import 'package:drift/drift.dart';
import 'package:drift_postgres/drift_postgres.dart';
import 'package:postgres/postgres.dart' as pg;
import 'dart:io';
import 'dart:convert';

// Импорт конвертеров (нужен для генерации кода)
import 'converters.dart';

// Импорт всех таблиц
import 'tables/users.dart';
import 'tables/auth.dart';
import 'tables/packs.dart';
import 'tables/relations.dart';
import 'tables/subscriptions.dart';
import 'tables/payments.dart';
import 'tables/tests.dart';
import 'tables/tasks.dart';
import 'tables/promo_codes.dart';
import 'tables/discounts.dart';
import 'tables/statistics.dart';
import 'tables/telegram.dart';
import 'tables/achievements.dart';
import 'tables/word_statistics.dart';
import 'tables/audit.dart';

// Импорт DAOs
import 'daos/user_dao.dart';
import 'daos/pack_dao.dart';
import 'daos/test_dao.dart';
import 'daos/payment_dao.dart';
import 'daos/subscription_dao.dart';
import 'daos/task_dao.dart';
import 'daos/promo_code_dao.dart';
import 'daos/discount_dao.dart';
import 'daos/statistics_dao.dart';
import 'daos/achievement_dao.dart';
import 'daos/word_statistics_dao.dart';
import 'daos/audit_dao.dart';

// Сгенерированный код будет здесь
part 'database.g.dart';

@DriftDatabase(
  tables: [
    // User tables
    Users,
    UserDatas,

    // Auth tables
    Tokens,
    RefreshTokens,
    TelegramAuthCodes,

    // Pack tables
    CardPacks,
    GameCards,
    VoiceModels,

    // Relations
    UserPacks,
    PreviewCards,
    CardPackCards,
    CardVoices,

    // Subscription tables
    SubscriptionPlans,
    UserSubscriptions,

    // Payment tables
    Payments,

    // Test tables
    Tests,
    TestQuestions,
    TestPackRelations,
    TestStatistics,

    // Task tables
    Tasks,
    UserTasks,
    UserTaskProgresses,
    UserTaskResults,

    // Promo code tables
    PromoCodesCampaigns,
    PromoCodes,

    // Discount tables
    DiscountCampaigns,
    Discounts,
    DiscountUserDatas,

    // Statistics tables
    StudySessions,
    WordStatistics,

    // Achievements tables
    UserAchievements,

    // Telegram tables
    ShareRequests,

    // Audit tables
    AuditLogs,
  ],
  daos: [
    UserDao,
    PackDao,
    TestDao,
    PaymentDao,
    SubscriptionDao,
    TaskDao,
    PromoCodeDao,
    DiscountDao,
    StatisticsDao,
    AchievementDao,
    WordStatisticsDao,
    AuditDao,
  ],
)
class AppDatabase extends _$AppDatabase {
  AppDatabase(super.e);

  @override
  int get schemaVersion => 3;

  /// Factory для подключения к PostgreSQL
  static AppDatabase connect({
    required String host,
    required int port,
    required String database,
    required String username,
    required String password,
    bool useSsl = false,
  }) {
    final endpoint = pg.Endpoint(
      host: host,
      port: port,
      database: database,
      username: username,
      password: password,
    );

    final connection = PgDatabase(
      endpoint: endpoint,
      settings: pg.ConnectionSettings(
        sslMode: useSsl ? pg.SslMode.require : pg.SslMode.disable,
        connectTimeout: const Duration(seconds: 10),
      ),
    );

    return AppDatabase(connection);
  }

  /// Factory для подключения из environment variables
  static AppDatabase fromEnvironment() {
    return connect(
      host: Platform.environment['DB_HOST'] ?? 'localhost',
      port: int.parse(Platform.environment['DB_PORT'] ?? '5432'),
      database: Platform.environment['DB_NAME'] ?? 'mnemo_cards_dev',
      username: Platform.environment['DB_USER'] ?? 'mnemo_user',
      password: Platform.environment['DB_PASSWORD'] ?? '',
      useSsl: Platform.environment['DB_SSL_MODE'] == 'require',
    );
  }

