import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:tasq/providers/connectivity_provider.dart';
import 'package:tasq/widgets/offline_banner.dart';

// ---------------------------------------------------------------------------
// Offline / Connectivity Tests
//
// Three test tiers:
//   1. Unit — pure provider state (no Flutter, no Supabase)
//   2. Widget — OfflineBanner visibility
//   3. Integration stubs — AppRepository + SQLite (require Supabase setup,
//      skipped in CI; see comments for manual verification steps)
// ---------------------------------------------------------------------------

void main() {
  // ──────────────────────────────────────────────────────────────────────────
  // Tier 1 — Provider unit tests
  // ──────────────────────────────────────────────────────────────────────────
  group('isOnlineProvider', () {
    test('starts as true (online by default)', () {
      final container = ProviderContainer();
      addTearDown(container.dispose);

      expect(container.read(isOnlineProvider), isTrue);
    });

    test('can be set to false (simulate going offline)', () {
      final container = ProviderContainer();
      addTearDown(container.dispose);

      container.read(isOnlineProvider.notifier).state = false;
      expect(container.read(isOnlineProvider), isFalse);
    });

    test('can transition false → true (simulate reconnect)', () {
      final container = ProviderContainer();
      addTearDown(container.dispose);

      container.read(isOnlineProvider.notifier).state = false;
      expect(container.read(isOnlineProvider), isFalse);

      container.read(isOnlineProvider.notifier).state = true;
      expect(container.read(isOnlineProvider), isTrue);
    });

    test('listeners are notified on state change', () {
      final container = ProviderContainer();
      addTearDown(container.dispose);

      final states = <bool>[];
      container.listen(isOnlineProvider, (_, next) => states.add(next));

      container.read(isOnlineProvider.notifier).state = false;
      container.read(isOnlineProvider.notifier).state = true;
      container.read(isOnlineProvider.notifier).state = false;

      expect(states, equals([false, true, false]));
    });
  });

  // ──────────────────────────────────────────────────────────────────────────
  // Tier 2 — Widget tests for OfflineBanner
  // ──────────────────────────────────────────────────────────────────────────
  group('OfflineBanner widget', () {
    /// Builds OfflineBanner inside a ProviderScope that overrides
    /// [isOnlineProvider] to [online] and [connectivityMonitorProvider]
    /// to a no-op so no real HTTP calls are made.
    Widget buildBanner({required bool online}) {
      return ProviderScope(
        overrides: [
          isOnlineProvider.overrideWith((ref) => online),
          // Suppress the real connectivity poll — no network in tests.
          connectivityMonitorProvider.overrideWith((_) {}),
        ],
        child: const MaterialApp(
          home: Scaffold(
            body: OfflineBanner(child: SizedBox.expand()),
          ),
        ),
      );
    }

    testWidgets('hides banner when online', (tester) async {
      await tester.pumpWidget(buildBanner(online: true));
      await tester.pump();

      expect(find.byIcon(Icons.wifi_off), findsNothing);
      expect(
        find.text(
          'No internet \u2014 changes saved locally, will sync automatically',
        ),
        findsNothing,
      );
    });

    testWidgets('shows banner when offline', (tester) async {
      await tester.pumpWidget(buildBanner(online: false));
      await tester.pump();

      expect(find.byIcon(Icons.wifi_off), findsOneWidget);
      expect(
        find.text(
          'No internet \u2014 changes saved locally, will sync automatically',
        ),
        findsOneWidget,
      );
    });

    testWidgets('banner transitions from offline to online', (tester) async {
      // Use UncontrolledProviderScope so we can update provider state in-place
      // without replacing the widget tree (which would reset AnimatedSize).
      final container = ProviderContainer(
        overrides: [connectivityMonitorProvider.overrideWith((_) {})],
      );
      addTearDown(container.dispose);

      container.read(isOnlineProvider.notifier).state = false;

      await tester.pumpWidget(
        UncontrolledProviderScope(
          container: container,
          child: const MaterialApp(
            home: Scaffold(body: OfflineBanner(child: SizedBox.expand())),
          ),
        ),
      );
      await tester.pump();
      expect(find.byIcon(Icons.wifi_off), findsOneWidget);

