SpotiFLAC-Mobile/lib/services/history_database.dart

import 'dart:convert';
import 'package:sqflite/sqflite.dart';
import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:spotiflac_android/utils/logger.dart';

final _log = AppLogger('HistoryDatabase');

/// SQLite database service for download history
/// Provides O(1) lookups by spotify_id and isrc with proper indexing
class HistoryDatabase {
  static final HistoryDatabase instance = HistoryDatabase._init();
  static Database? _database;
  
  HistoryDatabase._init();
  
  Future<Database> get database async {
    if (_database != null) return _database!;
    _database = await _initDB('history.db');
    return _database!;
  }
  
  Future<Database> _initDB(String fileName) async {
    final dbPath = await getApplicationDocumentsDirectory();
    final path = join(dbPath.path, fileName);
    
    _log.i('Initializing database at: $path');
    
    return await openDatabase(
      path,
      version: 1,
      onCreate: _createDB,
      onUpgrade: _upgradeDB,
    );
  }
  
  Future<void> _createDB(Database db, int version) async {
    _log.i('Creating database schema v$version');
    
    await db.execute('''
      CREATE TABLE history (
        id TEXT PRIMARY KEY,
        track_name TEXT NOT NULL,
        artist_name TEXT NOT NULL,
        album_name TEXT NOT NULL,
        album_artist TEXT,
        cover_url TEXT,
        file_path TEXT NOT NULL,
        service TEXT NOT NULL,
        downloaded_at TEXT NOT NULL,
        isrc TEXT,
        spotify_id TEXT,
        track_number INTEGER,
        disc_number INTEGER,
        duration INTEGER,
        release_date TEXT,
        quality TEXT,
        bit_depth INTEGER,
        sample_rate INTEGER,
        genre TEXT,
        label TEXT,
        copyright TEXT
      )
    ''');
    
    // Indexes for fast lookups
    await db.execute('CREATE INDEX idx_spotify_id ON history(spotify_id)');
    await db.execute('CREATE INDEX idx_isrc ON history(isrc)');
    await db.execute('CREATE INDEX idx_downloaded_at ON history(downloaded_at DESC)');
    await db.execute('CREATE INDEX idx_album ON history(album_name, album_artist)');
    
    _log.i('Database schema created with indexes');
  }
  
  Future<void> _upgradeDB(Database db, int oldVersion, int newVersion) async {
    _log.i('Upgrading database from v$oldVersion to v$newVersion');
    // Future migrations go here
  }
  
  /// Migrate data from SharedPreferences to SQLite
  /// Returns true if migration was performed, false if already migrated
  Future<bool> migrateFromSharedPreferences() async {
    final prefs = await SharedPreferences.getInstance();
    final migrationKey = 'history_migrated_to_sqlite';
    
    if (prefs.getBool(migrationKey) == true) {
      _log.d('Already migrated to SQLite');
      return false;
    }
    
    final jsonStr = prefs.getString('download_history');
    if (jsonStr == null || jsonStr.isEmpty) {
      _log.d('No SharedPreferences history to migrate');
      await prefs.setBool(migrationKey, true);
      return false;
    }
    
    try {
      final List<dynamic> jsonList = jsonDecode(jsonStr);
      _log.i('Migrating ${jsonList.length} items from SharedPreferences to SQLite');
      
      final db = await database;
      final batch = db.batch();
      
      for (final json in jsonList) {
        final map = json as Map<String, dynamic>;
        batch.insert(
          'history',
          _jsonToDbRow(map),
          conflictAlgorithm: ConflictAlgorithm.replace,
        );
      }
      
      await batch.commit(noResult: true);
      
      // Mark as migrated but keep old data for safety
      await prefs.setBool(migrationKey, true);
      _log.i('Migration complete: ${jsonList.length} items');
      
      return true;
    } catch (e, stack) {
      _log.e('Migration failed: $e', e, stack);
      return false;
    }
  }
  
  /// Convert JSON format (camelCase) to DB row (snake_case)
  Map<String, dynamic> _jsonToDbRow(Map<String, dynamic> json) {
    return {
      'id': json['id'],
      'track_name': json['trackName'],
      'artist_name': json['artistName'],
      'album_name': json['albumName'],
      'album_artist': json['albumArtist'],
      'cover_url': json['coverUrl'],
      'file_path': json['filePath'],
      'service': json['service'],
      'downloaded_at': json['downloadedAt'],
      'isrc': json['isrc'],
      'spotify_id': json['spotifyId'],
      'track_number': json['trackNumber'],
      'disc_number': json['discNumber'],
      'duration': json['duration'],
      'release_date': json['releaseDate'],
      'quality': json['quality'],
      'bit_depth': json['bitDepth'],
      'sample_rate': json['sampleRate'],
      'genre': json['genre'],
      'label': json['label'],
      'copyright': json['copyright'],
    };
  }
  
