erpsaas/app/Observers/BillObserver.php

<?php

namespace App\Observers;

use App\Enums\Accounting\BillStatus;
use App\Models\Accounting\Bill;
use App\Models\Accounting\DocumentLineItem;
use App\Models\Accounting\Transaction;
use Illuminate\Support\Facades\DB;

class BillObserver
{
    public function created(Bill $bill): void
    {
        // $bill->createInitialTransaction();
    }

    public function saving(Bill $bill): void
    {
        if ($bill->is_currently_overdue) {
            $bill->status = BillStatus::Overdue;
        }
    }

    /**
     * Handle the Bill "deleted" event.
     */
    public function deleted(Bill $bill): void
    {
        DB::transaction(function () use ($bill) {
            $bill->lineItems()->each(function (DocumentLineItem $lineItem) {
                $lineItem->delete();
            });

            $bill->transactions()->each(function (Transaction $transaction) {
                $transaction->delete();
            });
        });
    }
}