🔗 CHAINLINK ORACLES: Datos del Mundo Real en Blockchain

Health Factor en Tiempo Real

Solidity ” Chainlink Price Feed + HF

import "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";

contract LendingWithOracle {
  AggregatorV3Interface immutable ethPriceFeed;
  uint256 constant LIQUIDATION_THRESHOLD = 80; // 80%
  uint256 constant STALENESS_THRESHOLD  = 3600; // 1 hora

  function getEthPrice() public view returns (uint256) {
    (
      ,          // roundId
      int256 price,    // precio con 8 decimales
      ,          // startedAt
      uint256 updatedAt,  // timestamp crítico
    ) = ethPriceFeed.latestRoundData();

    // CRÍTICO: verificar que el precio no sea stale
    require(
      block.timestamp - updatedAt < STALENESS_THRESHOLD,
      "Oracle: stale price"
    );
    require(price > 0, "Oracle: invalid price");
    return uint256(price) / 1e8; // normalizar a USD
  }

  function healthFactor(address user) public view
    returns (uint256) {
    uint256 collateralUSD =
      positions[user].ethAmount * getEthPrice();
    uint256 maxBorrow =
      collateralUSD * LIQUIDATION_THRESHOLD / 100;
    // HF = colateral ajustado / deuda (× 1e18 para precision)
    return maxBorrow * 1e18 / positions[user].debtUSD;
  }
}