import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:kouyu_english/core/app_state.dart';
import 'package:kouyu_english/core/courses/courses.dart';
import 'package:kouyu_english/core/models.dart';
import 'package:kouyu_english/features/review/review_page.dart';

/// Knowing what a sentence means is not knowing when to say it. The packs
/// carry that as `usage`; these cover what the app does with it — learning
/// engine 3.1 (what counts as which evidence) and 3.5 (recognition inside a
/// situation).
void main() {
  ReviewItem due(String id) => ReviewItem(
    id: id,
    target: coreItemEnglish(id),
    prompt: coreReviewTemplate(id).prompt,
    hint: coreItemEnglish(id),
    dueAt: DateTime.now().subtract(const Duration(hours: 1)),
    skill: '回忆表达',
  );

  test('the pack says when a pattern is used and what it is confused with', () {
    final usage = coreUsage('A0-P02')!;
    expect(usage.when, isNotEmpty);
    expect(usage.reply, isNotEmpty);
    expect(
      usage.confuse.map((entry) => entry.id),
      contains('A0-P05'),
      reason: 'What\'s your name? 和 How are you? 正是分不清的那一对',
    );
  });

  test('a contrast question asks which sentence the situation calls for', () {
    final question = coreContrastQuestion('A0-P02')!;
    expect(question.situation, coreUsage('A0-P02')!.when);
    expect(question.answer, coreItemSpoken('A0-P02'));
    expect(question.options, contains(coreItemSpoken('A0-P05')));
    expect(question.note, isNotEmpty);
  });

  test('an untaught confusable is left out of the question', () {
    // `How are you?` is taught two units later than `What's your name?`, so
    // on the day P02 is first reviewed it is not a choice the learner could
    // make sense of. Its same-unit partner still is.
    final early = coreContrastQuestion('A0-P02', isTaught: (_) => false)!;
    expect(early.options, isNot(contains(coreItemSpoken('A0-P05'))));
    expect(early.options, contains(coreItemSpoken('A0-P01')));
    // Once the learner has met it, it is the option worth offering.
    final later = coreContrastQuestion(
      'A0-P02',
      isTaught: (id) => id == 'A0-P05',
    )!;
    expect(later.options, contains(coreItemSpoken('A0-P05')));
  });

  test('a contrast question never offers more than three sentences', () {
    // `What's your name?` is confused with three other taught sentences.
    expect(coreUsage('A0-P02')!.confuse.length, greaterThan(2));
    expect(coreContrastQuestion('A0-P02')!.options, hasLength(3));
  });

  test('answering a contrast question records 认识, not a checkpoint', () {
    final state = AppState();
    final item = due('A0-P02');
    state.reviewQueue.add(item);
    state.recordContrastAnswer(item, correct: true);
    final mastery = state.mastery['A0-P02']!;
    expect(mastery.status, MasteryStatus.recognize);
    expect(mastery.checkpoint, 0);
    // It is not recall either: the learner picked the sentence, not said it.
    expect(mastery.status, isNot(MasteryStatus.recall));
  });

  test('a contrast answer survives rebuilding mastery from evidence', () {
    final state = AppState();
    final item = due('A0-P02');
    state.reviewQueue.add(item);
    state.recordContrastAnswer(item, correct: true);
    state.rebuildMasteryFromEvidence();
    expect(state.mastery['A0-P02']!.checkpoint, 0);
    expect(state.mastery['A0-P02']!.status, MasteryStatus.recognize);
  });

  test('the contrast question cannot undo the miss that led to it', () {
    final state = AppState();
    final item = due('A0-P02');
    state.reviewQueue.add(item);
    state.reportReviewFailure(item);
    expect(state.mastery['A0-P02']!.needsReview, isTrue);
    state.recordContrastAnswer(item, correct: true);
    expect(state.mastery['A0-P02']!.needsReview, isTrue);
    expect(state.mastery['A0-P02']!.checkpoint, 0);
  });

  test('getting the contrast wrong is not a language failure', () {
    final state = AppState();
    final item = due('A0-P02');
    state.reviewQueue.add(item);
    state.recordContrastAnswer(item, correct: false);
    expect(state.mastery['A0-P02']!.needsReview, isFalse);
    expect(state.mastery['A0-P02']!.checkpoint, 0);
  });

  testWidgets('a miss opens the explanation, then the contrast question', (
    tester,
  ) async {
    final messenger = tester.binding.defaultBinaryMessenger;
    for (final name in const [
      'com.llfbandit.record/messages',
      'xyz.luan/audioplayers',
      'xyz.luan/audioplayers.global',
    ]) {
      messenger.setMockMethodCallHandler(MethodChannel(name), (_) async => null);
    }
    messenger.setMockStreamHandler(
      const EventChannel('xyz.luan/audioplayers.global/events'),
      MockStreamHandler.inline(onListen: (_, _) {}),
    );
    final reportError = FlutterError.onError;
    FlutterError.onError = (details) {
      if (details.exception is! MissingPluginException) {
        reportError?.call(details);
      }
    };
    addTearDown(() => FlutterError.onError = reportError);

    final state = AppState();
    state.reviewQueue.add(due('A0-P02'));
    // Past the first checkpoint, so the review opens on the production task
    // rather than the recognition question.
    state.mastery['A0-P02'] = const MasteryItem(
      id: 'A0-P02',
      label: "What's your name?",
      status: MasteryStatus.recall,
      evidence: [],
      checkpoint: 1,
    );
    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          body: ReviewPage(
            state: state,
            onFinished: () {},
            onOpenAdaptiveLesson: () {},
          ),
        ),
      ),
    );

    final giveUp = find.text('暂时想不起来');
    await tester.ensureVisible(giveUp);
    await tester.tap(giveUp);
    await tester.pumpAndSettle();

    expect(find.text('先弄清楚什么时候用'), findsOneWidget);
    expect(find.textContaining(coreUsage('A0-P02')!.when), findsWidgets);

    final checkpointAfterMiss = state.mastery['A0-P02']!.checkpoint;
    final wrong = find.widgetWithText(
      OutlinedButton,
      coreItemSpoken('A0-P01'),
    );
    await tester.ensureVisible(wrong);
    await tester.tap(wrong);
    await tester.pumpAndSettle();
    // The answer is named and the difference explained, and the miss stands.
    expect(
      find.textContaining('这里要说 ${coreItemSpoken('A0-P02')}'),
      findsOneWidget,
    );
    expect(state.mastery['A0-P02']!.needsReview, isTrue);
    expect(state.mastery['A0-P02']!.checkpoint, checkpointAfterMiss);
  });
}