create app.py

app.py

@@ -0,0 +1,95 @@
+import os
+import streamlit as st
+from langchain.chains import ConversationChain
+from langchain_openai import ChatOpenAI
+from langchain.memory import ConversationBufferMemory
+from streamlit_extras.add_vertical_space import add_vertical_space
+
+# Set up OpenAI API Key securely
+if "HPToken" in st.secrets:
+    os.environ["OPENAI_API_KEY"] = st.secrets["HPToken"]
+else:
+    st.error("🔑 OpenAI API Key is missing! Please add it to Streamlit secrets.")
+    st.stop()
+
+# Initialize chatbot with memory
+def init_chatbot(model="gpt-4o-mini"):
+    try:
+        memory = ConversationBufferMemory()
+        chatbot = ConversationChain(llm=ChatOpenAI(model=model), memory=memory, verbose=False)
+        return chatbot
+    except Exception as e:
+        st.error(f"⚠️ Error initializing chatbot: {e}")
+        return None
+
+if "chatbot" not in st.session_state:
+    st.session_state.chatbot = init_chatbot()
+
+# Custom Styling
+st.markdown("""
+    <style>
+        body {
+            background-color: #f5f5f5;
+        }
+        .stChatMessage {
+            padding: 10px;
+            border-radius: 10px;
+            margin: 5px 0;
+        }
+        .user-message {
+            background-color: #dcf8c6;
+            text-align: right;
+        }
+        .bot-message {
+            background-color: #ffffff;
+        }
+    </style>
+""", unsafe_allow_html=True)
+
+# Sidebar - Model Selection
+st.sidebar.title("⚙️ Settings")
+model_choice = st.sidebar.radio("Select Model", ("gpt-4o-mini", "gpt-4", "gpt-3.5-turbo"))
+
+# Update chatbot model if changed
+if model_choice != st.session_state.chatbot.llm.model_name:
+    st.session_state.chatbot = init_chatbot(model_choice)
+
+# Title and Description
+st.title("💬 LangChain AI Chatbot")
+st.write("### Hi, I'm a chatbot powered by GPT. How can I assist you today?")
+
+# Chat history storage
+if "chat_history" not in st.session_state:
+    st.session_state.chat_history = []
+
+# User Input via Chat Input (better UX)
+user_input = st.chat_input("Type your message here...")
+
+# Process input
+if user_input:
+    with st.spinner("Thinking..."):
+        try:
+            response = st.session_state.chatbot.run(user_input)
+            if response:
+                st.session_state.chat_history.append(("user", user_input))
+                st.session_state.chat_history.append(("bot", response))
+        except Exception as e:
+            st.error(f"⚠️ Error generating response: {e}")
+
+# Display chat history
+st.write("### 🗨️ Conversation")
+for role, text in st.session_state.chat_history:
+    with st.chat_message(role):
+        st.markdown(f"**{role.capitalize()}**: {text}")
+
+# Collapsible Chat History
+with st.expander("📜 View Full Chat History"):
+    for role, text in st.session_state.chat_history:
+        st.write(f"**{role.capitalize()}**: {text}")
+
+# Add spacing
+add_vertical_space(2)
+
+# Footer
+st.markdown("---")
+st.markdown("Developed with ❤️ using Streamlit & LangChain")