changes

app/workflow_utils.py

@@ -86,6 +86,48 @@ def resolve_value(expr, context):
         target_list.append(element_to_append)
         return target_list
 
+    # =============================================
+    # 2.2. Hàm tổng hợp list: $agg(list, operation, field?)
+    # =============================================
+    agg_match = re.match(r"^\$agg\(([^,]+),\s*'([^']+)'(?:,\s*['\"]?([^'\"]+)['\"]?)?\)$", expr.strip())
+    if agg_match:
+        list_expr = agg_match.group(1).strip()
+        operation = agg_match.group(2).strip()
+        field_expr = agg_match.group(3).strip() if agg_match.group(3) else None
+
+        # 1. Resolve the list
+        target_list = resolve_value(list_expr, context)
+        if target_list is None:
+            target_list = []
+        
+        if not isinstance(target_list, list):
+            return 0
+
+        # 2. Perform operation
+        if operation == 'count':
+            return len(target_list)
+        
+        if operation == 'sum':
+            if not field_expr:
+                return 0
+            
+            total = 0
+            for item in target_list:
+                value = 0
+                if isinstance(item, dict):
+                    value = item.get(field_expr)
+                else:
+                    value = getattr(item, field_expr, 0)
+                
+                try:
+                    total += float(value or 0)
+                except (ValueError, TypeError):
+                    pass
+            return total
+
+        print(f"      [ERROR] Unknown $agg operation: {operation}")
+        return 0
+
     # =============================================
     # 3. Helper: Lấy giá trị từ context theo đường dẫn dotted
     # =============================================