from __future__ import annotations

import logging
from contextlib import asynccontextmanager

from fastapi import FastAPI
from fastapi.staticfiles import StaticFiles

from app import __version__
from app.config import Settings
from app.db import init_db
from app.pool import PoolValidationError, load_pool_from_file
from app.room import RoomManager
from app.routes_admin import router as admin_router
from app.routes_student import router as student_router

log = logging.getLogger("quiz")


def create_app(settings: Settings | None = None) -> FastAPI:
    settings = settings or Settings.from_env()
    rooms = RoomManager(settings)

    @asynccontextmanager
    async def lifespan(_app: FastAPI):
        await init_db(settings.db_path)
        try:
            pool = load_pool_from_file(settings.pool_path)
        except PoolValidationError as exc:
            log.error("Pool load failed at %s: %s", settings.pool_path, exc)
            log.error("Server is starting without an active session.")
            log.error("Drop a valid pool JSON at %s and restart.", settings.pool_path)
        else:
            sid = pool.get("session_id", settings.default_session_id)
            await rooms.ensure_single_session(sid, pool)
            rooms.canonical_sid = sid
            log.info("Session ready: sid=%s title=%r questions=%d",
                     sid, pool["title"], len(pool["questions"]))
        yield

    app = FastAPI(title="Live In-Lecture Quiz Portal", lifespan=lifespan)
    app.state.settings = settings
    app.state.rooms = rooms

    @app.get("/healthz")
    async def healthz():
        return {
            "ok": True,
            "version": __version__,
            "sessions_active": await rooms.sessions_active(),
            "ws_clients": rooms.ws_client_count(),
        }

    app.mount("/static", StaticFiles(directory="static"), name="static")
    app.include_router(admin_router(settings, rooms))
    app.include_router(student_router(settings, rooms))
    return app


app = create_app()