Update app.py

app.py

@@ -4,7 +4,11 @@ import json
 import time
 import gradio as gr
 import logging
+
+# Load local .env only if it exists
 from dotenv import load_dotenv
+load_dotenv()
+
 import google.generativeai as genai
 
 from langgraph.graph import START, MessagesState, StateGraph
@@ -18,19 +22,20 @@ from langchain_core.prompts.chat import (
 )
 from langchain_google_genai import ChatGoogleGenerativeAI
 
-
-# === Setup Logging & API Key ===
-logging.basicConfig(level=logging.INFO)
+# === Logging ===
+logging.basicConfig(level=logging.INFO, format="%(asctime)s - %(levelname)s - %(message)s")
 logger = logging.getLogger(__name__)
-load_dotenv()  # For local .env use
 
-GEMINI_API_KEY = os.getenv("GEMINI_API_KEY")
-if not GEMINI_API_KEY:
-    raise ValueError("Missing GEMINI_API_KEY")
-genai.configure(api_key=GEMINI_API_KEY)
+# === Load API Key ===
+os.environ["GOOGLE_API_KEY"] = os.getenv["GEMINI_API_KEY"]
+
+# GEMINI_API_KEY = os.getenv("GEMINI_API_KEY")
+# if not GEMINI_API_KEY:
+    #raise ValueError("GEMINI_API_KEY is missing. Set it as an environment variable or Hugging Face Secret.")
 
+genai.configure(api_key=GEMINI_API_KEY)
 
-# === Chat History Storage ===
+# === Chat Storage ===
 HISTORY_FILE = "chat_history.json"
 
 def load_all_sessions():
@@ -45,8 +50,7 @@ def save_all_sessions(sessions):
 
 sessions = load_all_sessions()
 
-
-# === Gemini Chatbot Class ===
+# === Gemini LLM Chatbot ===
 class GeminiChatbot:
     def __init__(self):
         self.setup_model()
@@ -54,7 +58,7 @@ class GeminiChatbot:
     def setup_model(self):
         system_template = """
         You are a helpful, respectful and honest assistant. Always answer as helpfully as possible, while being safe.
-        Your answers should be informative, engaging, and accurate. If a question doesn't make any sense, or isn't factually coherent, explain why instead of answering something incorrect.
+        Your answers should be informative, engaging, and accurate. If a question doesn't make any sense, or isn't factually coherent, explain why.
         If you don't know the answer to a question, please don't share false information.
         """
 
@@ -75,12 +79,7 @@ class GeminiChatbot:
         def call_model(state: MessagesState):
             chat_history = state["messages"][:-1]
             user_input = state["messages"][-1].content
-
-            formatted_messages = self.prompt.format_messages(
-                chat_history=chat_history,
-                input=user_input
-            )
-
+            formatted_messages = self.prompt.format_messages(chat_history=chat_history, input=user_input)
             response = self.model.invoke(formatted_messages)
             return {"messages": response}
 
@@ -92,52 +91,50 @@ class GeminiChatbot:
         self.app = workflow.compile(checkpointer=self.memory)
 
     def get_response(self, user_message, history, thread_id):
-        try:
-            from langchain_core.messages import HumanMessage, AIMessage
+        from langchain_core.messages import HumanMessage, AIMessage
 
-            messages = []
+        try:
+            # Format chat history for LangChain
+            langchain_history = []
             for user, bot in history:
-                messages.append(HumanMessage(content=user))
-                messages.append(AIMessage(content=bot))
+                langchain_history.append(HumanMessage(content=user))
+                langchain_history.append(AIMessage(content=bot))
 
             input_msg = HumanMessage(content=user_message)
-            full_history = messages + [input_msg]
+            full_history = langchain_history + [input_msg]
             config = {"configurable": {"thread_id": thread_id}}
 
+            # Get final response
             response = self.app.invoke({"messages": full_history}, config)
-            final_text = response["messages"][-1].content
+            full_text = response["messages"][-1].content
 
             full_response = ""
-            for char in final_text:
+            for char in full_text:
                 full_response += char
                 yield full_response
                 time.sleep(0.01)
 
         except Exception as e:
             logger.error(f"Response error: {e}")
-            yield f"Error: {str(e)}"
+            yield f"⚠ Error: {type(e).__name__} — {str(e)}"
 
 
-# === Gradio UI ===
 chatbot = GeminiChatbot()
 
