// lib/screens/quiz_screen.dart
// (Manter as importações)

import 'package:flutter/material.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:provider/provider.dart';
import 'package:intl/intl.dart';
import 'package:shared_preferences/shared_preferences.dart';

import 'package:kzeduca_app/services/i18n_service.dart';
import 'package:kzeduca_app/services/firebase_service.dart';
import 'package:kzeduca_app/models/app_models.dart';
import 'dart:math';

import 'daily_quiz_screen.dart'; // Importar a nova tela do quiz diário

class QuizScreen extends StatefulWidget {
  const QuizScreen({super.key});

  @override
  State<QuizScreen> createState() => _QuizScreenState();
}

class _QuizScreenState extends State<QuizScreen> {
  List<QuizQuestion> _allQuestions = [];
  List<QuizQuestion> _currentQuizQuestions = [];
  List<UserQuizResult> _quizResults = [];
  bool _isLoading = true;
  String _error = '';
  bool _quizStarted = false;
  int _currentQuestionIndex = 0;
  int _score = 0;
  String? _selectedOption;
  bool _showAnswerFeedback = false;
  bool _quizFinished = false;

  FinancialChallenge? _dailyChallengeNotification;

  @override
  void initState() {
    super.initState();
    _loadAllQuizData();
    _checkDailyChallengeStatus();
  }

  // (Manter _showAlertDialog e _checkDailyChallengeStatus)
  void _showAlertDialog(String message, {bool isError = false}) {
    final i18n = Provider.of<I18nService>(context, listen: false);
    showDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        title: Text(isError ? i18n.t('error_prefix') : 'Info'),
        content: Text(message),
        actions: <Widget>[
          TextButton(
            child: const Text('Ok'),
            onPressed: () {
              Navigator.of(ctx).pop();
            },
          )
        ],
      ),
    );
  }

  Future<void> _checkDailyChallengeStatus() async {
    final prefs = await SharedPreferences.getInstance();
    final lastCompletionDate = prefs.getString('daily_quiz_completion_date');
    final today = DateFormat('yyyy-MM-dd').format(DateTime.now());

    // A notificação deve aparecer se nunca foi completada hoje
    if (lastCompletionDate != today) {
      final firebaseService = Provider.of<FirebaseService>(context, listen: false);
      try {
        final allChallenges = await firebaseService.getAllChallenges();
        if (allChallenges.isNotEmpty) {
          final random = Random();
          setState(() {
            _dailyChallengeNotification = allChallenges[random.nextInt(allChallenges.length)];
          });
        }
      } catch (e) {
        print("Erro ao carregar desafios para notificação: $e");
      }
    } else {
      setState(() {
        _dailyChallengeNotification = null;
      });
    }
  }

  Future<void> _loadAllQuizData() async {
    final firebaseService = Provider.of<FirebaseService>(context, listen: false);
    final userId = FirebaseAuth.instance.currentUser?.uid;

    setState(() {
      _isLoading = true;
      _error = '';
    });

    try {
      final querySnapshot = await firebaseService.firestore
          .collection('artifacts')
          .doc('default-kzeduca-app')
          .collection('public')
          .doc('data')
          .collection('quizQuestions')
          .get();
      
      _allQuestions = querySnapshot.docs.map((doc) => QuizQuestion.fromFirestore(doc)).toList();
      
      // Carrega resultados do utilizador
      firebaseService.streamUserQuizResults(userId!).listen((snapshot) {
        if (mounted) {
          setState(() {
            _quizResults = snapshot.docs.map((doc) => UserQuizResult.fromFirestore(doc)).toList();
            _quizResults.sort((a, b) => DateTime.parse(b.timestamp).compareTo(DateTime.parse(a.timestamp)));
          });
        }
      });
    } catch (e) {
      print("Erro geral ao carregar dados do quiz: $e");
      if (mounted) {
        _showAlertDialog("Erro ao carregar dados do quiz.", isError: true);
      }
    } finally {
      if (mounted) {
        setState(() {
          _isLoading = false;
        });
      }
    }
  }

  void _startRandomQuiz() {
    if (_allQuestions.length < 5) {
      _showAlertDialog('Não há perguntas suficientes para começar o quiz.');
      return;
    }
    
