app.py

from fastapi import FastAPI, Request, Form, UploadFile, File
from fastapi.templating import Jinja2Templates
from fastapi.responses import HTMLResponse, RedirectResponse
from fastapi.staticfiles import StaticFiles
from dotenv import load_dotenv
import os, io
from PIL import Image
import markdown
import google.generativeai as genai

# Load environment variable
load_dotenv()
API_KEY = os.getenv("GOOGLE_API_KEY") or "AIzaSyDXqoZkx92J1jt_XAYxCGEHmYQtg2XwfLU"
genai.configure(api_key=API_KEY)

app = FastAPI()
templates = Jinja2Templates(directory="templates")
app.mount("/static", StaticFiles(directory="static"), name="static")

model = genai.GenerativeModel('gemini-2.0-flash')

# Create a global chat session
chat = None
chat_history = []

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

@app.post("/", response_class=HTMLResponse)
async def handle_input(
    request: Request,
    user_input: str = Form(...),
    image: UploadFile = File(None)
):
    global chat, chat_history
    
    # Initialize chat session if needed
    if chat is None:
        chat = model.start_chat(history=[])
    
    parts = []
    if user_input:
        parts.append(user_input)

    # For display in the UI
    user_message = user_input
    
    if image and image.content_type.startswith("image/"):
        data = await image.read()
        try:
            img = Image.open(io.BytesIO(data))
            parts.append(img)
            user_message += " [Image uploaded]"  # Indicate image in chat history
        except Exception as e:
            chat_history.append({
                "role": "model",
                "content": markdown.markdown(f"**Error loading image:** {e}")
            })
            return RedirectResponse("/", status_code=303)

    # Store user message for display
    chat_history.append({"role": "user", "content": user_message})

    try:
        # Send message to Gemini model
        resp = chat.send_message(parts)
        # Add model response to history
        raw = resp.text
        chat_history.append({"role": "model", "content": raw})

    except Exception as e:
        err = f"**Error:** {e}"
        chat_history.append({
            "role": "model",
            "content": markdown.markdown(err)
        })

    # Post-Redirect-Get
    return RedirectResponse("/", status_code=303)

# Clear chat history and start fresh
@app.post("/new")
async def new_chat():
    global chat, chat_history
    chat = None
    chat_history.clear()
    return RedirectResponse("/", status_code=303)