  @override
  MigrationStrategy get migration => MigrationStrategy(
    onCreate: (Migrator m) async {
      print('Creating database schema...');
      await m.createAll();
      print('Database schema created successfully');

      // Создать индексы для оптимизации
      await _createIndexes();
    },
    onUpgrade: (Migrator m, int from, int to) async {
      print('Migrating database from version $from to $to');

      // Миграция с версии 1 на 2: обновление структуры тестов
      if (from < 2) {
        await _migrateToV2(m);
      }

      // Миграция с версии 2 на 3: добавление telegram в users
      if (from < 3) {
        await _migrateToV3(m);
      }
    },
    beforeOpen: (details) async {
      print('Opening database connection...');

      // Проверка подключения
      final result = await customSelect('SELECT 1 as test').getSingle();
      print('Database connection successful: ${result.data}');

      // Включить foreign key constraints
      await customStatement('SET CONSTRAINTS ALL IMMEDIATE');
    },
  );

  /// Создание индексов для оптимизации запросов
  Future<void> _createIndexes() async {
    print('Creating indexes...');

    // Users indexes
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_users_email ON users(email) WHERE email IS NOT NULL',
    );
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_users_telegram ON users(telegram) WHERE telegram IS NOT NULL',
    );
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_users_admin ON users(admin) WHERE admin = TRUE',
    );
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_users_not_deleted ON users(is_deleted) WHERE is_deleted = FALSE',
    );

    // UserDatas indexes
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_user_datas_user_id ON user_datas(user_id)',
    );
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_user_datas_last_online ON user_datas(last_time_online DESC)',
    );

    // Auth indexes
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_tokens_user_id ON tokens(user_id)',
    );
    // Индекс на expires без предиката (NOW() не может быть использована в предикате индекса)
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_tokens_expires ON tokens(expires)',
    );
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_refresh_tokens_user_id ON refresh_tokens(user_id)',
    );
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_refresh_tokens_jti ON refresh_tokens(jti)',
    );
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_refresh_tokens_not_blacklisted ON refresh_tokens(is_blacklisted) WHERE is_blacklisted = FALSE',
    );
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_telegram_codes_code ON telegram_auth_codes(code)',
    );
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_telegram_codes_not_used ON telegram_auth_codes(is_used) WHERE is_used = FALSE',
    );

    // CardPacks indexes
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_packs_enabled ON card_packs(enabled) WHERE enabled = TRUE',
    );
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_packs_order ON card_packs("order")',
    );

    // GameCards indexes
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_cards_original ON game_cards(original)',
    );

    // UserPacks indexes
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_user_packs_user_id ON user_packs(user_id)',
    );
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_user_packs_pack_id ON user_packs(pack_id)',
    );

    // Payments indexes
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_payments_user_id ON payments(user_id)',
    );
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_payments_status ON payments(status)',
    );
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_payments_created ON payments(date DESC)',
    );

    // Subscriptions indexes
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_subscriptions_user_id ON user_subscriptions(user_id)',
    );
    // Индекс на finish без предиката (NOW() не может быть использована в предикате индекса)
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_subscriptions_finish ON user_subscriptions(finish)',
    );

    // Tests indexes
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_test_questions_test_id ON test_questions(test_id)',
    );

    // StudySessions indexes
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_sessions_user_id ON study_sessions(user_id)',
    );
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_sessions_started ON study_sessions(start_time DESC)',
    );

