from django.conf import settings
from django.shortcuts import redirect


class UnderConstructionMiddleware:
    """
    When SITE_UNDER_CONSTRUCTION is true, redirect public traffic to the holding page.

    Exempt: health, static/media, admin, auth login/logout, SMS webhook, and the
    under-construction page itself (so notify-me POSTs work).
    """

    EXEMPT_PREFIXES = (
        "/healthz",
        "/static/",
        "/media/",
        "/admin/",
        "/accounts/login",
        "/accounts/logout",
        "/under-construction",
        "/portal/messaging/webhooks/",
        "/unsubscribe/",
        "/api/address-suggest",
        "/robots.txt",
        "/sitemap.xml",
    )

    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        if settings.SITE_UNDER_CONSTRUCTION and not self._is_exempt(request):
            return redirect("public:under_construction")
        return self.get_response(request)

    def _is_exempt(self, request) -> bool:
        path = request.path
        if any(path.startswith(prefix) for prefix in self.EXEMPT_PREFIXES):
            return True
        user = getattr(request, "user", None)
        if (
            user is not None
            and getattr(user, "is_authenticated", False)
            and getattr(user, "is_staff", False)
            and path.startswith("/portal/")
        ):
            return True
        return False