<?php

// create a liveAware trait

trait LiveAware
{
  public function scopeLive(Builder $builder)
  {
      return $builder->whereNotNull('live_at');
  }

  public function isLive()
  {
      return $this->live_at !== null;
  }

  public function isNotLive()
  {
    // the reason we use this way instead of checking $this->live_at === null
    // is if we change the implementation of how to check live. We only need to change code in isLive().
    // So it is more maintable
    return ! $this->isLive();
  }
}


// in our controller
class ArticleController
{
    public function show(Article $article)
    {
       abort($article->isNotLive(), 404);

      // ...
    }
}

// We may wanto use globl scope to tidy things up. But if we create admin pannel, we may want the admin to see the not live
// articles. We may want to add if check in the global scope. Another way is we can create a middleware for thhis

class IsLive
{
    public function handle(Request $request, Closure $next, $model)
    {
         if ($request->{$model}->isNotLive())
         {
           return abort(404);
         }

          return $next($request);

    }
}

// In our Cnotroller, we just need to

class ArticlesController
{
    public function __construct()
    {
        // register the middleware as is.live in the kernel
        $this->middleware(['is.live:article']);
    }

    public function show(Article $article)
    {
      // ...
    }
}