import 'package:practice_engine/practice_engine.dart';
import '../data/default_deck.dart';

/// Service for managing deck storage and retrieval.
/// Currently uses in-memory storage. Can be extended to use persistent storage.
class DeckStorage {
  static final DeckStorage _instance = DeckStorage._internal();
  factory DeckStorage() => _instance;
  DeckStorage._internal();

  final Map<String, Deck> _decks = {};
  bool _initialized = false;

  /// Initialize storage with default deck if empty
  void initialize() {
    if (_initialized) return;
    _initialized = true;

    // Add default deck if no decks exist
    if (_decks.isEmpty) {
      final defaultDeck = DefaultDeck.deck;
      _decks[defaultDeck.id] = defaultDeck;
    }
  }

  /// Get all decks
  List<Deck> getAllDecks() {
    initialize();
    return _decks.values.toList();
  }

  /// Get a deck by ID
  Deck? getDeck(String id) {
    initialize();
    return _decks[id];
  }

  /// Add or update a deck
  void saveDeck(Deck deck) {
    initialize();
    _decks[deck.id] = deck;
  }

  /// Delete a deck
  void deleteDeck(String id) {
    _decks.remove(id);
  }

  /// Check if a deck exists
  bool hasDeck(String id) {
    initialize();
    return _decks.containsKey(id);
  }

  /// Get the number of decks
  int get deckCount {
    initialize();
    return _decks.length;
  }
}