import asyncio
from contextlib import asynccontextmanager
from pathlib import Path

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

from app.api.admin import router as admin_router
from app.api.public import router as public_router
from app.config import settings
from app.db import Base, SessionLocal, engine
from app import models  # noqa: F401 — register models with Base.metadata
from app.services import cleaner as cleaner_service


def _resolve_frontend_dist() -> Path | None:
    """Locate frontend/dist in Docker (/app/frontend/dist) or monorepo checkout."""
    here = Path(__file__).resolve()
    candidates = (
        here.parents[2] / "frontend" / "dist",  # .../backend/app/main.py → repo root
        here.parents[1] / "frontend" / "dist",  # /app/app/main.py → /app/frontend/dist
        Path("/app/frontend/dist"),
    )
    for path in candidates:
        if (path / "index.html").is_file():
            return path
    return None


async def _cleaner_loop() -> None:
    while True:
        db = SessionLocal()
        try:
            cleaner_service.run_once(db)
        except Exception:
            pass
        finally:
            db.close()
        await asyncio.sleep(60)


@asynccontextmanager
async def lifespan(_app: FastAPI):
    settings.data_dir.mkdir(parents=True, exist_ok=True)
    settings.uploads_dir.mkdir(parents=True, exist_ok=True)
    Base.metadata.create_all(bind=engine)
    task = asyncio.create_task(_cleaner_loop())
    try:
        yield
    finally:
        task.cancel()
        try:
            await task
        except asyncio.CancelledError:
            pass


app = FastAPI(title="MincedPad", lifespan=lifespan)
app.include_router(public_router)
app.include_router(admin_router)


@app.get("/api/health")
def health():
    return {"ok": True, "name": "MincedPad"}


_dist = _resolve_frontend_dist()
if _dist is not None:
    assets_dir = _dist / "assets"
    if assets_dir.is_dir():
        app.mount("/assets", StaticFiles(directory=assets_dir), name="assets")

    @app.api_route("/{full_path:path}", methods=["GET", "HEAD"])
    async def spa(full_path: str):
        if full_path == "api" or full_path.startswith("api/"):
            raise HTTPException(status_code=404, detail="Not Found")
        file_path = _dist / full_path
        if full_path and file_path.is_file():
            return FileResponse(file_path)
        return FileResponse(_dist / "index.html")