"""Visibility scoping for HQ executives.

- director / director_admin: all sites / city sites / GMs
- buh / bu_admin: only GMs (and gm_admins) they manage, plus those GMs' sites
- gm / gm_admin: only their own sites / city sites they registered

Farm Site rows are only visible to non-directors when linked to an active
CitySite in the viewer's Pengaturan registry.
"""

from __future__ import annotations

from django.db.models import QuerySet

from apps.accounts.models import User

DIRECTOR_STATUSES = frozenset(
    {
        User.STATUS_DIRECTOR,
        User.STATUS_DIRECTOR_ADMIN,
        User.STATUS_SUPERUSER,
    }
)

BUH_STATUSES = frozenset(
    {
        User.STATUS_BUH,
        User.STATUS_BU_ADMIN,
    }
)

GM_STATUSES = frozenset(
    {
        User.STATUS_GM,
        User.STATUS_GM_ADMIN,
    }
)


def is_director_scope(user: User) -> bool:
    return bool(user and user.status in DIRECTOR_STATUSES)


def is_buh_scope(user: User) -> bool:
    return bool(user and user.status in BUH_STATUSES)


def is_gm_scope(user: User) -> bool:
    return bool(user and user.status in GM_STATUSES)


def managed_gm_ids(buh: User) -> list[int]:
    """User pks for GMs / GM Admins reporting to this BUH."""
    return list(
        User.objects.filter(
            managed_by=buh,
            status__in=GM_STATUSES,
        ).values_list("pk", flat=True)
    )


def visible_owner_ids(user: User) -> list[int] | None:
    """
    Site.user / CitySite.registered_by ids this viewer may see.

    Returns None when there is no restriction (director / superuser).
    """
    if is_director_scope(user):
        return None
    if is_buh_scope(user):
        return managed_gm_ids(user)
    if is_gm_scope(user):
        return [user.pk]
    return []


def visible_active_city_site_ids(user: User) -> list[int] | None:
    """
    Active CitySite pks in this viewer's Pengaturan registry.

    Returns None for directors (no restriction). Empty list means no farm sites.
    """
    from apps.sync.models import CitySite

    owners = visible_owner_ids(user)
    if owners is None:
        return None
    if not owners:
        return []
    return list(
        CitySite.objects.filter(
            registered_by_id__in=owners,
            is_active=True,
        ).values_list("pk", flat=True)
    )


def is_account_admin_scope(user: User) -> bool:
    return bool(user and user.status == User.STATUS_ACCOUNT_ADMIN)


def filter_users_queryset(qs: QuerySet, viewer: User) -> QuerySet:
    """BUH sees managed GMs; director / account_admin see product users.

    Break-glass status=superuser is never listed in the user directory.
    """
    qs = qs.exclude(status=User.STATUS_SUPERUSER)
    if is_director_scope(viewer) or is_account_admin_scope(viewer):
        return qs
    if is_buh_scope(viewer):
        return qs.filter(pk__in=managed_gm_ids(viewer))
    if is_gm_scope(viewer):
        return qs.filter(pk=viewer.pk)
    return qs.none()


def filter_sites_queryset(qs: QuerySet, viewer: User) -> QuerySet:
    owners = visible_owner_ids(viewer)
    if owners is None:
        return qs
    if not owners:
        return qs.none()
    city_ids = visible_active_city_site_ids(viewer)
    if not city_ids:
        return qs.none()
    return qs.filter(user_id__in=owners, city_site_id__in=city_ids)


def filter_city_sites_queryset(qs: QuerySet, viewer: User) -> QuerySet:
    owners = visible_owner_ids(viewer)
    if owners is None:
        return qs
    if not owners:
        return qs.none()
    return qs.filter(registered_by_id__in=owners)


def filter_kandangs_queryset(qs: QuerySet, viewer: User) -> QuerySet:
    owners = visible_owner_ids(viewer)
    if owners is None:
        return qs
    if not owners:
        return qs.none()
    city_ids = visible_active_city_site_ids(viewer)
    if not city_ids:
        return qs.none()
    return qs.filter(site__user_id__in=owners, site__city_site_id__in=city_ids)


def filter_flocks_queryset(qs: QuerySet, viewer: User) -> QuerySet:
    owners = visible_owner_ids(viewer)
    if owners is None:
        return qs
    if not owners:
        return qs.none()
    city_ids = visible_active_city_site_ids(viewer)
    if not city_ids:
        return qs.none()
    return qs.filter(
        kandang__site__user_id__in=owners,
        kandang__site__city_site_id__in=city_ids,
    )


def filter_cycles_queryset(qs: QuerySet, viewer: User) -> QuerySet:
    owners = visible_owner_ids(viewer)
    if owners is None:
        return qs
    if not owners:
        return qs.none()
    city_ids = visible_active_city_site_ids(viewer)
    if not city_ids:
        return qs.none()
    return qs.filter(
        kandang__site__user_id__in=owners,
        kandang__site__city_site_id__in=city_ids,
    )