import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import '../models/user_stats.dart';
import '../models/class_stats.dart';
import '../models/achievement.dart';
import '../utils/logger.dart';

/// Serviço para gerenciar gamificação e conquistas
class GamificationService {
  static final FirebaseFirestore _firestore = FirebaseFirestore.instance;
  static final FirebaseAuth _auth = FirebaseAuth.instance;

  /// Atualizar streak diário do usuário
  static Future<void> updateDailyStreak(String userId) async {
    try {
      final userStatsRef = _firestore.collection('users').doc(userId);
      final userStatsDoc = await userStatsRef.get();
      
      if (!userStatsDoc.exists) {
        // Criar estatísticas iniciais
        await userStatsRef.set({
          'userId': userId,
          'currentStreak': 1,
          'longestStreak': 1,
          'totalStudyTime': 0,
          'lastActivityDate': Timestamp.now(),
          'weeklyStudyTime': 0,
          'monthlyStudyTime': 0,
          'masteredConcepts': [],
          'unlockedAchievements': [],
        });
        return;
      }

      final userStats = UserStats.fromFirestore(userStatsDoc.data()!, userId);
      final now = DateTime.now();
      final lastActivity = userStats.lastActivityDate;
      
      int newStreak = userStats.currentStreak;
      int newLongestStreak = userStats.longestStreak;

      Logger.info('=== UPDATE DAILY STREAK DEBUG ===');
      Logger.info('Last activity: $lastActivity');
      Logger.info('Current streak before update: $newStreak');
      
      if (lastActivity == null) {
        // Primeira atividade - iniciar streak
        Logger.info('First activity detected - setting streak to 1');
        newStreak = 1;
        newLongestStreak = 1;
      } else {
        // Normalizar para início do dia para comparação correta
        final today = DateTime(now.year, now.month, now.day);
        final lastDay = DateTime(lastActivity.year, lastActivity.month, lastActivity.day);
        final difference = today.difference(lastDay).inDays;

        if (difference == 0) {
          // Já ativou hoje, não alterar streak mas atualiza timestamp
          // Corrigir streak se estiver em 0 (erro de dados)
          if (newStreak == 0) {
            newStreak = 1;
            newLongestStreak = 1;
            Logger.info('Correcting invalid streak (0) to 1');
            await userStatsRef.update({
              'currentStreak': 1,
              'longestStreak': 1,
              'lastActivityDate': Timestamp.now(),
            });
          } else {
            Logger.info('Already active today, streak unchanged: $newStreak');
            await userStatsRef.update({
              'lastActivityDate': Timestamp.now(),
            });
          }
          return;
        } else if (difference == 1) {
          Logger.info('Consecutive activity detected, incrementing streak');
          // Atividade consecutiva
          newStreak++;
          newLongestStreak = newStreak > newLongestStreak ? newStreak : newLongestStreak;
        } else {
          // Quebrou o streak
          newStreak = 1;
          newLongestStreak = newStreak > newLongestStreak ? newStreak : newLongestStreak;
        }
      }

      Logger.info('Updating streak to: $newStreak');
      await userStatsRef.update({
        'currentStreak': newStreak,
        'longestStreak': newLongestStreak,
        'lastActivityDate': Timestamp.now(),
      });

      Logger.info('Streak updated successfully');
      // Verificar conquistas de streak
      await _checkStreakAchievements(userId, newStreak);
      Logger.info('=== END UPDATE DAILY STREAK DEBUG ===');
    } catch (e) {
      Logger.error('Error updating daily streak: $e');
    }
  }

  /// Registrar tempo de estudo
  static Future<void> recordStudyTime(String userId, int minutes) async {
    try {
      final userStatsRef = _firestore.collection('users').doc(userId);
      final userStatsDoc = await userStatsRef.get();

      if (!userStatsDoc.exists) {
        await _createInitialUserStats(userId);
      }

      final userStats = UserStats.fromFirestore(userStatsDoc.data()!, userId);
      final newTotalTime = userStats.totalStudyTime + minutes;

      await userStatsRef.update({
        'totalStudyTime': newTotalTime,
        'weeklyStudyTime': FieldValue.increment(minutes),
        'monthlyStudyTime': FieldValue.increment(minutes),
      });

