// lib/presentation/pages/offers_page.dart

import 'dart:async';
import 'dart:math' as math; // برای محاسبات ریاضی
import 'package:animations/animations.dart';
import 'package:collection/collection.dart';
import 'package:connectivity_plus/connectivity_plus.dart';
import 'package:dio/dio.dart';
import 'package:flutter/material.dart';
import 'package:flutter_animate/flutter_animate.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:flutter_background_service/flutter_background_service.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'package:flutter_svg/svg.dart';
import 'package:geolocator/geolocator.dart';
import 'package:proxibuy/core/config/api_config.dart';
import 'package:proxibuy/core/config/app_colors.dart';
import 'package:proxibuy/core/gen/assets.gen.dart';
import 'package:proxibuy/data/models/offer_model.dart';
import 'package:proxibuy/presentation/notification_preferences/bloc/notification_preferences_bloc.dart';
import 'package:proxibuy/presentation/notification_preferences/bloc/notification_preferences_event.dart';
import 'package:proxibuy/presentation/offer/bloc/offer_bloc.dart';
import 'package:proxibuy/presentation/offer/bloc/offer_event.dart';
import 'package:proxibuy/presentation/offer/bloc/offer_state.dart';
import 'package:proxibuy/presentation/offer/bloc/widgets/category_offers_row.dart';
import 'package:proxibuy/presentation/pages/notification_preferences_page.dart';
import 'package:proxibuy/presentation/pages/reserved_list_page.dart';
import 'package:proxibuy/presentation/reservation/cubit/reservation_cubit.dart';
import 'package:proxibuy/presentation/widgets/gps_dialog.dart';
import 'package:proxibuy/presentation/widgets/notification_panel.dart';
import 'package:proxibuy/presentation/widgets/notification_permission_dialog.dart';
import 'package:proxibuy/services/mqtt_service.dart';
import 'package:shared_preferences/shared_preferences.dart';

class OffersPage extends StatefulWidget {
  final bool showDialogsOnLoad;

  const OffersPage({super.key, this.showDialogsOnLoad = false});

  @override
  State<OffersPage> createState() => _OffersPageState();
}

class _OffersPageState extends State<OffersPage> with SingleTickerProviderStateMixin {
  List<String> _selectedCategories = [];
  StreamSubscription? _locationServiceSubscription;
  StreamSubscription? _connectivitySubscription;
  bool _isGpsEnabled = false;
  bool _isConnectedToInternet = true;
  bool _isSearchingRandomly = false;

  bool _showNotificationPanel = false;
  final GlobalKey _notificationIconKey = GlobalKey();
  late AnimationController _animationController;
  late Animation<double> _animation;
  int _notificationCount = 0;

  @override
  void initState() {
    super.initState();

    _animationController = AnimationController(
      vsync: this,
      duration: const Duration(milliseconds: 400),
    );

    _checkInitialConnectivity();
    _initializePage();
    _initConnectivityListener();
    _fetchInitialReservations();
    _fetchNotificationCount();
  }

  @override
  void dispose() {
    _locationServiceSubscription?.cancel();
    _connectivitySubscription?.cancel();
    _animationController.dispose();
    super.dispose();
  }

  void _toggleNotificationPanel() {
    setState(() {
      _showNotificationPanel = !_showNotificationPanel;
      if (_showNotificationPanel) {
        _animationController.forward();
      } else {
        _animationController.reverse();
        _fetchNotificationCount();
      }
    });
  }
    
  Future<void> _handleRandomSearch() async {
    setState(() => _isSearchingRandomly = true);

    const storage = FlutterSecureStorage();
    final mqttService = context.read<MqttService>();
    final userID = await storage.read(key: 'userID');

    if (!mounted) return;

    if (userID == null) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('برای این کار باید وارد حساب کاربری خود شوید.')),
      );
      setState(() => _isSearchingRandomly = false);
      return;
    }

    if (!mqttService.isConnected) {
      final token = await storage.read(key: 'accessToken');
      if (token != null) {
        await mqttService.connect(token);
      } else {
        setState(() => _isSearchingRandomly = false);
        return;
      }
    }
    
    final randomTopic = 'user-proxybuy-random/$userID';
    mqttService.subscribe(randomTopic);
    mqttService.publish('proxybuy-random', {'userID': userID});
    
    Future.delayed(const Duration(seconds: 2), () {
      if (mounted) {
        setState(() => _isSearchingRandomly = false);
      }
    });
  }

