Update app.py

app.py

@@ -25,14 +25,23 @@ def has_certificate_entry(username):
 
 # Function to add certificate entry
 def add_certificate_entry(username, name):
+    # Load current dataset
+    ds = load_dataset(CERTIFICATES_DATASET, split="train", download_mode="force_redownload")
+    
+    # Remove any existing entry with the same username
+    filtered_rows = [row for row in ds if row["username"] != username]
+
+    # Append the updated/new entry
     new_entry = {
         "username": username,
         "name": name,
-        "timestamp": datetime.now().strftime("%Y-%m-%d"),
+        "timestamp": datetime.now().isoformat()
     }
-    ds = load_dataset(CERTIFICATES_DATASET, split="train")
-    ds = ds.add_item(new_entry)
-    ds.push_to_hub(CERTIFICATES_DATASET)
+    filtered_rows.append(new_entry)
+
+    # Rebuild dataset and push
+    updated_ds = Dataset.from_list(filtered_rows)
+    updated_ds.push_to_hub(CERTIFICATES_DATASET)
 
 # Function to generate certificate PDF
 def generate_certificate(name, score):