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

import '../../../../core/services/auth_service.dart';
import '../../../../core/utils/logger.dart';

/// Página para gerenciar quizzes (eliminar quizzes feitos)
class QuizManagementPage extends StatefulWidget {
  const QuizManagementPage({super.key});

  @override
  State<QuizManagementPage> createState() => _QuizManagementPageState();
}

class _QuizManagementPageState extends State<QuizManagementPage> {
  List<Map<String, dynamic>> _quizHistory = [];
  bool _loading = true;
  String _userRole = '';

  // Turma seleccionada (null = vista de turmas)
  String? _selectedClassId;
  Map<String, String> _classNames = {}; // classId → name

  // Search and filter
  final TextEditingController _searchController = TextEditingController();
  DateTime? _selectedDate;

  @override
  void initState() {
    super.initState();
    _loadUserRole();
    _loadQuizHistory();
  }

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

  Future<void> _selectDate() async {
    final DateTime? picked = await showDatePicker(
      context: context,
      initialDate: _selectedDate ?? DateTime.now(),
      firstDate: DateTime(2020),
      lastDate: DateTime.now().add(const Duration(days: 365)),
    );
    if (picked != null) {
      setState(() => _selectedDate = picked);
    }
  }

  Future<void> _loadUserRole() async {
    final user = AuthService.currentUser;
    if (user != null) {
      final userDoc = await FirebaseFirestore.instance
          .collection('users')
          .doc(user.uid)
          .get();

      if (userDoc.exists) {
        setState(() {
          _userRole = userDoc.data()?['role'] ?? '';
        });
      }
    }
  }

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

      Query query;

      if (_userRole == 'teacher') {
        // Professor: ver todos os quizzes criados
        query = FirebaseFirestore.instance
            .collection('teacherQuizzes')
            .where('teacherId', isEqualTo: user.uid)
            .orderBy('createdAt', descending: true);
      } else {
        // Aluno: ver quizzes criados pelo próprio aluno + conceitos dominados
        final results = await Future.wait([
          FirebaseFirestore.instance
              .collection('userStats')
              .doc(user.uid)
              .get(),
          FirebaseFirestore.instance
              .collection('quizHistory')
              .doc(user.uid)
              .collection('quizzes')
              .orderBy('createdAt', descending: true)
              .get(),
        ]);

        final userStatsSnapshot = results[0] as DocumentSnapshot;
        final studentQuizzesSnapshot = results[1] as QuerySnapshot;

        List<Map<String, dynamic>> quizList = [];

        // Adicionar quizzes criados pelo aluno
        for (final doc in studentQuizzesSnapshot.docs) {
          final data = Map<String, dynamic>.from(doc.data() as Map);
          data['id'] = doc.id;
          data['title'] = data['materialName'] ?? 'Quiz sem nome';
          data['type'] = 'created';
          quizList.add(data);
        }

        // Adicionar conceitos dominados
        if (userStatsSnapshot.exists) {
          final stats = userStatsSnapshot.data() as Map<String, dynamic>?;
          if (stats != null) {
            final masteredConcepts =
                (stats['masteredConcepts'] as List<dynamic>?)
                    ?.map((c) => Map<String, dynamic>.from(c as Map))
                    .toList() ??
                [];

            for (final concept in masteredConcepts) {
              quizList.add({
                'id': concept['conceptName'] ?? '',
                'title': concept['conceptName'] ?? 'Conceito sem nome',
                'score': concept['masteryLevel'] ?? 0,
                'totalQuestions': 100, // Simulado
                'completedAt': concept['masteredAt'] ?? Timestamp.now(),
                'type': 'concept',
              });
            }
          }
        }

        setState(() {
          _quizHistory = quizList;
          _loading = false;
        });
        return;
      }

      final snapshot = await query.get();
      final quizzes = snapshot.docs
          .map((doc) {
            final data = Map<String, dynamic>.from(doc.data() as Map);
            data['id'] = doc.id;
            return data;
          })
          .cast<Map<String, dynamic>>()
          .toList();

      // Obter nomes das disciplinas
      final classIdSet = <String>{};
      for (final q in quizzes) {
        final ids = (q['classIds'] as List?)?.cast<String>() ?? [];
        classIdSet.addAll(ids);
      }
      final classNamesMap = <String, String>{};
      if (classIdSet.isNotEmpty) {
        final docs = await Future.wait(
          classIdSet.map(
            (id) =>
                FirebaseFirestore.instance.collection('classes').doc(id).get(),
          ),
        );
        for (final doc in docs.where((d) => d.exists)) {
          classNamesMap[doc.id] = doc.data()?['name'] as String? ?? doc.id;
        }
      }

      setState(() {
        _quizHistory = quizzes;
        _classNames = classNamesMap;
        _loading = false;
      });
    } catch (e) {
      Logger.error('Error loading quiz history: $e');
      setState(() {
        _loading = false;
      });
    }
  }

