from django.contrib import admin
from django.db.models import Q
from django.utils import timezone

from .models import Service, ServiceType, IPResource, ResourceAllocation
from banking.admin import PaymentInline, ValidatedPaymentInline, PendingOrNewPaymentInline


class AllocationInline(admin.TabularInline):
    model = ResourceAllocation
    extra = 1
    can_delete = False


class ServiceTypeFilter(admin.SimpleListFilter):
    title = 'type de service'
    parameter_name = 'type'

    def lookups(self, request, model_admin):
        service_types = ServiceType.objects.all()
        if not request.user.is_superuser:
            service_types = service_types.filter(group=request.user.groups.all())
        return service_types.values_list('pk', 'name')

    def queryset(self, request, queryset):
        if self.value():
            return queryset.filter(service_type__pk=self.value())


class ServiceAdmin(admin.ModelAdmin):
    list_display = ('id', 'adherent', 'service_type', 'label', 'active')
    list_filter = ('active', ServiceTypeFilter,)

    def get_form(self, request, obj=None, **kwargs):
        # get_inlines does not exists :-(
        if request.user.has_perm('banking.validate_payment'):
            self.inlines = (PaymentInline,)
        else:
            self.inlines = (ValidatedPaymentInline, PendingOrNewPaymentInline,)
        self.inlines = self.inlines + (AllocationInline,)
        return super().get_form(request, obj, **kwargs)

    def get_queryset(self, request):
        qs = super().get_queryset(request)
        if request.user.is_superuser:
            return qs
        return qs.filter(service_type__group__in=request.user.groups.all())

    def get_readonly_fields(self, request, obj=None):
        fields = super().get_readonly_fields(request, obj)
        if not request.user.is_superuser:
            return fields + ('service_type', 'ip_resources',)
        return fields


class InUseFilter(admin.SimpleListFilter):
    title = 'disponibilité'
    parameter_name = 'available'

    def lookups(self, request, model_admin):
        return (
            (1, 'Disponible'),
            (0, 'Non disponible'),
        )

    def queryset(self, request, queryset):
        # On utilise le même filtre que get_active_filter(), mais préfixé par « allocation__ » …
        # Ce billet donne une technique avec une classe PrefixedQ pour éviter cette duplication de code :
        # https://hackerluddite.wordpress.com/2012/07/07/making-django-orm-more-dry-with-prefixes-and-qs/
        now = timezone.now()
        if self.value() == '0': # non disponible
            return queryset.filter(Q(allocation__start__lte=now) & (Q(allocation__end__isnull=True) | Q(allocation__end__gte=now)))
        if self.value() == '1': # disponible
            return queryset.exclude(Q(allocation__start__lte=now) & (Q(allocation__end__isnull=True) | Q(allocation__end__gte=now)))


class IPResourceAdmin(admin.ModelAdmin):
    list_display = ('__str__', 'in_use_view')
    list_filter = (InUseFilter,)
    inlines = (AllocationInline,)

    def in_use_view(self, obj):
        return not obj.in_use
    in_use_view.short_description = 'Disponible'
    in_use_view.boolean = True


admin.site.register(ServiceType)
admin.site.register(Service, ServiceAdmin)
admin.site.register(IPResource, IPResourceAdmin)
admin.site.register(ResourceAllocation)