// File: contracts/oracle/PriceOracleAggregator.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {UUPSProxiable} from "../upgradability/UUPSProxiable.sol";
import "../interfaces/IPriceOracleAggregator.sol";
import "../interfaces/IOracle.sol";

////////////////////////////////////////////////////////////////////////////////////////////
/// @title PriceOracleAggregator
/// @author @samparsky
/// @notice aggregator of price oracle for assets in LendingPairs
////////////////////////////////////////////////////////////////////////////////////////////

contract PriceOracleAggregator is IPriceOracleAggregator {
    /// STATE VARIABLES ////

    /// @dev admin allowed to update price oracle
    address public owner;

    /// @dev new owner
    address internal newOwner;

    /// @notice token to the oracle address
    mapping(IERC20 => IOracle) public assetToOracle;

    /// @notice stable to is stable status
    mapping(IERC20 => bool) public stableTokens;

    modifier onlyOwner() {
        require(msg.sender == owner, "ONLY_OWNER");
        _;
    }

    constructor(address _owner) {
        require(_owner != address(0), "INVALID_OWNER");
        owner = _owner;
    }

    /// @notice adds oracle for an asset e.g. ETH
    /// @param _asset the oracle for the asset
    /// @param _oracle the oracle address
    function setOracleForAsset(IERC20[] calldata _asset, IOracle[] calldata _oracle)
        external
        override
        onlyOwner
    {
        require(_asset.length == _oracle.length, "INV");
        uint256 size = _asset.length;

        for (uint256 i = 0; i < size; i++) {
            IOracle oracle = _oracle[i];
            require(address(oracle) != address(0), "INVALID_ORACLE");
            assetToOracle[_asset[i]] = oracle;
            emit UpdateOracle(_asset[i], oracle);
        }
    }

    /// @notice remove oracle
    function removeOracleForAsset(IERC20 _asset) external onlyOwner {
        assetToOracle[_asset] = IOracle(address(0));
        emit UpdateOracle(_asset, IOracle(address(0)));
    }

    /// @notice addStable use to add stablecoin asset that should be hardcoded
    function addStable(IERC20[] calldata _tokens) public onlyOwner {
        uint256 size = _tokens.length;
        for (uint256 i = 0; i < size; i++) {
            stableTokens[_tokens[i]] = true;
            emit StableTokenAdded(_tokens[i], block.timestamp);
        }
    }

    /// @notice returns price of token in USD in 1e8 decimals
    /// @param _token token to fetch price
    function getPriceInUSD(IERC20 _token) public view override returns (uint256 price) {
        IOracle oracle = assetToOracle[_token];

        if (address(oracle) != address(0)) {
            price = uint256(assetToOracle[_token].latestAnswer());
        } else if (stableTokens[_token] == true) {
            price = 1e8;
        }

        require(price > 0, "INVALID_PRICE");
    }

    function getPriceInUSDMultiple(IERC20[] calldata _tokens)
        external
        view
        override
        returns (uint256[] memory prices)
    {
        uint256 size = _tokens.length;
        for (uint256 i = 0; i < size; i++) {
            prices[i] = getPriceInUSD(_tokens[i]);
        }
    }

    /// @notice accept transfer of control
    function acceptOwnership() external {
        require(msg.sender == newOwner, "invalid owner");

        // emit event before state change to do not trigger null address
        emit OwnershipAccepted(owner, newOwner, block.timestamp);

        owner = newOwner;
        newOwner = address(0);
    }

    /// @notice Transfer control from current owner address to another
    /// @param _newOwner The new team
    function transferOwnership(address _newOwner) external onlyOwner {
        require(_newOwner != address(0), "INVALID_NEW_OWNER");
        newOwner = _newOwner;
        emit TransferControl(_newOwner, block.timestamp);
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: contracts/upgradability/UUPSProxiable.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;

import {UUPSUtils} from "./UUPSUtils.sol";
import {Initializable} from "@openzeppelin/contracts/proxy/utils/Initializable.sol";

