import 'dart:io';
import 'dart:math';
import 'package:drift/drift.dart';
import 'package:drift/native.dart';
import 'package:path_provider/path_provider.dart';
import 'package:path/path.dart' as p;
import 'package:flutter_riverpod/flutter_riverpod.dart';

import 'tables.dart';

part 'database.g.dart';

@DriftDatabase(tables: [Rides, PerformanceRuns, TelemetrySamples, RideEvents, GarageMotorcycles, FieldTestSessions, FieldTestEvents, FieldTestSummaries, FieldTestGpsRecords, FieldTestImuRecords])
class AppDatabase extends _$AppDatabase {
  AppDatabase() : super(_openConnection());
  AppDatabase.forTesting(super.e);

  static final Random _random = Random.secure();

  @override
  int get schemaVersion => 6;

  @override
  MigrationStrategy get migration => MigrationStrategy(
    onCreate: (Migrator m) async => m.createAll(),
    onUpgrade: (Migrator m, int from, int to) async {
      if (from < 2) {
        await m.addColumn(rides, rides.distance);
        await m.addColumn(rides, rides.movingTime);
        await m.addColumn(rides, rides.stoppedTime);
        await m.addColumn(rides, rides.averageSpeed);
        await m.addColumn(rides, rides.topSpeed);
        await m.addColumn(rides, rides.elevationGain);
        await m.addColumn(rides, rides.elevationLoss);
        await m.createTable(telemetrySamples);
        await m.createTable(rideEvents);
      }
      if (from < 3) {
        await m.createTable(garageMotorcycles);
        await m.addColumn(rides, rides.motorcycleId);
        await m.addColumn(rides, rides.motorcycleYear);
        await m.addColumn(rides, rides.motorcycleMake);
        await m.addColumn(rides, rides.motorcycleModel);
        await m.addColumn(rides, rides.motorcycleVariant);
      }
      if (from < 4) {
        await m.createTable(fieldTestSessions);
        await m.createTable(fieldTestEvents);
        await m.createTable(fieldTestGpsRecords);
        await m.createTable(fieldTestImuRecords);
      }
      if (from < 5) {
        await m.createTable(fieldTestSummaries);
        try {
          await m.addColumn(fieldTestEvents, fieldTestEvents.rideId);
          await m.addColumn(fieldTestEvents, fieldTestEvents.telemetryTimestamp);
          await m.addColumn(fieldTestEvents, fieldTestEvents.gpsAgeMs);
          await m.addColumn(fieldTestEvents, fieldTestEvents.speed);
          await m.addColumn(fieldTestEvents, fieldTestEvents.latitude);
          await m.addColumn(fieldTestEvents, fieldTestEvents.longitude);
          await m.addColumn(fieldTestEvents, fieldTestEvents.gpsAccuracy);
          await m.addColumn(fieldTestEvents, fieldTestEvents.leanAngle);
          await m.addColumn(fieldTestEvents, fieldTestEvents.longitudinalG);
          await m.addColumn(fieldTestEvents, fieldTestEvents.lateralG);
          await m.addColumn(fieldTestEvents, fieldTestEvents.overallConfidence);
          await m.addColumn(fieldTestEvents, fieldTestEvents.metadata);
        } catch (_) {}
      }
      if (from < 6) {
        // Nullable during migration so existing installations can be upgraded
        // without losing rides. We immediately backfill every existing ride
        // with a stable random identifier that is independent of local ID.
        await m.addColumn(rides, rides.cloudRideId);
        final rows = await customSelect('SELECT id FROM rides').get();
        for (final row in rows) {
          await customStatement(
            'UPDATE rides SET cloud_ride_id = ? WHERE id = ?',
            [_newCloudRideId(), row.data['id']],
          );
        }
      }
    },
  );

  String _newCloudRideId() {
    final bytes = List<int>.generate(16, (_) => _random.nextInt(256));
    final hex = bytes.map((b) => b.toRadixString(16).padLeft(2, '0')).join();
    return 'ride_$hex';
  }

  /// Returns the persisted stable MotorCloud identity for a local ride.
  /// Uses raw SQL until `database.g.dart` is regenerated; this keeps the
  /// migration deployable without hand-editing generated Drift output.
  Future<String?> getCloudRideId(int rideId) async {
    final rows = await customSelect(
      'SELECT cloud_ride_id FROM rides WHERE id = ?',
      variables: [Variable<int>(rideId)],
    ).get();
    if (rows.isEmpty) return null;
    return rows.first.data['cloud_ride_id'] as String?;
  }

  Future<String> ensureCloudRideId(int rideId) async {
    final existing = await getCloudRideId(rideId);
    if (existing != null && existing.isNotEmpty) return existing;
    final created = _newCloudRideId();
    await customStatement(
      'UPDATE rides SET cloud_ride_id = ? WHERE id = ?',
      [created, rideId],
    );
    return created;
  }

  Future<int> startRide() async {
    final id = await into(rides).insert(RidesCompanion.insert(
      startTime: DateTime.now(),
    ));
    await ensureCloudRideId(id);
    return id;
  }

  Future<void> endRide(int rideId, RidesCompanion data) async {
    await (update(rides)..where((t) => t.id.equals(rideId))).write(data.copyWith(endTime: Value(DateTime.now())));
  }
}

LazyDatabase _openConnection() {
  return LazyDatabase(() async {
    final dbFolder = await getApplicationDocumentsDirectory();
    final file = File(p.join(dbFolder.path, 'motorsignal.sqlite'));
    return NativeDatabase.createInBackground(file);
  });
}

final databaseProvider = Provider<AppDatabase>((ref) {
  final db = AppDatabase();
  ref.onDispose(db.close);
  return db;
});