    _allQuestions.shuffle();
    _currentQuizQuestions = _allQuestions.take(5).toList();

    setState(() {
      _quizStarted = true;
      _quizFinished = false;
      _currentQuestionIndex = 0;
      _score = 0;
      _selectedOption = null;
      _showAnswerFeedback = false;
    });
  }
  
  // Resto da lógica do quiz (handleAnswer, handleNextQuestion, saveQuizResult)

  Future<void> _handleAnswer(String option) async {
    if (_showAnswerFeedback) return;

    setState(() {
      _selectedOption = option;
      _showAnswerFeedback = true;
      if (option == _currentQuizQuestions[_currentQuestionIndex].answer) {
        _score++;
      }
    });

    // Lógica para ir para a próxima pergunta
    await Future.delayed(const Duration(seconds: 2));
    if (mounted) {
       _handleNextQuestion();
    }
  }

  Future<void> _handleNextQuestion() async {
    setState(() {
      _selectedOption = null;
      _showAnswerFeedback = false;
    });

    if (_currentQuestionIndex < _currentQuizQuestions.length - 1) {
      setState(() {
        _currentQuestionIndex++;
      });
    } else {
      await _saveQuizResult();
      setState(() {
        _quizStarted = false;
        _quizFinished = true;
      });
    }
  }

  Future<void> _saveQuizResult() async {
    final i18n = Provider.of<I18nService>(context, listen: false);
    final firebaseService = Provider.of<FirebaseService>(context, listen: false);
    final userId = FirebaseAuth.instance.currentUser?.uid;

    if (userId == null || _currentQuizQuestions.isEmpty) {
      _showAlertDialog(i18n.t('quiz_save_error'), isError: true);
      return;
    }

    try {
      await firebaseService.saveQuizResult(userId, {
        'score': _score,
        'totalQuestions': _currentQuizQuestions.length,
        'timestamp': DateTime.now().toIso8601String(),
      });
      _showAlertDialog(i18n.t('quiz_saved'));
    } catch (e) {
      print("Erro ao salvar resultado do quiz: $e");
      _showAlertDialog(i18n.t('quiz_save_error'), isError: true);
    }
  }

  void _showDailyChallengeNotificationDialog(FinancialChallenge challenge) {
    final i18n = Provider.of<I18nService>(context, listen: false);
    showDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(20)),
        backgroundColor: Colors.purple[900]?.withOpacity(0.8),
        title: Text(
          i18n.t('bonus_daily_challenge'),
          style: const TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
        ),
        content: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            const Icon(Icons.star, color: Colors.amber, size: 40),
            const SizedBox(height: 10),
            Text(
              '${i18n.t('congratulations_quiz_bonus_intro')}!',
              style: const TextStyle(color: Colors.white, fontSize: 16),
            ),
            const SizedBox(height: 20),
            Text(
              challenge.nome,
              style: const TextStyle(
                color: Colors.white,
                fontWeight: FontWeight.bold,
                fontSize: 18,
              ),
            ),
            const SizedBox(height: 5),
            Text(
              challenge.meta,
              style: TextStyle(color: Colors.white.withOpacity(0.8), fontSize: 14),
            ),
          ],
        ),
        actions: <Widget>[
          TextButton(
            child: Text(
              i18n.t('accept_challenge'),
              style: const TextStyle(color: Colors.amber, fontWeight: FontWeight.bold),
            ),
            onPressed: () {
              Navigator.of(ctx).pop();
            },
          ),
          TextButton(
            child: Text(
              i18n.t('later'),
              style: TextStyle(color: Colors.white.withOpacity(0.7)),
            ),
            onPressed: () {
              Navigator.of(ctx).pop();
            },
          ),
        ],
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final i18n = Provider.of<I18nService>(context);

