import streamlit as st
import openai
import os

st.set_page_config(page_title="GPT Code Explainer", layout="centered")
st.title("🧠 GPT-3.5 Code Explainer")
st.write("Paste your Python code below and get a detailed explanation using OpenAI GPT-3.5.")

code_input = st.text_area("Paste Python Code", height=200)

# ✅ Use correct client for openai>=1.0.0
api_key = os.getenv("OPENAI_API_KEY")
client = openai.Client(api_key=api_key) if api_key else None

if st.button("Explain"):
    if not client:
        st.error("❌ OPENAI_API_KEY not set. Add it as a secret in your Hugging Face Space.")
    elif code_input.strip():
        with st.spinner("Asking GPT-3.5..."):
            try:
                prompt = f"Explain the following Python function step-by-step:\n\n{code_input.strip()}"
                response = client.chat.completions.create(
                    model="gpt-3.5-turbo",
                    messages=[{"role": "user", "content": prompt}],
                    max_tokens=512,
                    temperature=0.5,
                )
                explanation = response.choices[0].message.content.strip()
                st.subheader("✅ Explanation")
                st.write(explanation)
            except Exception as e:
                st.error(f"OpenAI API error: {e}")
    else:
        st.warning("Please paste some code to explain.")