"""FastAPI application entry point.

Importing this module must NOT require a live database connection (the engine is
created lazily in :mod:`app.db.session`), so the OpenAPI schema can be exported
offline.
"""

from __future__ import annotations

import os

from fastapi import FastAPI
from fastapi.responses import FileResponse
from fastapi.staticfiles import StaticFiles

from app.api.funnels import router as funnels_router

app = FastAPI(
    title="hs-data API",
    version="0.1.0",
    description=(
        "Group-buy (拼团) funnel service over ads_trd_group_funnel_daily "
        "(single day, full history) + ads_trd_group_funnel_rolling (7d/30d)."
    ),
)

app.include_router(funnels_router)


@app.get("/health", tags=["meta"])
async def health() -> dict[str, str]:
    """Liveness probe. Does not touch the database."""
    return {"status": "ok"}


# Optional single-origin static hosting: when STATIC_DIR points at a built SPA
# (apps/web/dist), this process serves the frontend alongside /api on one port,
# so the deployed page can call the real API same-origin (no CORS, no proxy).
# Unset locally / in tests → api-only, Vite serves the frontend. Registered
# AFTER the router so /api and /health keep priority; the GET catch-all does
# SPA fallback (real files served, unknown routes → index.html).
_STATIC_DIR = os.environ.get("STATIC_DIR")
if _STATIC_DIR and os.path.isdir(_STATIC_DIR):
    _assets = os.path.join(_STATIC_DIR, "assets")
    if os.path.isdir(_assets):
        app.mount("/assets", StaticFiles(directory=_assets), name="assets")

    @app.get("/{full_path:path}", include_in_schema=False)
    async def spa_fallback(full_path: str) -> FileResponse:
        candidate = os.path.join(_STATIC_DIR, full_path)
        if full_path and os.path.isfile(candidate):
            return FileResponse(candidate)
        return FileResponse(os.path.join(_STATIC_DIR, "index.html"))