    return Scaffold(
      extendBodyBehindAppBar: true,
      appBar: AppBar(
        title: Text(i18n.t('financial_quiz')),
        backgroundColor: Colors.black.withOpacity(0.5),
        foregroundColor: Colors.white,
        elevation: 0,
      ),
      body: Stack(
        children: [
          Container(
            decoration: const BoxDecoration(
              image: DecorationImage(
                image: AssetImage('assets/images/quiz_background.png'),
                fit: BoxFit.cover,
              ),
            ),
          ),
          Center(
            child: SingleChildScrollView(
              padding: const EdgeInsets.all(16.0),
              child: Container(
                padding: const EdgeInsets.all(32.0),
                decoration: BoxDecoration(
                  color: Colors.black.withOpacity(0.7),
                  borderRadius: BorderRadius.circular(24.0),
                  border: Border.all(color: Colors.white.withOpacity(0.2)),
                  boxShadow: [
                    BoxShadow(
                      color: Colors.black.withOpacity(0.5),
                      blurRadius: 32,
                      offset: const Offset(0, 8),
                    ),
                  ],
                ),
                constraints: const BoxConstraints(maxWidth: 600),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.stretch,
                  children: [
                    if (_dailyChallengeNotification != null)
                      GestureDetector(
                        onTap: () {
                          // Navegar para a tela do quiz diário
                          Navigator.push(
                            context,
                            MaterialPageRoute(
                              builder: (context) => DailyQuizScreen(
                                dailyChallenge: _dailyChallengeNotification!,
                              ),
                            ),
                          ).then((_) => _checkDailyChallengeStatus()); // Atualiza o estado ao voltar
                        },
                        child: Container(
                          padding: const EdgeInsets.all(16),
                          margin: const EdgeInsets.only(bottom: 24),
                          decoration: BoxDecoration(
                            color: Colors.purple[800]?.withOpacity(0.8),
                            borderRadius: BorderRadius.circular(12),
                            border: Border.all(color: Colors.amber, width: 2),
                          ),
                          child: Row(
                            children: [
                              const Icon(Icons.notifications_active, color: Colors.amber, size: 30),
                              const SizedBox(width: 16),
                              Expanded(
                                child: Text(
                                  i18n.t('daily_challenge_notification'),
                                  style: const TextStyle(
                                    color: Colors.white,
                                    fontWeight: FontWeight.bold,
                                    fontSize: 16,
                                  ),
                                ),
                              ),
                              const Icon(Icons.arrow_forward_ios, color: Colors.white, size: 16),
                            ],
                          ),
                        ),
                      ),
                    
