import 'package:test/test.dart';
import 'package:practice_engine/models/question.dart';
import 'package:practice_engine/models/deck_config.dart';
import 'package:practice_engine/logic/deck_service.dart';

void main() {
  group('Question State Transitions', () {
    late DeckConfig config;

    setUp(() {
      config = const DeckConfig(requiredConsecutiveCorrect: 3);
    });

    test('correct answer increments streak', () {
      final question = Question(
        id: 'q1',
        prompt: 'Test',
        answers: ['A', 'B'],
        correctAnswerIndices: [0],
        consecutiveCorrect: 1,
      );

      final updated = DeckService.updateQuestionAfterAnswer(
        question: question,
        isCorrect: true,
        config: config,
        currentAttemptIndex: 0,
      );

      expect(updated.consecutiveCorrect, equals(2));
    });

    test('incorrect answer resets streak', () {
      final question = Question(
        id: 'q1',
        prompt: 'Test',
        answers: ['A', 'B'],
        correctAnswerIndices: [0],
        consecutiveCorrect: 2,
      );

      final updated = DeckService.updateQuestionAfterAnswer(
        question: question,
        isCorrect: false,
        config: config,
        currentAttemptIndex: 0,
      );

      expect(updated.consecutiveCorrect, equals(0));
    });

    test('question becomes known when streak reaches threshold', () {
      final question = Question(
        id: 'q1',
        prompt: 'Test',
        answers: ['A', 'B'],
        correctAnswerIndices: [0],
        consecutiveCorrect: 2,
        isKnown: false,
      );

      final updated = DeckService.updateQuestionAfterAnswer(
        question: question,
        isCorrect: true,
        config: config,
        currentAttemptIndex: 0,
      );

      expect(updated.consecutiveCorrect, equals(3));
      expect(updated.isKnown, equals(true));
    });

    test('incorrect answer sets isKnown to false', () {
      final question = Question(
        id: 'q1',
        prompt: 'Test',
        answers: ['A', 'B'],
        correctAnswerIndices: [0],
        consecutiveCorrect: 3,
        isKnown: true,
      );

      final updated = DeckService.updateQuestionAfterAnswer(
        question: question,
        isCorrect: false,
        config: config,
        currentAttemptIndex: 0,
      );

      expect(updated.isKnown, equals(false));
      expect(updated.consecutiveCorrect, equals(0));
    });

    test('priority increases on incorrect answer', () {
      final question = Question(
        id: 'q1',
        prompt: 'Test',
        answers: ['A', 'B'],
        correctAnswerIndices: [0],
        priorityPoints: 5,
      );

      final updated = DeckService.updateQuestionAfterAnswer(
        question: question,
        isCorrect: false,
        config: config,
        currentAttemptIndex: 0,
      );

      expect(updated.priorityPoints,
          equals(5 + config.priorityIncreaseOnIncorrect));
    });

    test('priority decreases on correct answer', () {
      final question = Question(
        id: 'q1',
        prompt: 'Test',
        answers: ['A', 'B'],
        correctAnswerIndices: [0],
        priorityPoints: 10,
      );

      final updated = DeckService.updateQuestionAfterAnswer(
        question: question,
        isCorrect: true,
        config: config,
        currentAttemptIndex: 0,
      );

      expect(updated.priorityPoints,
          equals(10 - config.priorityDecreaseOnCorrect));
    });

    test('priority cannot go below 0', () {
      final question = Question(
        id: 'q1',
        prompt: 'Test',
        answers: ['A', 'B'],
        correctAnswerIndices: [0],
        priorityPoints: 1,
      );

      final updated = DeckService.updateQuestionAfterAnswer(
        question: question,
        isCorrect: true,
        config: config,
        currentAttemptIndex: 0,
      );

      expect(updated.priorityPoints, equals(0));
    });

    test('lastAttemptIndex is updated', () {
      final question = Question(
        id: 'q1',
        prompt: 'Test',
        answers: ['A', 'B'],
        correctAnswerIndices: [0],
        lastAttemptIndex: 5,
      );

      final updated = DeckService.updateQuestionAfterAnswer(
        question: question,
        isCorrect: true,
        config: config,
        currentAttemptIndex: 10,
      );

      expect(updated.lastAttemptIndex, equals(10));
    });

    test('totalAttempts increments on both correct and incorrect', () {
      final question = Question(
        id: 'q1',
        prompt: 'Test',
        answers: ['A', 'B'],
        correctAnswerIndices: [0],
        totalAttempts: 5,
        totalCorrectAttempts: 3,
      );

      final updatedCorrect = DeckService.updateQuestionAfterAnswer(
        question: question,
        isCorrect: true,
        config: config,
        currentAttemptIndex: 0,
      );

      expect(updatedCorrect.totalAttempts, equals(6));
      expect(updatedCorrect.totalCorrectAttempts, equals(4));

      final updatedIncorrect = DeckService.updateQuestionAfterAnswer(
        question: question,
        isCorrect: false,
        config: config,
        currentAttemptIndex: 0,
      );

      expect(updatedIncorrect.totalAttempts, equals(6));
      expect(updatedIncorrect.totalCorrectAttempts, equals(3));
    });
  });
}