  Future<void> _deleteQuiz(String quizId, String quizTitle, String type) async {
    try {
      String confirmMessage;
      String successMessage;

      if (_userRole == 'teacher') {
        confirmMessage =
            'Tem certeza que deseja eliminar o quiz "$quizTitle"? Esta ação não pode ser desfeita.';
        successMessage = 'Quiz eliminado com sucesso!';
      } else {
        if (type == 'created') {
          confirmMessage =
              'Tem certeza que deseja eliminar seu quiz "$quizTitle"?';
          successMessage = 'Quiz eliminado com sucesso!';
        } else {
          confirmMessage =
              'Tem certeza que deseja remover o conceito "$quizTitle" do seu histórico?';
          successMessage = 'Conceito removido com sucesso!';
        }
      }

      final confirmed = await _showDeleteConfirmation(
        quizTitle,
        confirmMessage,
      );
      if (!confirmed) return;

      if (_userRole == 'teacher') {
        // Professor: eliminar quiz criado
        await FirebaseFirestore.instance
            .collection('teacherQuizzes')
            .doc(quizId)
            .delete();

        // Também eliminar do histórico de alunos
        final historySnapshot = await FirebaseFirestore.instance
            .collection('quizHistory')
            .where('quizId', isEqualTo: quizId)
            .get();

        for (final doc in historySnapshot.docs) {
          await doc.reference.delete();
        }
      } else {
        // Aluno: remover quiz criado ou conceito dominado
        if (type == 'created') {
          // Remover quiz criado pelo aluno
          final user = AuthService.currentUser;
          if (user != null) {
            await FirebaseFirestore.instance
                .collection('quizHistory')
                .doc(user.uid)
                .collection('quizzes')
                .doc(quizId)
                .delete();
          }
        } else {
          // Remover conceito dominado
          final user = AuthService.currentUser;
          if (user != null) {
            final userStatsDoc = await FirebaseFirestore.instance
                .collection('userStats')
                .doc(user.uid)
                .get();

            if (userStatsDoc.exists) {
              final userStats = userStatsDoc.data() as Map<String, dynamic>;
              final masteredConcepts =
                  (userStats['masteredConcepts'] as List<dynamic>?)
                      ?.map((c) => Map<String, dynamic>.from(c as Map))
                      .toList() ??
                  [];

              // Encontrar o conceito específico para remover
              final conceptToRemove = masteredConcepts.firstWhere(
                (c) => c['conceptName'] == quizId,
                orElse: () => {},
              );

              if (conceptToRemove.isNotEmpty) {
                await FirebaseFirestore.instance
                    .collection('userStats')
                    .doc(user.uid)
                    .update({
                      'masteredConcepts': FieldValue.arrayRemove([
                        conceptToRemove,
                      ]),
                    });
              }
            }
          }
        }
      }

      _loadQuizHistory(); // Recarregar lista

      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(successMessage),
            backgroundColor: Colors.green,
          ),
        );
      }
    } catch (e) {
      Logger.error('Error deleting quiz: $e');
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text('Erro ao eliminar: $e'),
            backgroundColor: Colors.red,
          ),
        );
      }
    }
  }

  Future<bool> _showDeleteConfirmation(String quizTitle, String message) async {
    final result = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: Text(
          _userRole == 'teacher' ? 'Eliminar Quiz' : 'Confirmar Eliminação',
        ),
        content: Text(message),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(context).pop(false),
            child: const Text('Cancelar'),
          ),
          ElevatedButton(
            onPressed: () => Navigator.of(context).pop(true),
            style: ElevatedButton.styleFrom(backgroundColor: Colors.red),
            child: const Text('Eliminar'),
          ),
        ],
      ),
    );
    return result ?? false;
  }