                    Text(
                      i18n.t('test_knowledge'),
                      style: TextStyle(fontSize: 16, color: Colors.white.withOpacity(0.7)),
                      textAlign: TextAlign.center,
                    ),
                    const SizedBox(height: 24),
                    if (_isLoading)
                      const Center(child: CircularProgressIndicator())
                    else if (_allQuestions.isEmpty)
                      Text(
                        'Nenhuma pergunta de quiz disponível. Por favor, adicione perguntas no Firestore.',
                        style: TextStyle(color: Colors.white.withOpacity(0.8)),
                        textAlign: TextAlign.center,
                      )
                    else if (!_quizStarted && !_quizFinished)
                      Column(
                        children: [
                          Icon(Icons.lightbulb_outline, size: 80, color: Colors.teal[400]),
                          const SizedBox(height: 16),
                          Text(
                            i18n.t('ready_for_challenge'),
                            style: TextStyle(fontSize: 22, fontWeight: FontWeight.bold, color: Colors.white),
                            textAlign: TextAlign.center,
                          ),
                          const SizedBox(height: 10),
                          Text(
                            'Teste os seus conhecimentos sobre finanças de forma divertida e interativa!',
                            style: TextStyle(fontSize: 16, color: Colors.white.withOpacity(0.7)),
                            textAlign: TextAlign.center,
                          ),
                          const SizedBox(height: 24),
                          ElevatedButton.icon(
                            onPressed: _startRandomQuiz, // Inicia o quiz aleatório de 5 perguntas
                            icon: const Icon(Icons.play_arrow),
                            label: Text(i18n.t('start_quiz')),
                            style: ElevatedButton.styleFrom(
                              backgroundColor: Colors.teal[500],
                              foregroundColor: Colors.white,
                              padding: const EdgeInsets.symmetric(vertical: 16, horizontal: 30),
                              shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
                              elevation: 8,
                              shadowColor: Colors.teal[300]?.withOpacity(0.5),
                            ),
                          ),
                          const SizedBox(height: 30),
                          Text(
                            i18n.t('quiz_results_history'),
                            style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold, color: Colors.white),
                            textAlign: TextAlign.center,
                          ),
                          const SizedBox(height: 16),
                          _quizResults.isEmpty
                              ? Text(i18n.t('no_quiz_results'), style: TextStyle(color: Colors.white.withOpacity(0.6)), textAlign: TextAlign.center)
                              : ListView.builder(
                                  shrinkWrap: true,
                                  physics: const NeverScrollableScrollPhysics(),
                                  itemCount: _quizResults.length,
                                  itemBuilder: (context, index) {
                                    final result = _quizResults[index];
                                    return Card(
                                      elevation: 2,
                                      margin: const EdgeInsets.symmetric(vertical: 8),
                                      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
                                      color: Colors.black.withOpacity(0.4),
                                      child: Padding(
                                        padding: const EdgeInsets.all(16.0),
                                        child: Column(
                                          crossAxisAlignment: CrossAxisAlignment.start,
                                          children: [
                                            Text(
                                              i18n.t('your_score', options: {
                                                'score': result.score.toString(),
                                                'total': result.totalQuestions.toString(),
                                              }),
                                              style: const TextStyle(fontSize: 16, fontWeight: FontWeight.w600, color: Colors.white),
                                            ),
                                            Text(
                                              'Em: ${DateFormat('dd/MM/yyyy HH:mm').format(DateTime.parse(result.timestamp).toLocal())}',
                                              style: TextStyle(fontSize: 14, color: Colors.white.withOpacity(0.7)),
                                            ),
                                            if (result.score / result.totalQuestions >= 0.7)
                                              Align(
                                                alignment: Alignment.bottomRight,
                                                child: Text('Parabéns! Ótimo resultado!', style: TextStyle(color: Colors.green[300], fontStyle: FontStyle.italic)),
                                              )
                                          ],
                                        ),
                                      ),
                                    );
                                  },
                                ),
                        ],
                      )
                    else if (_quizStarted && !_quizFinished)
                      Column(
                        children: [
                          LinearProgressIndicator(
                            value: (_currentQuestionIndex + 1) / _currentQuizQuestions.length,
                            backgroundColor: Colors.white.withOpacity(0.3),
                            color: Colors.teal[400],
                            minHeight: 10,
                            borderRadius: BorderRadius.circular(5),
                          ),
                          const SizedBox(height: 16),
                          Text(
                            'Questão ${_currentQuestionIndex + 1} de ${_currentQuizQuestions.length}',
                            style: TextStyle(fontSize: 14, color: Colors.white.withOpacity(0.6)),
                            textAlign: TextAlign.center,
                          ),
                          const SizedBox(height: 16),
                          Text(
                            _currentQuizQuestions[_currentQuestionIndex].question,
                            style: const TextStyle(fontSize: 20, fontWeight: FontWeight.bold, color: Colors.white),
                            textAlign: TextAlign.center,
                          ),
                          const SizedBox(height: 24),
                          ..._currentQuizQuestions[_currentQuestionIndex].options.map((option) {
                            bool isCorrect = option == _currentQuizQuestions[_currentQuestionIndex].answer;
                            bool isSelected = option == _selectedOption;
                            return Padding(
                              padding: const EdgeInsets.symmetric(vertical: 8.0),
