fix: 5933 - less greedy language refresh

packages/smooth_app/lib/background/background_task_language_refresh.dart

@@ -59,20 +59,22 @@ class BackgroundTaskLanguageRefresh extends BackgroundTask {
       );
 
   static Future<void> addTask(
+    final LocalDatabase localDatabase,
+  ) async {
+    for (final ProductType productType in ProductType.values) {
+      await _addTask(
+        localDatabase,
+        excludeBarcodes: <String>[],
+        productType: productType,
+      );
+    }
+  }
+
+  static Future<void> _addTask(
     final LocalDatabase localDatabase, {
-    final List<String> excludeBarcodes = const <String>[],
-    final ProductType? productType,
+    required final List<String> excludeBarcodes,
+    required final ProductType productType,
   }) async {
-    if (productType == null) {
-      for (final ProductType item in ProductType.values) {
-        await addTask(
-          localDatabase,
-          excludeBarcodes: excludeBarcodes,
-          productType: item,
-        );
-      }
-      return;
-    }
     final String uniqueId = await _operationType.getNewKey(
       localDatabase,
       productType: productType,
@@ -167,9 +169,10 @@ class BackgroundTaskLanguageRefresh extends BackgroundTask {
     for (final Product product in searchResult.products!) {
       newExcludeBarcodes.remove(product.barcode);
     }
-    await addTask(
+    await _addTask(
       localDatabase,
       excludeBarcodes: newExcludeBarcodes,
+      productType: productType,
     );
   }
 }

packages/smooth_app/lib/background/operation_type.dart

@@ -116,33 +116,30 @@ enum OperationType {
     return int.parse(keyItems[1]);
   }
 
-  static String getBarcode(final String key) {
-    final List<String> keyItems = key.split(_transientHeaderSeparator);
-    return keyItems[2];
-  }
+  static String getBarcode(final String key) => _getNthParameter(key, 2)!;
 
-  static int? getTotalSize(final String key) {
-    final List<String> keyItems = key.split(_transientHeaderSeparator);
-    if (keyItems.length <= 3) {
-      return null;
-    }
-    return int.tryParse(keyItems[3]);
-  }
+  static int? getTotalSize(final String key) => _getNthIntParameter(key, 3);
+
+  static int? getSoFarSize(final String key) => _getNthIntParameter(key, 4);
+
+  static String? getWork(final String key) => _getNthParameter(key, 5);
 
-  static int? getSoFarSize(final String key) {
+  static String? getProductType(final String key) => _getNthParameter(key, 6);
+
+  static String? _getNthParameter(final String key, final int index) {
     final List<String> keyItems = key.split(_transientHeaderSeparator);
-    if (keyItems.length <= 4) {
+    if (keyItems.length <= index) {
       return null;
     }
-    return int.tryParse(keyItems[4]);
+    return keyItems[index];
   }
 
-  static String? getWork(final String key) {
-    final List<String> keyItems = key.split(_transientHeaderSeparator);
-    if (keyItems.length <= 5) {
+  static int? _getNthIntParameter(final String key, final int index) {
+    final String? parameter = _getNthParameter(key, index);
+    if (parameter == null) {
       return null;
     }
-    return keyItems[5];
+    return int.tryParse(parameter);
   }
 
