main.py

"""FastAPI application for HF Agent web interface - API ONLY MODE.

This backend runs in API-only mode without serving static files.
The frontend is hosted separately and communicates via HTTP/WebSocket.
"""

import logging
import os
from contextlib import asynccontextmanager

from dotenv import load_dotenv

load_dotenv()

# Ensure HF_TOKEN is set — fall back to HF_ADMIN_TOKEN if available (HF Spaces)
if not os.environ.get("HF_TOKEN") and os.environ.get("HF_ADMIN_TOKEN"):
    os.environ["HF_TOKEN"] = os.environ.get("HF_ADMIN_TOKEN")

from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware

from routes.agent import router as agent_router
from routes.auth import router as auth_router

# Configure logging
logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s - %(name)s - %(levelname)s - %(message)s",
)
logger = logging.getLogger(__name__)


@asynccontextmanager
async def lifespan(app: FastAPI):
    """Application lifespan handler."""
    logger.info("Starting HF Agent backend (API-only mode)...")
    logger.info(f"CORS allowed origins: {os.environ.get('CORS_ORIGINS', '*')}")
    yield
    logger.info("Shutting down HF Agent backend...")


app = FastAPI(
    title="HF Agent API",
    description="ML Engineering Assistant API - Separate Frontend/Backend Mode",
    version="1.0.0",
    lifespan=lifespan,
)

# CORS middleware - allow all origins for separate hosting
# In production, set CORS_ORIGINS env var to your frontend URL(s)
cors_origins = os.environ.get("CORS_ORIGINS", "*")
if cors_origins != "*":
    cors_origins = [origin.strip() for origin in cors_origins.split(",")]

app.add_middleware(
    CORSMiddleware,
    allow_origins=cors_origins if isinstance(cors_origins, list) else ["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Include routers
app.include_router(agent_router)
app.include_router(auth_router)


@app.get("/api")
async def api_root():
    """API root endpoint."""
    return {
        "name": "HF Agent API",
        "version": "1.0.0",
        "mode": "api-only",
        "docs": "/docs",
    }


@app.get("/")
async def root():
    """Root endpoint - indicates API-only mode."""
    return {
        "status": "ok",
        "mode": "api-only",
        "message": "Backend is running in API-only mode. Frontend is hosted separately.",
        "api_docs": "/docs",
        "api_endpoints": "/api",
    }


if __name__ == "__main__":
    import uvicorn

    port = int(os.environ.get("PORT", 7860))
    host = os.environ.get("HOST", "0.0.0.0")
    uvicorn.run(app, host=host, port=port)