import 'package:flutter/material.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'training_detail_screen.dart';

class FavoritesTab extends StatefulWidget {
  final String? categoryFilter;
  const FavoritesTab({super.key, this.categoryFilter});

  @override
  State<FavoritesTab> createState() => _FavoritesTabState();
}

class _FavoritesTabState extends State<FavoritesTab> {
  static const List<String> _categories = [
    'Aufwärmen & Mobilisation',
    'Wurf- & Torabschluss',
    'Torwarttraining',
    'Athletik',
    'Pass',
    'Koordination',
  ];
  String? _selectedCategory;

  @override
  void initState() {
    super.initState();
    _selectedCategory = widget.categoryFilter;
  }

  @override
  Widget build(BuildContext context) {
    final user = FirebaseAuth.instance.currentUser;
    if (user == null) {
      return const Center(child: Text('Nicht eingeloggt'));
    }

    return Scaffold(
      appBar: AppBar(
        title: const Text('Favoriten'),
      ),
      body: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          // Filter-Chip-Leiste
          Padding(
            padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 8),
            child: Wrap(
              spacing: 8,
              runSpacing: 8,
              children: [
                FilterChip(
                  label: const Text('Alle'),
                  selected: _selectedCategory == null,
                  onSelected: (selected) {
                    setState(() => _selectedCategory = null);
                  },
                ),
                ..._categories.map((cat) => FilterChip(
                  label: Text(cat),
                  selected: _selectedCategory == cat,
                  onSelected: (selected) {
                    setState(() => _selectedCategory = selected ? cat : null);
                  },
                )),
              ],
            ),
          ),
          Expanded(
            child: StreamBuilder<DocumentSnapshot>(
              stream: FirebaseFirestore.instance.collection('User').doc(user.uid).snapshots(),
              builder: (context, snapshot) {
                if (snapshot.connectionState == ConnectionState.waiting) {
                  return const Center(child: CircularProgressIndicator());
                }
                if (!snapshot.hasData || !snapshot.data!.exists) {
                  return const Center(child: Text('Keine Favoriten gefunden'));
                }
                final data = snapshot.data!.data() as Map<String, dynamic>;
                final allFavorites = List<String>.from(data['favorites'] ?? []);

                if (allFavorites.isEmpty) {
                  return const Center(child: Text('Keine Favoriten gefunden'));
                }

                // Lade alle Favoriten-Dokumente auf einmal
                return FutureBuilder<List<DocumentSnapshot>>(
                  future: Future.wait(allFavorites.map((id) =>
                    FirebaseFirestore.instance.collection('Training').doc(id).get()
                  )),
                  builder: (context, multiSnapshot) {
                    if (multiSnapshot.connectionState == ConnectionState.waiting) {
                      return const Center(child: CircularProgressIndicator());
                    }
                    if (!multiSnapshot.hasData) {
                      return const Center(child: Text('Favoriten konnten nicht geladen werden'));
                    }
                    
                    // Filtere die Favoriten basierend auf der Kategorie
                    final filteredFavorites = multiSnapshot.data!.where((doc) {
                      if (!doc.exists) return false;
                      if (_selectedCategory == null) return true;
                      final trainingData = doc.data() as Map<String, dynamic>;
                      return trainingData['category'] == _selectedCategory;
                    }).toList();

                    if (filteredFavorites.isEmpty) {
                      return const Center(child: Text('Keine Favoriten in dieser Kategorie gefunden'));
                    }
                    
                    return GridView.builder(
                      padding: const EdgeInsets.all(8),
                      gridDelegate: const SliverGridDelegateWithMaxCrossAxisExtent(
                        maxCrossAxisExtent: 300,
                        childAspectRatio: 0.75,
                        crossAxisSpacing: 10,
                        mainAxisSpacing: 10,
                      ),
                      itemCount: filteredFavorites.length,
                      itemBuilder: (context, index) {
                        final doc = filteredFavorites[index];
                        final trainingData = doc.data() as Map<String, dynamic>;
                        
                        return Card(
                          child: Stack(
                            children: [
                              InkWell(
                                onTap: () {
                                  Navigator.push(
                                    context,
                                    MaterialPageRoute(
                                      builder: (context) => TrainingDetailScreen(trainingId: doc.id),
                                    ),
                                  );
                                },
                                child: Column(
                                  crossAxisAlignment: CrossAxisAlignment.stretch,
                                  children: [
                                    Expanded(
                                      child: Container(
                                        color: Colors.grey[200],
                                        child: const Center(
                                          child: Icon(Icons.fitness_center, size: 50),
                                        ),
                                      ),
                                    ),
                                    Padding(
                                      padding: const EdgeInsets.all(8.0),
                                      child: Column(
                                        crossAxisAlignment: CrossAxisAlignment.start,
                                        children: [
                                          Text(
                                            trainingData['title'] ?? 'Unbekannt',
                                            style: const TextStyle(
                                              fontWeight: FontWeight.bold,
                                              fontSize: 16,
                                            ),
                                            maxLines: 2,
                                            overflow: TextOverflow.ellipsis,
                                          ),
                                          const SizedBox(height: 4),
                                          Row(
                                            children: [
                                              const Icon(Icons.star, color: Colors.amber, size: 16),
                                              const SizedBox(width: 4),
                                              Text(
                                                (trainingData['rating overall'] ?? 0.0).toStringAsFixed(1),
                                                style: const TextStyle(fontSize: 12),
                                              ),
                                            ],
                                          ),
                                          const SizedBox(height: 4),
                                          Text(
                                            'Dauer: \t${trainingData['duration'] ?? '-'} Minuten',
                                            style: const TextStyle(fontSize: 12, color: Colors.grey),
                                          ),
                                        ],
                                      ),
                                    ),
                                  ],
                                ),
                              ),
                              Positioned(
                                top: 4,
                                right: 4,
                                child: IconButton(
                                  icon: const Icon(Icons.favorite, color: Colors.red),
                                  onPressed: () async {
                                    await FirebaseFirestore.instance.collection('User').doc(user.uid).update({
                                      'favorites': FieldValue.arrayRemove([doc.id]),
                                    });
                                  },
                                ),
                              ),
                            ],
                          ),
                        );
                      },
                    );
                  },
                );
              },
            ),
          ),
        ],
      ),
    );
  }
}