import 'dart:convert';
import 'dart:typed_data';

import 'package:flutter/material.dart';
import 'package:flutter_localizations/flutter_localizations.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:tane/data/export_import/inventory_json_codec.dart';
import 'package:tane/data/export_import/inventory_snapshot.dart';
import 'package:tane/db/database.dart';
import 'package:tane/i18n/strings.g.dart';
import 'package:tane/services/export_import_service.dart';
import 'package:tane/services/file_service.dart';
import 'package:tane/ui/backup_section.dart';
import 'package:tane/ui/settings_screen.dart';

import '../support/test_support.dart';

/// Records calls instead of opening real dialogs.
class FakeFileService implements FileService {
  String? savedName;
  Uint8List? savedBytes;
  Uint8List? bytesToPick;

  @override
  Future<String?> saveFile({
    required String suggestedName,
    required Uint8List bytes,
  }) async {
    savedName = suggestedName;
    savedBytes = bytes;
    return '/picked/$suggestedName';
  }

  @override
  Future<Uint8List?> pickFileBytes({List<String>? allowedExtensions}) async =>
      bytesToPick;
}

void main() {
  late AppDatabase db;
  late FakeFileService files;
  late ExportImportService service;

  setUp(() {
    db = newTestDatabase();
    files = FakeFileService();
    service = ExportImportService(
      repository: newTestRepository(db),
      files: files,
    );
  });
  tearDown(() => db.close());

  Widget wrap(Widget child) {
    LocaleSettings.setLocaleSync(AppLocale.en);
    return TranslationProvider(
      child: MaterialApp(
        supportedLocales: AppLocaleUtils.supportedLocales,
        localizationsDelegates: const [
          GlobalMaterialLocalizations.delegate,
          GlobalWidgetsLocalizations.delegate,
          GlobalCupertinoLocalizations.delegate,
        ],
        home: child,
      ),
    );
  }

  testWidgets('settings shows the backup section with its three actions', (
    tester,
  ) async {
    await tester.binding.setSurfaceSize(const Size(800, 1400));
    addTearDown(() => tester.binding.setSurfaceSize(null));
    await tester.pumpWidget(wrap(SettingsScreen(exportImport: service)));

    expect(find.text('Backup'), findsOneWidget);
    expect(find.text('Export as CSV'), findsOneWidget);
    expect(find.text('Export as JSON'), findsOneWidget);
    expect(find.text('Import from JSON'), findsOneWidget);
  });

  testWidgets('export CSV saves a .csv file and confirms', (tester) async {
    await tester.pumpWidget(
      wrap(Scaffold(body: BackupSection(service: service))),
    );
    await tester.tap(find.text('Export as CSV'));
    await tester.pumpAndSettle();

    expect(files.savedName, endsWith('.csv'));
    expect(utf8.decode(files.savedBytes!), startsWith('variety_id,'));
    expect(find.text('Copy saved'), findsOneWidget);
  });

  testWidgets('export JSON saves a versioned .json file', (tester) async {
    await tester.pumpWidget(
      wrap(Scaffold(body: BackupSection(service: service))),
    );
    await tester.tap(find.text('Export as JSON'));
    await tester.pumpAndSettle();

    expect(files.savedName, endsWith('.json'));
    final root =
        jsonDecode(utf8.decode(files.savedBytes!)) as Map<String, dynamic>;
    expect(root['formatVersion'], inventoryFormatVersion);
    expect(find.text('Copy saved'), findsOneWidget);
  });

  testWidgets('import asks for confirmation, imports and reports counts', (
    tester,
  ) async {
    // A valid one-variety export produced by another repository.
    final otherDb = newTestDatabase();
    addTearDown(otherDb.close);
    final other = newTestRepository(otherDb, nodeId: 'node-other');
    await other.addQuickVariety(label: 'Imported bean');
    files.bytesToPick = utf8.encode(
      const InventoryJsonCodec().encode(await other.exportInventory()),
    );

    await tester.pumpWidget(
      wrap(Scaffold(body: BackupSection(service: service))),
    );
    await tester.tap(find.text('Import from JSON'));
    await tester.pumpAndSettle();
    expect(find.text('Import a saved copy?'), findsOneWidget);

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

    expect(find.text('Imported: 1 new, 0 updated'), findsOneWidget);
    final varieties = await db.select(db.varieties).get();
    expect(varieties.single.label, 'Imported bean');
  });

  testWidgets('an unreadable file reports a friendly error', (tester) async {
    files.bytesToPick = utf8.encode('this is not json');
    await tester.pumpWidget(
      wrap(Scaffold(body: BackupSection(service: service))),
    );
    await tester.tap(find.text('Import from JSON'));
    await tester.pumpAndSettle();
    await tester.tap(find.text('Import'));
    await tester.pumpAndSettle();

    expect(
      find.text('This file could not be read as a Tanemaki copy'),
      findsOneWidget,
    );
  });
}