Django admin customization with ModelAdmin

                  from django.contrib import admin
from django.utils.html import format_html
from .models import Post, Comment


class CommentInline(admin.TabularInline):
    model = Comment
    extra = 0
    readonly_fields = ['author', 'created_at']
    can_delete = False


@admin.register(Post)
class PostAdmin(admin.ModelAdmin):
    list_display = ['title', 'author', 'status', 'comment_count', 'published_at']
    list_filter = ['status', 'created_at', 'author']
    search_fields = ['title', 'content']
    readonly_fields = ['created_at', 'updated_at']
    date_hierarchy = 'published_at'

    fieldsets = [
        ('Content', {
            'fields': ['title', 'content', 'author']
        }),
        ('Publishing', {
            'fields': ['status', 'published_at']
        }),
        ('Metadata', {
            'fields': ['created_at', 'updated_at'],
            'classes': ['collapse']
        }),
    ]

    inlines = [CommentInline]

    @admin.display(description='Comments')
    def comment_count(self, obj):
        count = obj.comments.count()
        return format_html('<strong>{}</strong>', count)

    def get_queryset(self, request):
        """Optimize queries."""
        return super().get_queryset(request).select_related('author').prefetch_related('comments')

    actions = ['publish_posts']

    @admin.action(description='Publish selected posts')
    def publish_posts(self, request, queryset):
        updated = queryset.update(status='published')
        self.message_user(request, f'{updated} posts published successfully.')