second commit

lib/domain/repositories/sync_repository.dart

@@ -0,0 +1,38 @@
+import '../entities/shift_report.dart';
+import '../entities/sync_event.dart';
+
+/// The terminal's two network touchpoints, plus the durable event log.
+abstract class SyncRepository {
+  /// True once products have been pulled onto this terminal.
+  bool get hasCatalogue;
+
+  DateTime? get lastImportAt;
+  String? get catalogueRevision;
+
+  /// Pulls the catalogue and writes it locally.
+  ///
+  /// Records a [SyncEventType.catalogueImport] event whether or not it
+  /// succeeds, so the log reflects every attempt.
+  Future<SyncEvent> importCatalogue({
+    void Function(double progress, String stage)? onProgress,
+  });
+
+  /// Builds the day's report from locally stored sales.
+  ShiftReport buildShiftReport({
+    required DateTime businessDate,
+    required String terminalId,
+    required String cashierName,
+  });
+
+  /// Queues the report and attempts to push it.
+  ///
+  /// On failure the event is kept in [SyncStatus.failed] so nothing is lost.
+  Future<SyncEvent> pushShiftReport(ShiftReport report);
+
+  /// Retries a previously failed or pending push.
+  Future<SyncEvent> retry(String eventId);
+
+  List<SyncEvent> get events;
+
+  bool get hasUnsyncedEvents;
+}