Update app.py

app.py

@@ -200,14 +200,14 @@ def validate_pdf(pdf):
     return "الملف صالح للدردشة", True
 
 def upload_pdf(pdf_file):
-    global vectorstore, chain  # Use global variables to store state
-    
+    global vectorstore, chain,chat_history  # Use global variables to store state
+    chat_history = []
     data = load_pdf(pdf_file)
     vectorstore = prepare_vectorstore(data)
     chain = create_chain(vectorstore)
     return "تم تحميل الملف بنجاح !", True
 
-chat_history = []
+
 def chat(user_input):
     global chain chat_history # Access the global chain variable