from django.contrib import admin
from .models import Order, OrderItem

class OrderItemInline(admin.TabularInline):
    model = OrderItem
    extra = 0
    readonly_fields = ('product', 'quantity', 'price', 'get_total_price')
    fields = ('product', 'quantity', 'price', 'get_total_price')
    
    def get_total_price(self, obj):
        if obj.pk:
            return f"${obj.price * obj.quantity:.2f}"
        return "-"
    get_total_price.short_description = "Total"

@admin.register(Order)
class OrderAdmin(admin.ModelAdmin):
    list_display = ('order_number', 'user', 'status', 'payment_status', 'total_amount', 'created_at')
    list_filter = ('status', 'payment_status', 'created_at', 'updated_at')
    search_fields = ('order_number', 'user__username', 'user__email', 'user__first_name', 'user__last_name')
    readonly_fields = ('order_number', 'total_amount', 'created_at', 'updated_at', 'get_items_count')
    inlines = [OrderItemInline]
    list_per_page = 25
    date_hierarchy = 'created_at'
    
    fieldsets = (
        ('Order Information', {
            'fields': ('order_number', 'user', 'get_items_count', 'total_amount'),
            'classes': ('wide',)
        }),
        ('Status & Payment', {
            'fields': ('status', 'payment_method', 'payment_status'),
            'classes': ('wide',)
        }),
        ('Shipping Information', {
            'fields': ('shipping_address',),
            'classes': ('collapse',)
        }),
        ('Timestamps', {
            'fields': ('created_at', 'updated_at'),
            'classes': ('collapse',)
        }),
    )
    
    def get_items_count(self, obj):
        return obj.items.count()
    get_items_count.short_description = "Number of Items"
    
    def get_queryset(self, request):
        """Optimize queries by prefetching related objects"""
        return super().get_queryset(request).select_related('user').prefetch_related('items')
    
    actions = ['mark_as_confirmed', 'mark_as_shipped', 'mark_as_delivered']
    
    def mark_as_confirmed(self, request, queryset):
        updated = queryset.update(status='confirmed')
        self.message_user(request, f'{updated} orders marked as confirmed.')
    mark_as_confirmed.short_description = "Mark selected orders as confirmed"
    
    def mark_as_shipped(self, request, queryset):
        updated = queryset.update(status='shipped')
        self.message_user(request, f'{updated} orders marked as shipped.')
    mark_as_shipped.short_description = "Mark selected orders as shipped"
    
    def mark_as_delivered(self, request, queryset):
        updated = queryset.update(status='delivered')
        self.message_user(request, f'{updated} orders marked as delivered.')
    mark_as_delivered.short_description = "Mark selected orders as delivered"
    
    # Disable adding new orders - orders should only be created through checkout
    def has_add_permission(self, request):
        return False

    # Optional: Also disable deletion to prevent accidental data loss
    def has_delete_permission(self, request, obj=None):
        return False