lan_kiosk/app/Models/Customer.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use App\Models\Puchase;
use App\Models\Deposit;

class Customer extends Model
{
    /**
     * The attributes that are mass assignable.
     *
     * @var array<int, string>
     */
    protected $fillable = [
        'lan_id',
        'name',
        'guardian_name',
        'amount_left',
        'deposit',
        'give_leftover',
        'comment',
        'customer_group_id',
        'is_in_group'
    ];

    /**
     * Make this customer a member of a group and hand over the balance they have
     * left to spend. Returns the amount that was moved, for the caller to add to
     * the group's own row.
     *
     * Membership and money move together — a member keeps no balance of their own.
     */
    public function joinGroup(int $groupId): int
    {
        $moved = (int) $this->amount_left;

        $this->customer_group_id = $groupId;
        $this->is_in_group = 1;
        $this->deposit = 0;
        $this->amount_left = 0;
        $this->save();

        return $moved;
    }

    /**
     * Get the purchases for the customer.
     */
    public function purchases()
    {
        return $this->hasMany(Purchase::class);
    }

    /**
     * Get the deposit for the customer.
     */
    public function deposits()
    {
        return $this->hasMany(Deposit::class);
    }
}