backend/app/main.py

from __future__ import annotations

import logging
from contextlib import asynccontextmanager
from pathlib import Path

from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from fastapi.staticfiles import StaticFiles
from starlette.responses import FileResponse

from app.config import settings
from app.clients.hana_client import hana_client
from app.api import models, compare, history

STATIC_DIR = Path(__file__).resolve().parent.parent / "static"

logging.basicConfig(level=logging.INFO)
LOG = logging.getLogger(__name__)


@asynccontextmanager
async def lifespan(app: FastAPI):
    LOG.info("Starting up — authenticating with HANA...")
    try:
        await hana_client.authenticate()
        await hana_client.get_models()
        LOG.info("HANA auth complete, persona cache populated.")
    except Exception as exc:
        LOG.warning("HANA auth failed at startup (%s) — will retry on first request", exc)
    yield
    LOG.info("Shutting down — closing HTTP clients...")
    await hana_client.close()


app = FastAPI(title="LLM Comparison Tool", version="0.1.0", lifespan=lifespan)

LOG.info("CORS origins: %s", settings.cors_origin_list)
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

app.include_router(models.router, prefix="/api")
app.include_router(compare.router, prefix="/api")
app.include_router(history.router, prefix="/api")


@app.get("/api/health")
async def health():
    return {"status": "ok"}


if STATIC_DIR.is_dir():
    app.mount("/static", StaticFiles(directory=str(STATIC_DIR / "static")), name="static-assets")

    @app.get("/{full_path:path}")
    async def spa_fallback(full_path: str):
        file_path = STATIC_DIR / full_path
        if full_path and file_path.is_file():
            return FileResponse(file_path)
        return FileResponse(STATIC_DIR / "index.html")