"""FastAPI-Server des Planers (Phase 2).

Start: `uvicorn server:app --port 8100` aus backend/ — OHNE --reload: der Reload killt
laufende Scans im eigenen Prozess (Creator-Lehre; siehe README, Selbst-Änderungs-Regel).
"""
import sys
from contextlib import asynccontextmanager
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parent))

from fastapi import FastAPI  # noqa: E402
from fastapi.staticfiles import StaticFiles  # noqa: E402
from starlette.responses import Response  # noqa: E402

import agents  # noqa: E402
import config  # noqa: E402
import database as db  # noqa: E402
from routes import router  # noqa: E402

FRONTEND_DIST = config.PROJECT_ROOT / "frontend" / "dist"


@asynccontextmanager
async def lifespan(app: FastAPI):
    await db.init_db()
    agents.on_event = db.add_event
    yield
    await db.close_db()


class CachedStatic(StaticFiles):
    """assets/ = unveränderlich (gehashte Namen), index.html = nie cachen."""

    def file_response(self, full_path, stat_result, scope, status_code=200) -> Response:
        resp = super().file_response(full_path, stat_result, scope, status_code)
        pfad = str(full_path)
        if "/assets/" in pfad:
            resp.headers["Cache-Control"] = "public, max-age=31536000, immutable"
        elif pfad.endswith("index.html"):
            resp.headers["Cache-Control"] = "no-cache"
        return resp


app = FastAPI(title="Planer", lifespan=lifespan)
app.include_router(router)
if FRONTEND_DIST.exists():
    app.mount("/", CachedStatic(directory=FRONTEND_DIST, html=True), name="frontend")