Update app.py

app.py

@@ -3,7 +3,6 @@ from openai import OpenAI
 import os
 
 # --- CONFIGURATION ---
-# You can change this to any breed you want (e.g., "Pugs", "German Shepherds")
 CHOSEN_BREED = "Golden Retrievers"
 
 # Page setup
@@ -12,21 +11,19 @@ st.title(f"🐕 Only {CHOSEN_BREED}")
 st.caption(f"Powered by Perplexity API. I strictly refuse to talk about cats, other dogs, or anything else!")
 
 # --- AUTHENTICATION ---
-# This retrieves the key you will save in Hugging Face Secrets
 perplexity_api_key = os.getenv("PERPLEXITY_API_KEY")
 
 if not perplexity_api_key:
     st.error("⚠️ PERPLEXITY_API_KEY not found in secrets. Please add it to your Hugging Face Space settings.")
     st.stop()
 
-# Initialize the Client (Perplexity is compatible with the OpenAI library)
+# Initialize Client
 client = OpenAI(
     api_key=perplexity_api_key,
     base_url="https://api.perplexity.ai"
 )
 
 # --- STRICT SYSTEM PROMPT ---
-# This is the "Brain" that restricts the AI.
 system_instruction = f"""
 You are a highly specialized AI assistant with a STRICT filter.
 You must adhere to the following funnel of allowed topics:
@@ -47,35 +44,49 @@ Refusal Message Style: Be polite but firm. Do not apologize profusely, just stat
 
 # --- CHAT LOGIC ---
 
-# Initialize chat history in session state if it doesn't exist
+# Initialize chat history
 if "messages" not in st.session_state:
+    # We keep the greeting in the UI state, but we will filter it out for the API later
     st.session_state["messages"] = [
         {"role": "assistant", "content": f"Hello! I am your expert on {CHOSEN_BREED}. Ask me anything about them!"}
     ]
 
-# Display previous chat messages
+# Display chat messages
 for msg in st.session_state.messages:
     st.chat_message(msg["role"]).write(msg["content"])
 
 # Handle new user input
 if prompt := st.chat_input():
-    # 1. Display user message
+    
+    # --- ERROR FIX: CLEANUP STALE MESSAGES ---
+    # If the last message was from the user, it means the previous API call failed.
+    # We must remove it to prevent sending "User, User" sequence which breaks the API.
+    if st.session_state.messages and st.session_state.messages[-1]["role"] == "user":
+        st.session_state.messages.pop()
+
+    # 1. Display current user message
     st.session_state.messages.append({"role": "user", "content": prompt})
     st.chat_message("user").write(prompt)
 
-    # 2. Prepare messages for API (System Prompt + History)
+    # 2. Prepare messages for API
+    # Start with System Prompt
     api_messages = [{"role": "system", "content": system_instruction}]
     
-    # Add recent conversation history (limit to last 10 messages to save context)
-    for msg in st.session_state.messages[-10:]:
-        api_messages.append(msg)
+    # Add history, but SKIP the very first artificial greeting to ensure System -> User flow
+    # Perplexity prefers the conversation to start with a User query, not an Assistant greeting.
+    history_to_send = st.session_state.messages[-10:] # Get last 10
+    
+    for msg in history_to_send:
+        # Only append if it's NOT that initial fake greeting
+        if msg["content"] != f"Hello! I am your expert on {CHOSEN_BREED}. Ask me anything about them!":
+            api_messages.append(msg)
 
     # 3. Call Perplexity API
     try:
         response = client.chat.completions.create(
-            model="sonar",  # 'sonar' is a good general-purpose Perplexity model
+            model="sonar", 
             messages=api_messages,
-            temperature=0.1, # Low temperature keeps it strict and factual
+            temperature=0.1,
         )
         
         bot_reply = response.choices[0].message.content
@@ -85,4 +96,6 @@ if prompt := st.chat_input():
         st.chat_message("assistant").write(bot_reply)
 
     except Exception as e:
-        st.error(f"An error occurred: {e}")
+        st.error(f"An error occurred: {e}")
+        # Optional: Print the message structure for debugging if needed
+        # st.write(api_messages)