/**
 * @dev UUPS (Universal Upgradeable Proxy Standard) Proxiable contract.
 */
abstract contract UUPSProxiable is Initializable {
    /**
     * @dev Get current implementation code address.
     */
    function getCodeAddress() public view returns (address codeAddress) {
        return UUPSUtils.implementation();
    }

    function updateCode(address newAddress) external virtual;

    /**
     * @dev Proxiable UUID marker function.
     *      This would help to avoid wrong logic contract to be used for upgrading.
     */
    function proxiableUUID() public view virtual returns (bytes32);

    /**
     * @dev Update code address function.
     *      It is internal, so the derived contract could setup its own permission logic.
     */
    function _updateCodeAddress(address newAddress) internal {
        require(UUPSUtils.implementation() != address(0), "UUPSProxiable: not upgradable");
        require(
            proxiableUUID() == UUPSProxiable(newAddress).proxiableUUID(),
            "UUPSProxiable: not compatible logic"
        );
        UUPSUtils.setImplementation(newAddress);
        emit CodeUpdated(proxiableUUID(), newAddress);
    }

    event CodeUpdated(bytes32 uuid, address codeAddress);
}

// File: contracts/interfaces/IPriceOracleAggregator.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "./IOracle.sol";

interface IPriceOracleAggregator {
    event UpdateOracle(IERC20 token, IOracle oracle);

    function getPriceInUSD(IERC20 _token) external view returns (uint256);

    function getPriceInUSDMultiple(IERC20[] calldata _tokens)
        external
        view
        returns (uint256[] memory);

    function setOracleForAsset(IERC20[] calldata _asset, IOracle[] calldata _oracle) external;

    event OwnershipAccepted(address prevOwner, address newOwner, uint256 timestamp);
    event TransferControl(address _newTeam, uint256 timestamp);
    event StableTokenAdded(IERC20 _token, uint256 timestamp);
}

// File: contracts/interfaces/IOracle.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;

interface IOracle {
    /// @notice Price update event
    /// @param asset the asset
    /// @param newPrice price of the asset
    event PriceUpdated(address asset, uint256 newPrice);

    /// @dev returns latest answer
    function latestAnswer() external view returns (int256);
}

// File: contracts/upgradability/UUPSUtils.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;

/**
 * @title UUPS (Universal Upgradeable Proxy Standard) Shared Library
 */
library UUPSUtils {
    /**
     * @dev Implementation slot constant.
     * Using https://eips.ethereum.org/EIPS/eip-1967 standard
     * Storage slot 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc
     * (obtained as bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1)).
     */
    bytes32 internal constant _IMPLEMENTATION_SLOT =
        0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;

    /// @dev Get implementation address.
    function implementation() internal view returns (address impl) {
        assembly {
            // solium-disable-line
            impl := sload(_IMPLEMENTATION_SLOT)
        }
    }

    /// @dev Set new implementation address.
    function setImplementation(address codeAddress) internal {
        assembly {
            // solium-disable-line
            sstore(_IMPLEMENTATION_SLOT, codeAddress)
        }
    }
}

// File: @openzeppelin/contracts/proxy/utils/Initializable.sol



// SPDX-License-Identifier: MIT

// solhint-disable-next-line compiler-version
pragma solidity ^0.8.0;

import "../../utils/Address.sol";

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {UpgradeableProxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 */
abstract contract Initializable {

    /**
     * @dev Indicates that the contract has been initialized.
     */
    bool private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Modifier to protect an initializer function from being invoked twice.
     */
    modifier initializer() {
        require(_initializing || !_initialized, "Initializable: contract is already initialized");

        bool isTopLevelCall = !_initializing;
        if (isTopLevelCall) {
            _initializing = true;
            _initialized = true;
        }

        _;

        if (isTopLevelCall) {
            _initializing = false;
        }
    }
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}