Update app.py

app.py

@@ -26,29 +26,35 @@ def respond(user_message, history, selected_method):
 
     valid_methods = ["bar model", "double number line", "equation"]
 
+    # ✅ Ensure history is a list of strictly two-element tuples
+    if not isinstance(history, list):
+        history = []
+    history = [(str(h[0]), str(h[1])) for h in history if isinstance(h, tuple) and len(h) == 2]
+
     # ✅ If user selects a method, store it and provide the method-specific prompt
     if user_message in valid_methods:
         selected_method = user_message  # Store the method
         method_prompt = get_prompt_for_method(user_message)
-        history.append((user_message, method_prompt))  # Ensure tuple format
+        history.append((user_message, method_prompt))  # Ensure correct format
         return method_prompt, history, selected_method
 
     # ✅ If a method has already been selected, provide feedback
     if selected_method:
         feedback = get_feedback_for_method(selected_method, user_message)
-        history.append((user_message, feedback))  # Ensure tuple format
+        history.append((user_message, feedback))  # Ensure correct format
         return feedback, history, selected_method
 
+    # ✅ Ensure chatbot always responds with a valid tuple
     error_msg = "❌ Please select a method first (Bar Model, Double Number Line, or Equation)."
-    history.append((user_message, error_msg))  # Ensure tuple format
+    history.append((user_message, error_msg))  # Ensure correct format
     return error_msg, history, selected_method
 
 # ✅ Gradio UI Setup
 with gr.Blocks() as demo:
     gr.Markdown("## 🤖 AI-Guided Math PD Chatbot")
 
-    chatbot = gr.Chatbot(value=[(INITIAL_PROMPT, "")], height=500)
-    state_history = gr.State([(INITIAL_PROMPT, "")])
+    chatbot = gr.Chatbot(value=[(INITIAL_PROMPT, "Hello! Please select a method to begin.")], height=500)
+    state_history = gr.State([(INITIAL_PROMPT, "Hello! Please select a method to begin.")])
     state_selected_method = gr.State(None)  # ✅ New state to track selected method
 
     user_input = gr.Textbox(placeholder="Type your message here...", label="Your Input")