

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

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

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



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}