feat: add remote products and qr code for payconic

lib/services/product_service.dart

@@ -2,6 +2,7 @@ import 'package:drift/drift.dart';
 import 'package:uuid/uuid.dart';
 
 import '../database/app_database.dart';
+import '../database/catalog_queries.dart';
 import '../database/stock_queries.dart';
 import '../models/product.dart';
 import '../models/tab_event.dart';
@@ -87,6 +88,8 @@ class DriftProductService implements ProductService {
     return _mapRowToProduct(row);
   }
 
+  /// Queues the new product for the server (which takes this tablet's id), its
+  /// starting stock as a count, and its picture for upload.
   @override
   Future<void> createProduct({
     required String name,
@@ -114,16 +117,29 @@ class DriftProductService implements ProductService {
               imagePath: Value(imagePath),
             ),
           );
+      await database.queueEvent(
+        eventFactory.productCreated(
+          productId: id,
+          fields: {
+            'name': name,
+            'category': _serverCategory(category),
+            'priceInCents': priceInCents,
+            'lowStockThreshold': lowStockThreshold,
+          },
+        ),
+      );
       // The server starts a product it doesn't know as untracked
       if (!infiniteStock) {
-        await database.queueStockSet(
+        await database.queueEvent(
           eventFactory.stockSet(productId: id, quantity: stockQuantity),
         );
       }
+      if (imagePath != null) await database.queueImageUpload(id, imagePath);
     });
   }
 
-  /// A changed stock or tracking is queued for the server as a count.
+  /// Queues what changed for the server: the changed fields, a changed stock
+  /// or tracking as a count, and a new picture for upload.
   @override
   Future<void> updateProduct(Product product) async {
     await database.transaction(() async {
@@ -147,28 +163,57 @@ class DriftProductService implements ProductService {
       );
 
       if (current == null) return;
+      final fields = <String, Object?>{
+        if (current.name != product.name) 'name': product.name,
+        if (current.category != product.category)
+          'category': _serverCategory(product.category),
+        if (current.priceInCents != product.priceInCents)
+          'priceInCents': product.priceInCents,
+        if (current.lowStockThreshold != product.lowStockThreshold)
+          'lowStockThreshold': product.lowStockThreshold,
+      };
+      if (fields.isNotEmpty) {
+        await database.queueEvent(
+          eventFactory.productUpdated(productId: product.id, fields: fields),
+        );
+      }
+
       final stockChanged = product.infiniteStock
           ? !current.infiniteStock
           : current.infiniteStock ||
                 current.stockQuantity != product.stockQuantity;
       if (stockChanged) {
-        await database.queueStockSet(
+        await database.queueEvent(
           eventFactory.stockSet(
             productId: product.id,
             quantity: product.infiniteStock ? null : product.stockQuantity,
           ),
         );
       }
+
+      final picture = product.imagePath;
+      if (picture != null && picture != current.imagePath) {
+        await database.queueImageUpload(product.id, picture);
+      }
     });
   }
 
-  /// Only hidden, since open tabs and history still refer to it.
+  /// Only hidden, since open tabs and history still refer to it; the server
+  /// archives it for every tablet.
   @override
   Future<void> deleteProduct(String id) async {
-    final query = database.update(database.products)
-      ..where((product) => product.id.equals(id));
+    await database.transaction(() async {
+      await (database.update(database.products)
+            ..where((product) => product.id.equals(id)))
+          .write(const ProductsCompanion(active: Value(false)));
+      await database.queueEvent(eventFactory.productArchived(productId: id));
+    });
+  }
 
-    await query.write(const ProductsCompanion(active: Value(false)));
+  /// The server has no category for an empty one.
+  static String? _serverCategory(String category) {
+    final trimmed = category.trim();
+    return trimmed.isEmpty ? null : trimmed;
   }
 
   @override