                              child: ElevatedButton(
                                onPressed: _showAnswerFeedback ? null : () => _handleAnswer(option),
                                style: ElevatedButton.styleFrom(
                                  backgroundColor: _showAnswerFeedback
                                      ? (isCorrect ? Colors.green[500] : Colors.red[500])
                                      : Colors.black.withOpacity(0.4),
                                  foregroundColor: Colors.white,
                                  side: BorderSide(
                                    color: _showAnswerFeedback
                                        ? (isCorrect ? Colors.green[400]! : Colors.red[400]!)
                                        : Colors.white.withOpacity(0.3),
                                    width: 1,
                                  ),
                                  padding: const EdgeInsets.all(16),
                                  shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
                                  elevation: isSelected ? 4 : 2,
                                ),
                                child: Align(
                                  alignment: Alignment.centerLeft,
                                  child: Text(option, style: const TextStyle(fontSize: 16)),
                                ),
                              ),
                            );
                          }),
                          if (_showAnswerFeedback) ...[
                            const SizedBox(height: 16),
                            Card(
                              elevation: 4,
                              shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
                              color: _selectedOption == _currentQuizQuestions[_currentQuestionIndex].answer
                                  ? Colors.green[900]?.withOpacity(0.6)
                                  : Colors.red[900]?.withOpacity(0.6),
                              child: Padding(
                                padding: const EdgeInsets.all(16.0),
                                child: Column(
                                  crossAxisAlignment: CrossAxisAlignment.start,
                                  children: [
                                    Text(
                                      _selectedOption == _currentQuizQuestions[_currentQuestionIndex].answer
                                          ? i18n.t('correct')
                                          : i18n.t('incorrect'),
                                      style: const TextStyle(
                                        fontSize: 18,
                                        fontWeight: FontWeight.bold,
                                        color: Colors.white,
                                      ),
                                    ),
                                    const SizedBox(height: 8),
                                    Text(
                                      _currentQuizQuestions[_currentQuestionIndex].explanation,
                                      style: TextStyle(fontSize: 16, color: Colors.white.withOpacity(0.9)),
                                    ),
                                  ],
                                ),
                              ),
                            ),
                          ],
                          const SizedBox(height: 24),
                          ElevatedButton.icon(
                            onPressed: _showAnswerFeedback ? _handleNextQuestion : null,
                            icon: Icon(_currentQuestionIndex < _currentQuizQuestions.length - 1 ? Icons.arrow_forward : Icons.bar_chart),
                            label: Text(
                              _currentQuestionIndex < _currentQuizQuestions.length - 1
                                  ? i18n.t('next_question')
                                  : i18n.t('view_results'),
                            ),
                            style: ElevatedButton.styleFrom(
                              backgroundColor: Colors.blue[500],
                              foregroundColor: Colors.white,
                              padding: const EdgeInsets.symmetric(vertical: 16),
                              shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
                              elevation: 8,
                              shadowColor: Colors.blue[300]?.withOpacity(0.5),
                            ),
                          ),
                        ],
                      )
                    else if (_quizFinished)
                      Column(
                        children: [
                          Icon(Icons.emoji_events, size: 80, color: Colors.amber[600]),
                          const SizedBox(height: 16),
                          Text(
                            i18n.t('quiz_finished'),
                            style: TextStyle(fontSize: 22, fontWeight: FontWeight.bold, color: Colors.white),
                            textAlign: TextAlign.center,
                          ),
                          const SizedBox(height: 10),
                          Text(
                            i18n.t('your_final_score', options: {
                              'score': _score.toString(),
                              'total': _currentQuizQuestions.length.toString(),
                            }),
                            style: TextStyle(fontSize: 20, color: Colors.teal[300], fontWeight: FontWeight.bold),
                            textAlign: TextAlign.center,
                          ),
                          const SizedBox(height: 24),
                          ElevatedButton.icon(
                            onPressed: () {
                              _startRandomQuiz();
                            },
                            icon: const Icon(Icons.refresh),
                            label: Text(i18n.t('retake_quiz')),
                            style: ElevatedButton.styleFrom(
                              backgroundColor: Colors.teal[500],
                              foregroundColor: Colors.white,
                              padding: const EdgeInsets.symmetric(vertical: 16, horizontal: 30),
                              shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
                              elevation: 8,
                              shadowColor: Colors.teal[300]?.withOpacity(0.5),
                            ),
                          ),
                          const SizedBox(height: 16),
                          ElevatedButton.icon(
                            onPressed: () {
                              _quizFinished = false;
                              _quizStarted = false;
                              setState(() {});
                            },
                            icon: const Icon(Icons.history),
                            label: Text(i18n.t('view_all_results')),
                            style: ElevatedButton.styleFrom(
                              backgroundColor: Colors.blueGrey[500],
                              foregroundColor: Colors.white,
                              padding: const EdgeInsets.symmetric(vertical: 16, horizontal: 30),
                              shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
                              elevation: 8,
                            ),
                          ),
                        ],
                      ),
                  ],
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}