backend/app/main.py

from contextlib import asynccontextmanager
from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from fastapi.middleware.trustedhost import TrustedHostMiddleware
import logging
import os

from .core.config import settings
from .api.v1.router import api_router


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


@asynccontextmanager
async def lifespan(app: FastAPI):
    """
    Context manager for handling startup and shutdown events
    """
    # Startup
    logger.info("Starting FastAPI application...")
    yield
    # Shutdown
    logger.info("Shutting down FastAPI application...")


def create_app() -> FastAPI:
    """
    Application factory pattern for creating FastAPI instance
    """
    app = FastAPI(
        title=settings.PROJECT_NAME,
        description="A scalable FastAPI application",
        version="1.0.0",
        lifespan=lifespan,
    )

    # Add CORS middleware - allow frontend to access API
    app.add_middleware(
        CORSMiddleware,
        allow_origins=[
            "http://localhost:3000",
            "http://127.0.0.1:3000",
            "http://localhost:8000",
            "http://127.0.0.1:8000",
            "https://*.hf.space",
            "https://*.huggingface.co",
            "*",  # Allow all origins for Hugging Face deployment
        ],
        allow_credentials=True,
        allow_methods=["GET", "POST", "PUT", "DELETE", "OPTIONS"],
        allow_headers=["*"],
    )

    app.add_middleware(
        TrustedHostMiddleware,
        allowed_hosts=["localhost", "127.0.0.1", "0.0.0.0", "*"],
    )

    return app


app = create_app()


# Health check endpoint
@app.get("/health")
async def health_check():
    return {"status": "healthy", "message": "Backend is running"}


# OpenAI connection test endpoint
# @app.get("/api/test-openai")
# async def test_openai():
#     """Test OpenAI connection without making actual API calls"""
#     try:
#         from .core.config import settings

#         if not settings.OPENAI_API_KEY:
#             return {"status": "error", "message": "OPENAI_API_KEY not configured"}

#         api_key_preview = (
#             settings.OPENAI_API_KEY[:10] + "..."
#             if len(settings.OPENAI_API_KEY) > 10
#             else "Too short"
#         )

#         return {
#             "status": "ok",
#             "message": "OpenAI API key is configured",
#             "api_key_preview": api_key_preview,
#             "environment": (
#                 "production" if os.getenv("NODE_ENV") == "production" else "development"
#             ),
#         }
#     except Exception as e:
#         return {"status": "error", "message": f"OpenAI configuration error: {str(e)}"}


# Test chat completions endpoint
# @app.get("/api/test-chat")
# async def test_chat():
#     """Test if OpenAI chat completions work on Hugging Face"""
#     try:
#         from .core.config import settings
#         from openai import OpenAI

#         if not settings.OPENAI_API_KEY:
#             return {"status": "error", "message": "OPENAI_API_KEY not configured"}

#         client = OpenAI(api_key=settings.OPENAI_API_KEY, timeout=30.0)

#         # Test a simple chat completion
#         response = client.chat.completions.create(
#             model="gpt-3.5-turbo",
#             messages=[
#                 {
#                     "role": "user",
#                     "content": "Say 'Hello from Hugging Face!' in exactly those words.",
#                 }
#             ],
#             max_tokens=20,
#         )

#         return {
#             "status": "success",
#             "message": "Chat completions work!",
#             "response": response.choices[0].message.content,
#             "model": response.model,
#         }

#     except Exception as e:
#         return {
#             "status": "error",
#             "message": f"Chat completion failed: {str(e)}",
#             "error_type": type(e).__name__,
#         }


# Include API router
app.include_router(api_router, prefix=settings.API_V1_STR)