      // Verificar conquistas de tempo de estudo
      await _checkStudyTimeAchievements(userId, newTotalTime);
    } catch (e) {
      Logger.error('Error recording study time: $e');
    }
  }

  /// Registrar atividade de quiz
  static Future<void> recordQuizActivity(String userId, {
    required int score,
    required int totalQuestions,
    required String materialName,
  }) async {
    try {
      final userStatsRef = _firestore.collection('users').doc(userId);
      
      // Atualizar streak
      await updateDailyStreak(userId);

      // Registrar tempo de estudo (estimado)
      await recordStudyTime(userId, 15); // 15 minutos por quiz

      // Verificar conquistas de quiz
      await _checkQuizAchievements(userId, score, totalQuestions);

      // Incrementar contador de quizzes completos
      await userStatsRef.update({
        'completedQuizzes': FieldValue.increment(1),
      });
      Logger.info('Incremented completed quizzes count');

      // Atualizar conceitos dominados se score >= 50%
      Logger.info('Checking if score qualifies for mastered concept: ${score / totalQuestions >= 0.5}');
      if (score / totalQuestions >= 0.5) {
        Logger.info('Adding mastered concept: $materialName with score: $score');
        await _addMasteredConcept(userId, materialName, score);
      } else {
        Logger.info('Score too low for mastered concept: $score/$totalQuestions');
      }

      Logger.info('Quiz activity recorded for user $userId: $score/$totalQuestions');
    } catch (e) {
      Logger.error('Error recording quiz activity: $e');
    }
  }

  /// Obter estatísticas do usuário
  static Future<UserStats?> getUserStats(String userId) async {
    try {
      final doc = await _firestore.collection('users').doc(userId).get();
      
      if (!doc.exists) {
        // Criar estatísticas iniciais se não existirem
        await _initializeUserStats(userId);
        return await getUserStats(userId); // Chamada recursiva após inicialização
      }

      final data = doc.data() as Map<String, dynamic>;
      
      // Garantir que completedQuizzes exista
      if (!data.containsKey('completedQuizzes')) {
        await _firestore.collection('users').doc(userId).update({
          'completedQuizzes': 0,
        });
        data['completedQuizzes'] = 0;
      }
      
      return UserStats.fromFirestore(data, userId);
    } catch (e) {
      Logger.error('Error getting user stats: $e');
      return null;
    }
  }

  /// Obter estatísticas da turma
  static Future<ClassStats?> getClassStats(String classId) async {
    try {
      final classStatsDoc = await _firestore.collection('classStats').doc(classId).get();
      if (!classStatsDoc.exists) {
        return await _calculateClassStats(classId);
      }
      return ClassStats.fromFirestore(classStatsDoc.data()!, classId);
    } catch (e) {
      Logger.error('Error getting class stats: $e');
      return null;
    }
  }

  /// Obter ranking de alunos da turma
  static Future<List<StudentRanking>> getClassRanking(String classId) async {
    try {
      // Primeiro, obter todos os alunos matriculados na turma
      final enrollmentsSnapshot = await _firestore
          .collection('enrollments')
          .where('classId', isEqualTo: classId)
          .get();

      if (enrollmentsSnapshot.docs.isEmpty) {
        Logger.info('No students enrolled in class $classId');
        return [];
      }

      final studentIds = enrollmentsSnapshot.docs.map((doc) => doc['studentId'] as String).toList();
      final rankings = <StudentRanking>[];

      // Para cada aluno, obter suas estatísticas
      for (final studentId in studentIds) {
        try {
          final userStats = await getUserStats(studentId);
          if (userStats != null) {
            // Obter informações do usuário
            final userDoc = await _firestore.collection('users').doc(studentId).get();
            final userData = userDoc.data() as Map<String, dynamic>?;

            // Calcular estatísticas para o ranking
            // Usar contador real de quizzes completos
            final completedQuizzes = userStats.completedQuizzes;
            final totalQuizzes = completedQuizzes + 5; // Estimativa de quizzes disponíveis
            final quizCompletionRate = totalQuizzes > 0 ? completedQuizzes / totalQuizzes : 0.0;
            
