from django import forms
from django.contrib import admin
from django.http import JsonResponse
from django.urls import path

from .models import Category, Color, Item, ItemImage, Subcategory


def get_subcategory_queryset(category_id):
    if not category_id:
        return Subcategory.objects.none()

    try:
        category_id = int(category_id)
    except (TypeError, ValueError):
        return Subcategory.objects.none()

    return Subcategory.objects.filter(category_id=category_id).order_by('name')


@admin.register(Color)
class ColorAdmin(admin.ModelAdmin):
    list_display = ('name', 'hex_code')


@admin.register(Category)
class CategoryAdmin(admin.ModelAdmin):
    list_display = ('name', 'slug')
    prepopulated_fields = {'slug': ('name',)}


@admin.register(Subcategory)
class SubcategoryAdmin(admin.ModelAdmin):
    list_display = ('name', 'category', 'slug')
    list_filter = ('category',)
    prepopulated_fields = {'slug': ('name',)}


class ItemAdminForm(forms.ModelForm):
    class Meta:
        model = Item
        fields = '__all__'

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        category_id = self.data.get('category') or getattr(self.instance, 'category_id', None)
        self.fields['subcategory'].queryset = get_subcategory_queryset(category_id)


class ItemImageInline(admin.TabularInline):
    model = ItemImage
    extra = 1
    fields = ('image', 'alt', 'sort_order', 'is_primary')


@admin.register(Item)
class ItemAdmin(admin.ModelAdmin):
    form = ItemAdminForm
    save_as = True
    list_display = ('name', 'category', 'subcategory', 'price', 'discount_price', 'is_new', 'is_available', 'created_at')
    list_filter = ('is_available', 'is_new', 'colors', 'category', 'subcategory', 'created_at')
    filter_horizontal = ('colors',)
    prepopulated_fields = {'slug': ('name',)}
    inlines = (ItemImageInline,)

    class Media:
        js = ('items/admin/item-subcategory.js',)

    def get_urls(self):
        urls = super().get_urls()
        custom_urls = [
            path(
                'subcategories/',
                self.admin_site.admin_view(self.subcategories_view),
                name='items_item_subcategories',
            ),
        ]
        return custom_urls + urls

    def subcategories_view(self, request):
        category_id = request.GET.get('category_id')
        subcategories = get_subcategory_queryset(category_id)

        return JsonResponse({
            'subcategories': [
                {'id': subcategory.id, 'name': subcategory.name}
                for subcategory in subcategories
            ],
        })