"""Lizenzen aus dem Plugin NetBox-SLM (netbox_slm.SoftwareLicense)."""
from datetime import date
from itertools import groupby

from django.apps import apps
from django.db.models import Q

from .blocks import EMPTY, H, T

SOON_DAYS = 90  # „läuft bald ab“, wenn das Ablaufdatum näher liegt


def is_installed():
    return apps.is_installed("netbox_slm")


def _tenant_groups(scope):
    """Mandantengruppen, deren mandantenlose Lizenzen zum Scope gehören."""
    from tenancy.models import TenantGroup

    if scope.kind == "tenantgroup":
        return scope.obj.get_descendants(include_self=True)
    if scope.kind == "tenant" and scope.obj.group_id:
        # Lizenzen der eigenen Gruppe und übergeordneter Gruppen gelten auch für den Mandanten
        return scope.obj.group.get_ancestors(include_self=True)
    return TenantGroup.objects.none()


def licenses_for_scope(scope):
    """SoftwareLicense-Queryset für den Scope: über Installationen (Gerät/VM/Cluster) und Mandant(engruppe)."""
    from virtualization.models import Cluster

    SoftwareLicense = apps.get_model("netbox_slm", "SoftwareLicense")
    devices = scope.devices()
    vms = scope.virtual_machines()
    clusters = Cluster.objects.filter(Q(virtual_machines__in=vms) | Q(devices__in=devices)).distinct()

    q = (
        Q(installation__device__in=devices)
        | Q(installation__virtualmachine__in=vms)
        | Q(installation__cluster__in=clusters)
    )
    if scope.tenants is not None:
        q |= Q(tenant__in=scope.tenants) | Q(tenant__isnull=True, tenant_group__in=_tenant_groups(scope))
    return (
        scope.restrict(SoftwareLicense.objects.filter(q).distinct())
        .select_related(
            "software_product__manufacturer", "version", "tenant", "tenant_group",
            "installation__device", "installation__virtualmachine", "installation__cluster",
        )
        .order_by("software_product__name", "name")
    )


def _validity(lic, today):
    """(Laufzeit-Text, Status-Text)."""
    if lic.lifetime:
        return "unbefristet", "aktiv"
    start = lic.start_date.strftime("%d.%m.%Y") if lic.start_date else ""
    end = lic.expiration_date.strftime("%d.%m.%Y") if lic.expiration_date else ""
    period = f"{start} – {end}" if start and end else (f"bis {end}" if end else (f"ab {start}" if start else EMPTY))
    if lic.renewal_interval and lic.renewal_interval_unit:
        if lic.renewal_interval == 1:
            every = {"days": "täglich", "months": "monatlich", "years": "jährlich"}.get(lic.renewal_interval_unit, "")
        else:
            unit = {"days": "Tage", "months": "Monate", "years": "Jahre"}.get(lic.renewal_interval_unit, lic.renewal_interval_unit)
            every = f"alle {lic.renewal_interval} {unit}"
        period += f" (Verlängerung {every})"
    if not lic.expiration_date:
        return period, "aktiv"
    days = (lic.expiration_date - today).days
    if days < 0:
        return period, "abgelaufen"
    if days <= SOON_DAYS:
        return period, f"läuft in {days} Tagen ab"
    return period, "aktiv"


def _support(value):
    return {True: "Ja", False: "Nein"}.get(value, EMPTY)


def _installed_on(lic):
    inst = lic.installation
    if not inst:
        return None
    target = inst.device or inst.virtualmachine or inst.cluster
    kind = "Gerät" if inst.device_id else ("VM" if inst.virtualmachine_id else "Cluster")
    return f"{target} ({kind})" if target else None


def slm_blocks(scope, opts):
    """Tabellen je Hersteller; leer, wenn keine Lizenz zum Scope passt."""
    qs = list(licenses_for_scope(scope))
    if not qs:
        return []
    today = date.today()
    show_key = bool(opts.get("include_secrets"))
    headers = ["Lizenz", "Produkt / Version", "Typ", "Anzahl", "Laufzeit", "Status", "Support", "Installiert auf", "Mandant"]
    if show_key:
        headers.append("Lizenzschlüssel")

    blocks = []
    by_manufacturer = sorted(qs, key=lambda lic: (str(lic.software_product.manufacturer or "~"), str(lic.software_product), lic.name))
    for manufacturer, items in groupby(by_manufacturer, key=lambda lic: lic.software_product.manufacturer):
        rows = []
        for lic in items:
            period, status = _validity(lic, today)
            product = str(lic.software_product) + (f" {lic.version}" if lic.version else "")
            row = [
                lic.name + (f"\n{lic.description}" if lic.description else ""),
                product,
                lic.type or lic.spdx_expression,
                lic.license_amount,
                period,
                status,
                _support(lic.support),
                _installed_on(lic),
                lic.tenant or lic.tenant_group,
            ]
            if show_key:
                row.append(lic.license_key)
            rows.append(row)
        blocks.append(H(2, str(manufacturer) if manufacturer else "Ohne Hersteller"))
        blocks.append(T(headers, rows))
    return blocks