Update app.py

app.py

@@ -6,9 +6,11 @@ from datetime import datetime
 from openpyxl import Workbook, load_workbook
 import re
 
+from langchain.memory import ConversationBufferMemory
+
 # ========== CONFIGURATION ==========
-API_KEY = "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"  
-MODEL = "google/gemma-3n-e2b-it:free"  # You can also try "mistral/mixtral-8x7b"
+API_KEY = "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"
+MODEL = "google/gemma-3n-e2b-it:free"
 
 MENU = {
     "Cheeseburger": 5.99,
@@ -19,7 +21,7 @@ MENU = {
     "Salad": 6.99
 }
 
-chat_history = []
+memory = ConversationBufferMemory(return_messages=True)
 order = []
 customer_name = ""
 
@@ -59,7 +61,9 @@ def speak(text, filename="response.mp3"):
 
 # ========== OpenRouter API ==========
 def generate_response(user_input):
-    global chat_history, customer_name, order
+    global customer_name, order
+
+    memory.chat_memory.add_user_message(user_input)
 
     menu_description = "\n".join([f"{item}: ${price}" for item, price in MENU.items()])
     order_summary = ", ".join([f"{qty} x {item}" for item, qty in order]) if order else "No items yet"
@@ -75,12 +79,16 @@ Instructions:
 - Show menu if requested.
 - Extract item names and quantities from messages.
 - Say 'Order summary' and ask 'Confirm?' when user is done.
-- Respond only as the bot, no need to prefix with "Bot:".
+- Respond only as the bot, no need to prefix with \"Bot:\".
 - Keep tone human, natural, and friendly.
 Conversation:
 """
-    for u, b in chat_history:
-        context += f"\nCustomer: {u}\nBot: {b}"
+
+    for msg in memory.chat_memory.messages:
+        if msg.type == "human":
+            context += f"\nCustomer: {msg.content}"
+        else:
+            context += f"\nBot: {msg.content}"
 
     context += f"\nCustomer: {user_input}\nBot:"
 
@@ -97,7 +105,9 @@ Conversation:
     try:
         response = requests.post("https://openrouter.ai/api/v1/chat/completions", headers=headers, json=payload)
         response.raise_for_status()
-        return response.json()["choices"][0]["message"]["content"]
+        reply = response.json()["choices"][0]["message"]["content"]
+        memory.chat_memory.add_ai_message(reply)
+        return reply
     except Exception as e:
         return f"❌ OpenRouter Error: {str(e)}"
 
@@ -107,11 +117,9 @@ def handle_chat(user_input):
 
     bot_reply = generate_response(user_input)
 
-    # Extract name
     if "my name is" in user_input.lower():
         customer_name = user_input.split("my name is")[-1].strip().split()[0].title()
 
-    # Extract items
     for item in MENU:
         if item.lower() in user_input.lower():
             qty = 1
@@ -121,13 +129,11 @@ def handle_chat(user_input):
                     break
             order.append((item, qty))
 
-    # Confirm order
     if "confirm" in user_input.lower() or "yes" in user_input.lower():
         if customer_name and order:
             order_id = save_to_excel(customer_name, order)
             bot_reply += f"\n✅ Your order ID is {order_id}. Thank you for ordering from Saad's Restaurant!"
 
-    chat_history.append((user_input, bot_reply))
     audio_file = speak(bot_reply)
     return bot_reply, audio_file
 
@@ -139,7 +145,7 @@ gr.Interface(
         gr.Textbox(label="🤖 Bot Response"),
         gr.Audio(label="🔊 Speaking", autoplay=True)
     ],
-    title="🍔 SysTaurant Voice Bot (OpenRouter powered)",
-    description="Talk to the bot and it will handle your order using OpenRouter API.",
+    title="🍔 SysTaurant Voice Bot (LangChain + OpenRouter)",
+    description="Smart restaurant assistant powered by LangChain memory and OpenRouter API.",
     theme="soft"
 ).launch(share=True)