gistfile1.txt

// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;

import "@api3/contracts/v0.8/interfaces/IProxy.sol";

contract Api3AggregatorAdaptor {  

   // Updating the proxy address is a security-critical action which is why
   // we have made it immutable.
   address public immutable ethToUsdProxy;
   address public immutable methToEthProxy;

   constructor(address _ethToUsdProxy,address _methToEthProxy) {
       ethToUsdProxy = _ethToUsdProxy;
       methToEthProxy = _methToEthProxy;
   }

   function latestAnswer() external view returns (int256 value) {
       (value, ) = readDataFeed();
   }

   function latestTimestamp() external view returns (uint256 timestamp) {
       ( , timestamp) = readDataFeed();
   }
   
   function decimals() external view returns (uint8) {
       return 18;
   }

   function readDataFeed()
       internal
       view
       returns (int224 value, uint256 timestamp)
   {
       (int224 ethValueInUsd, uint256 ethToUsdTimestamp) = IProxy(ethToUsdProxy).read();
       (int224 methValueInEth, uint256 methToEthTimestamp) = IProxy(methToEthProxy).read();
       value = methValueInEth * ethValueInUsd / (10 ** 18);
       // use oldest timestamp
       timestamp = ethToUsdTimestamp > methToEthTimestamp ? methToEthTimestamp : ethToUsdTimestamp;
   }       

   function getTokenType() external pure returns (uint256) {
       return 1;
   }    
}