oficial/app/src/Model/Venta/Promotion.php

<?php
namespace Incoviba\Model\Venta;

use DateTimeInterface;
use Incoviba\Common;
use Incoviba\Model\Proyecto\Broker;

class Promotion extends Common\Ideal\Model
{
    public float $amount;
    public DateTimeInterface $startDate;
    public DateTimeInterface $endDate;
    public DateTimeInterface $validUntil;
    public int $state;

    protected array $contracts;
    public function contracts(): array
    {
        if (empty($this->contracts)) {
            $this->contracts = $this->runFactory('contracts');
        }
        return $this->contracts;
    }

    protected array $units;
    public function units(): array
    {
        if (empty($this->units)) {
            $this->units = $this->runFactory('units');
        }
        return $this->units;
    }

    protected function jsonComplement(): array
    {
        return [
            'amount' => $this->amount,
            'start_date' => $this->startDate->format('Y-m-d'),
            'end_date' => $this->endDate->format('Y-m-d'),
            'valid_until' => $this->validUntil->format('Y-m-d'),
            'state' => [
                'id' => $this->state,
                'description' => Promotion\State::name($this->state)
            ],
            'contracts' => $this->contracts() ?? [],
            'units' => $this->units() ?? []
        ];
    }
}