import React, { useEffect } from 'react';
import { Stack, useRouter, useSegments } from 'expo-router';
import { StatusBar } from 'expo-status-bar';
import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
import { useColorScheme } from 'react-native';
import { Colors } from '../constants/Colors';
import { useAuthStore, setupAuthListener } from '../stores/authStore';
import { LoadingScreen } from '../components/LoadingScreen';

// Create a client
const queryClient = new QueryClient({
  defaultOptions: {
    queries: {
      staleTime: 5000, // Data is fresh for 5 seconds
      retry: 2, // Retry failed requests twice
      refetchOnWindowFocus: false, // Don't refetch on app focus (mobile)
    },
    mutations: {
      retry: 1,
    },
  },
});

/**
 * Auth state handler component
 * Redirects users based on authentication status
 */
function AuthStateHandler({ children }: { children: React.ReactNode }) {
  const router = useRouter();
  const segments = useSegments();
  const session = useAuthStore((state) => state.session);
  const isInitialized = useAuthStore((state) => state.isInitialized);
  const initialize = useAuthStore((state) => state.initialize);

  // Initialize auth state on mount
  useEffect(() => {
    initialize();
  }, [initialize]);

  // Setup auth listener on mount
  useEffect(() => {
    const unsubscribe = setupAuthListener();
    return unsubscribe;
  }, []);

  // Handle auth-based routing
  useEffect(() => {
    if (!isInitialized) return;

    const inAuthGroup = segments[0] === '(auth)';
    const isAuthenticated = session !== null;

    if (!isAuthenticated && !inAuthGroup) {
      // Redirect to login if not authenticated and not already on auth screens
      router.replace('/(auth)/login');
    } else if (isAuthenticated && inAuthGroup) {
      // Redirect to main app if authenticated and on auth screens
      router.replace('/(tabs)');
    }
  }, [session, segments, isInitialized, router]);

  // Show loading screen while initializing
  if (!isInitialized) {
    return <LoadingScreen message="Checking authentication..." />;
  }

  return <>{children}</>;
}

export default function RootLayout() {
  const colorScheme = useColorScheme() ?? 'light';
  const colors = Colors[colorScheme];

  return (
    <QueryClientProvider client={queryClient}>
      <StatusBar style={colorScheme === 'dark' ? 'light' : 'dark'} />
      <AuthStateHandler>
        <Stack
          screenOptions={{
            headerStyle: {
              backgroundColor: colors.background,
            },
            headerTintColor: colors.text,
            headerTitleStyle: {
              fontWeight: '600',
            },
            contentStyle: {
              backgroundColor: colors.background,
            },
          }}
        >
          <Stack.Screen
            name="(auth)"
            options={{ headerShown: false }}
          />
          <Stack.Screen
            name="(tabs)"
            options={{ headerShown: false }}
          />
          <Stack.Screen
            name="task/[id]"
            options={{
              presentation: 'card',
              headerBackTitle: 'Back',
            }}
          />
        </Stack>
      </AuthStateHandler>
    </QueryClientProvider>
  );
}