  Future<void> _checkInitialConnectivity() async {
    final connectivityResult = await Connectivity().checkConnectivity();
    if (!mounted) return;
    setState(() {
      _isConnectedToInternet = !connectivityResult.contains(ConnectivityResult.none);
    });
  }

  Future<void> _initializePage() async {
    if (widget.showDialogsOnLoad) {
      WidgetsBinding.instance.addPostFrameCallback((_) async {
        if (mounted) {
          await showNotificationPermissionDialog(context);
          await showGPSDialog(context);
        }
      });
    }
    await _loadPreferences();
    _initLocationListener();
    _listenToBackgroundService();
  }

  void _listenToBackgroundService() {
    FlutterBackgroundService().on('update').listen((event) {
      if (event == null || event['offers'] == null) return;
      final data = event['offers']['data'];
      if (data == null || data is! List) {
        if (mounted) {
          context.read<OffersBloc>().add(const OffersReceivedFromMqtt([]));
        }
        return;
      }
      try {
        List<OfferModel> offers = data.whereType<Map<String, dynamic>>().map((json) => OfferModel.fromJson(json)).toList();
        if (mounted) {
          context.read<OffersBloc>().add(OffersReceivedFromMqtt(offers));
        }
      } catch (e, stackTrace) {
        debugPrint("❌ Error parsing offers from Background Service: $e");
        debugPrint(stackTrace.toString());
      }
    });
  }

  void _initConnectivityListener() {
    _connectivitySubscription = Connectivity().onConnectivityChanged.listen((results) {
      final hasConnection = !results.contains(ConnectivityResult.none);
      if (mounted && _isConnectedToInternet != hasConnection) {
        setState(() => _isConnectedToInternet = hasConnection);
        if (hasConnection) {
          ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('اتصال به اینترنت برقرار شد.'), backgroundColor: Colors.green));
          _fetchNotificationCount(); 
        } else {
          context.read<OffersBloc>().add(ClearOffers());
          setState(() => _notificationCount = 0); 
          ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('اتصال به اینترنت قطع شد.'), backgroundColor: Colors.red));
        }
      }
    });
  }

  Future<void> _fetchInitialReservations() async {
    if (!_isConnectedToInternet) return;
    try {
      const storage = FlutterSecureStorage();
      final token = await storage.read(key: 'accessToken');
      if (token == null) return;
      final dio = Dio();
      final response = await dio.get(ApiConfig.baseUrl + ApiConfig.getReservations, options: Options(headers: {'Authorization': 'Bearer $token'}));
      if (response.statusCode == 200 && mounted) {
        final List<dynamic> reserves = response.data['reserves'];
        final List<String> reservedIds = reserves.map((reserveData) => (reserveData['Discount']['ID'] as String?) ?? '').where((id) => id.isNotEmpty).toList();
        context.read<ReservationCubit>().setReservedIds(reservedIds);
      }
    } catch (e) {
      debugPrint("Error fetching initial reservations: $e");
    }
  }

  Future<void> _fetchNotificationCount() async {
    if (!_isConnectedToInternet) return;
    try {
      const storage = FlutterSecureStorage();
      final token = await storage.read(key: 'accessToken');
      if (token == null) return;
      
      final dio = Dio();
      final response = await dio.get(
        '${ApiConfig.baseUrl}/notify/get',
        options: Options(headers: {'Authorization': 'Bearer $token'}),
      );

      if (response.statusCode == 200 && mounted) {
        final List<dynamic> data = response.data['data'];
        setState(() {
          _notificationCount = data.length;
        });
      }
    } catch (e) {
      debugPrint("Error fetching notification count: $e");
    }
  }

  void _initLocationListener() {
    _checkInitialGpsStatus();
    _locationServiceSubscription = Geolocator.getServiceStatusStream().listen((status) {
      final isEnabled = status == ServiceStatus.enabled;
      if (mounted && _isGpsEnabled != isEnabled) {
        setState(() => _isGpsEnabled = isEnabled);
        if (!isEnabled) context.read<OffersBloc>().add(ClearOffers());
      }
    });
  }

  Future<void> _checkInitialGpsStatus() async {
    final status = await Geolocator.isLocationServiceEnabled();
    if (mounted) setState(() => _isGpsEnabled = status);
  }

  Future<void> _loadPreferences() async {
    final prefs = await SharedPreferences.getInstance();
    final savedCategories = prefs.getStringList('user_selected_categories') ?? [];
    if (mounted) setState(() => _selectedCategories = savedCategories);
  }

