import 'package:flutter/material.dart';
import 'package:practice_engine/practice_engine.dart';
import '../routes.dart';
import '../widgets/question_card.dart';
import '../widgets/answer_option.dart';

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

  @override
  State<AttemptScreen> createState() => _AttemptScreenState();
}

class _AttemptScreenState extends State<AttemptScreen> {
  Deck? _deck;
  Attempt? _attempt;
  AttemptService? _attemptService;
  int _currentQuestionIndex = 0;
  int? _selectedAnswerIndex;
  final Map<String, int> _answers = {};
  final Map<String, bool> _manualOverrides = {};

  @override
  void initState() {
    super.initState();
    _attemptService = AttemptService();
  }

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    if (_deck == null) {
      // Get deck from route arguments
      final args = ModalRoute.of(context)?.settings.arguments;
      _deck = args is Deck ? args : _createSampleDeck();
      _attempt = _attemptService!.createAttempt(deck: _deck!);
    }
  }

  Deck _createSampleDeck() {
    const config = DeckConfig();
    final questions = List.generate(10, (i) {
      return Question(
        id: 'q$i',
        prompt: 'Sample Question $i?',
        answers: ['A', 'B', 'C', 'D'],
        correctAnswerIndex: i % 4,
      );
    });
    return Deck(
      id: 'sample',
      title: 'Sample',
      description: 'Sample',
      questions: questions,
      config: config,
    );
  }

  Question get _currentQuestion => _attempt!.questions[_currentQuestionIndex];
  bool get _isLastQuestion => _currentQuestionIndex == _attempt!.questions.length - 1;
  bool get _hasAnswer => _selectedAnswerIndex != null;

  void _selectAnswer(int index) {
    setState(() {
      _selectedAnswerIndex = index;
    });

    if (_deck != null && _deck!.config.immediateFeedbackEnabled) {
      // Show feedback immediately
    }
  }

  void _submitAnswer() {
    if (_selectedAnswerIndex == null) return;

    _answers[_currentQuestion.id] = _selectedAnswerIndex!;

    if (_isLastQuestion) {
      _completeAttempt();
    } else {
      setState(() {
        _currentQuestionIndex++;
        _selectedAnswerIndex = null;
      });
    }
  }

  void _markAsKnown() {
    if (_deck == null) return;
    setState(() {
      _manualOverrides[_currentQuestion.id] = false; // Not needs practice
      _deck = DeckService.markQuestionAsKnown(
        deck: _deck!,
        questionId: _currentQuestion.id,
      );
    });

    ScaffoldMessenger.of(context).showSnackBar(
      const SnackBar(
        content: Text('Question marked as Known'),
        backgroundColor: Colors.green,
      ),
    );
  }

  void _markAsNeedsPractice() {
    if (_deck == null) return;
    setState(() {
      _manualOverrides[_currentQuestion.id] = true;
      _deck = DeckService.markQuestionAsNeedsPractice(
        deck: _deck!,
        questionId: _currentQuestion.id,
      );
    });

    ScaffoldMessenger.of(context).showSnackBar(
      const SnackBar(
        content: Text('Question marked as Needs Practice'),
      ),
    );
  }

  void _completeAttempt() {
    if (_deck == null || _attempt == null || _attemptService == null) return;
    
    final result = _attemptService!.processAttempt(
      deck: _deck!,
      attempt: _attempt!,
      answers: _answers,
      manualOverrides: _manualOverrides,
      endTime: DateTime.now().millisecondsSinceEpoch,
    );

    Navigator.pushReplacementNamed(
      context,
      Routes.attemptResult,
      arguments: {
        'deck': result.updatedDeck,
        'result': result.result,
        'attempt': _attempt,
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    if (_deck == null || _attempt == null) {
      return const Scaffold(
        body: Center(child: CircularProgressIndicator()),
      );
    }

    return Scaffold(
      appBar: AppBar(
        title: Text('Attempt - ${_deck!.title}'),
      ),
      body: Column(
        children: [
          // Progress Indicator
          LinearProgressIndicator(
            value: (_currentQuestionIndex + 1) / _attempt!.questions.length,
            minHeight: 4,
          ),
          const SizedBox(height: 8),
          Padding(
            padding: const EdgeInsets.symmetric(horizontal: 16),
            child: Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                Text(
                  'Question ${_currentQuestionIndex + 1} of ${_attempt!.questions.length}',
                  style: Theme.of(context).textTheme.bodyMedium,
                ),
                if (_currentQuestion.isKnown)
                  Chip(
                    label: const Text('Known'),
                    avatar: const Icon(Icons.check_circle, size: 18),
                  ),
              ],
            ),
          ),

          // Question Card
          Expanded(
            child: SingleChildScrollView(
              padding: const EdgeInsets.all(16),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: [
                  QuestionCard(question: _currentQuestion),
                  const SizedBox(height: 24),

                  // Answer Options
                  ...List.generate(
                    _currentQuestion.answers.length,
                    (index) => Padding(
                      padding: const EdgeInsets.only(bottom: 8),
                      child: AnswerOption(
                        text: _currentQuestion.answers[index],
                        isSelected: _selectedAnswerIndex == index,
                        onTap: () => _selectAnswer(index),
                        isCorrect: _deck != null && _deck!.config.immediateFeedbackEnabled &&
                                _selectedAnswerIndex == index
                            ? index == _currentQuestion.correctAnswerIndex
                            : null,
                      ),
                    ),
                  ),

                  const SizedBox(height: 24),

                  // Manual Override Buttons
                  Card(
                    child: Padding(
                      padding: const EdgeInsets.all(16),
                      child: Column(
                        crossAxisAlignment: CrossAxisAlignment.stretch,
                        children: [
                          Text(
                            'Manual Override',
                            style: Theme.of(context).textTheme.titleSmall,
                          ),
                          const SizedBox(height: 12),
                          Row(
                            children: [
                              Expanded(
                                child: OutlinedButton.icon(
                                  onPressed: _markAsKnown,
                                  icon: const Icon(Icons.check_circle),
                                  label: const Text('Mark as Known'),
                                ),
                              ),
                              const SizedBox(width: 8),
                              Expanded(
                                child: OutlinedButton.icon(
                                  onPressed: _markAsNeedsPractice,
                                  icon: const Icon(Icons.school),
                                  label: const Text('Needs Practice'),
                                ),
                              ),
                            ],
                          ),
                        ],
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ),

          // Submit/Next Button
          Padding(
            padding: const EdgeInsets.all(16),
            child: FilledButton(
              onPressed: _hasAnswer ? _submitAnswer : null,
              style: FilledButton.styleFrom(
                padding: const EdgeInsets.symmetric(vertical: 16),
              ),
              child: Text(_isLastQuestion ? 'Complete Attempt' : 'Next Question'),
            ),
          ),
        ],
      ),
    );
  }
}