from pathlib import Path

from starlette.exceptions import HTTPException as StarletteHTTPException
from starlette.responses import Response
from starlette.staticfiles import StaticFiles
from starlette.types import ASGIApp, Receive, Scope, Send

from app.core.config import get_settings

ADMIN_DIST_DIR = Path(__file__).parent / "admin_dist"

# Præfikser der altid rammer det almindelige API, uanset domæne — skal
# holdes i sync med routerne registreret i app/main.py
_API_PREFIXES = (
    "/auth",
    "/participants",
    "/purchase-rounds",
    "/wine-offerings",
    "/wine-categories",
    "/mail-templates",
    "/mail-logs",
    "/orders",
    "/routes",
    "/webhooks",
    "/public",
    "/health",
    "/docs",
    "/redoc",
    "/openapi.json",
)


class SPAStaticFiles(StaticFiles):
    """Standard SPA-fallback: ukendte stier (client-side routing)
    falder tilbage til index.html i stedet for 404."""

    async def get_response(self, path: str, scope: Scope) -> Response:
        try:
            return await super().get_response(path, scope)
        except StarletteHTTPException as exc:
            if exc.status_code == 404:
                return await super().get_response("index.html", scope)
            raise


class AdminDomainDispatch:
    """Sender requests mod admin-domænet til den byggede React-SPA i
    stedet for den domæne-opløste offentlige side (public_site.py) —
    men lader API-kald (/auth, /participants, ...) passere uændret,
    så admin-UI'et kan kalde API'et uden CORS (samme origin)."""

    def __init__(self, app: ASGIApp) -> None:
        self.app = app
        self.admin_domain = get_settings().admin_domain
        self.spa_app = SPAStaticFiles(directory=str(ADMIN_DIST_DIR), html=True) if ADMIN_DIST_DIR.is_dir() else None

    async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
        if scope["type"] != "http" or self.spa_app is None:
            await self.app(scope, receive, send)
            return
        headers = dict(scope["headers"])
        host = headers.get(b"host", b"").decode().split(":")[0]
        if host == self.admin_domain and not scope["path"].startswith(_API_PREFIXES):
            await self.spa_app(scope, receive, send)
            return
        await self.app(scope, receive, send)