import importlib
import logging
from contextlib import asynccontextmanager

from fastapi import Depends, FastAPI, Request, WebSocket
from fastapi.responses import HTMLResponse, RedirectResponse
from fastapi.staticfiles import StaticFiles
from fastapi.templating import Jinja2Templates

from app.core.config import get_settings
from app.core.database import get_db
from app.modules.auth.dependencies import (
    RequiresLoginException,
    check_permission,
    get_current_user,
    get_current_user_optional,
)
from app.modules.auth.router import router as auth_router

logger = logging.getLogger(__name__)
settings = get_settings()

MODULES = [
    {
        "slug": "rss",
        "icon": "📡",
        "name": "RSS-Feed Server",
        "description": "Aggregiert und verteilt Neuigkeiten der Fakultät als standardkonformen RSS 2.0 Feed.",
        "status": "active",
        "permission": ["authenticated"],
    },
    {
        "slug": "kalender",
        "icon": "📅",
        "name": "Kalender",
        "description": "Veranstaltungen, Prüfungstermine und Fristen im iCal-Format.",
        "status": "planned",
        "permission": ["authenticated"],
    },
    {
        "slug": "benachrichtigungen",
        "icon": "🔔",
        "name": "Benachrichtigungen",
        "description": "Push-Nachrichten und WebSocket-basierte Echtzeit-Alerts für Studierende.",
        "status": "planned",
        "permission": ["authenticated"],
    },
    {
        "slug": "auslastung",
        "icon": "📊",
        "name": "Auslastung",
        "description": "Raum- und Ressourcenauslastung der Fakultät in Echtzeit.",
        "status": "planned",
        "permission": ["authenticated"],
    },
    {
        "slug": "lehrveranstaltungen",
        "icon": "📚",
        "name": "Lehrveranstaltungen",
        "description": "Stundenplan-API und Kursinformationen aus dem Campus-System.",
        "status": "planned",
        "permission": ["authenticated"],
    },
]

NAV_ITEMS = [
    {"label": "Übersicht", "url": "/", "active": True},
    {"label": "RSS-Feeds", "url": "/rss", "active": False},
    {"label": "Kalender", "url": "/kalender", "active": False},
    {"label": "Docs", "url": "/docs", "active": False},
]


def _reset_admin() -> None:
    from app.core.database import Base, SessionLocal, engine
    from app.modules.auth.models import User  # noqa: F401
    from app.modules.auth.service import get_user, hash_password

    Base.metadata.create_all(bind=engine)
    with SessionLocal() as db:
        user = get_user(db, settings.ADMIN_USERNAME)
        if user is None:
            user = User(username=settings.ADMIN_USERNAME, full_name="Administrator")
            db.add(user)
        user.pw_hash = hash_password(settings.ADMIN_PASSWORD)
        user.is_admin = True
        user.is_active = True
        db.commit()


@asynccontextmanager
async def lifespan(app: FastAPI):
    _reset_admin()
    yield


app = FastAPI(
    title="University Process Hub",
    root_path=settings.APP_PREFIX,
    lifespan=lifespan,
)

app.mount("/static", StaticFiles(directory="app/static"), name="static")
templates = Jinja2Templates(directory="app/templates")

app.include_router(auth_router)

for _module in MODULES:
    if _module["status"] == "active":
        try:
            _mod = importlib.import_module(f"app.modules.{_module['slug']}.router")
            app.include_router(_mod.router, prefix=f"/{_module['slug']}")
        except ModuleNotFoundError:
            logger.warning("Module router not found: app.modules.%s.router", _module["slug"])


@app.exception_handler(RequiresLoginException)
async def requires_login_handler(request: Request, exc: RequiresLoginException):
    return RedirectResponse(url="/auth/login", status_code=307)


def _db_mode() -> str:
    url = settings.DATABASE_URL
    return "SQLite (dev)" if url.startswith("sqlite") else "MariaDB (prod)"


@app.get("/", response_class=HTMLResponse)
async def root(request: Request, current_user=Depends(get_current_user_optional)):
    visible = [m for m in MODULES if check_permission(current_user, m["permission"])]
    return templates.TemplateResponse(
        request,
        "index.html",
        {
            "nav_items": NAV_ITEMS,
            "modules": visible,
            "db_mode": _db_mode(),
            "app_version": "0.1.0",
            "current_user": current_user,
        },
    )


@app.websocket("/ws/hello/{name}")
async def websocket_hello(websocket: WebSocket, name: str):
    await websocket.accept()
    await websocket.send_text(f"Hello, {name}!")
    await websocket.close()