  /// Convert DB row (snake_case) to JSON format (camelCase)
  Map<String, dynamic> _dbRowToJson(Map<String, dynamic> row) {
    return {
      'id': row['id'],
      'trackName': row['track_name'],
      'artistName': row['artist_name'],
      'albumName': row['album_name'],
      'albumArtist': row['album_artist'],
      'coverUrl': row['cover_url'],
      'filePath': row['file_path'],
      'service': row['service'],
      'downloadedAt': row['downloaded_at'],
      'isrc': row['isrc'],
      'spotifyId': row['spotify_id'],
      'trackNumber': row['track_number'],
      'discNumber': row['disc_number'],
      'duration': row['duration'],
      'releaseDate': row['release_date'],
      'quality': row['quality'],
      'bitDepth': row['bit_depth'],
      'sampleRate': row['sample_rate'],
      'genre': row['genre'],
      'label': row['label'],
      'copyright': row['copyright'],
    };
  }
  
  // ==================== CRUD Operations ====================
  
  /// Insert or update a history item
  Future<void> upsert(Map<String, dynamic> json) async {
    final db = await database;
    await db.insert(
      'history',
      _jsonToDbRow(json),
      conflictAlgorithm: ConflictAlgorithm.replace,
    );
  }
  
  /// Get all history items ordered by download date (newest first)
  Future<List<Map<String, dynamic>>> getAll({int? limit, int? offset}) async {
    final db = await database;
    final rows = await db.query(
      'history',
      orderBy: 'downloaded_at DESC',
      limit: limit,
      offset: offset,
    );
    return rows.map(_dbRowToJson).toList();
  }
  
  /// Get item by ID
  Future<Map<String, dynamic>?> getById(String id) async {
    final db = await database;
    final rows = await db.query(
      'history',
      where: 'id = ?',
      whereArgs: [id],
      limit: 1,
    );
    if (rows.isEmpty) return null;
    return _dbRowToJson(rows.first);
  }
  
  /// Get item by Spotify ID - O(1) with index
  Future<Map<String, dynamic>?> getBySpotifyId(String spotifyId) async {
    final db = await database;
    final rows = await db.query(
      'history',
      where: 'spotify_id = ?',
      whereArgs: [spotifyId],
      limit: 1,
    );
    if (rows.isEmpty) return null;
    return _dbRowToJson(rows.first);
  }
  
  /// Get item by ISRC - O(1) with index
  Future<Map<String, dynamic>?> getByIsrc(String isrc) async {
    final db = await database;
    final rows = await db.query(
      'history',
      where: 'isrc = ?',
      whereArgs: [isrc],
      limit: 1,
    );
    if (rows.isEmpty) return null;
    return _dbRowToJson(rows.first);
  }
  
  /// Check if spotify_id exists - O(1) with index
  Future<bool> existsBySpotifyId(String spotifyId) async {
    final db = await database;
    final result = await db.rawQuery(
      'SELECT 1 FROM history WHERE spotify_id = ? LIMIT 1',
      [spotifyId],
    );
    return result.isNotEmpty;
  }
  
  /// Get all spotify_ids as Set for fast in-memory lookup
  Future<Set<String>> getAllSpotifyIds() async {
    final db = await database;
    final rows = await db.rawQuery(
      'SELECT spotify_id FROM history WHERE spotify_id IS NOT NULL AND spotify_id != ""'
    );
    return rows.map((r) => r['spotify_id'] as String).toSet();
  }
  
  /// Delete by ID
  Future<void> deleteById(String id) async {
    final db = await database;
    await db.delete('history', where: 'id = ?', whereArgs: [id]);
  }
  
  /// Delete by Spotify ID
  Future<void> deleteBySpotifyId(String spotifyId) async {
    final db = await database;
    await db.delete('history', where: 'spotify_id = ?', whereArgs: [spotifyId]);
  }
  
  /// Clear all history
  Future<void> clearAll() async {
    final db = await database;
    await db.delete('history');
    _log.i('Cleared all history');
  }
  
  /// Get total count
  Future<int> getCount() async {
    final db = await database;
    final result = await db.rawQuery('SELECT COUNT(*) as count FROM history');
    return Sqflite.firstIntValue(result) ?? 0;
  }
  
  /// Find existing item by spotify_id or isrc (for deduplication)
  Future<Map<String, dynamic>?> findExisting({
    String? spotifyId,
    String? isrc,
  }) async {
    if (spotifyId != null && spotifyId.isNotEmpty) {
      final bySpotify = await getBySpotifyId(spotifyId);
      if (bySpotify != null) return bySpotify;
      
      // Check for deezer: prefix matching
      if (spotifyId.startsWith('deezer:')) {
        final deezerId = spotifyId.substring(7);
        final db = await database;
        final rows = await db.query(
          'history',
          where: 'spotify_id LIKE ?',
          whereArgs: ['deezer:$deezerId'],
          limit: 1,
        );
        if (rows.isNotEmpty) return _dbRowToJson(rows.first);
      }
    }
    
    if (isrc != null && isrc.isNotEmpty) {
      return await getByIsrc(isrc);
    }
    
    return null;
  }
  
  /// Close database
  Future<void> close() async {
    final db = await database;
    await db.close();
    _database = null;
  }
}