from django.contrib import admin
from django.contrib.gis import admin as geo_admin
from django.db import models
from django.db.models import Q
from django.forms import ModelForm, BaseInlineFormSet
from django.utils import timezone
from django.core.urlresolvers import reverse
from django.utils.html import format_html
from django.core.mail import mail_managers
from django.conf.urls import url
from django.template.response import TemplateResponse
from django.core.serializers import serialize
from django.http import HttpResponse

from adhesions.models import Adhesion
from .models import Service, ServiceType, IPPrefix, IPResource, Route, Tunnel, ServiceAllocation, Antenna, AntennaAllocation, Allocation
from .utils import notify_allocation


### Filters

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

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

    def queryset(self, request, queryset):
        available_filter = Q(reserved=False, in_use=False)
        if self.value() == '0': # non disponible
            return queryset.exclude(available_filter)
        if self.value() == '1': # disponible
            return queryset.filter(available_filter)


class RouteFilter(admin.SimpleListFilter):
    title = 'route'
    parameter_name = 'route'

    def lookups(self, request, model_admin):
        return ServiceAllocation.objects.filter(active=True).values_list('route__pk', 'route__name').distinct()

    def queryset(self, request, queryset):
        try:
            route = int(self.value())
        except (TypeError, ValueError):
            pass
        else:
            allocations = ServiceAllocation.objects.filter(active=True, route__pk=route).values_list('pk', flat=True)
            queryset = queryset.filter(service_allocation__in=allocations)
        return queryset


class AntennaPrefixFilter(admin.SimpleListFilter):
    title = 'préfix'
    parameter_name = 'prefix'

    def lookups(self, request, model_admin):
        resources = AntennaAllocation.objects.filter(active=True).values_list('resource__pk', flat=True)
        prefixes = IPPrefix.objects.filter(ipresource__in=resources).values_list('pk', 'prefix').distinct()
        return prefixes

    def queryset(self, request, queryset):
        try:
            prefix = int(self.value())
        except (TypeError, ValueError):
            pass
        else:
            allocations = AntennaAllocation.objects.filter(active=True, resource__prefixes__pk=prefix).values_list('pk', flat=True)
            queryset = queryset.filter(allocation__in=allocations)
        return queryset


class ActiveTunnelFilter(admin.SimpleListFilter):
    title = 'status'
    parameter_name = 'active'

    def lookups(self, request, model_admin):
        return (
            ('1', 'Actif'),
            ('0', 'Désactivé'),
        )

    def queryset(self, request, queryset):
        query = Q(ended__isnull=True)
        if self.value() == '0':
            return queryset.exclude(query)
        if self.value() == '1':
            return queryset.filter(query)
        return queryset


### Inlines

class AllocationInlineFormSet(BaseInlineFormSet):
    def save_new(self, form, commit=True):
        obj = super().save_new(form, commit)
        if type(obj) == ServiceAllocation:
            notify_allocation(self.request, obj)
        return obj

    def save_existing(self, form, instance, commit=True):
        old = type(instance).objects.get(pk=instance.pk)
        if type(instance) == ServiceAllocation:
            notify_allocation(self.request, instance, old)
        return super().save_existing(form, instance, commit)


class AllocationInline(admin.TabularInline):
    formset = AllocationInlineFormSet
    extra = 0
    verbose_name_plural = 'Allocations'
    show_change_link = True

    def get_formset(self, request, obj=None, **kwargs):
        formset = super().get_formset(request, obj, **kwargs)
        formset.request = request
        return formset

    def get_max_num(self, request, obj=None, **kwargs):
        existing = obj.allocations.count() if obj else 0
        # pour simplifier la validation, on ajoute qu’une allocation à la fois
        # il faudrait surcharger la méthode clean du formset pour supprimer cette limite
        return existing + 1

    def has_delete_permission(self, request, obj=None):
        return False


class ServiceAllocationInline(AllocationInline):
    model = ServiceAllocation
    fields = ('id', 'service', 'resource', 'route', 'start', 'end')
    raw_id_fields = ('service', 'resource',)


class AntennaAllocationInline(AllocationInline):
    model = AntennaAllocation
    fields = ('id', 'antenna', 'resource', 'start', 'end')
    raw_id_fields = ('antenna', 'resource',)


### Actions

def ends_resource(resource, request, queryset):
    now = timezone.now()
    queryset.exclude(start__lte=now, end__isnull=False).update(end=now)
    # TODO: send mail
ends_resource.short_description = 'Terminer les allocations sélectionnées'


### ModelAdmin

class ServiceAdmin(admin.ModelAdmin):
    list_display = ('id', 'get_adhesion_link', 'get_adherent_link', 'service_type', 'label', 'active')
    list_select_related = ('adhesion', 'adhesion__user', 'adhesion__user__profile', 'adhesion__corporation', 'service_type')
    list_filter = (
        'active',
        ('service_type', admin.RelatedOnlyFieldListFilter),
    )
    inlines = (ServiceAllocationInline,)
    search_fields = ('=id', 'service_type__name', 'label', 'notes',)
    raw_id_fields = ('adhesion',)

    get_adhesion_link = lambda self, service: service.adhesion.get_adhesion_link()
    get_adhesion_link.short_description = Adhesion.get_adhesion_link.short_description

    get_adherent_link = lambda self, service: service.adhesion.get_adherent_link()
    get_adherent_link.short_description = Adhesion.get_adherent_link.short_description

    def get_actions(self, request):
        actions = super().get_actions(request)
        if 'delete_selected' in actions:
            del actions['delete_selected']
        return actions

    def has_delete_permission(self, request, obj=None):
        return False


class IPPrefixAdmin(admin.ModelAdmin):
    readonly_fields = ('prefix',)

    def has_delete_permission(self, request, obj=None):
        # Interdiction de supprimer le préfix s’il est assigné à une route
        if obj and obj.tunnel_set.exists():
            return False
        else:
            return True

