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lib/services/deck_storage.dart

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+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;
+  }
+}
+