# -*- coding: utf-8 -*-
from django.contrib import admin
from .models import Discount, PromoCode, DiscountApplication


@admin.register(Discount)
class DiscountAdmin(admin.ModelAdmin):
    """Админ-панель для управления скидками."""
    list_display = [
        'name',
        'discount_type',
        'value_display',
        'scope',
        'is_auto',
        'is_active',
        'current_usage_count',
        'validity_period',
    ]

    list_filter = [
        'discount_type',
        'scope',
        'is_auto',
        'is_active',
    ]

    search_fields = [
        'name',
        'description',
    ]

    readonly_fields = [
        'current_usage_count',
        'created_at',
    ]

    fieldsets = (
        ('Основная информация', {
            'fields': ('name', 'description', 'is_active', 'priority')
        }),
        ('Параметры скидки', {
            'fields': ('discount_type', 'value', 'scope')
        }),
        ('Ограничения', {
            'fields': (
                'start_date',
                'end_date',
                'max_usage_count',
                'current_usage_count',
                'is_auto'
            )
        }),
        ('Условия применения', {
            'fields': (
                'min_order_amount',
                'products',
                'categories',
                'excluded_products'
            )
        }),
        ('Метаданные', {
            'fields': ('created_at', 'created_by'),
            'classes': ('collapse',)
        }),
    )

    def value_display(self, obj):
        if obj.discount_type == 'percentage':
            return f"{obj.value}%"
        return f"{obj.value} руб."
    value_display.short_description = "Значение"

    def validity_period(self, obj):
        if obj.start_date and obj.end_date:
            return f"{obj.start_date.date()} - {obj.end_date.date()}"
        elif obj.start_date:
            return f"с {obj.start_date.date()}"
        elif obj.end_date:
            return f"до {obj.end_date.date()}"
        return "Бессрочная"
    validity_period.short_description = "Период действия"


@admin.register(PromoCode)
class PromoCodeAdmin(admin.ModelAdmin):
    """Админ-панель для управления промокодами."""
    list_display = [
        'code',
        'discount_name',
        'is_active',
        'current_uses',
        'usage_limit',
        'validity_period',
    ]

    list_filter = [
        'is_active',
        'discount__scope',
    ]

    search_fields = [
        'code',
        'discount__name',
    ]

    readonly_fields = [
        'current_uses',
        'created_at',
    ]

    fieldsets = (
        ('Основная информация', {
            'fields': ('code', 'discount', 'is_active')
        }),
        ('Ограничения', {
            'fields': (
                'max_uses_per_user',
                'max_total_uses',
                'current_uses',
                'start_date',
                'end_date',
            )
        }),
        ('Метаданные', {
            'fields': ('created_at', 'created_by'),
            'classes': ('collapse',)
        }),
    )

    def discount_name(self, obj):
        return obj.discount.name
    discount_name.short_description = "Скидка"

    def usage_limit(self, obj):
        if obj.max_total_uses:
            return f"{obj.current_uses} / {obj.max_total_uses}"
        return str(obj.current_uses)
    usage_limit.short_description = "Использования"

    def validity_period(self, obj):
        if obj.start_date and obj.end_date:
            return f"{obj.start_date.date()} - {obj.end_date.date()}"
        elif obj.start_date:
            return f"с {obj.start_date.date()}"
        elif obj.end_date:
            return f"до {obj.end_date.date()}"
        return "Бессрочный"
    validity_period.short_description = "Период действия"


@admin.register(DiscountApplication)
class DiscountApplicationAdmin(admin.ModelAdmin):
    """Админ-панель для истории применения скидок."""
    list_display = [
        'order_link',
        'discount_name',
        'promo_code_display',
        'target',
        'discount_amount',
        'customer',
        'applied_at',
    ]

    list_filter = [
        'target',
        'applied_at',
        'discount__discount_type',
    ]

    readonly_fields = [
        'order',
        'order_item',
        'discount',
        'promo_code',
        'target',
        'base_amount',
        'discount_amount',
        'final_amount',
        'customer',
        'applied_at',
        'applied_by',
    ]

    def has_add_permission(self, request):
        return False  # Только чтение

    def has_change_permission(self, request, obj=None):
        return False  # Только чтение

    def order_link(self, obj):
        from django.urls import reverse
        url = reverse('admin:orders_order_change', args=[obj.order.id])
        return f'<a href="{url}">#{obj.order.order_number}</a>'
    order_link.short_description = "Заказ"
    order_link.allow_tags = True

    def discount_name(self, obj):
        return obj.discount.name if obj.discount else '-'
    discount_name.short_description = "Скидка"

    def promo_code_display(self, obj):
        return obj.promo_code.code if obj.promo_code else '-'
    promo_code_display.short_description = "Промокод"