    // PromoCodes indexes
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_promo_codes_code ON promo_codes(code)',
    );
    await customStatement(
      'CREATE INDEX IF NOT EXISTS idx_promo_codes_campaign_id ON promo_codes(campaign_id)',
    );

    print('Indexes created successfully');
  }

  /// Миграция с версии 1 на версию 2
  /// Обновление структуры тестов: добавление новых колонок и очистка старых данных
  Future<void> _migrateToV2(Migrator m) async {
    print(
      'Starting migration to v2: updating test questions and statistics...',
    );

    try {
      // 1. Добавляем новые колонки в test_questions
      print('Adding new columns to test_questions...');
      await customStatement(
        'ALTER TABLE test_questions '
        'ADD COLUMN IF NOT EXISTS order_index INTEGER DEFAULT 0, '
        'ADD COLUMN IF NOT EXISTS word TEXT DEFAULT \'\', '
        'ADD COLUMN IF NOT EXISTS answer TEXT DEFAULT \'\', '
        'ADD COLUMN IF NOT EXISTS options TEXT DEFAULT \'[]\', '
        'ADD COLUMN IF NOT EXISTS ui_data TEXT DEFAULT \'{}\'',
      );

      // 2. Удаляем все старые вопросы (soft delete)
      print('Soft-deleting all existing test questions...');
      final now = PgDateTime(DateTime.now());
      await (update(
        testQuestions,
      )..where((tq) => tq.isDeleted.equals(false))).write(
        TestQuestionsCompanion(
          isDeleted: const Value(true),
          deletedAt: Value(now),
          updatedAt: Value(now),
        ),
      );
      print(
        'All old questions marked as deleted. Create new questions via admin panel.',
      );

      // 3. Удаляем старую колонку body
      print('Dropping old body column...');
      await customStatement(
        'ALTER TABLE test_questions DROP COLUMN IF EXISTS body',
      );

      // 4. Добавляем новые колонки в test_statistics
      print('Adding new columns to test_statistics...');
      await customStatement(
        'ALTER TABLE test_statistics '
        'ADD COLUMN IF NOT EXISTS total_questions INTEGER DEFAULT 0, '
        'ADD COLUMN IF NOT EXISTS correct_answers INTEGER DEFAULT 0, '
        'ADD COLUMN IF NOT EXISTS incorrect_answers INTEGER DEFAULT 0, '
        'ADD COLUMN IF NOT EXISTS skipped_answers INTEGER DEFAULT 0, '
        'ADD COLUMN IF NOT EXISTS score_percentage REAL DEFAULT 0.0, '
        'ADD COLUMN IF NOT EXISTS time_spent_seconds INTEGER, '
        'ADD COLUMN IF NOT EXISTS question_results TEXT DEFAULT \'[]\', '
        'ADD COLUMN IF NOT EXISTS metadata TEXT DEFAULT \'{}\'',
      );

      // 5. Удаляем всю старую статистику (она будет создаваться заново)
      print('Deleting old test statistics...');
      await (delete(testStatistics)).go();
      print(
        'All old statistics deleted. New statistics will be collected automatically.',
      );

      // 6. Удаляем старую колонку results
      print('Dropping old results column...');
      await customStatement(
        'ALTER TABLE test_statistics DROP COLUMN IF EXISTS results',
      );

      print('Migration to v2 completed successfully!');
    } catch (e, stackTrace) {
      print('Error during migration to v2: $e');
      print('Stack trace: $stackTrace');
      rethrow;
    }
  }

  /// Миграция с версии 2 на версию 3
  /// Добавление поля telegram в users и перенос старых telegram-логинов из email
  Future<void> _migrateToV3(Migrator m) async {
    print('Starting migration to v3: adding telegram to users...');

    try {
      await customStatement(
        'ALTER TABLE users ADD COLUMN IF NOT EXISTS telegram TEXT',
      );

      // Раньше Telegram-username сохранялся в email. Переносим "похожие на username"
      // значения в telegram и очищаем email.
      await customStatement(
        'UPDATE users '
        'SET telegram = email, email = NULL '
        'WHERE (telegram IS NULL OR telegram = \'\') '
        'AND email IS NOT NULL AND email != \'\' '
        'AND POSITION(\'@\' IN email) = 0',
      );

      // Индексы на existing db
      await customStatement(
        'CREATE INDEX IF NOT EXISTS idx_users_telegram ON users(telegram) WHERE telegram IS NOT NULL',
      );

      print('Migration to v3 completed successfully!');
    } catch (e, stackTrace) {
      print('Error during migration to v3: $e');
      print('Stack trace: $stackTrace');
      rethrow;
    }
  }
}