  Future<void> _handleRefresh() {
    final completer = Completer<void>();
    final service = FlutterBackgroundService();
    final timeout = Timer(const Duration(seconds: 20), () {
      if (!completer.isCompleted) {
        completer.completeError('Request timed out.');
        if (mounted) ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('Request timed out. Please try again.')));
      }
    });
    final StreamSubscription<Map<String, dynamic>?> subscription = service.on('update').listen((event) {
      if (!completer.isCompleted) completer.complete();
    });
    completer.future.whenComplete(() {
      subscription.cancel();
      timeout.cancel();
    });
    service.invoke('force_refresh');
    return completer.future;
  }

  Widget _buildFavoriteCategoriesSection() {
    return Padding(
      padding: const EdgeInsets.fromLTRB(16.0, 16.0, 16.0, 0),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [
              const Text('دسته‌بندی‌های مورد علاقه شما', style: TextStyle(fontSize: 19, fontWeight: FontWeight.bold)),
              TextButton(
                onPressed: () async {
                  final result = await Navigator.of(context).push<bool>(MaterialPageRoute(builder: (context) => const NotificationPreferencesPage(loadFavoritesOnStart: true)));
                  if (!mounted) return;
                  context.read<NotificationPreferencesBloc>().add(ResetSubmissionStatus());
                  await _loadPreferences();
                  if (result == true) _handleRefresh();
                },
                child: Row(
                  children: [
                    SvgPicture.asset(Assets.icons.edit.path),
                    const SizedBox(width: 4),
                    const Text('ویرایش', style: TextStyle(color: AppColors.active)),
                  ],
                ),
              ),
            ],
          ),
          const Divider(height: 1),
          const SizedBox(height: 12),
          if (_selectedCategories.isEmpty)
            const Padding(
              padding: EdgeInsets.only(bottom: 8.0),
              child: Text('شما هنوز دسته‌بندی مورد علاقه خود را انتخاب نکرده‌اید.', style: TextStyle(color: Colors.grey)),
            )
          else
            Wrap(
              spacing: 8.0,
              runSpacing: 8.0,
              children: _selectedCategories.map((category) {
                return Container(
                  padding: const EdgeInsets.symmetric(horizontal: 12.0, vertical: 6.0),
                  decoration: BoxDecoration(border: Border.all(color: Colors.grey.shade300), borderRadius: BorderRadius.circular(20.0)),
                  child: Text(category),
                );
              }).toList(),
            ),
        ],
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Directionality(
      textDirection: TextDirection.rtl,
      child: Scaffold(
        appBar: AppBar(
          backgroundColor: Colors.white,
          automaticallyImplyLeading: false,
          title: Padding(
            padding: const EdgeInsets.symmetric(horizontal: 15.0, vertical: 0.0),
            child: Assets.icons.logoWithName.svg(height: 40, width: 200),
          ),
          actions: [
            Stack(
              alignment: Alignment.center,
              children: [
                IconButton(
                  key: _notificationIconKey,
                  onPressed: _toggleNotificationPanel,
                  icon: Assets.icons.notification.svg(),
                ),
                if (_notificationCount > 0)
                  Positioned(
                    top: 0,
                    right: 2,
                    child: GestureDetector(
                      onTap: _toggleNotificationPanel,
                      child: Container(
                        padding: const EdgeInsets.all(4),
                        decoration: BoxDecoration(color: Colors.red, shape: BoxShape.circle, border: Border.all(color: Colors.white, width: 1.5)),
                        constraints: const BoxConstraints(minWidth: 18, minHeight: 18),
                        child: Padding(
                          padding: const EdgeInsets.fromLTRB(2, 4, 2, 2),
                          child: Text('$_notificationCount', style: const TextStyle(color: Colors.white, fontSize: 11, fontWeight: FontWeight.bold), textAlign: TextAlign.center),
                        ),
                      ),
                    ),
                  ),
              ],
            ),
            BlocBuilder<ReservationCubit, ReservationState>(
              builder: (context, state) {
                final reservedCount = state.reservedProductIds.length;
                return Stack(
                  alignment: Alignment.center,
                  children: [
                    IconButton(
                      onPressed: () => Navigator.of(context).push(PageRouteBuilder(
                        pageBuilder: (context, animation, secondaryAnimation) => const ReservedListPage(),
                        transitionsBuilder: (context, animation, secondaryAnimation, child) =>
                            SharedAxisTransition(animation: animation, secondaryAnimation: secondaryAnimation, transitionType: SharedAxisTransitionType.horizontal, child: child),
                      )),
                      icon: Assets.icons.scanBarcode.svg(),
                    ),
                    if (reservedCount > 0)
                      Positioned(
                        top: 0,
                        right: 2,
                        child: GestureDetector(
                          onTap: () => Navigator.of(context).push(PageRouteBuilder(
                            pageBuilder: (context, animation, secondaryAnimation) => const ReservedListPage(),
                            transitionsBuilder: (context, animation, secondaryAnimation, child) =>
                                SharedAxisTransition(animation: animation, secondaryAnimation: secondaryAnimation, transitionType: SharedAxisTransitionType.horizontal, child: child),
                          )),
                          child: Container(
                            padding: const EdgeInsets.all(4),
                            decoration: BoxDecoration(color: Colors.green, shape: BoxShape.circle, border: Border.all(color: Colors.white, width: 1.5)),
                            constraints: const BoxConstraints(minWidth: 18, minHeight: 18),
                            child: Padding(
                              padding: const EdgeInsets.fromLTRB(2, 4, 2, 2),
                              child: Text('$reservedCount', style: const TextStyle(color: Colors.white, fontSize: 11, fontWeight: FontWeight.bold), textAlign: TextAlign.center),
                            ),
                          ),
                        ),
                      ),
                  ],
                );
              },
            ),
            const SizedBox(width: 8),
          ],
        ),
        body: Stack(
          children: [
            RefreshIndicator(
              onRefresh: _handleRefresh,
              child: SingleChildScrollView(
                physics: const AlwaysScrollableScrollPhysics(),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    _buildFavoriteCategoriesSection(),
                    OffersView(
                      isGpsEnabled: _isGpsEnabled,
                      isConnectedToInternet: _isConnectedToInternet,
                      selectedCategories: _selectedCategories,
                      onRandomSearch: _handleRandomSearch,
                      isSearchingRandomly: _isSearchingRandomly,
                    ),
                  ],
                ),
              ),
            ),
            _buildNotificationOverlay(),
          ],
        ),
      ),
    );
  }