      // Go online — update provider state, then let AnimatedSize animate.
      container.read(isOnlineProvider.notifier).state = true;
      await tester.pumpAndSettle();
      expect(find.byIcon(Icons.wifi_off), findsNothing);
    });

    testWidgets('banner transitions from online to offline', (tester) async {
      final container = ProviderContainer(
        overrides: [connectivityMonitorProvider.overrideWith((_) {})],
      );
      addTearDown(container.dispose);

      // Start online (default is true).
      await tester.pumpWidget(
        UncontrolledProviderScope(
          container: container,
          child: const MaterialApp(
            home: Scaffold(body: OfflineBanner(child: SizedBox.expand())),
          ),
        ),
      );
      await tester.pump();
      expect(find.byIcon(Icons.wifi_off), findsNothing);

      // Go offline — update provider state, then let AnimatedSize animate.
      container.read(isOnlineProvider.notifier).state = false;
      await tester.pumpAndSettle();
      expect(find.byIcon(Icons.wifi_off), findsOneWidget);
    });

    testWidgets('child widget is always rendered regardless of connectivity',
        (tester) async {
      const childKey = Key('test-child');

      for (final online in [true, false]) {
        await tester.pumpWidget(
          ProviderScope(
            overrides: [
              isOnlineProvider.overrideWith((ref) => online),
              connectivityMonitorProvider.overrideWith((_) {}),
            ],
            child: const MaterialApp(
              home: Scaffold(
                body: OfflineBanner(
                  child: SizedBox.expand(key: childKey),
                ),
              ),
            ),
          ),
        );
        await tester.pump();
        expect(find.byKey(childKey), findsOneWidget,
            reason: 'child must be visible when online=$online');
      }
    });
  });

  // ──────────────────────────────────────────────────────────────────────────
  // Tier 3 — Integration stubs (AppRepository + SQLite + Supabase)
  //
  // These tests are NOT run automatically because they require:
  //   • a real (or local) Supabase instance
  //   • the full AppRepository.configure() call with a valid client
  //
  // To run manually:
  //   1. Start a local Supabase dev stack: `supabase start`
  //   2. Set SUPABASE_URL / SUPABASE_ANON_KEY env vars
  //   3. Run: flutter test test/offline_sync_test.dart --name "integration"
  //
  // Scenario A — offline create → sync
  //   1. Set AppRepository offline (no network / airplane mode mock)
  //   2. Call AppRepository.instance.upsert<Task>(task)
  //   3. Read back with OfflineFirstGetPolicy.localOnly → expect task present
  //   4. Restore network
  //   5. Wait for Brick HTTP queue to replay
  //   6. Read with OfflineFirstGetPolicy.requireRemote → expect task synced
  //   7. Verify task_number is now server-assigned (not null)
  //
  // Scenario B — online read → go offline → read from cache
  //   1. Hydrate: AppRepository.instance.get<Task>() (pulls from Supabase)
  //   2. Simulate offline (cut network)
  //   3. AppRepository.instance.get<Task>(policy: localOnly) → expect cached
  //   4. No exception thrown
  //
  // Scenario C — task number placeholder
  //   1. Create task offline → task.taskNumber == null
  //   2. UI should display 'OFFLINE-001' (handled by displayTaskNumber helper)
  //   3. After sync → task.taskNumber != null → UI shows 'YYYY-MM-#####'
  // ──────────────────────────────────────────────────────────────────────────
  group('integration (manual only)', () {
    // Placeholder so the group shows up in test output with a clear note.
    test('see file comments for manual integration test instructions', () {
      // This test intentionally passes — it documents the manual steps above.
    });
  });
}