App.js

import React, { useEffect, useState } from 'react';
import { NavigationContainer } from '@react-navigation/native';
import { createStackNavigator } from '@react-navigation/stack';
import firebase from './firebaseConfig';
import WelcomeScreen from './WelcomeScreen';
import AuthScreen from './AuthScreen';
import HomeScreen from './HomeScreen';
import RainfallPredictionScreen from './RainfallPredictionScreen';
import YieldPredictionScreen from './YieldPredictionScreen';
import CropRecommendationScreen from './CropRecommendationScreen';
import PlantDiseasePredictionScreen from './PlantDiseasePredictionScreen';

const Stack = createStackNavigator();

const MainAppScreen = () => (
  <Stack.Navigator initialRouteName="Home">
    <Stack.Screen name="Home" component={HomeScreen} options={{ headerShown: false }} />
    <Stack.Screen name="RainfallPrediction" component={RainfallPredictionScreen} options={{ headerShown: false }} />
    <Stack.Screen name="YieldPrediction" component={YieldPredictionScreen} options={{ headerShown: false }} />
    <Stack.Screen name="CropRecommendation" component={CropRecommendationScreen} options={{ headerShown: false }} />
    <Stack.Screen name="PlantDiseasePrediction" component={PlantDiseasePredictionScreen} options={{ headerShown: false }} />
  </Stack.Navigator>
);

const App = () => {
  const [user, setUser] = useState(null);

  useEffect(() => {
    const unsubscribe = firebase.auth().onAuthStateChanged((user) => {
      setUser(user);
    });
    return unsubscribe; // Cleanup subscription on unmount
  }, []);

  return (
    <NavigationContainer>
      <Stack.Navigator screenOptions={{ headerShown: false }}>
        {user ? (
          <Stack.Screen name="MainApp" component={MainAppScreen} />
        ) : (
          <>
            <Stack.Screen name="Welcome" component={WelcomeScreen} />
            <Stack.Screen name="Auth" component={AuthScreen} />
          </>
        )}
      </Stack.Navigator>
    </NavigationContainer>
  );
};

export default App;