    # pour embêcher de by-passer le check has_delete_permission, on désactive l’action delete
    def get_actions(self, request):
        actions = super().get_actions(request)
        if 'delete_selected' in actions:
            del actions['delete_selected']
        return actions


class IPResourceAdmin(admin.ModelAdmin):
    list_display = ('__str__', 'available_display', 'last_use',)
    list_filter = (
        'category',
        ResourceInUseFilter,
        ('prefixes', admin.RelatedOnlyFieldListFilter),
        RouteFilter,
    )
    fields = ('ip', 'reserved', 'notes')
    readonly_fields = ('ip', 'reserved',)
    search_fields = ('=ip',)

    def get_inline_instances(self, request, obj=None):
        if obj:
            if obj.category == 0:
                inlines = (ServiceAllocationInline,)
            elif obj.category == 1:
                inlines = (AntennaAllocationInline,)
        else:
            inlines = ()
        return [inline(self.model, self.admin_site) for inline in inlines]

    def get_queryset(self, request):
        qs = super().get_queryset(request)
        qs = qs.annotate(last_use=models.Case(
                    models.When(category=0, then=models.Max('service_allocation__end')),
                    models.When(category=1, then=models.Max('antenna_allocation__end')),
                ))
        return qs

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

    def last_use(self, obj):
        if obj.allocations.exists():
            return obj.allocations.last().end
        else:
            return None
    last_use.short_description = 'Dernière utilisation'
    last_use.admin_order_field = 'last_use'

    def get_actions(self, request):
        actions = super().get_actions(request)
        if 'delete_selected' in actions:
            del actions['delete_selected']
        return actions

    def has_add_permission(self, request, obj=None):
        return False

    def has_delete_permission(self, request, obj=None):
        return False


class RouteAdmin(admin.ModelAdmin):
    list_display = ('name',)

    def get_readonly_fields(self, request, obj=None):
        if obj:
            return ('name',)
        else:
            return ()

    def get_actions(self, request):
        actions = super().get_actions(request)
        if 'delete_selected' in actions:
            del actions['delete_selected']
        return actions

    def has_delete_permission(self, request, obj=None):
        return False


class TunnelAdmin(RouteAdmin):
    list_display = ('name', 'description', 'created', 'active')
    list_filter = (
        ActiveTunnelFilter,
    )

    def active(self, obj):
        return not obj.ended
    active.short_description = 'Actif'
    active.boolean = True


class ServiceTypeAdmin(admin.ModelAdmin):
    fields = ('name',)
    readonly_fields = ('name',)

    def get_actions(self, request):
        actions = super().get_actions(request)
        if 'delete_selected' in actions:
            del actions['delete_selected']
        return actions

    def has_add_permission(self, request, obj=None):
        return False

    def has_delete_permission(self, request, obj=None):
        return False


class AntennaAdmin(geo_admin.OSMGeoAdmin):
    list_display = ('id', 'label', 'ip_display')
    inlines = (AntennaAllocationInline,)
    list_filter = (
        AntennaPrefixFilter,
    )

    def ip_display(self, obj):
        allocations = obj.allocations.filter(active=True)
        return ', '.join(allocations.values_list('resource__ip', flat=True)) or '-'
    ip_display.short_description = 'IP'

    def get_actions(self, request):
        actions = super().get_actions(request)
        if 'delete_selected' in actions:
            del actions['delete_selected']
        return actions

    def has_delete_permission(self, request, obj=None):
        return False

    def get_urls(self):
        urls = super().get_urls()
        from djgeojson.views import GeoJSONLayerView
        my_urls = [
            url(r'^map/$', self.admin_site.admin_view(self.map_view, cacheable=True), name='antenna-map'),
            url(r'^map/data.json$', self.admin_site.admin_view(GeoJSONLayerView.as_view(model=Antenna, geometry_field='position')), name='antenna-map-data'),
        ]
        return my_urls + urls

    def map_view(self, request):
        return TemplateResponse(request, 'services/antenna_map.html', {
            'json_url': reverse('admin:antenna-map-data'),
        })

    def map_data_view(self, request):
        geojson = serialize('geojson', Antenna.objects.all(), geometry_field='point', fields=('position',))
        return HttpResponse(geojson, content_type='application/json')


admin.site.register(ServiceType, ServiceTypeAdmin)
admin.site.register(Service, ServiceAdmin)
admin.site.register(IPPrefix, IPPrefixAdmin)
admin.site.register(IPResource, IPResourceAdmin)
admin.site.register(Route, RouteAdmin)
admin.site.register(Tunnel, TunnelAdmin)
geo_admin.site.register(Antenna, AntennaAdmin)