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_students_inline_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;
  final _classSearchController = TextEditingController();
  String _classSearchQuery = '';
  List<ClassStats> _classStats = [];
  bool _loading = true;
  String? _selectedClassId;
  String? _selectedClassName;

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

  @override
  void dispose() {
    _tabController.dispose();
    _classSearchController.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;
        // Forçar atualização para obter dados mais recentes
        final stats = await GamificationService.getClassStats(
          classId,
          forceRefresh: true,
        );
        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);

    return PopScope(
      canPop: false,
      onPopInvoked: (didPop) {
        if (didPop) return;
        context.go('/teacher-dashboard');
      },
      child: Scaffold(
        backgroundColor: Colors.transparent,
        resizeToAvoidBottomInset: false,
        body: DecoratedBox(
          decoration: BoxDecoration(
            gradient: LinearGradient(
              begin: Alignment.topCenter,
              end: Alignment.bottomCenter,
              colors: themeExtras.dashboardBackgroundGradient,
              stops: themeExtras.dashboardGradientStops,
            ),
          ),
          child: SafeArea(
            top: false,
            bottom: false,
            child: Column(
              children: [
                // Header
                Container(
                  padding: const EdgeInsets.only(
                    left: 24,
                    right: 24,
                    bottom: 28,
                    top: 52,
                  ),
                  child: Column(
                    children: [
                      Row(
                        crossAxisAlignment: CrossAxisAlignment.center,
                        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: 'Alunos'),
                        ],
                      ),
                    ],
                  ),
                ),

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

  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,
              ),
            ),
          ],
        ),
      );
    }

    final filtered = _classSearchQuery.isEmpty
        ? _classStats
        : _classStats
              .where(
                (s) => s.className.toLowerCase().contains(_classSearchQuery),
              )
              .toList();

    return CustomScrollView(
      slivers: [
        SliverPadding(
          padding: const EdgeInsets.fromLTRB(24, 24, 24, 0),
          sliver: SliverToBoxAdapter(
            child: Column(
              children: [
                // Overview Cards
                Center(
                  child: _buildOverviewCard(
                    'Total de Alunos',
                    '${_classStats.fold(0, (sum, s) => sum + s.totalStudents)}',
                    Icons.people,
                    Colors.blue,
                  ),
                ),
                const SizedBox(height: 20),
                // Search bar
                Container(
                  padding: const EdgeInsets.symmetric(
                    horizontal: 14,
                    vertical: 10,
                  ),
                  decoration: BoxDecoration(
                    color: Colors.white.withValues(alpha: 0.1),
                    borderRadius: BorderRadius.circular(12),
                    border: Border.all(
                      color: Colors.white.withValues(alpha: 0.2),
                    ),
                  ),
                  child: Row(
                    children: [
                      Icon(
                        Icons.search,
                        color: Colors.white.withValues(alpha: 0.7),
                        size: 20,
                      ),
                      const SizedBox(width: 10),
                      Expanded(
                        child: Theme(
                          data: ThemeData.dark().copyWith(
                            textSelectionTheme: const TextSelectionThemeData(
                              cursorColor: Colors.white,
                              selectionColor: Colors.white24,
                              selectionHandleColor: Colors.white,
                            ),
                          ),
                          child: TextField(
                            controller: _classSearchController,
                            onChanged: (v) => setState(
                              () => _classSearchQuery = v.trim().toLowerCase(),
                            ),
                            style: const TextStyle(
                              color: Colors.white,
                              fontSize: 14,
                            ),
                            cursorColor: Colors.white,
                            decoration: InputDecoration(
                              hintText: 'Pesquisar turma…',
                              hintStyle: TextStyle(
                                color: Colors.white.withValues(alpha: 0.5),
                                fontSize: 14,
                              ),
                              border: InputBorder.none,
                              isDense: true,
                              contentPadding: EdgeInsets.zero,
                            ),
                          ),
                        ),
                      ),
                      if (_classSearchQuery.isNotEmpty)
                        GestureDetector(
                          onTap: () {
                            _classSearchController.clear();
                            setState(() => _classSearchQuery = '');
                          },
                          child: Icon(
                            Icons.close,
                            color: Colors.white.withValues(alpha: 0.7),
                            size: 18,
                          ),
                        ),
                    ],
                  ),
                ),
                const SizedBox(height: 20),
              ],
            ),
          ),
        ),
        if (filtered.isEmpty)
          SliverFillRemaining(
            hasScrollBody: false,
            child: Center(
              child: Text(
                'Nenhuma turma encontrada',
                style: TextStyle(
                  color: Colors.white.withValues(alpha: 0.6),
                  fontSize: 15,
                ),
              ),
            ),
          )
        else
          SliverPadding(
            padding: const EdgeInsets.fromLTRB(24, 0, 24, 24),
            sliver: SliverList(
              delegate: SliverChildBuilderDelegate(
                (context, index) => ClassAnalyticsCard(
                  classStats: filtered[index],
                  onTap: () => _showClassStudents(filtered[index]),
                ),
                childCount: filtered.length,
              ),
            ),
          ),
      ],
    );
  }

  Widget _buildStudentsTab() {
    if (_selectedClassId == null) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              Icons.people_outline,
              size: 64,
              color: Colors.white.withValues(alpha: 0.5),
            ),
            const SizedBox(height: 16),
            Text(
              'Seleciona uma turma',
              style: TextStyle(
                color: Colors.white.withValues(alpha: 0.7),
                fontSize: 18,
              ),
            ),
            const SizedBox(height: 8),
            Text(
              'Clica numa turma no separador "Turmas" para ver os alunos',
              style: TextStyle(
                color: Colors.white.withValues(alpha: 0.5),
                fontSize: 14,
              ),
              textAlign: TextAlign.center,
            ),
          ],
        ),
      );
    }

    return ClassStudentsInlineWidget(
      classId: _selectedClassId!,
      className: _selectedClassName ?? '',
    );
  }

  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 _showClassStudents(ClassStats stats) {
    setState(() {
      _selectedClassId = stats.classId;
      _selectedClassName = stats.className;
    });
    _tabController.animateTo(1);
  }

  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,
            ),
          );
        },
      ),
    );
  }
}