import asyncio
import contextlib
from contextlib import asynccontextmanager
from pathlib import Path

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

import app.models  # noqa: F401 — registers models on Base.metadata before create_all
from app.config import settings
from app.db import Base, async_session_maker, engine
from app.routes.auth import router as auth_router
from app.routes.codex import router as codex_router
from app.routes.device import router as device_router
from app.routes.inventory import router as inventory_router
from app.routes.shop import router as shop_router
from app.session_cleanup import delete_expired_sessions
from app.ws import AUDIO_DIR
from app.ws import router as ws_router

FRONTEND_DIST = Path(__file__).resolve().parent.parent.parent / "frontend" / "dist"

SESSION_CLEANUP_INTERVAL_SECONDS = 30 * 60


async def _session_cleanup_loop() -> None:
    """Periodically sweeps expired auth_sessions rows so the table doesn't
    grow forever — get_current_user already rejects expired sessions on
    read, this just deletes the rows themselves."""
    try:
        while True:
            await asyncio.sleep(SESSION_CLEANUP_INTERVAL_SECONDS)
            try:
                async with async_session_maker() as db:
                    await delete_expired_sessions(db)
            except Exception:
                # A transient DB hiccup shouldn't kill the sweep loop —
                # just try again next interval.
                pass
    except asyncio.CancelledError:
        pass


@asynccontextmanager
async def lifespan(app: FastAPI):
    AUDIO_DIR.mkdir(parents=True, exist_ok=True)
    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)
        # No Alembic in this repo — `create_all` never alters existing
        # tables, so columns added to live models need a manual, idempotent
        # migration here. Safe to run on every startup.
        await conn.execute(text(
            "ALTER TABLE entities ADD COLUMN IF NOT EXISTS traits JSONB NOT NULL DEFAULT '{}'::jsonb"
        ))
    cleanup_task = asyncio.create_task(_session_cleanup_loop())
    try:
        yield
    finally:
        cleanup_task.cancel()
        with contextlib.suppress(asyncio.CancelledError):
            await cleanup_task


app = FastAPI(title="Quantumancy", lifespan=lifespan)
app.include_router(auth_router)
app.include_router(codex_router)
app.include_router(device_router)
app.include_router(inventory_router)
app.include_router(shop_router)
app.include_router(ws_router)


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


app.mount(
    "/assets",
    StaticFiles(directory=FRONTEND_DIST / "assets", check_dir=False),
    name="frontend-assets",
)
app.mount(
    "/audio",
    StaticFiles(directory=AUDIO_DIR, check_dir=False),
    name="spirit-audio",
)


@app.get("/{full_path:path}")
async def serve_spa(full_path: str):
    index_file = FRONTEND_DIST / "index.html"
    if not index_file.exists():
        raise HTTPException(
            status_code=503,
            detail="Frontend not built. Run `npm run build` in frontend/ and restart.",
        )

    # Vite emits root-level static files (favicon.ico, favicon.svg,
    # apple-touch-icon.png, og-image.png, …) straight into dist/ rather than
    # dist/assets/ — the only mounted static dir. Without this, requests for
    # them fall through to the SPA fallback below and get index.html back
    # instead of the actual file (browsers silently ignore it; social-media
    # link-preview crawlers fetching og:image get an HTML page).
    if full_path:
        dist_root = FRONTEND_DIST.resolve()
        candidate = (dist_root / full_path).resolve()
        if candidate.is_file() and dist_root in candidate.parents:
            return FileResponse(candidate)

    return FileResponse(index_file)