Update app.py

app.py

@@ -1,3 +1,7 @@
+# app.py — DDS HR Chatbot (RAG Demo) for Hugging Face Spaces
+# Fixes: Gradio Chatbot history format mismatch WITHOUT using Chatbot(type="messages")
+# Works across Gradio versions by auto-detecting whether Chatbot expects dict-messages or tuple-history.
+
 import os
 from pathlib import Path
 import requests
@@ -41,10 +45,10 @@ FAQ_ITEMS = [
 
 LOGO_RAW_URL = "https://raw.githubusercontent.com/Decoding-Data-Science/airesidency/main/dds-logo-removebg-preview.png"
 
-# PDFs in repo
+# PDFs live in repo under ./data/pdfs
 PDF_DIR = Path("data/pdfs")
 
-# Persistent disk if enabled on Spaces
+# Persistent disk if enabled on Spaces (recommended). Otherwise local folder.
 PERSIST_ROOT = Path("/data") if Path("/data").exists() else Path(".")
 VDB_DIR = PERSIST_ROOT / "chroma"
 
@@ -69,6 +73,7 @@ def download_logo() -> str | None:
         return None
 
 def build_or_load_index():
+    # Ensure OpenAI key exists (HF Spaces Secrets → OPENAI_API_KEY)
     if not os.getenv("OPENAI_API_KEY"):
         raise RuntimeError("OPENAI_API_KEY is not set. Add it in Space Settings → Repository secrets.")
 
@@ -84,6 +89,7 @@ def build_or_load_index():
     Settings.llm = LIOpenAI(model=LLM_MODEL, temperature=0.0)
     Settings.node_parser = SentenceSplitter(chunk_size=900, chunk_overlap=150)
 
+    # Read docs
     docs = SimpleDirectoryReader(
         input_dir=str(PDF_DIR),
         required_exts=[".pdf"],
@@ -94,7 +100,7 @@ def build_or_load_index():
     VDB_DIR.mkdir(parents=True, exist_ok=True)
     chroma_client = chromadb.PersistentClient(path=str(VDB_DIR))
 
-    # Reuse existing collection if it already has vectors
+    # Reuse existing collection if it has vectors
     try:
         col = chroma_client.get_collection(COLLECTION_NAME)
         try:
@@ -102,7 +108,8 @@ def build_or_load_index():
                 vector_store = ChromaVectorStore(chroma_collection=col)
                 storage_context = StorageContext.from_defaults(vector_store=vector_store)
                 return VectorStoreIndex.from_vector_store(
-                    vector_store=vector_store, storage_context=storage_context
+                    vector_store=vector_store,
+                    storage_context=storage_context,
                 )
         except Exception:
             pass
@@ -135,11 +142,14 @@ def format_sources(resp, max_sources=5) -> str:
         lines.append(f"{i}) {doc} | page {page} | score {score:.3f}")
     return "\n".join(lines)
 
+def _is_messages_history(history):
+    # messages history = list[{"role":..., "content":...}, ...]
+    return isinstance(history, list) and (len(history) == 0 or isinstance(history[0], dict))
+
 # -----------------------------
 # Build index + chat engine
 # -----------------------------
 INDEX = build_or_load_index()
-
 CHAT_ENGINE = INDEX.as_chat_engine(
     chat_mode="context",
     similarity_top_k=5,
@@ -147,10 +157,9 @@ CHAT_ENGINE = INDEX.as_chat_engine(
 )
 
 # -----------------------------
-# Gradio callbacks (MESSAGES format)
-# history is: [{"role":"user","content":"..."}, {"role":"assistant","content":"..."}, ...]
+# Gradio callbacks (version-compatible)
 # -----------------------------
-def answer(user_msg: str, history: list, show_sources: bool):
+def answer(user_msg: str, history, show_sources: bool):
     user_msg = (user_msg or "").strip()
     if not user_msg:
         return history, ""
@@ -161,11 +170,18 @@ def answer(user_msg: str, history: list, show_sources: bool):
     if show_sources:
         text = text + "\n\n" + format_sources(resp)
 
-    # Append messages (this fixes your error)
-    history = (history or []) + [
-        {"role": "user", "content": user_msg},
-        {"role": "assistant", "content": text},
-    ]
+    history = history or []
+
+    # If this Gradio Chatbot expects "messages" format
+    if _is_messages_history(history):
+        history = history + [
+            {"role": "user", "content": user_msg},
+            {"role": "assistant", "content": text},
+        ]
+        return history, ""
+
+    # Else assume legacy tuple format: [(user, bot), ...]
+    history = history + [(user_msg, text)]
     return history, ""
 
 def load_faq(faq_choice: str):
@@ -179,7 +195,7 @@ def clear_chat():
 # -----------------------------
 logo_path = download_logo()
 
-with gr.Blocks(theme=gr.themes.Soft()) as demo:
+with gr.Blocks() as demo:
     with gr.Row():
         if logo_path:
             gr.Image(value=logo_path, show_label=False, height=70, width=70, container=False)
@@ -199,8 +215,8 @@ with gr.Blocks(theme=gr.themes.Soft()) as demo:
             clear_btn = gr.Button("Clear chat")
 
         with gr.Column(scale=2, min_width=520):
-            # IMPORTANT: type="messages"
-            chatbot = gr.Chatbot(label="DDS HR Assistant", height=520, type="messages")
+            # NOTE: no 'type' kwarg to avoid version errors
+            chatbot = gr.Chatbot(label="DDS HR Assistant", height=520)
             user_input = gr.Textbox(label="Your question", placeholder="Ask a policy question and press Enter")
             send_btn = gr.Button("Send")