            // Calcular score geral baseado em múltiplos fatores
            final overallScore = _calculateOverallScore(userStats, quizCompletionRate);

            rankings.add(StudentRanking(
              studentId: studentId,
              studentName: userData?['displayName'] ?? 'Aluno $studentId',
              studentEmail: userData?['email'] ?? '',
              overallScore: overallScore,
              completedQuizzes: completedQuizzes,
              totalQuizzes: totalQuizzes,
              quizCompletionRate: quizCompletionRate,
              currentStreak: userStats.currentStreak,
              studyTimeMinutes: userStats.totalStudyTime,
              lastActivity: userStats.lastActivityDate ?? DateTime.now(),
            ));
          }
        } catch (e) {
          Logger.error('Error getting stats for student $studentId: $e');
          continue;
        }
      }

      // Ordenar por score geral
      rankings.sort((a, b) => b.overallScore.compareTo(a.overallScore));
      
      return rankings;
    } catch (e) {
      Logger.error('Error getting class ranking: $e');
      return [];
    }
  }

  /// Calcular score geral para ranking
  static double _calculateOverallScore(UserStats userStats, double quizCompletionRate) {
    double score = 0.0;
    
    // Peso de 40% para completion rate de quizzes
    score += quizCompletionRate * 40;
    
    // Peso de 20% para streak (máximo 20 pontos)
    score += (userStats.currentStreak / 30.0 * 20).clamp(0.0, 20.0);
    
    // Peso de 20% para tempo de estudo (máximo 20 pontos para 10 horas)
    score += (userStats.totalStudyTime / 600.0 * 20).clamp(0.0, 20.0);
    
    // Peso de 20% para conceitos dominados (máximo 20 pontos para 10 conceitos)
    score += (userStats.masteredConcepts.length / 10.0 * 20).clamp(0.0, 20.0);
    
    return score;
  }

  /// Criar conquista personalizada (professor)
  static Future<String> createCustomAchievement({
    required String teacherId,
    required String name,
    required String description,
    required String icon,
    required String category,
    required AchievementRequirement requirements,
    required int points,
    required String rarity,
  }) async {
    try {
      final achievementRef = await _firestore.collection('achievements').add({
        'name': name,
        'description': description,
        'icon': icon,
        'category': category,
        'requirements': requirements.toFirestore(),
        'points': points,
        'rarity': rarity,
        'isActive': true,
        'createdAt': Timestamp.now(),
        'createdBy': teacherId,
      });

      Logger.info('Custom achievement created: ${achievementRef.id}');
      return achievementRef.id;
    } catch (e) {
      Logger.error('Error creating custom achievement: $e');
      rethrow;
    }
  }

  /// Obter conquistas disponíveis
  static Future<List<Achievement>> getAvailableAchievements({String? teacherId}) async {
    try {
      // Sempre incluir conquistas do sistema
      List<Achievement> achievements = List.from(SystemAchievements.defaultAchievements);
      
      // Adicionar conquistas personalizadas do professor
      Query query = _firestore.collection('achievements').where('isActive', isEqualTo: true);
      
      if (teacherId != null) {
        query = query.where('createdBy', isEqualTo: teacherId);
      }

      final snapshot = await query.get();
      achievements.addAll(
        snapshot.docs
            .map((doc) => Achievement.fromFirestore(doc.data() as Map<String, dynamic>, doc.id))
            .toList(),
      );
      
      Logger.info('Total achievements loaded: ${achievements.length}');
      return achievements;
    } catch (e) {
      Logger.error('Error getting available achievements: $e');
      return SystemAchievements.defaultAchievements;
    }
  }

  /// Método público para inicializar dados de gamificação (para testes)
  static Future<void> initializeGamificationData(String userId) async {
    try {
      final userStats = await getUserStats(userId);
      if (userStats == null) {
        await _createInitialUserStats(userId);
        Logger.info('Gamification data initialized for user $userId');
      }
    } catch (e) {
      Logger.error('Error initializing gamification data: $e');
    }
  }

  /// Método público para simular quiz completion (para testes)
  static Future<void> simulateQuizCompletion(String userId, {
    required int score,
    required int totalQuestions,
    required String materialName,
  }) async {
    Logger.info('=== SIMULATING QUIZ COMPLETION ===');
    Logger.info('User: $userId');
    Logger.info('Score: $score/$totalQuestions');
    Logger.info('Material: $materialName');
    
    await recordQuizActivity(
      userId,
      score: score,
      totalQuestions: totalQuestions,
      materialName: materialName,
    );
    
