Import streamlit as st
import os
import time
import re
import requests
from PIL import Image
from io import BytesIO
from openai import OpenAI

# ------------------ App Configuration ------------------
st.set_page_config(page_title="Document AI Assistant", layout="wide")
st.title("📄 Document AI Assistant")
st.caption("Chat with an AI Assistant on your construction documents")

# ------------------ Load API Key and Assistant ID ------------------
OPENAI_API_KEY = os.environ.get("OPENAI_API_KEY")
ASSISTANT_ID = os.environ.get("ASSISTANT_ID")

if not OPENAI_API_KEY or not ASSISTANT_ID:
    st.error("❌ Missing secrets. Please set both OPENAI_API_KEY and ASSISTANT_ID in Hugging Face Space secrets.")
    st.stop()

client = OpenAI(api_key=OPENAI_API_KEY)

# ------------------ Session State Initialization ------------------
if "messages" not in st.session_state:
    st.session_state.messages = []
if "thread_id" not in st.session_state:
    st.session_state.thread_id = None
if "image_url" not in st.session_state:
    st.session_state.image_url = None
if "image_updated" not in st.session_state:
    st.session_state.image_updated = False

# ------------------ Sidebar Controls ------------------
st.sidebar.header("🔧 Settings")
if st.sidebar.button("🔄 Clear Chat"):
    st.session_state.messages = []
    st.session_state.thread_id = None
    st.session_state.image_url = None
    st.session_state.image_updated = False
    st.rerun()

show_image = st.sidebar.checkbox("📖 Show Document Image", value=True)

# ------------------ Layout: Image + Chat ------------------
col1, col2 = st.columns([1, 2])

# ------------------ Left Panel: Image ------------------
with col1:
    if show_image and st.session_state.image_url:
        try:
            response = requests.get(st.session_state.image_url)
            response.raise_for_status()
            img = Image.open(BytesIO(response.content))
            st.image(img, caption="📑 Extracted Page", use_container_width=True)
            st.session_state.image_updated = False
        except Exception as e:
            st.warning(f"⚠️ Failed to load image from URL:\n{st.session_state.image_url}\n\nError: {e}")

# ------------------ Right Panel: Chat ------------------
with col2:
    prompt = st.chat_input("Type your question about the document...")

    # Display chat history
    paired_messages = []
    buffer = []
    for msg in st.session_state.messages:
        buffer.append(msg)
        if msg["role"] == "assistant" and len(buffer) == 2:
            paired_messages.append(buffer.copy())
            buffer.clear()
    if buffer:
        paired_messages.append(buffer.copy())

    for pair in reversed(paired_messages):
        for msg in pair:
            with st.chat_message(msg["role"]):
                st.write(msg["content"])

    if prompt:
        st.session_state.messages.append({"role": "user", "content": prompt})

        try:
            # Create thread
            if st.session_state.thread_id is None:
                thread = client.beta.threads.create()
                st.session_state.thread_id = thread.id

            # Send user message
            client.beta.threads.messages.create(
                thread_id=st.session_state.thread_id,
                role="user",
                content=prompt
            )

            # Run assistant
            run = client.beta.threads.runs.create(
                thread_id=st.session_state.thread_id,
                assistant_id=ASSISTANT_ID
            )

            with st.spinner("Assistant is thinking..."):
                while True:
                    run_status = client.beta.threads.runs.retrieve(
                        thread_id=st.session_state.thread_id,
                        run_id=run.id
                    )
                    if run_status.status == "completed":
                        break
                    time.sleep(1)

            # Retrieve assistant reply
            messages = client.beta.threads.messages.list(thread_id=st.session_state.thread_id)
            assistant_message = None
            for message in reversed(messages.data):
                if message.role == "assistant":
                    assistant_message = message.content[0].text.value
                    break

            st.session_state.messages.append({"role": "assistant", "content": assistant_message})

            # ✅ Parse Document Reference line and generate correct image URL
            match = re.search(r'Document Reference:\s+(.+?),\s+Page\s+(\d+)', assistant_message)
            if match:
                doc_name = match.group(1).strip()
                page = int(match.group(2))
                page_str = f"{page:04d}"
                corrected_url = (
                    f"https://raw.githubusercontent.com/AndrewLORTech/c2ozschlaegerforrestdale/main/"
                    f"{doc_name}/{doc_name}_page_{page_str}.png"
                )
                st.session_state.image_url = corrected_url
                st.session_state.image_updated = True

            st.rerun()

        except Exception as e:
            st.error(f"❌ Error: {str(e)}")