  Widget _buildNotificationOverlay() {
    if (!_showNotificationPanel && _animationController.isDismissed) {
      return const SizedBox.shrink();
    }

    final RenderBox? renderBox = _notificationIconKey.currentContext?.findRenderObject() as RenderBox?;
    if (renderBox == null) return const SizedBox.shrink();

    final position = renderBox.localToGlobal(Offset.zero);
    final size = renderBox.size;
    final iconCenter = Offset(position.dx + size.width / 2, position.dy + size.height / 2);
    
    final screenHeight = MediaQuery.of(context).size.height;
    final screenWidth = MediaQuery.of(context).size.width;
    final maxRadius = math.sqrt(math.pow(screenWidth, 2) + math.pow(screenHeight, 2));

    _animation = Tween<double>(begin: 0.0, end: maxRadius).animate(
      CurvedAnimation(parent: _animationController, curve: Curves.easeInCubic),
    );

    return AnimatedBuilder(
      animation: _animation,
      builder: (context, child) {
        return Stack(
          children: [
            if (_showNotificationPanel || !_animationController.isDismissed)
              Positioned.fill(
                child: GestureDetector(
                  onTap: _toggleNotificationPanel,
                  child: Container(
                    color: Colors.black.withOpacity(0.4 * _animationController.value),
                  ),
                ),
              ),
            ClipPath(
              clipper: CircularRevealClipper(
                radius: _animation.value,
                center: iconCenter,
              ),
              child: Align(
                alignment: Alignment.topLeft,
                child: Padding(
                  padding: const EdgeInsets.only(top: kToolbarHeight - 40, left: 16, right: 16),
                  child: Material(
                    elevation: 12.0,
                    borderRadius: BorderRadius.circular(16),
                    child: Container(
                      height: MediaQuery.of(context).size.height * 0.40,
                      decoration: BoxDecoration(
                        color: Colors.white,
                        borderRadius: BorderRadius.circular(16),
                      ),
                      child: NotificationPanel(
                        onClose: _toggleNotificationPanel,
                      ),
                    ),
                  ),
                ),
              ),
            ),
          ],
        );
      },
    );
  }
}

class OffersView extends StatelessWidget {
  final bool isGpsEnabled;
  final bool isConnectedToInternet;
  final List<String> selectedCategories;
  final VoidCallback onRandomSearch;
  final bool isSearchingRandomly;

  const OffersView({
    super.key,
    required this.isGpsEnabled,
    required this.isConnectedToInternet,
    required this.selectedCategories,
    required this.onRandomSearch,
    required this.isSearchingRandomly,
  });

