# app.py
import os
import openai
import streamlit as st

# Load API key from environment variable
client = openai.OpenAI(api_key=os.getenv("OPENAI_API_KEY"))

# Page setup
st.set_page_config(page_title="OpenAI Chatbot", layout="centered")
st.title("🤖 OpenAI Chatbot")
st.markdown("Talk to GPT-4 using OpenAI's latest API.")

# Initialize chat history
if "messages" not in st.session_state:
    st.session_state.messages = [
        {"role": "system", "content": "You are a helpful assistant."}
    ]

# Show chat history
for msg in st.session_state.messages[1:]:
    with st.chat_message(msg["role"]):
        st.markdown(msg["content"])

# User input
if prompt := st.chat_input("Type your message..."):
    # Show user message
    st.chat_message("user").markdown(prompt)
    st.session_state.messages.append({"role": "user", "content": prompt})

    try:
        # Call OpenAI's chat model using v1.x API
        response = client.chat.completions.create(
            model="gpt-4",  # or "gpt-3.5-turbo"
            messages=st.session_state.messages,
            temperature=0.7
        )
        reply = response.choices[0].message.content
        st.chat_message("assistant").markdown(reply)
        st.session_state.messages.append({"role": "assistant", "content": reply})
    except Exception as e:
        st.error(f"Error: {e}")