main.py

from fastapi import FastAPI, Depends, HTTPException, status, Query
from fastapi.responses import FileResponse, StreamingResponse, JSONResponse
from fastapi.staticfiles import StaticFiles
from jose import JWTError
from schemas import UserRegister, TokenResponse, RefreshTokenRequest, QueryInput
from auth import  register_user, get_db, authenticate_user, create_token, verify_token, verify_access_token, Session
from utils import generate_stream, generate_response, shutdown_event
from fastapi.security import OAuth2PasswordRequestForm
from pathlib import Path
from datetime import timedelta
import os
import logging

logging.basicConfig(level=logging.INFO)

SECRET_KEY = os.getenv("SECRET_KEY", 'def6nQHONW99pOPyba9DShny6FB1CJJBigZault')
REFRESH_SECRET_KEY = os.getenv("REFRESH_SECRET_KEY", SECRET_KEY)
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 30
REFRESH_TOKEN_EXPIRE_DAYS = 7

app = FastAPI()

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

# Entry Endpoint 
@app.get('/')
def index() -> FileResponse:
    file_path = Path(__file__).parent / 'static' / 'index.html'
    return FileResponse(path=str(file_path), media_type='text/html')

@app.post("/register")
async def register(user: UserRegister, db: Session = Depends(get_db)):
    """Registers a new user."""
    new_user = register_user(user.username, user.password, db)
    return {"message": "User registered successfully", "user": new_user.username}

@app.post("/login", response_model=TokenResponse)
async def login(form_data: OAuth2PasswordRequestForm = Depends(), db: Session = Depends(get_db)):
    try:
        user = authenticate_user(form_data.username, form_data.password, db)

        if not user:
           raise HTTPException(
               status_code=status.HTTP_401_UNAUTHORIZED,
               detail="Invalid username or password",
               headers={"WWW-Authenticate": "Bearer"},
           )

        access_token_expires = timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
        refresh_token_expires = timedelta(days=REFRESH_TOKEN_EXPIRE_DAYS)
        
        access_token = create_token(
            data={"sub": user.username}, 
            expires_delta=access_token_expires, 
            secret_key=SECRET_KEY
        )
        refresh_token = create_token(
            data={"sub": user.username}, 
            expires_delta=refresh_token_expires, 
            secret_key=REFRESH_SECRET_KEY
        )

        return {
            "access_token": access_token, 
            "refresh_token": refresh_token, 
            "token_type": "bearer"
        }
    except Exception as e:
        logging.error(f"Login error: {str(e)}")
        raise HTTPException(status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, detail="Internal server error")

@app.post("/refresh", response_model=TokenResponse)
async def refresh(refresh_request: RefreshTokenRequest):
    try:
        # Verify the refresh token
        username = verify_token(refresh_request.refresh_token, REFRESH_SECRET_KEY)
        
        # Create new access token
        access_token_expires = timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
        access_token = create_token(
            data={"sub": username},
            expires_delta=access_token_expires,
            secret_key=SECRET_KEY
        )
        
        return {
            "access_token": access_token,
            "refresh_token": refresh_request.refresh_token,  # Return the same refresh token
            "token_type": "bearer"
        }
        
    except JWTError:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Could not validate credentials",
            headers={"WWW-Authenticate": "Bearer"},
        )
    
@app.post("/generate")
async def generate(
    query_input: QueryInput,
    username: str = Depends(verify_access_token),
    stream: bool = Query(False, description="Enable streaming response"),
):
    """Handles both streaming and non-streaming responses, with shutdown detection."""
    if shutdown_event.is_set():
        return JSONResponse({"message": "Server shutting down..."})

    try:
        if stream:
            return StreamingResponse(generate_stream(query_input.query), media_type="text/event-stream")
        else:
            return JSONResponse(await generate_response(query_input.query))
    except Exception as e:
        logging.error(f"Error in generate endpoint: {e}")
        raise HTTPException(status_code=500, detail="Internal server error")

# WebSocket endpoint for streaming
@app.on_event("startup")
async def startup_event():
    os.makedirs("./cache", exist_ok=True)

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=7860)