import 'dart:io';

import 'package:flutter_test/flutter_test.dart';
import 'package:fuel_tax_tracker/services/database_service.dart';
import 'package:path/path.dart' as p;
import 'package:path_provider_platform_interface/path_provider_platform_interface.dart';
import 'package:plugin_platform_interface/plugin_platform_interface.dart';
import 'package:sqflite_common_ffi/sqflite_ffi.dart';

/// Confirms the version 3 → 4 migration (VIN becomes editable; a hidden
/// `id` takes over as vehicles' primary key/merge key) preserves existing
/// local data rather than dropping it, unlike the earlier VIN-as-primary-key
/// migration which was a from-scratch rebuild. Builds a real on-disk
/// version-3 database by hand (the old schema, pre-dating this change), then
/// runs [DatabaseService.init] against it and checks what comes out.
void main() {
  late Directory tempDir;

  setUpAll(() {
    sqfliteFfiInit();
    databaseFactory = databaseFactoryFfi;
  });

  setUp(() async {
    tempDir = await Directory.systemTemp.createTemp('vehicle_id_migration_test_');
    PathProviderPlatform.instance = _FakePathProviderPlatform(tempDir.path);
  });

  tearDown(() async {
    await tempDir.delete(recursive: true);
  });

  test('migrates a version-3 database, preserving vehicles and fuel entries', () async {
    final dbDir = Directory(p.join(tempDir.path, 'FuelTaxTracker'));
    await dbDir.create(recursive: true);
    final dbPath = p.join(dbDir.path, dbFileName);

    final oldDb = await databaseFactory.openDatabase(
      dbPath,
      options: OpenDatabaseOptions(
        version: 3,
        onCreate: (db, version) async {
          await db.execute('''
            CREATE TABLE vehicles (
              vin TEXT PRIMARY KEY,
              nickname TEXT,
              updated_at INTEGER NOT NULL,
              deleted_at INTEGER,
              dirty INTEGER NOT NULL DEFAULT 1
            )
          ''');
          await db.execute('''
            CREATE TABLE fuel_entries (
              id TEXT PRIMARY KEY,
              vehicle_vin TEXT NOT NULL,
              date INTEGER NOT NULL,
              gallons REAL NOT NULL,
              price_per_gallon REAL NOT NULL,
              total_cost REAL NOT NULL,
              receipt_image_path TEXT,
              receipt_drive_file_id TEXT,
              updated_at INTEGER NOT NULL,
              deleted_at INTEGER,
              dirty INTEGER NOT NULL DEFAULT 1
            )
          ''');
        },
      ),
    );
    await oldDb.insert('vehicles', {
      'vin': 'VIN1',
      'nickname': "Mom's Car",
      'updated_at': 1000,
      'deleted_at': null,
      'dirty': 0,
    });
    await oldDb.insert('vehicles', {
      'vin': 'VIN2',
      'nickname': null,
      'updated_at': 1500,
      'deleted_at': 2000, // a soft-deleted vehicle, should still migrate
      'dirty': 0,
    });
    await oldDb.insert('fuel_entries', {
      'id': 'f1',
      'vehicle_vin': 'VIN1',
      'date': 1200,
      'gallons': 12.5,
      'price_per_gallon': 3.2,
      'total_cost': 40.0,
      'receipt_image_path': '/local/receipt.jpg',
      'receipt_drive_file_id': null,
      'updated_at': 1200,
      'deleted_at': null,
      'dirty': 0,
    });
    await oldDb.close();

    final databaseService = DatabaseService();
    await databaseService.init();
    addTearDown(() => databaseService.rawDb.close());

    final vehicles = await databaseService.getVehicles();
    expect(vehicles, hasLength(1), reason: 'the soft-deleted vehicle should not show as active');
    expect(vehicles.first.vin, 'VIN1');
    expect(vehicles.first.nickname, "Mom's Car");
    expect(vehicles.first.id, isNotEmpty);

    final allVehicleRows = await databaseService.rawDb.query('vehicles');
    expect(allVehicleRows, hasLength(2), reason: 'the soft-deleted vehicle should still exist');
    final ids = {for (final row in allVehicleRows) row['vin']: row['id'] as String};
    expect(ids['VIN1'], isNotEmpty);
    expect(ids['VIN2'], isNotEmpty);
    expect(ids['VIN1'], isNot(ids['VIN2']), reason: 'each vehicle gets its own generated id');
    for (final row in allVehicleRows) {
      expect(row['dirty'], 1, reason: 'migrated rows must be re-pushed under the new schema');
    }

    final fuelEntries = await databaseService.getFuelEntries();
    expect(fuelEntries, hasLength(1));
    expect(fuelEntries.first.vehicleId, ids['VIN1'],
        reason: "the fuel entry's foreign key should now point at VIN1's new id");
    expect(fuelEntries.first.gallons, 12.5);
    expect(fuelEntries.first.receiptImagePath, '/local/receipt.jpg');
  });
}

class _FakePathProviderPlatform extends PathProviderPlatform with MockPlatformInterfaceMixin {
  final String tempPath;
  _FakePathProviderPlatform(this.tempPath);

  @override
  Future<String?> getApplicationDocumentsPath() async => tempPath;

  @override
  Future<String?> getTemporaryPath() async => tempPath;
}