import 'dart:convert';

import 'package:bible_tracker/data/bible.dart';
import 'package:bible_tracker/models/tracker.dart';
import 'package:bible_tracker/screens/book_screen.dart';
import 'package:bible_tracker/screens/home_screen.dart';
import 'package:bible_tracker/screens/tracker_screen.dart';
import 'package:bible_tracker/services/last_location.dart';
import 'package:bible_tracker/services/tracker_service.dart';
import 'package:bible_tracker/services/tracker_storage.dart';
import 'package:bible_tracker/widgets/theme.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:shared_preferences/shared_preferences.dart';

Future<Widget> _pumpApp({
  Map<String, Object>? initialPrefs,
  LastLocation? pending,
}) async {
  SharedPreferences.setMockInitialValues(initialPrefs ?? <String, Object>{});
  final prefs = await SharedPreferences.getInstance();
  return ProviderScope(
    overrides: <Override>[
      sharedPreferencesProvider.overrideWithValue(prefs),
      pendingRestoreProvider.overrideWithValue(pending),
    ],
    child: MaterialApp(
      theme: AppTheme.light(),
      home: const HomeScreen(),
      navigatorObservers: <NavigatorObserver>[
        LastLocationObserver(
          (LastLocation? loc) => LastLocationService(prefs).save(loc),
        ),
      ],
    ),
  );
}

String _seedTrackerJson(Tracker tracker) =>
    jsonEncode(<Map<String, dynamic>>[tracker.toJson()]);

void main() {
  testWidgets('shows empty state when no trackers exist', (tester) async {
    await tester.pumpWidget(await _pumpApp());
    await tester.pumpAndSettle();
    expect(find.text('Start your first tracker'), findsOneWidget);
    expect(find.text('New Tracker'), findsOneWidget);
  });

  testWidgets('creating a tracker shows it on the list', (tester) async {
    await tester.pumpWidget(await _pumpApp());
    await tester.pumpAndSettle();

    final BuildContext context = tester.element(find.byType(HomeScreen));
    final ProviderContainer container = ProviderScope.containerOf(context);
    await container
        .read(trackerServiceProvider.notifier)
        .create(name: 'My Plan', color: const Color(0xFF3F51B5));
    await tester.pumpAndSettle();

    expect(find.text('My Plan'), findsOneWidget);
    expect(find.text('0%'), findsOneWidget);
  });

  testWidgets(
    'restores tracker + book on launch when pending location matches',
    (tester) async {
      final tracker = Tracker(
        id: 'seed-1',
        name: 'Persisted',
        colorValue: 0xFF3F51B5,
        startDate: DateTime(2024),
      );
      const int bookIndex = 42; // John

      await tester.pumpWidget(
        await _pumpApp(
          initialPrefs: <String, Object>{
            'bible_tracker.trackers.v1': _seedTrackerJson(tracker),
          },
          pending: LastLocation(trackerId: tracker.id, bookIndex: bookIndex),
        ),
      );
      await tester.pumpAndSettle();

      // TrackerScreen sits underneath BookScreen and is offstage.
      expect(
        find.byType(TrackerScreen, skipOffstage: false),
        findsOneWidget,
      );
      expect(find.byType(BookScreen), findsOneWidget);
      expect(find.text(Bible.books[bookIndex].name), findsWidgets);
    },
  );

  testWidgets('restores tracker only when no book index is saved', (
    tester,
  ) async {
    final tracker = Tracker(
      id: 'seed-2',
      name: 'Resumed',
      colorValue: 0xFF3F51B5,
      startDate: DateTime(2024),
    );
    await tester.pumpWidget(
      await _pumpApp(
        initialPrefs: <String, Object>{
          'bible_tracker.trackers.v1': _seedTrackerJson(tracker),
        },
        pending: LastLocation(trackerId: tracker.id),
      ),
    );
    await tester.pumpAndSettle();

    expect(find.byType(TrackerScreen), findsOneWidget);
    expect(find.byType(BookScreen), findsNothing);
    expect(find.text('Resumed'), findsWidgets);
  });

  testWidgets('skips restore when the saved tracker no longer exists', (
    tester,
  ) async {
    await tester.pumpWidget(
      await _pumpApp(pending: const LastLocation(trackerId: 'missing')),
    );
    await tester.pumpAndSettle();

    expect(find.byType(TrackerScreen), findsNothing);
    expect(find.byType(BookScreen), findsNothing);
    expect(find.text('Start your first tracker'), findsOneWidget);
  });

  testWidgets('navigating into a book persists the location via the observer', (
    tester,
  ) async {
    SharedPreferences.setMockInitialValues(<String, Object>{});
    final prefs = await SharedPreferences.getInstance();
    await tester.pumpWidget(
      ProviderScope(
        overrides: <Override>[
          sharedPreferencesProvider.overrideWithValue(prefs),
        ],
        child: MaterialApp(
          theme: AppTheme.light(),
          home: const HomeScreen(),
          navigatorObservers: <NavigatorObserver>[
            LastLocationObserver(
              (LastLocation? loc) => LastLocationService(prefs).save(loc),
            ),
          ],
        ),
      ),
    );
    await tester.pumpAndSettle();

    final BuildContext context = tester.element(find.byType(HomeScreen));
    final ProviderContainer container = ProviderScope.containerOf(context);
    final tracker = await container
        .read(trackerServiceProvider.notifier)
        .create(name: 'Plan', color: const Color(0xFF3F51B5));
    await tester.pumpAndSettle();

    await tester.tap(find.text('Plan'));
    await tester.pumpAndSettle();

    expect(
      LastLocationService(prefs).load(),
      LastLocation(trackerId: tracker.id),
    );

    await tester.tap(find.text('Genesis'));
    await tester.pumpAndSettle();

    expect(
      LastLocationService(prefs).load(),
      LastLocation(trackerId: tracker.id, bookIndex: 0),
    );

    // Pop back to the tracker screen — the persisted location should
    // shrink back to "tracker only".
    final NavigatorState navigator = tester.state<NavigatorState>(
      find.byType(Navigator).first,
    );
    navigator.pop();
    await tester.pumpAndSettle();

    expect(
      LastLocationService(prefs).load(),
      LastLocation(trackerId: tracker.id),
    );

    // Pop all the way to home — location should clear.
    navigator.pop();
    await tester.pumpAndSettle();

    expect(LastLocationService(prefs).load(), isNull);
  });
}