import 'package:sqflite/sqflite.dart';
import 'package:path/path.dart' as p;
import '../models/track.dart';

/// SQLite adatbázis-réteg a nyomvonalakhoz.
/// Singleton — [TrackDatabase.instance]-on keresztül érhető el.
class TrackDatabase {
  TrackDatabase._();
  static final instance = TrackDatabase._();

  static Database? _db;

  Future<Database> get database async {
    _db ??= await _open();
    return _db!;
  }

  Future<Database> _open() async {
    final dbPath = p.join(await getDatabasesPath(), 'tracks.db');
    return openDatabase(
      dbPath,
      version: 1,
      onCreate: _onCreate,
    );
  }

  Future<void> _onCreate(Database db, int version) async {
    await db.execute('''
      CREATE TABLE tracks (
        id              INTEGER PRIMARY KEY AUTOINCREMENT,
        name            TEXT    NOT NULL,
        start_time      TEXT    NOT NULL,
        end_time        TEXT,
        status          TEXT    NOT NULL DEFAULT 'recording',
        source          TEXT    NOT NULL DEFAULT 'Telefon GPS',
        distance_meters REAL    NOT NULL DEFAULT 0,
        point_count     INTEGER NOT NULL DEFAULT 0
      )
    ''');

    await db.execute('''
      CREATE TABLE track_points (
        id        INTEGER PRIMARY KEY AUTOINCREMENT,
        track_id  INTEGER NOT NULL REFERENCES tracks(id) ON DELETE CASCADE,
        latitude  REAL    NOT NULL,
        longitude REAL    NOT NULL,
        altitude  REAL,
        accuracy  REAL,
        speed     REAL,
        heading   REAL,
        timestamp TEXT    NOT NULL
      )
    ''');

    await db.execute(
        'CREATE INDEX idx_tp_track ON track_points(track_id, timestamp)');
  }

  // ─── Tracks CRUD ───────────────────────────────────────────────────────────

  Future<int> insertTrack(Track track) async {
    final db = await database;
    return db.insert('tracks', track.toMap());
  }

  Future<void> updateTrack(Track track) async {
    final db = await database;
    await db.update('tracks', track.toMap(),
        where: 'id = ?', whereArgs: [track.id]);
  }

  Future<void> deleteTrack(int id) async {
    final db = await database;
    await db.delete('tracks', where: 'id = ?', whereArgs: [id]);
  }

  Future<List<Track>> listTracks() async {
    final db = await database;
    final rows = await db.query('tracks', orderBy: 'start_time DESC');
    return rows.map(Track.fromMap).toList();
  }

  Future<Track?> getTrack(int id) async {
    final db = await database;
    final rows =
        await db.query('tracks', where: 'id = ?', whereArgs: [id], limit: 1);
    return rows.isEmpty ? null : Track.fromMap(rows.first);
  }

  // ─── TrackPoints ───────────────────────────────────────────────────────────

  /// Egyetlen pont hozzáadása + track statisztikák atomi frissítése.
  Future<void> addPoint(TrackPoint point, double newDistance) async {
    final db = await database;
    await db.transaction((txn) async {
      await txn.insert('track_points', point.toMap());
      await txn.rawUpdate('''
        UPDATE tracks
        SET distance_meters = ?,
            point_count     = point_count + 1
        WHERE id = ?
      ''', [newDistance, point.trackId]);
    });
  }

  Future<List<TrackPoint>> getPoints(int trackId) async {
    final db = await database;
    final rows = await db.query(
      'track_points',
      where: 'track_id = ?',
      whereArgs: [trackId],
      orderBy: 'timestamp ASC',
    );
    return rows.map(TrackPoint.fromMap).toList();
  }

  /// Csak a koordinátákat adja vissza — a térkép polyline-hoz elég.
  Future<List<({double lat, double lon})>> getLatLons(int trackId) async {
    final db = await database;
    final rows = await db.query(
      'track_points',
      columns: ['latitude', 'longitude'],
      where: 'track_id = ?',
      whereArgs: [trackId],
      orderBy: 'timestamp ASC',
    );
    return rows
        .map((r) =>
            (lat: r['latitude'] as double, lon: r['longitude'] as double))
        .toList();
  }
}