from django.contrib import admin
from django.db import models
from django.core.urlresolvers import reverse
from django.forms import BaseInlineFormSet
from django.utils.html import format_html

from services.models import ServiceType
from services.admin import ServiceAdmin
from adhesions.admin import AdhesionAdmin
from .models import RecurringPayment, PaymentUpdate
from .utils import notify_payment_update


### Inlines

class PaymentTypeFilter(admin.SimpleListFilter):
    title = 'type'
    parameter_name = 'type'

    def lookups(self, request, model_admin):
        return (
            ('adhesion', 'Adhésion'),
            ('service', 'Service'),
        )

    def queryset(self, request, queryset):
        if self.value() == 'adhesion':
            return queryset.filter(adhesion__isnull=False)
        if self.value() == 'service':
            return queryset.filter(service__isnull=False)


class PaymentStatusFilter(admin.SimpleListFilter):
    title = 'actif'
    parameter_name = 'active'

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

    def queryset(self, request, queryset):
        actives = PaymentUpdate.objects.filter(validated=True).order_by('payment', '-start') \
                        .distinct('payment').exclude(payment_method=PaymentUpdate.STOP) \
                        .values_list('payment__pk', flat=True)
        if self.value() == '0':
            return queryset.exclude(pk__in=actives)
        if self.value() == '1':
            return queryset.filter(pk__in=actives)


class PendingPaymentFilter(admin.SimpleListFilter):
    title = 'opérations en attente'
    parameter_name = 'pending'

    def lookups(self, request, model_admin):
        return (
            (0, 'À jour'),
            (1, 'En attente'),
        )

    def queryset(self, request, queryset):
        pending = PaymentUpdate.objects.filter(validated=False).values_list('payment__pk', flat=True)
        if self.value() == '0':
            return queryset.exclude(pk__in=pending)
        if self.value() == '1':
            return queryset.filter(pk__in=pending)


### Inlines

class PendingPaymentUpdateFormSet(BaseInlineFormSet):
    def save_new(self, form, commit=True):
        obj = super().save_new(form, commit)
        notify_payment_update(self.request, obj)
        return obj

    def save_existing(self, form, instance, commit=True):
        old = PaymentUpdate.objects.get(pk=instance.pk)
        notify_payment_update(self.request, instance, old)
        return super().save_existing(form, instance, commit)


class PendingPaymentUpdateInline(admin.TabularInline):
    model = PaymentUpdate
    formset = PendingPaymentUpdateFormSet
    extra = 1
    verbose_name_plural = 'En attente de saisie bancaire'

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

    def get_queryset(self, request):
        return super().get_queryset(request).filter(validated=False)


class ValidatedPaymentUpdateInline(admin.TabularInline):
    model = PaymentUpdate
    verbose_name_plural = 'Historique'
    max_num = 0
    fields = ('amount', 'period', 'payment_method', 'start',)
    readonly_fields = ('amount', 'period', 'payment_method', 'start',)

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

    def get_queryset(self, request):
        return super().get_queryset(request).filter(validated=True)


### Helpers

def prefix_search_field(prefix, field):
    if field[0] == '=':
        return '=' + prefix + '__' + field[1:]
    else:
        return prefix + '__' + field


### ModelAdmin

class RecurringPaymentAdmin(admin.ModelAdmin):
    list_display = ('id', 'payment_type', 'payment_object_link', 'get_status', 'get_last_validated_update', 'get_pending',)
    list_select_related = ('adhesion', 'service', 'service__service_type',)
    inlines = (PendingPaymentUpdateInline, ValidatedPaymentUpdateInline,)
    list_filter = (PaymentTypeFilter, PaymentStatusFilter, PendingPaymentFilter,)
    fields = ('payment_type', 'payment_object_link',)
    readonly_fields = ('payment_type', 'payment_object_link',)
    search_fields = \
        tuple([prefix_search_field('adhesion', f) for f in AdhesionAdmin.search_fields]) \
        + tuple([prefix_search_field('service', f) for f in ServiceAdmin.search_fields])

    def get_queryset(self, request):
        qs = super().get_queryset(request)
        qs = qs.prefetch_related('updates')
        qs = qs.prefetch_related(
                models.Prefetch(
                    'updates',
                    queryset=PaymentUpdate.objects.filter(validated=False),
                    to_attr='pending_updates'
                )
        )
        return qs

    def get_pending(self, obj):
        return len(obj.pending_updates)
    get_pending.short_description = 'Opérations en attente'

    def payment_object_link(self, obj):
        obj = obj.payment_object()
        return format_html(u'<a href="{}">{}</a>', obj.get_absolute_url(), obj)
    payment_object_link.short_description = 'Objet'

    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


admin.site.register(RecurringPayment, RecurringPaymentAdmin)