JobcardSystem/app/Domain/Jobcard/StatusTransitionValidator.php

<?php
declare(strict_types=1);

namespace App\Domain\Jobcard;

final class StatusTransitionValidator
{
    public const STATUSES = ['new', 'assigned', 'in_progress', 'awaiting_client', 'awaiting_parts', 'completed', 'closed'];

    private const TRANSITIONS = [
        'new' => ['assigned'],
        'assigned' => ['in_progress'],
        'in_progress' => ['awaiting_client', 'awaiting_parts', 'completed'],
        'awaiting_client' => ['in_progress', 'completed'],
        'awaiting_parts' => ['in_progress', 'completed'],
        'completed' => ['closed'],
        'closed' => ['in_progress'],
    ];

    public function canTransition(string $from, string $to): bool
    {
        return in_array($from, self::STATUSES, true)
            && in_array($to, self::STATUSES, true)
            && ($from === $to || in_array($to, self::TRANSITIONS[$from], true));
    }

    public function allowedFrom(string $from): array
    {
        return in_array($from, self::STATUSES, true) ? array_merge([$from], self::TRANSITIONS[$from]) : [];
    }
}