Update app.py

app.py

@@ -138,6 +138,13 @@ body {
 .stSpinner > div > div {
     border-top-color: var(--primary) !important;
 }
+
+.token-input {
+    background: var(--light);
+    padding: 1rem;
+    border-radius: 15px;
+    margin-bottom: 1rem;
+}
 </style>
 """, unsafe_allow_html=True)
 
@@ -179,13 +186,26 @@ def process_pdf(pdf_file):
     return vector_store
 
 # Setup QA Chain
-def setup_qa_chain(vector_store):
-    # Use Mistral-7B from Hugging Face Hub
-    repo_id = "mistralai/Mistral-7B-Instruct-v0.1"
-    llm = HuggingFaceHub(
-        repo_id=repo_id, 
-        model_kwargs={"temperature": 0.5, "max_new_tokens": 500}
-    )
+def setup_qa_chain(vector_store, hf_token=None):
+    # Use free open-source model that doesn't require authentication
+    repo_id = "google/flan-t5-xxl"  # Free model that doesn't require token
+    
+    try:
+        if hf_token:
+            llm = HuggingFaceHub(
+                repo_id=repo_id,
+                huggingfacehub_api_token=hf_token,
+                model_kwargs={"temperature": 0.5, "max_new_tokens": 500}
+            )
+        else:
+            # Try without token (works for some open models)
+            llm = HuggingFaceHub(
+                repo_id=repo_id,
+                model_kwargs={"temperature": 0.5, "max_new_tokens": 500}
+            )
+    except Exception as e:
+        st.error(f"Error loading model: {str(e)}")
+        return None
     
     memory = ConversationBufferMemory(
         memory_key="chat_history", 
@@ -201,6 +221,15 @@ def setup_qa_chain(vector_store):
     
     return qa_chain
 
+# Hugging Face Token Input
+st.markdown("""
+<div class="token-input">
+    <h3>🔑 Hugging Face Token (Optional)</h3>
+    <p>For better models like Mistral, enter your <a href="https://huggingface.co/settings/tokens" target="_blank">Hugging Face token</a></p>
+""", unsafe_allow_html=True)
+hf_token = st.text_input("", type="password", label_visibility="collapsed", placeholder="hf_xxxxxxxxxxxxxxxxxx")
+st.markdown("</div>", unsafe_allow_html=True)
+
 # File upload section
 st.markdown("""
 <div class="upload-area">
@@ -214,8 +243,9 @@ st.markdown("</div>", unsafe_allow_html=True)
 if uploaded_file:
     with st.spinner("Processing PDF..."):
         st.session_state.vector_store = process_pdf(uploaded_file)
-        st.session_state.qa_chain = setup_qa_chain(st.session_state.vector_store)
-    st.success("PDF processed successfully! You can now ask questions.")
+        st.session_state.qa_chain = setup_qa_chain(st.session_state.vector_store, hf_token)
+        if st.session_state.qa_chain:
+            st.success("PDF processed successfully! You can now ask questions.")
 
 # Chat interface
 st.markdown("""
@@ -233,6 +263,10 @@ if prompt := st.chat_input("Your question..."):
     if not st.session_state.vector_store:
         st.warning("Please upload a PDF first")
         st.stop()
+    
+    if not st.session_state.qa_chain:
+        st.error("Model not initialized. Please check your Hugging Face token or try again.")
+        st.stop()
         
     # Add user message to chat history
     st.session_state.chat_history.append({"role": "user", "content": prompt})
@@ -242,8 +276,11 @@ if prompt := st.chat_input("Your question..."):
     # Get assistant response
     with st.chat_message("assistant"):
         with st.spinner("Thinking..."):
-            response = st.session_state.qa_chain({"question": prompt})
-            answer = response["answer"]
+            try:
+                response = st.session_state.qa_chain({"question": prompt})
+                answer = response["answer"]
+            except Exception as e:
+                answer = f"Error: {str(e)}"
         st.markdown(answer)
         
     # Add assistant response to chat history
@@ -254,6 +291,6 @@ st.markdown("</div>", unsafe_allow_html=True)
 # Footer
 st.markdown("""
 <div class="footer">
-    <p>EduQuery - Helping students learn smarter • Powered by Mistral-7B and LangChain</p>
+    <p>EduQuery - Helping students learn smarter • Powered by Flan-T5 and LangChain</p>
 </div>
 """, unsafe_allow_html=True)