osb/app/Models/Checkout.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Collection;
use Illuminate\Database\Eloquent\Model;
use Leenooks\Traits\ScopeActive;

use App\Traits\SiteID;

class Checkout extends Model
{
	use ScopeActive,SiteID;

	protected $casts = [
		'plugin_data'=>'json',
	];

	/* RELATIONS */

	public function payments()
	{
		return $this->hasMany(Payment::class);
	}

	/* STATIC METHODS */

	public static function available(): Collection
	{
		return self::active()->get();
	}

	/* ATTRIBUTES */

	public function getIconAttribute(): string
	{
		switch(strtolower($this->name)) {
			case 'paypal': return 'fab fa-cc-paypal';
			default: return 'fas fa-money-bill-alt';
		}
	}

	/* METHODS */

	public function fee(float $amt,int $items=1): float
	{
		if (! $this->fee_passon OR ! $items)
			return 0;

		$fee = $amt+$this->fee_fixed/$items;
		$fee /= (1-$this->fee_variable);

		return round($fee-$amt,2);
	}
}