import * as LocalAuthentication from "expo-local-authentication";

async function checkBiometrics() {
  // Check if hardware supports biometrics
  const compatible = await LocalAuthentication.hasHardwareAsync();
  if (!compatible) return false;

  // Check if user has enrolled biometrics (face/fingerprint registered)
  const enrolled = await LocalAuthentication.isEnrolledAsync();
  if (!enrolled) return false;

  return true;
}

const types = await LocalAuthentication.supportedAuthenticationTypesAsync();
// Returns: [1] for fingerprint, [2] for facial recognition, or both

async function authenticateWithBiometrics() {
  const result = await LocalAuthentication.authenticateAsync({
    promptMessage: "Authenticate to continue",
    fallbackLabel: "Use passcode",
    cancelLabel: "Cancel",
    disableDeviceFallback: false, // Allow passcode as fallback
  });

  if (result.success) {
    // User authenticated successfully
    return true;
  } else {
    // Authentication failed or was cancelled
    console.log(result.error);
    return false;
  }
}

import { useEffect, useRef } from "react";
import { AppState } from "react-native";

function useBiometricLock() {
  const appState = useRef(AppState.currentState);
  const [isLocked, setIsLocked] = useState(false);

  useEffect(() => {
    const subscription = AppState.addEventListener("change", (nextState) => {
      if (
        appState.current.match(/inactive|background/) &&
        nextState === "active"
      ) {
        setIsLocked(true);
        authenticateWithBiometrics().then((success) => {
          if (success) setIsLocked(false);
        });
      }
      appState.current = nextState;
    });

    return () => subscription.remove();
  }, []);

  return isLocked;
}

{
  "expo": {
    "ios": {
      "infoPlist": {
        "NSFaceIDUsageDescription": "We use Face ID to secure your account"
      }
    }
  }
}