Handling relationships in Laravel - php

Question

I am building a system to support referral programs. It allows you to track links, programs and for how long will cookie last. Also allows you to easily decide how will user benefit after referring other user to for example sign up.
This' for generating unique referral code on creating a referral link. I am able to use this code to track the link and and relate it to original user who shared it. Factory method getReferral is creating single referral link for each user for a given program.
// ReferralLink Model
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
use Ramsey\Uuid\Uuid;
class ReferralLink extends Model
{
protected $fillable = ['user_id', 'referral_program_id'];
protected static function boot()
{
static::creating(function (ReferralLink $model) {
$model->generateCode();
});
parent::boot();
}
private function generateCode()
{
$this->code = (string)Uuid::uuid1();
}
public static function getReferral($user, $program)
{
return static::firstOrCreate([
'user_id' => $user->id,
'referral_program_id' => $program->id
]);
}
public function getLinkAttribute()
{
return url($this->program->uri) . '?ref=' . $this->code;
}
public function user()
{
return $this->belongsTo(User::class);
}
public function program()
{
return $this->belongsTo(ReferralProgram::class, 'referral_program_id');
}
public function relationships()
{
return $this->hasMany(ReferralRelationship::class);
}
}
StoreReferralCode middleware
use App\ReferralLink;
// ...
public function handle($request, Closure $next)
{
$response = $next($request);
if ($request->has('ref')){
$referral = ReferralLink::whereCode($request->get('ref'))->first();
$response->cookie('ref', $referral->id, $referral->lifetime_minutes);
}
return $response;
}
UserReferred Event handler
class UserReferred
{
use SerializesModels;
public $referralId;
public $user;
public function __construct($referralId, $user)
{
$this->referralId = $referralId;
$this->user = $user;
}
public function broadcastOn()
{
return [];
}
}
And of course this' how I am broadcasting the event on RegistrationController
protected function create(array $data)
{
$user = User::create([
'name' => $data['name'],
'email' => $data['email'],
'password' => bcrypt($data['password']),
]);
event(new \App\Events\UserReferred(request()->cookie('ref'), $user));
return $user;
}
I am not able to create a relationship in the DB on grounds of who shared a link with who. What could be wrong with my code ?
//referral_relationships schema
Schema::create('referral_relationships', function (Blueprint $table) {
$table->bigIncrements('id');
$table->integer('referral_link_id');
$table->integer('user_id');
$table->timestamps();
});