  Map<String, List<Map<String, dynamic>>> _groupByClass() {
    final Map<String, List<Map<String, dynamic>>> groups = {};
    for (final quiz in _quizHistory) {
      final quizClassIds = (quiz['classIds'] as List?)?.cast<String>() ?? [];
      String? groupId = quizClassIds.cast<String?>().firstWhere(
        (cid) => cid != null && _classNames.containsKey(cid),
        orElse: () => null,
      );
      groupId ??= quizClassIds.isNotEmpty ? quizClassIds.first : '__geral__';
      groups.putIfAbsent(groupId, () => []).add(quiz);
    }
    return groups;
  }

  List<Map<String, dynamic>> _getFilteredQuizzes() {
    final searchQuery = _searchController.text.toLowerCase();

    return _quizHistory.where((quiz) {
      // Filter by date if selected
      if (_selectedDate != null) {
        final quizDate = quiz['createdAt'] as Timestamp?;
        if (quizDate == null) return false;
        final quizDateTime = quizDate.toDate();
        if (quizDateTime.year != _selectedDate!.year ||
            quizDateTime.month != _selectedDate!.month ||
            quizDateTime.day != _selectedDate!.day) {
          return false;
        }
      }

      // Filter by search query (class name or quiz title)
      if (searchQuery.isNotEmpty) {
        final title = (quiz['title'] as String? ?? '').toLowerCase();
        final quizClassIds = (quiz['classIds'] as List?)?.cast<String>() ?? [];
        bool matchesSearch = title.contains(searchQuery);

        for (final classId in quizClassIds) {
          if (_classNames.containsKey(classId)) {
            final className = _classNames[classId]!.toLowerCase();
            if (className.contains(searchQuery)) {
              matchesSearch = true;
              break;
            }
          }
        }

        if (!matchesSearch) return false;
      }

      return true;
    }).toList();
  }

  Map<String, List<Map<String, dynamic>>> _getFilteredGroups() {
    final filteredQuizzes = _getFilteredQuizzes();
    final Map<String, List<Map<String, dynamic>>> groups = {};
    for (final quiz in filteredQuizzes) {
      final quizClassIds = (quiz['classIds'] as List?)?.cast<String>() ?? [];
      String? groupId = quizClassIds.cast<String?>().firstWhere(
        (cid) => cid != null && _classNames.containsKey(cid),
        orElse: () => null,
      );
      groupId ??= quizClassIds.isNotEmpty ? quizClassIds.first : '__geral__';
      groups.putIfAbsent(groupId, () => []).add(quiz);
    }
    return groups;
  }

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

    return PopScope(
      canPop: _selectedClassId == null,
      onPopInvokedWithResult: (didPop, _) {
        if (!didPop && _selectedClassId != null) {
          setState(() => _selectedClassId = null);
        }
      },
      child: Scaffold(
        backgroundColor: cs.surface,
        appBar: AppBar(
          title: Text(
            _userRole == 'teacher' ? 'Gerenciar Quizzes' : 'Meu Histórico',
          ),
          backgroundColor: cs.surface,
          foregroundColor: cs.onSurface,
          elevation: 0,
          leading: IconButton(
            icon: const Icon(Icons.arrow_back),
            onPressed: () {
              if (_userRole == 'teacher' && _selectedClassId != null) {
                setState(() => _selectedClassId = null);
                return;
              }
              if (Navigator.of(context).canPop()) {
                Navigator.of(context).pop();
              } else {
                context.go(
                  _userRole == 'teacher'
                      ? '/teacher-dashboard'
                      : '/student-dashboard',
                );
              }
            },
          ),
          actions: [
            IconButton(
              icon: const Icon(Icons.calendar_today),
              onPressed: _selectDate,
              tooltip: 'Filtrar por data',
            ),
            if (_selectedDate != null)
              IconButton(
                icon: const Icon(Icons.clear),
                onPressed: () {
                  setState(() => _selectedDate = null);
                },
                tooltip: 'Limpar filtro',
              ),
          ],
          bottom: _selectedClassId == null
              ? PreferredSize(
                  preferredSize: const Size.fromHeight(60),
                  child: Padding(
                    padding: const EdgeInsets.all(8),
                    child: TextField(
                      controller: _searchController,
                      decoration: InputDecoration(
                        hintText: 'Pesquisar turma...',
                        prefixIcon: const Icon(Icons.search),
                        border: OutlineInputBorder(
                          borderRadius: BorderRadius.circular(12),
                        ),
                        contentPadding: const EdgeInsets.symmetric(
                          horizontal: 16,
                          vertical: 12,
                        ),
                      ),
                      onChanged: (value) => setState(() {}),
                    ),
                  ),
                )
              : null,
        ),
        body: Container(
          decoration: BoxDecoration(
            gradient: LinearGradient(
              begin: Alignment.topCenter,
              end: Alignment.bottomCenter,
              colors: [cs.primary.withValues(alpha: 0.05), cs.surface],
            ),
          ),
          child: _loading
              ? const Center(child: CircularProgressIndicator())
              : _getFilteredQuizzes().isEmpty
              ? _buildEmptyState()
              : _userRole == 'teacher'
              ? _buildTeacherBody(cs)
              : ListView.builder(
                  padding: const EdgeInsets.all(16),
                  itemCount: _getFilteredQuizzes().length,
                  itemBuilder: (context, index) {
                    final quiz = _getFilteredQuizzes()[index];
                    return _buildQuizCard(quiz)
                        .animate()
                        .slideX(duration: const Duration(milliseconds: 300))
                        .then(delay: Duration(milliseconds: index * 50));
                  },
                ),
        ),
      ),
    );
  }