  @override
  Widget build(BuildContext context) {
    if (!isConnectedToInternet) {
      return _buildNoInternetUI(context);
    }

    if (!isGpsEnabled) {
      return _buildGpsActivationUI(context);
    }

    return BlocBuilder<OffersBloc, OffersState>(
      builder: (context, state) {
        if (state is OffersInitial) {
          return const SizedBox(
            height: 300,
            child: Center(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  CircularProgressIndicator(),
                  SizedBox(height: 20),
                  Text("در حال یافتن بهترین پیشنهادها برای شما..."),
                ],
              ),
            ),
          );
        }

        if (state is OffersLoadSuccess) {
          final filteredOffers = selectedCategories.isEmpty
              ? state.offers
              : state.offers.where((offer) => selectedCategories.contains(offer.category)).toList();

          if (filteredOffers.isEmpty) {
            return const SizedBox(
              height: 300,
              child: Center(
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: [
                    Text("فعلاً تخفیفی در این اطراف نیست!"),
                    Text("کمی قدم بزنید..."),
                  ],
                ),
              ),
            );
          }

          final groupedOffers = groupBy(filteredOffers, (OfferModel offer) => offer.category);
          final categories = groupedOffers.keys.toList();

          return ListView.builder(
            shrinkWrap: true,
            physics: const NeverScrollableScrollPhysics(),
            padding: const EdgeInsets.only(top: 16),
            itemCount: categories.length,
            itemBuilder: (context, index) {
              final category = categories[index];
              final offersForCategory = groupedOffers[category]!;
              return CategoryOffersRow(categoryTitle: category, offers: offersForCategory)
                  .animate()
                  .fade(duration: 500.ms)
                  .slideY(begin: 0.3, duration: 400.ms, curve: Curves.easeOut);
            },
          );
        }

        if (state is OffersLoadFailure) {
          return SizedBox(
            height: 200,
            child: Center(child: Text("خطا در بارگذاری: ${state.error}")),
          );
        }

        return const SizedBox.shrink();
      },
    );
  }

  Widget _buildGpsActivationUI(BuildContext context) {
    return Center(
      child: SizedBox(
        child: Center(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.center,
            children: [
              const SizedBox(height: 85),
              SvgPicture.asset(Assets.images.emptyHome.path),
              const SizedBox(height: 60),
              ElevatedButton(
                onPressed: () async {
                  await Geolocator.openLocationSettings();
                },
                style: ElevatedButton.styleFrom(
                  backgroundColor: AppColors.confirm,
                  foregroundColor: Colors.white,
                  disabledBackgroundColor: Colors.grey,
                  padding: const EdgeInsets.symmetric(vertical: 12, horizontal: 125),
                  shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(50)),
                ),
                child: const Text('فعال‌سازی GPS', style: TextStyle(fontFamily: 'Dana', fontSize: 16, fontWeight: FontWeight.normal)),
              ),
              const SizedBox(height: 15),
              InkWell(
                onTap: isSearchingRandomly ? null : onRandomSearch,
                borderRadius: BorderRadius.circular(8),
                child: Padding(
                  padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
                  child: isSearchingRandomly
                      ? const Row(
                          mainAxisSize: MainAxisSize.min,
                          children: [
                            Text('در حال جستجو...'),
                            SizedBox(width: 8),
                            SizedBox(
                              width: 16,
                              height: 16,
                              child: CircularProgressIndicator(strokeWidth: 2),
                            ),
                          ],
                        )
                      : const Text('جست‌وجوی تصادفی'),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildNoInternetUI(BuildContext context) {
    return SizedBox(
      height: 300,
      child: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(Icons.wifi_off_rounded, size: 80, color: Colors.grey[400]),
            const SizedBox(height: 20),
            const Text("اتصال به اینترنت برقرار نیست", style: TextStyle(fontSize: 18, color: Colors.grey)),
            const SizedBox(height: 10),
            const Text("لطفاً اتصال خود را بررسی کرده و دوباره تلاش کنید.", style: TextStyle(color: Colors.grey)),
          ],
        ),
      ),
    );
  }
}

class CircularRevealClipper extends CustomClipper<Path> {
  final double radius;
  final Offset center;

  CircularRevealClipper({required this.radius, required this.center});

  @override
  Path getClip(Size size) {
    return Path()..addOval(Rect.fromCircle(center: center, radius: radius));
  }

  @override
  bool shouldReclip(covariant CustomClipper<Path> oldClipper) {
    return true;
  }
}