-
+# === Gradio UI ===
 def launch_interface():
     with gr.Blocks(
         theme=gr.themes.Base(),
         css="""
-            body { background-color: black; }
-            .gr-textbox textarea { background-color: #2f2f2f; color: white; }
-            .gr-chatbot { background-color: #2f2f2f; color: white; }
-            .gr-button, .gr-dropdown {
-                margin: 5px auto;
-                display: block;
-                width: 50%;
-            }
-            .gr-markdown h2 {
-                text-align: center;
-                color: white;
-            }
+        body { background-color: black; }
+        .gr-textbox textarea { background-color: #2f2f2f; color: white; }
+        .gr-chatbot { background-color: #2f2f2f; color: white; }
+        .gr-button, .gr-dropdown {
+            margin: 5px auto;
+            display: block;
+            width: 50%;
+        }
+        .gr-markdown h2 { text-align: center; color: white; }
         """
     ) as demo:
         demo.title = "LangChain Powered ChatBot"
@@ -147,23 +144,28 @@ def launch_interface():
         session_names = gr.State()
         history = gr.State([])
 
-        # Startup session
         if not sessions:
             new_id = str(uuid.uuid4())
             sessions[new_id] = []
             save_all_sessions(sessions)
+            current_thread_id.value = new_id
+            session_names.value = [f"NEW: {new_id}"]
         else:
-            new_id = next(iter(sessions.keys()))
-
-        current_thread_id.value = new_id
-        session_names.value = [f"PREVIOUS: {k}" for k in sessions if sessions[k]]
+            current_thread_id.value = next(iter(sessions))
+            session_names.value = [f"PREVIOUS: {k}" for k in sessions if sessions[k]]
 
         def get_dropdown_choices():
-            return [f"PREVIOUS: {k}" for k in sessions if sessions[k]] + \
-                   [f"NEW: {current_thread_id.value}"]
+            return [f"PREVIOUS: {k}" for k in sessions if sessions[k]] + [f"NEW: {current_thread_id.value}"]
 
+        # UI
         new_chat_btn = gr.Button("New Chat", variant="primary")
-        session_selector = gr.Dropdown(label="Chats", choices=get_dropdown_choices(), value=f"NEW: {new_id}", interactive=True)
+        session_selector = gr.Dropdown(
+            label="Chats",
+            choices=get_dropdown_choices(),
+            value=f"NEW: {current_thread_id.value}",
+            interactive=True
+        )
+
         chatbot_ui = gr.Chatbot(label="Conversation", height=350)
 
         with gr.Row():
@@ -172,25 +174,28 @@ def launch_interface():
 
         clear = gr.Button("Clear Current Chat")
 
+        # === Event Functions ===
         def start_new_chat():
             new_id = str(uuid.uuid4())
             sessions[new_id] = []
             save_all_sessions(sessions)
-            updated_choices = [f"PREVIOUS: {k}" for k in sessions if sessions[k]] + [f"NEW: {new_id}"]
-            return new_id, [], updated_choices, f"NEW: {new_id}"
+            display = f"NEW: {new_id}"
+            updated = [f"PREVIOUS: {k}" for k in sessions if sessions[k]] + [display]
+            return new_id, [], gr.update(choices=updated, value=display), display
 
-        def switch_chat(display_name):
-            true_id = display_name.split(": ", 1)[-1]
-            return true_id, sessions.get(true_id, []), display_name
+        def switch_chat(display_id):
+            true_id = display_id.split(": ", 1)[-1]
+            return true_id, sessions.get(true_id, []), display_id
 
         def respond(message, history, thread_id):
+            if not message.strip():
+                yield history
+                return
             history.append((message, ""))
             yield history
 
-            full_response = ""
             for chunk in chatbot.get_response(message, history[:-1], thread_id):
-                full_response = chunk
-                history[-1] = (message, full_response)
+                history[-1] = (message, chunk)
                 yield history
 
             sessions[thread_id] = history
@@ -201,7 +206,7 @@ def launch_interface():
             save_all_sessions(sessions)
             return []
 
-        # Events
+        # === Bind Events ===
         new_chat_btn.click(start_new_chat, outputs=[current_thread_id, chatbot_ui, session_selector, session_selector])
         session_selector.change(switch_chat, inputs=session_selector, outputs=[current_thread_id, chatbot_ui, session_selector])
         send.click(respond, [msg, chatbot_ui, current_thread_id], [chatbot_ui]).then(lambda: "", None, msg)
@@ -210,8 +215,7 @@ def launch_interface():
 
     return demo
 
-
-# === Launch ===
+# === Run App ===
 if __name__ == "__main__":
     try:
         demo = launch_interface()