app.py

import os
import logging
from dotenv import load_dotenv
from fastapi import FastAPI, Request, Form
from fastapi.responses import JSONResponse, HTMLResponse
from fastapi.middleware.cors import CORSMiddleware
from fastapi.templating import Jinja2Templates
from langchain_community.chat_models import ChatOpenAI  # Correct import
from langchain_community.embeddings import OpenAIEmbeddings  # Correct import
from langchain.chains import LLMChain
from langchain.prompts import PromptTemplate
from langchain_community.vectorstores import FAISS  # Correct import

# Load environment variables
load_dotenv()

# Securely retrieve the OpenAI API key
openai_api_key = os.getenv("OPENAI_API_KEY")
import os

# Securely retrieve the OpenAI API key from the environment variable
openai_api_key = os.getenv("OPENAI_API_KEY")

if not openai_api_key:
    raise ValueError("Missing OpenAI API key. Set OPENAI_API_KEY in your environment variables.")
openai_api_key = os.getenv("OPENAI_API_KEY")
if openai_api_key:
    print("API Key loaded successfully!")
else:
    print("API Key not found.")

# Initialize FastAPI app
app = FastAPI()
templates = Jinja2Templates(directory="templates")

# Configure CORS
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# Initialize OpenAI embeddings
embeddings = OpenAIEmbeddings(openai_api_key=openai_api_key)

# Load FAISS index with error handling
# Load FAISS index with error handling
faiss_index_path = "/Users/sasi/Downloads/Multimodal/faiss_index/index.faiss"  # Path on Hugging Face Space

try:
    db = FAISS.load_local(faiss_index_path, embeddings, allow_dangerous_deserialization=True)
    logger.info(f"FAISS index loaded successfully from {faiss_index_path}.")
except Exception as e:
    logger.error(f"Error loading FAISS index from {faiss_index_path}: {e}")
    db = None  # Avoid crashing


# Define the prompt template
prompt_template = """
You are an expert in skin cancer research.
Answer the question based only on the provided context, which may include text, images, or tables.

Context:
{context}

Question: {question}

If the context does not contain sufficient information, say: "Sorry, I don't have much information about it."

Answer:
"""

qa_chain = LLMChain(
    llm=ChatOpenAI(model="gpt-4", openai_api_key=openai_api_key, max_tokens=1024),
    prompt=PromptTemplate.from_template(prompt_template),
)

@app.get("/", response_class=HTMLResponse)
async def index(request: Request):
    return templates.TemplateResponse("index.html", {"request": request})

@app.post("/get_answer")
async def get_answer(question: str = Form(...)):
    if db is None:
        return JSONResponse({"error": "FAISS database is unavailable."}, status_code=500)

    try:
        # Retrieve relevant documents from FAISS
        relevant_docs = db.similarity_search(question)
        context = ""
        relevant_images = []

        for d in relevant_docs:
            doc_type = d.metadata.get('type', 'text')
            original_content = d.metadata.get('original_content', '')

            if doc_type == 'text':
                context += f"[text] {original_content}\n"
            elif doc_type == 'table':
                context += f"[table] {original_content}\n"
            elif doc_type == 'image':
                context += f"[image] {d.page_content}\n"
                relevant_images.append(original_content)

        # Run the question-answering chain
        result = qa_chain.run({'context': context, 'question': question})

        # Handle cases where no relevant images are found
        return JSONResponse({
            "relevant_images": relevant_images[0] if relevant_images else None,
            "result": result,
        })
    except Exception as e:
        logger.error(f"Error processing request: {e}")
        return JSONResponse({"error": "Internal server error."}, status_code=500)