import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:supabase_flutter/supabase_flutter.dart';

import '../../providers/auth_provider.dart';
import '../../features/authentication/presentation/pages/login_page.dart';
import '../../features/authentication/presentation/pages/signup_page.dart';
import '../../features/home/presentation/pages/home_page.dart';
import '../../features/authentication/presentation/pages/splash_page.dart';

/// Application router configuration
/// 
/// Handles navigation with authentication state awareness and protected routes
class AppRouter {
  static GoRouter _router({required WidgetRef ref}) {
    return GoRouter(
      initialLocation: '/',
      debugLogDiagnostics: true,
      redirect: (context, state) {
        // For now, use Supabase directly for auth state checking
        // This will be improved when auth provider integration is complete
        final currentUser = Supabase.instance.client.auth.currentUser;
        
        // Allow splash page regardless of auth state
        if (state.location == '/splash') {
          return null;
        }
        
        // If not authenticated and trying to access protected route, redirect to login
        if (currentUser == null && !state.location.startsWith('/login') && !state.location.startsWith('/signup')) {
          return '/login';
        }
        
        // If authenticated and on auth pages, redirect to home
        if (currentUser != null && (state.location.startsWith('/login') || state.location.startsWith('/signup'))) {
          return '/home';
        }
        
        return null;
      },
    routes: [
      // Splash route - initial loading screen
      GoRoute(
        path: '/splash',
        builder: (context, state) => const SplashPage(),
      ),
      
      // Authentication routes (public)
      GoRoute(
        path: '/login',
        builder: (context, state) => const LoginPage(),
      ),
      
      GoRoute(
        path: '/signup',
        builder: (context, state) => const SignupPage(),
      ),
      
      // Protected routes (require authentication)
      GoRoute(
        path: '/home',
        builder: (context, state) => const HomePage(),
      ),
      
      // Root route - redirects based on auth state
      GoRoute(
        path: '/',
        redirect: (context, state) {
          final currentUser = Supabase.instance.client.auth.currentUser;
          return currentUser != null ? '/home' : '/splash';
        },
      ),
      
      // Additional routes will be added here
      // Example:
      // GoRoute(
      //   path: '/inventory',
      //   builder: (context, state) => const InventoryPage(),
      // ),
    ],
    errorBuilder: (context, state) => Scaffold(
      appBar: AppBar(
        title: const Text('Error'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Icon(
              Icons.error_outline,
              size: 64,
              color: Colors.red,
            ),
            const SizedBox(height: 16),
            Text(
              'Page not found',
              style: Theme.of(context).textTheme.headlineSmall,
            ),
            const SizedBox(height: 8),
            Text(
              'Could not find: ${state.location}',
              style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                color: Colors.grey[600],
              ),
            ),
            const SizedBox(height: 24),
            ElevatedButton(
              onPressed: () {
                // Navigate to home or login based on auth state
                final currentUser = Supabase.instance.client.auth.currentUser;
                if (currentUser != null) {
                  context.go('/home');
                } else {
                  context.go('/login');
                }
              },
              child: const Text('Go Home'),
            ),
          ],
        ),
      ),
    ),
  );

  /// Get the router instance
  static GoRouter router({required WidgetRef ref}) => _router(ref: ref);
}

/// Router provider for Riverpod integration
final routerProvider = Provider<GoRouter>((ref) {
  return AppRouter.router(ref: ref);
});