import 'package:flutter/material.dart';
import 'package:flutter_animate/flutter_animate.dart';
import 'package:go_router/go_router.dart';
import 'package:cloud_firestore/cloud_firestore.dart';

import '../../../../core/theme/app_theme_extension.dart';
import '../../../../core/services/auth_service.dart';
import '../../../../core/services/gamification_service.dart';
import '../../../../core/models/class_stats.dart';
import '../../../../core/models/achievement.dart';
import '../widgets/class_analytics_card.dart';
import '../widgets/class_ranking_widget.dart';
import '../widgets/create_achievement_dialog.dart';

/// Analytics page for teachers with class breakdowns and rankings
class AnalyticsPage extends StatefulWidget {
  const AnalyticsPage({super.key});

  @override
  State<AnalyticsPage> createState() => _AnalyticsPageState();
}

class _AnalyticsPageState extends State<AnalyticsPage>
    with SingleTickerProviderStateMixin {
  late TabController _tabController;
  List<ClassStats> _classStats = [];
  bool _loading = true;
  String? _selectedClassId;

  @override
  void initState() {
    super.initState();
    _tabController = TabController(length: 2, vsync: this);
    _loadClassStats();
  }

  @override
  void dispose() {
    _tabController.dispose();
    super.dispose();
  }

  Future<void> _loadClassStats() async {
    try {
      final user = AuthService.currentUser;
      if (user == null) return;

      // Obter turmas do professor
      final classesSnapshot = await FirebaseFirestore.instance
          .collection('classes')
          .where('teacherId', isEqualTo: user.uid)
          .get();

      final classStatsList = <ClassStats>[];
      
      for (final classDoc in classesSnapshot.docs) {
        final classId = classDoc.id;
        final stats = await GamificationService.getClassStats(classId);
        if (stats != null) {
          classStatsList.add(stats);
        }
      }

      if (mounted) {
        setState(() {
          _classStats = classStatsList;
          _loading = false;
        });
      }
    } catch (e) {
      print('Error loading class stats: $e');
      if (mounted) {
        setState(() {
          _loading = false;
        });
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final themeExtras = AppThemeExtras.of(context);
    final cs = Theme.of(context).colorScheme;

    return Scaffold(
      backgroundColor: cs.surface,
      body: Container(
        decoration: BoxDecoration(
          gradient: LinearGradient(
            begin: Alignment.topCenter,
            end: Alignment.bottomCenter,
            colors: themeExtras.dashboardBackgroundGradient,
            stops: themeExtras.dashboardGradientStops,
          ),
        ),
        child: SafeArea(
          child: Column(
            children: [
              // Header
              Container(
                padding: const EdgeInsets.all(24),
                child: Column(
                  children: [
                    Row(
                      children: [
                        IconButton(
                          icon: const Icon(Icons.arrow_back, color: Colors.white),
                          onPressed: () => context.go('/teacher-dashboard'),
                        ),
                        const SizedBox(width: 16),
                        Expanded(
                          child: Column(
                            crossAxisAlignment: CrossAxisAlignment.start,
                            children: [
                              const Text(
                                'Analytics',
                                style: TextStyle(
                                  color: Colors.white,
                                  fontSize: 28,
                                  fontWeight: FontWeight.bold,
                                ),
                              ),
                              const SizedBox(height: 4),
                              Text(
                                'Acompanhe o desempenho das turmas',
                                style: TextStyle(
                                  color: Colors.white.withValues(alpha: 0.8),
                                  fontSize: 16,
                                ),
                              ),
                            ],
                          ),
                        ),
                        IconButton(
                          icon: const Icon(Icons.add, color: Colors.white),
                          onPressed: _showCreateAchievementDialog,
                          tooltip: 'Criar Conquista',
                        ),
                      ],
                    ),
                    const SizedBox(height: 20),
                    TabBar(
                      controller: _tabController,
                      labelColor: Colors.white,
                      unselectedLabelColor: Colors.white.withValues(alpha: 0.7),
                      indicatorColor: Colors.white,
                      indicatorWeight: 2,
                      tabs: const [
                        Tab(text: 'Turmas'),
                        Tab(text: 'Rankings'),
                      ],
                    ),
                  ],
                ),
              ),

