from contextlib import asynccontextmanager
from pathlib import Path
from urllib.parse import quote

from fastapi import FastAPI, Request
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import RedirectResponse
from fastapi.staticfiles import StaticFiles

from app.api.router import api_router
from app.core.config import settings
from app.core.database import init_db
from app.deps import NotAuthenticated
from app.web.admin import router as admin_router
from app.web.pages import router as pages_router
from app.web.scopes import router as scopes_router

STATIC_DIR = Path(__file__).resolve().parent / "static"


@asynccontextmanager
async def lifespan(app: FastAPI):
    # Dev/SQLite convenience. Use Alembic migrations in production.
    if settings.auto_create_tables:
        await init_db()
    yield


def create_app() -> FastAPI:
    app = FastAPI(title=settings.app_name, debug=settings.debug, lifespan=lifespan)

    app.add_middleware(
        CORSMiddleware,
        allow_origins=settings.cors_origins,
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
    )

    app.mount("/static", StaticFiles(directory=str(STATIC_DIR)), name="static")

    app.include_router(api_router, prefix="/api")
    app.include_router(pages_router)
    app.include_router(scopes_router)
    app.include_router(admin_router)

    @app.exception_handler(NotAuthenticated)
    async def _redirect_to_login(request: Request, exc: NotAuthenticated):
        # Preserve the originally requested URL so we can return there after
        # login. Only meaningful for GET navigations (the ones users deep-link).
        login_url = "/login"
        if request.method == "GET" and request.url.path not in ("/", "/login"):
            target = request.url.path
            if request.url.query:
                target += "?" + request.url.query
            login_url = f"/login?next={quote(target, safe='')}"
        return RedirectResponse(url=login_url, status_code=302)

    @app.get("/healthz", tags=["health"])
    async def healthz():
        return {"status": "ok"}

    return app


app = create_app()