  Widget _buildTeacherBody(ColorScheme cs) {
    final groups = _searchController.text.isNotEmpty || _selectedDate != null
        ? _getFilteredGroups()
        : _groupByClass();

    // Vista de quizzes de uma turma
    if (_selectedClassId != null) {
      final quizzes = groups[_selectedClassId] ?? [];
      final className =
          _classNames[_selectedClassId] ??
          (_selectedClassId == '__geral__' ? 'Geral' : _selectedClassId!);
      return Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Padding(
            padding: const EdgeInsets.fromLTRB(8, 8, 16, 0),
            child: Row(
              children: [
                IconButton(
                  icon: Icon(Icons.arrow_back, color: cs.onSurface),
                  onPressed: () => setState(() => _selectedClassId = null),
                ),
                const SizedBox(width: 4),
                Expanded(
                  child: Text(
                    className,
                    maxLines: 1,
                    overflow: TextOverflow.ellipsis,
                    style: TextStyle(
                      fontSize: 16,
                      fontWeight: FontWeight.bold,
                      color: cs.onSurface,
                    ),
                  ),
                ),
                Text(
                  '${quizzes.length} quiz${quizzes.length != 1 ? 'zes' : ''}',
                  style: TextStyle(fontSize: 13, color: cs.onSurfaceVariant),
                ),
              ],
            ),
          ),
          const Divider(height: 1),
          Expanded(
            child: ListView.builder(
              padding: const EdgeInsets.all(16),
              itemCount: quizzes.length,
              itemBuilder: (context, index) {
                final quiz = quizzes[index];
                return _buildQuizCard(quiz)
                    .animate()
                    .slideX(duration: const Duration(milliseconds: 300))
                    .then(delay: Duration(milliseconds: index * 50));
              },
            ),
          ),
        ],
      );
    }

    // Vista de turmas
    final classIds = groups.keys.toList();
    return ListView.separated(
      padding: const EdgeInsets.all(16),
      itemCount: classIds.length,
      separatorBuilder: (_, __) => const SizedBox(height: 12),
      itemBuilder: (context, i) {
        final cId = classIds[i];
        final cName = _classNames[cId] ?? (cId == '__geral__' ? 'Geral' : cId);
        final count = groups[cId]!.length;
        return InkWell(
          borderRadius: BorderRadius.circular(16),
          onTap: () => setState(() => _selectedClassId = cId),
          child: Container(
            padding: const EdgeInsets.all(20),
            decoration: BoxDecoration(
              color: cs.surface,
              borderRadius: BorderRadius.circular(16),
              border: Border.all(color: cs.outline.withValues(alpha: 0.15)),
              boxShadow: [
                BoxShadow(
                  color: cs.shadow.withValues(alpha: 0.05),
                  blurRadius: 8,
                  offset: const Offset(0, 2),
                ),
              ],
            ),
            child: Row(
              children: [
                Container(
                  width: 48,
                  height: 48,
                  decoration: BoxDecoration(
                    color: cs.primary.withValues(alpha: 0.1),
                    borderRadius: BorderRadius.circular(12),
                  ),
                  child: Icon(Icons.school, color: cs.primary, size: 26),
                ),
                const SizedBox(width: 16),
                Expanded(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text(
                        cName,
                        maxLines: 2,
                        overflow: TextOverflow.ellipsis,
                        style: TextStyle(
                          fontSize: 15,
                          fontWeight: FontWeight.bold,
                          color: cs.onSurface,
                        ),
                      ),
                      const SizedBox(height: 4),
                      Text(
                        '$count quiz${count != 1 ? 'zes' : ''} criado${count != 1 ? 's' : ''}',
                        style: TextStyle(
                          fontSize: 13,
                          color: cs.onSurfaceVariant,
                        ),
                      ),
                    ],
                  ),
                ),
                Icon(Icons.chevron_right, color: cs.onSurfaceVariant),
              ],
            ),
          ),
        );
      },
    );
  }