              // Content
              Expanded(
                child: TabBarView(
                  controller: _tabController,
                  children: [
                    _buildClassesTab(),
                    _buildRankingsTab(),
                  ],
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildClassesTab() {
    if (_loading) {
      return const Center(child: CircularProgressIndicator(color: Colors.white));
    }

    if (_classStats.isEmpty) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              Icons.analytics_outlined,
              size: 64,
              color: Colors.white.withValues(alpha: 0.5),
            ),
            const SizedBox(height: 16),
            Text(
              'Nenhuma turma encontrada',
              style: TextStyle(
                color: Colors.white.withValues(alpha: 0.7),
                fontSize: 18,
              ),
            ),
            const SizedBox(height: 8),
            Text(
              'Crie turmas para ver as analytics aqui',
              style: TextStyle(
                color: Colors.white.withValues(alpha: 0.5),
                fontSize: 14,
              ),
            ),
          ],
        ),
      );
    }

    return SingleChildScrollView(
      padding: const EdgeInsets.all(24),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          // Overview Cards
          Row(
            children: [
              Expanded(
                child: _buildOverviewCard(
                  'Total de Alunos',
                  '${_classStats.fold(0, (sum, stats) => sum + stats.totalStudents)}',
                  Icons.people,
                  Colors.blue,
                ),
              ),
              const SizedBox(width: 12),
              Expanded(
                child: _buildOverviewCard(
                  'Alunos Ativos',
                  '${_classStats.fold(0, (sum, stats) => sum + stats.activeStudents)}',
                  Icons.trending_up,
                  Colors.green,
                ),
              ),
            ],
          ),
          const SizedBox(height: 20),

          // Class Cards
          ..._classStats.map((stats) => Padding(
            padding: const EdgeInsets.only(bottom: 16),
            child: ClassAnalyticsCard(
              classStats: stats,
              onTap: () => _showClassRanking(stats),
            ),
          )),
        ],
      ),
    );
  }

  Widget _buildRankingsTab() {
    if (_selectedClassId == null) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              Icons.leaderboard,
              size: 64,
              color: Colors.white.withValues(alpha: 0.5),
            ),
            const SizedBox(height: 16),
            Text(
              'Selecione uma turma',
              style: TextStyle(
                color: Colors.white.withValues(alpha: 0.7),
                fontSize: 18,
              ),
            ),
            const SizedBox(height: 8),
            Text(
              'Clique em uma turma na aba "Turmas" para ver o ranking',
              style: TextStyle(
                color: Colors.white.withValues(alpha: 0.5),
                fontSize: 14,
              ),
            ),
          ],
        ),
      );
    }

    return ClassRankingWidget(classId: _selectedClassId!);
  }

  Widget _buildOverviewCard(String title, String value, IconData icon, Color color) {
    return Container(
      padding: const EdgeInsets.all(20),
      decoration: BoxDecoration(
        color: Colors.white.withValues(alpha: 0.1),
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: Colors.white.withValues(alpha: 0.2)),
      ),
      child: Column(
        children: [
          Icon(icon, color: color, size: 32),
          const SizedBox(height: 12),
          Text(
            value,
            style: const TextStyle(
              color: Colors.white,
              fontSize: 24,
              fontWeight: FontWeight.bold,
            ),
          ),
          const SizedBox(height: 4),
          Text(
            title,
            style: TextStyle(
              color: Colors.white.withValues(alpha: 0.8),
              fontSize: 14,
            ),
            textAlign: TextAlign.center,
          ),
        ],
      ),
    ).animate().scale(duration: 600.ms, curve: Curves.elasticOut);
  }

  void _showClassRanking(ClassStats stats) {
    setState(() {
      _selectedClassId = stats.classId;
    });
    _tabController.animateTo(1); // Mudar para aba de rankings
  }

  void _showCreateAchievementDialog() {
    showDialog(
      context: context,
      builder: (context) => CreateAchievementDialog(
        onAchievementCreated: (achievement) {
          ScaffoldMessenger.of(context).showSnackBar(
            SnackBar(
              content: Text('Conquista "${achievement.name}" criada com sucesso!'),
              backgroundColor: Colors.green,
            ),
          );
        },
      ),
    );
  }
}