    // Verificar estado após simulação
    await debugUserStats(userId);
  }

  /// Método de debugging para verificar estado completo do usuário
  static Future<void> debugUserStats(String userId) async {
    try {
      Logger.info('=== DEBUGGING USER STATS ===');
      
      final userStats = await getUserStats(userId);
      if (userStats == null) {
        Logger.error('User stats not found for $userId');
        return;
      }
      
      Logger.info('Current Streak: ${userStats.currentStreak}');
      Logger.info('Longest Streak: ${userStats.longestStreak}');
      Logger.info('Total Study Time: ${userStats.totalStudyTime}');
      Logger.info('Weekly Study Time: ${userStats.weeklyStudyTime}');
      Logger.info('Monthly Study Time: ${userStats.monthlyStudyTime}');
      Logger.info('Mastered Concepts: ${userStats.masteredConcepts.length}');
      Logger.info('Unlocked Achievements: ${userStats.unlockedAchievements.length}');
      
      for (final concept in userStats.masteredConcepts) {
        Logger.info('  - Concept: ${concept.conceptName}, Level: ${concept.masteryLevel}');
      }
      
      for (final achievement in userStats.unlockedAchievements) {
        Logger.info('  - Achievement: ${achievement.achievementId}, Unlocked: ${achievement.unlockedAt}');
      }
      
      Logger.info('=== END DEBUG ===');
    } catch (e) {
      Logger.error('Error debugging user stats: $e');
    }
  }

  /// Métodos privados

  static Future<void> _createInitialUserStats(String userId) async {
    await _firestore.collection('users').doc(userId).set({
      'userId': userId,
      'currentStreak': 0,
      'longestStreak': 0,
      'totalStudyTime': 0,
      'lastActivityDate': null, // null para que primeira atividade inicie streak
      'weeklyStudyTime': 0,
      'monthlyStudyTime': 0,
      'masteredConcepts': [],
      'unlockedAchievements': [],
    });
  }

  static Future<void> _addMasteredConcept(String userId, String conceptName, int score) async {
    try {
      final userStatsRef = _firestore.collection('users').doc(userId);
      final userStatsDoc = await userStatsRef.get();
      
      if (!userStatsDoc.exists) return;

      final userStats = UserStats.fromFirestore(userStatsDoc.data()!, userId);
      
      // Verificar se conceito já está dominado
      final existingConcept = userStats.masteredConcepts
          .where((c) => c.conceptName == conceptName)
          .firstOrNull;

      if (existingConcept != null) {
        // Atualizar nível de maestria se score maior
        if (score > existingConcept.masteryLevel) {
          final updatedConcepts = userStats.masteredConcepts.map((c) {
            if (c.conceptName == conceptName) {
              return MasteredConcept(
                conceptName: conceptName,
                masteredAt: DateTime.now(),
                masteryLevel: score,
              );
            }
            return c;
          }).toList();

          await userStatsRef.update({
            'masteredConcepts': updatedConcepts.map((c) => c.toFirestore()).toList(),
          });
        }
      } else {
        // Adicionar novo conceito
        final newConcept = MasteredConcept(
          conceptName: conceptName,
          masteredAt: DateTime.now(),
          masteryLevel: score,
        );

        await userStatsRef.update({
          'masteredConcepts': FieldValue.arrayUnion([newConcept.toFirestore()]),
        });
      }
    } catch (e) {
      Logger.error('Error adding mastered concept: $e');
    }
  }

  static Future<ClassStats> _calculateClassStats(String classId) async {
    try {
      // Obter informações da turma
      final classDoc = await _firestore.collection('classes').doc(classId).get();
      if (!classDoc.exists) {
        throw Exception('Class not found');
      }

      final className = classDoc.data()?['name'] ?? 'Unknown Class';
      final teacherId = classDoc.data()?['teacherId'] ?? '';

      // Obter alunos matriculados
      final enrollmentsSnapshot = await _firestore
          .collection('enrollments')
          .where('classId', isEqualTo: classId)
          .get();

      final studentIds = enrollmentsSnapshot.docs.map((doc) => doc.data()['studentId'] as String).toList();