  Widget _buildEmptyState() {
    final cs = Theme.of(context).colorScheme;

    return Center(
      child: Padding(
        padding: const EdgeInsets.all(32),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              _userRole == 'teacher'
                  ? Icons.quiz_outlined
                  : Icons.history_edu_outlined,
              size: 64,
              color: cs.onSurfaceVariant,
            ),
            const SizedBox(height: 16),
            Text(
              _userRole == 'teacher'
                  ? 'Nenhum quiz criado'
                  : 'Nenhum quiz no histórico',
              style: TextStyle(
                color: cs.onSurface,
                fontSize: 20,
                fontWeight: FontWeight.bold,
              ),
              textAlign: TextAlign.center,
            ),
            const SizedBox(height: 8),
            Text(
              _userRole == 'teacher'
                  ? 'Crie seu primeiro quiz para começar!'
                  : 'Complete alguns quizzes para ver seu histórico aqui.',
              style: TextStyle(color: cs.onSurfaceVariant, fontSize: 14),
              textAlign: TextAlign.center,
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildQuizCard(Map<String, dynamic> quiz) {
    final cs = Theme.of(context).colorScheme;

    return Container(
      margin: const EdgeInsets.only(bottom: 12),
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: cs.surface,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: cs.outline.withValues(alpha: 0.2)),
        boxShadow: [
          BoxShadow(
            color: cs.shadow.withValues(alpha: 0.1),
            blurRadius: 10,
            offset: const Offset(0, 4),
          ),
        ],
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      quiz['title'] ?? 'Quiz sem título',
                      style: TextStyle(
                        color: cs.onSurface,
                        fontSize: 16,
                        fontWeight: FontWeight.bold,
                      ),
                    ),
                    const SizedBox(height: 4),
                    if (_userRole == 'student' && quiz['score'] != null) ...[
                      Text(
                        'Pontuação: ${quiz['score']}/${quiz['totalQuestions'] ?? '?'}',
                        style: TextStyle(
                          color: cs.primary,
                          fontSize: 14,
                          fontWeight: FontWeight.w500,
                        ),
                      ),
                    ],
                    Text(
                      _userRole == 'teacher' || quiz['type'] == 'created'
                          ? 'Criado em: ${_formatDate(quiz['createdAt'])}'
                          : 'Completado em: ${_formatDate(quiz['completedAt'])}',
                      style: TextStyle(
                        color: cs.onSurfaceVariant,
                        fontSize: 12,
                      ),
                    ),
                  ],
                ),
              ),
              IconButton(
                onPressed: () => _deleteQuiz(
                  quiz['id'],
                  quiz['title'] ?? 'Quiz',
                  quiz['type'] ?? 'unknown',
                ),
                icon: Icon(Icons.delete_outline, color: Colors.red),
                tooltip: _userRole == 'teacher' ? 'Eliminar Quiz' : 'Remover',
              ),
            ],
          ),
          if (_userRole == 'teacher' &&
              quiz['classIds'] != null &&
              _selectedClassId == null) ...[
            const SizedBox(height: 8),
            Wrap(
              spacing: 4,
              children: (quiz['classIds'] as List<dynamic>).map((classId) {
                return Container(
                  padding: const EdgeInsets.symmetric(
                    horizontal: 8,
                    vertical: 4,
                  ),
                  decoration: BoxDecoration(
                    color: cs.primaryContainer,
                    borderRadius: BorderRadius.circular(8),
                  ),
                  child: Text(
                    'Disciplina: $classId',
                    style: TextStyle(
                      color: cs.onPrimaryContainer,
                      fontSize: 10,
                    ),
                  ),
                );
              }).toList(),
            ),
          ],
        ],
      ),
    );
  }

  String _formatDate(dynamic date) {
    if (date == null) return 'Data desconhecida';

    DateTime dateTime;
    if (date is Timestamp) {
      dateTime = date.toDate();
    } else if (date is DateTime) {
      dateTime = date;
    } else {
      return 'Data desconhecida';
    }

    return '${dateTime.day}/${dateTime.month}/${dateTime.year}';
  }
}