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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^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 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) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: contracts/common/ChainLinkPriceFeed.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/utils/Context.sol";
import "./IPriceFeed.sol";
import "./Ownable.sol";

contract ChainLinkPriceFeed is IPriceFeed, Context, Ownable {

    mapping(address => IChainLinkPriceProvider) _priceProxy;

    function setProvider(address[] calldata assets, IChainLinkPriceProvider[] calldata providers) external onlyOwner {
        require(assets.length == providers.length, 'Assets and providers are mismatched');
        for (uint i = 0; i < assets.length; i++) 
            _priceProxy[assets[i]] = providers[i];
    }

    function proxyOf(address asset) external view returns(IChainLinkPriceProvider) {
        return _priceProxy[asset];
    }

    function getAssetPrice(address asset) external override view returns(uint) {
        IChainLinkPriceProvider provider = _priceProxy[asset];
        if (address(provider) != address(0))
            return provider.latestAnswer();
        return 0;
    }

}
// File: contracts/common/IPriceFeed.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
@dev The interface for the price feed consumed by PriceOracle.
 */
interface IPriceFeed {
    
    /**
    @dev Query the latest price of the specified asset.
     */
    function getAssetPrice(address asset) external view returns(uint);
}

interface IChainLinkPriceProvider {
    function latestAnswer() external view returns(uint256);
}
// File: contracts/common/Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/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.
 */
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 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 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 onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0), 'Ownable: new owner is the zero address');
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}