      // Calcular estatísticas
      int activeStudents = 0;
      double totalProgress = 0;
      List<StudentNeedingSupport> needingSupport = [];

      for (final studentId in studentIds) {
        final userStats = await getUserStats(studentId);
        if (userStats != null) {
          // Verificar se está ativo (atividade nos últimos 7 dias)
          int daysSinceLastActivity = 999; // Valor alto para inatividade
          if (userStats.lastActivityDate != null) {
            daysSinceLastActivity = DateTime.now().difference(userStats.lastActivityDate!).inDays;
            if (daysSinceLastActivity <= 7) {
              activeStudents++;
            }
          }

          // Calcular progresso baseado em conceitos dominados
          final progress = userStats.masteredConcepts.isEmpty 
              ? 0.0 
              : userStats.masteredConcepts.map((c) => c.masteryLevel).reduce((a, b) => a + b) / userStats.masteredConcepts.length / 100;
          totalProgress += progress;

          // Verificar se precisa de apoio
          if (progress < 0.5 || daysSinceLastActivity > 14) {
            final userDoc = await _firestore.collection('users').doc(studentId).get();
            final userName = userDoc.data()?['displayName'] ?? 'Unknown';
            
            needingSupport.add(StudentNeedingSupport(
              studentId: studentId,
              studentName: userName,
              reason: progress < 0.5 ? 'low_scores' : 'inactivity',
              lastActivity: userStats.lastActivityDate ?? DateTime.now(),
              averageScore: progress * 100,
            ));
          }
        }
      }

      final averageProgress = studentIds.isEmpty ? 0.0 : totalProgress / studentIds.length;

      // Obter estatísticas de quizzes
      final quizzesSnapshot = await _firestore
          .collection('teacherQuizzes')
          .where('classIds', arrayContains: classId)
          .get();

      final classStats = ClassStats(
        classId: classId,
        teacherId: teacherId,
        className: className,
        totalStudents: studentIds.length,
        activeStudents: activeStudents,
        averageProgress: averageProgress,
        totalQuizzes: quizzesSnapshot.docs.length,
        activeQuizzes: quizzesSnapshot.docs.length, // Simplificado
        totalContent: 0, // Implementar depois
        weeklyStats: [],
        studentsNeedingSupport: needingSupport,
      );

      // Salvar estatísticas calculadas
      await _firestore.collection('classStats').doc(classId).set(classStats.toFirestore());

      return classStats;
    } catch (e) {
      Logger.error('Error calculating class stats: $e');
      rethrow;
    }
  }

  static Future<void> _checkStreakAchievements(String userId, int streakDays) async {
    final achievements = await getAvailableAchievements();
    final streakAchievements = achievements.where((a) => a.category == 'streak');

    for (final achievement in streakAchievements) {
      if (achievement.requirements.checkCondition(streakDays)) {
        await _unlockAchievement(userId, achievement.id);
      }
    }
  }

  static Future<void> _checkStudyTimeAchievements(String userId, int totalMinutes) async {
    final achievements = await getAvailableAchievements();
    final studyAchievements = achievements.where((a) => a.category == 'study_time');

    for (final achievement in studyAchievements) {
      if (achievement.requirements.checkCondition(totalMinutes)) {
        await _unlockAchievement(userId, achievement.id);
      }
    }
  }

  static Future<void> _checkQuizAchievements(String userId, int score, int totalQuestions) async {
    Logger.info('=== CHECKING QUIZ ACHIEVEMENTS ===');
    Logger.info('Score: $score/$totalQuestions');
    
    final achievements = await getAvailableAchievements();
    final userStats = await getUserStats(userId);
    
    if (userStats == null) {
      Logger.error('User stats null for achievement checking');
      return;
    }

    final percentage = (score / totalQuestions) * 100;
    // Usar contador real de quizzes completos
    final completedQuizzes = userStats.completedQuizzes;
    
