$stateTransitions = [
    'created'     => ['paid', 'cancelled'],
    'paid'        => ['shipped', 'refunded'],
    'shipped'     => ['delivered', 'returned'],
    'delivered'   => ['completed'],
    'cancelled'   => [], // 终止状态
    'refunded'    => ['completed'],
    'returned'    => ['refunded', 'completed']
];

class OrderStateMachine {
    private $transitions;

    public function __construct($transitions) {
        $this->transitions = $transitions;
    }

    public function canTransition($from, $to) {
        return isset($this->transitions[$from]) 
            && in_array($to, $this->transitions[$from]);
    }

    public function transition($from, $to) {
        if (!$this->canTransition($from, $to)) {
            throw new \InvalidArgumentException("Invalid state transition: {$from} → {$to}");
        }
        return true;
    }
}

$machine = new OrderStateMachine($stateTransitions);
try {
    $machine->transition('created', 'paid');     // 允许
    $machine->transition('cancelled', 'paid');   // 抛出异常
} catch (\Exception $e) {
    echo $e->getMessage();
}

public function setStatus($newStatus) {
    $machine = new OrderStateMachine(config('order.transitions'));
    
    if (!$machine->canTransition($this->status, $newStatus)) {
        throw new \DomainException("Cannot change status from {$this->status} to {$newStatus}");
    }

    \DB::transaction(function () use ($newStatus) {
        $this->status = $newStatus;
        $this->s*e();

        // 记录日志
        OrderLog::create([
            'order_id' => $this->id,
            'action'   => 'status_change',
            'from'     => $this->getOriginal('status'),
            'to'       => $newStatus
        ]);
    });
}