Polymorphic Coupons with Eloquent

2015_09_03_142321_create_coupons_table.php

<?php

use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class CreateCouponsTable extends Migration
{
    public function up()
    {
        Schema::create('coupons', function (Blueprint $table) {
            $table->increments('id');
            $table->string('type');
            $table->string('code')->unique();
            $table->integer('value')->nullable();
            $table->integer('min_quantity')->nullable();
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::drop('coupons');
    }
}

Coupon.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Coupon extends Model
{
    protected $table = 'coupons';

    public function __construct(array $attributes = [])
    {
        parent::__construct($attributes);

        $this->type = static::class;
    }

    public static function findByCode($code)
    {
        $type = self::whereCode($code)->value('type');

        return (new $type)->whereCode($code)->first();
    }
}

CouponSeeder.php

<?php

use Illuminate\Database\Seeder;

class CouponSeeder extends Seeder
{
    public function run()
    {
        \App\Coupon::create([
            'code' => '001',
            'value' => '0'
        ]);

        \App\FixedValueCoupon::create([
            'code' => 'AA1',
            'value' => '1000'
        ]);

        \App\PercentOffCoupon::create([
            'code' => 'BB1',
            'value' => '15'
        ]);

        \App\MinimumQuantityCoupon::create([
            'code' => 'CC1',
            'value' => '15',
            'min_quantity' => 2
        ]);
    }
}

FixedValueCoupon.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class FixedValueCoupon extends Coupon
{
    public function discount()
    {
        return 'Fixed value';
    }
}

MinimumQuantityCoupon.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class MinimumQuantityCoupon extends Coupon
{
    public function discount()
    {
        return 'Minimum quantity';
    }
}

PercentOffCoupon.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class PercentOffCoupon extends Coupon
{
    public function discount()
    {
        return 'Percent off';
    }
}

routes.php

<?php

Route::get('/', function () {

    $coupon = \App\Coupon::findByCode('001');
    var_dump($coupon->toArray());

    $fixedValue = \App\Coupon::findByCode('AA1');
    var_dump($fixedValue->toArray());

    $percentOff = \App\Coupon::findByCode('BB1');
    var_dump($percentOff->toArray());

    $minimumQuantity = \App\Coupon::findByCode('CC1');
    var_dump($minimumQuantity->toArray());

});