   static OperationType? getOperationType(final String key) {

packages/smooth_app/lib/database/dao_product.dart

@@ -345,54 +345,64 @@ class DaoProduct extends AbstractSqlDao implements BulkDeletable {
     required final List<String> excludeBarcodes,
     required final ProductType productType,
   }) async {
-    /// Unfortunately, some SQFlite implementations don't support "nulls last"
-    String getRawQuery(final bool withNullsLast) =>
+    final List<String> result = <String>[];
+
+    const String tableJoin =
+        'p.$_TABLE_PRODUCT_COLUMN_BARCODE = a.${DaoProductLastAccess.COLUMN_BARCODE}';
+    final String languageCondition = ' ('
+        'p.$_TABLE_PRODUCT_COLUMN_LANGUAGE is null '
+        "or p.$_TABLE_PRODUCT_COLUMN_LANGUAGE != '${language.offTag}'"
+        ') ';
+
+    final String queryWithLastAccess =
         'select p.$_TABLE_PRODUCT_COLUMN_GZIPPED_JSON '
         'from'
-        ' $_TABLE_PRODUCT p'
-        ' left outer join ${DaoProductLastAccess.TABLE} a'
-        '  on p.$_TABLE_PRODUCT_COLUMN_BARCODE = a.${DaoProductLastAccess.COLUMN_BARCODE} '
+        ' $_TABLE_PRODUCT p '
+        ' inner join ${DaoProductLastAccess.TABLE} a'
+        '  on $tableJoin '
         'where'
-        ' p.$_TABLE_PRODUCT_COLUMN_LANGUAGE is null'
-        ' or p.$_TABLE_PRODUCT_COLUMN_LANGUAGE != ? '
-        'order by a.${DaoProductLastAccess.COLUMN_LAST_ACCESS} desc ${withNullsLast ? 'nulls last' : ''} ';
-
-    List<Map<String, dynamic>> queryResults = <Map<String, dynamic>>[];
-    try {
-      queryResults = await localDatabase.database.rawQuery(
-        getRawQuery(true),
-        <Object>[
-          language.offTag,
-        ],
-      );
-    } catch (e) {
-      if (!e.toString().startsWith(
-            'DatabaseException(near "nulls": syntax error (code 1 SQLITE_ERROR',
-          )) {
-        rethrow;
-      }
-      queryResults = await localDatabase.database.rawQuery(
-        getRawQuery(false),
-        <Object>[
-          language.offTag,
-        ],
-      );
-    }
+        ' $languageCondition '
+        'order by a.${DaoProductLastAccess.COLUMN_LAST_ACCESS} desc';
 
-    final List<String> result = <String>[];
+    final String queryWithoutLastAccess =
+        'select p.$_TABLE_PRODUCT_COLUMN_GZIPPED_JSON '
+        'from'
+        ' $_TABLE_PRODUCT p '
+        'where'
+        ' not exists('
+        '  select null'
+        '  from ${DaoProductLastAccess.TABLE} a '
+        '  where $tableJoin '
+        ' ) '
+        ' and $languageCondition';
 
-    for (final Map<String, dynamic> row in queryResults) {
-      final Product product = _getProductFromQueryResult(row);
-      final String barcode = product.barcode!;
-      if (excludeBarcodes.contains(barcode)) {
-        continue;
-      }
-      if ((product.productType ?? ProductType.food) != productType) {
-        continue;
-      }
-      result.add(barcode);
-      if (result.length == limit) {
-        break;
+    // optimization: using 2 more simple queries than a "left join" that proved
+    // more expensive (less than .1s for each simple query, .5s for "left join")
+    final List<String> queries = <String>[
+      queryWithLastAccess,
+      queryWithoutLastAccess,
+    ];
+    for (final String query in queries) {
+      // optimization: using a cursor, as we don't want all the rows,
+      // and we don't know how many rows we'll need.
+      final QueryCursor queryCursor =
+          await localDatabase.database.rawQueryCursor(
+        query,
+        null,
+      );
+      while (await queryCursor.moveNext()) {
+        final Product product = _getProductFromQueryResult(queryCursor.current);
+        final String barcode = product.barcode!;
+        if (excludeBarcodes.contains(barcode)) {
+          continue;
+        }
+        if ((product.productType ?? ProductType.food) != productType) {
+          continue;
+        }
+        result.add(barcode);
+        if (result.length == limit) {
+          return result;
+        }
       }
     }
 

packages/smooth_app/lib/pages/offline_tasks_page.dart

@@ -80,6 +80,8 @@ class _OfflineTaskState extends State<OfflineTaskPage> {
                   info = '';
                 }
                 final BackgroundTaskQueue queue = queues[taskId]!;
+                final String? productType =
+                    OperationType.getProductType(taskId);
                 return ListTile(
                   leading: Icon(queue.iconData),
                   onTap: () async {
@@ -110,7 +112,8 @@ class _OfflineTaskState extends State<OfflineTaskPage> {
                     '$info'
                     '(${OperationType.getOperationType(taskId)?.getLabel(
                           appLocalizations,
-                        ) ?? appLocalizations.background_task_operation_unknown})',
+                        ) ?? appLocalizations.background_task_operation_unknown})'
+                    '${productType == null ? '' : ' ($productType)'}',
                   ),
                   subtitle: Text(_getMessage(status, appLocalizations)),
                   trailing: const Icon(Icons.clear),