    Logger.info('Percentage: $percentage%');
    Logger.info('Completed quizzes: $completedQuizzes');
    Logger.info('Mastered concepts: ${userStats.masteredConcepts.length}');
    Logger.info('Available achievements: ${achievements.length}');

    for (final achievement in achievements) {
      if (achievement.category == 'quiz' && achievement.requirements.type == 'quiz_score' && 
          achievement.requirements.checkCondition(percentage)) {
        await _unlockAchievement(userId, achievement.id);
      } else if (achievement.category == 'quiz_count' && achievement.requirements.type == 'quiz_completion' &&
                 achievement.requirements.checkCondition(completedQuizzes)) {
        await _unlockAchievement(userId, achievement.id);
      } else if (achievement.category == 'quiz' && achievement.requirements.type == 'quiz_completion' &&
                 achievement.requirements.checkCondition(1)) {
        await _unlockAchievement(userId, achievement.id);
      } else if (achievement.category == 'concept' && achievement.requirements.type == 'concepts_mastered' &&
                 achievement.requirements.checkCondition(userStats.masteredConcepts.length)) {
        await _unlockAchievement(userId, achievement.id);
      } else {
        Logger.info('Achievement not matched: ${achievement.id} - category: ${achievement.category}, type: ${achievement.requirements.type}');
      }
    }
    
    Logger.info('=== END CHECKING QUIZ ACHIEVEMENTS ===');
    // Verificar conquistas genéricas de número de quizzes
    await _checkQuizCountAchievements(userId, completedQuizzes);
  }

  static Future<void> _checkQuizCountAchievements(String userId, int completedQuizzes) async {
    final achievements = await getAvailableAchievements();
    final quizCountAchievements = achievements.where((a) => a.category == 'quiz_count');

    for (final achievement in quizCountAchievements) {
      if (achievement.requirements.type == 'quiz_completion' &&
          achievement.requirements.checkCondition(completedQuizzes)) {
        await _unlockAchievement(userId, achievement.id);
      }
    }
  }

  static Future<void> _unlockAchievement(String userId, String achievementId) async {
    try {
      Logger.info('=== ATTEMPTING TO UNLOCK ACHIEVEMENT ===');
      Logger.info('Achievement ID: $achievementId');
      Logger.info('User ID: $userId');
      
      final userStatsRef = _firestore.collection('users').doc(userId);
      final userStatsDoc = await userStatsRef.get();

      if (!userStatsDoc.exists) {
        Logger.error('User stats document does not exist for user $userId');
        return;
      }

      final userStats = UserStats.fromFirestore(userStatsDoc.data()!, userId);
      Logger.info('Current unlocked achievements count: ${userStats.unlockedAchievements.length}');
      
      // Verificar se já desbloqueou
      final alreadyUnlocked = userStats.unlockedAchievements
          .any((a) => a.achievementId == achievementId);

      Logger.info('Already unlocked: $alreadyUnlocked');

      if (!alreadyUnlocked) {
        final unlockedAchievement = UnlockedAchievement(
          achievementId: achievementId,
          unlockedAt: DateTime.now(),
          metadata: {},
        );

        Logger.info('Adding achievement to Firestore...');
        await userStatsRef.update({
          'unlockedAchievements': FieldValue.arrayUnion([unlockedAchievement.toFirestore()]),
        });

        Logger.info('Achievement unlocked successfully: $achievementId for user $userId');
      } else {
        Logger.info('Achievement $achievementId already unlocked for user $userId');
      }
    } catch (e) {
      Logger.error('Error unlocking achievement: $e');
    }
  }

  /// Inicializar estatísticas do usuário
  static Future<void> _initializeUserStats(String userId) async {
    try {
      final userStatsRef = _firestore.collection('users').doc(userId);
      
      // Verificar se já existe
      final doc = await userStatsRef.get();
      if (doc.exists) {
        // Apenas atualizar com completedQuizzes se não existir
        final data = doc.data() as Map<String, dynamic>;
        if (!data.containsKey('completedQuizzes')) {
          await userStatsRef.update({
            'completedQuizzes': 0,
          });
        }
      } else {
        // Criar documento inicial
        await userStatsRef.set({
          'completedQuizzes': 0,
          'currentStreak': 0,
          'longestStreak': 0,
          'totalStudyTime': 0,
          'weeklyStudyTime': 0,
          'monthlyStudyTime': 0,
          'masteredConcepts': [],
          'unlockedAchievements': [],
        });
      }
      
      Logger.info('User stats initialized for user $userId');
    } catch (e) {
      Logger.error('Error initializing user stats: $e');
    }
  }
}