invoiceninja/app/Ninja/Reports/CreditReport.php

<?php

namespace App\Ninja\Reports;

use App\Models\Client;
use Auth;

class CreditReport extends AbstractReport
{
    public function getColumns()
    {
        $columns = [
            'client' => [],
            'amount' => [],
            'balance' => [],
        ];

        return $columns;
    }

    public function run()
    {
        $account = Auth::user()->account;

        $clients = Client::scope()
                        ->orderBy('name')
                        ->withArchived()
                        ->with(['credits' => function ($query) {
                            $query->where('credit_date', '>=', $this->startDate)
                                  ->where('credit_date', '<=', $this->endDate)
                                  ->withArchived();
                        }]);

        foreach ($clients->get() as $client) {
            $amount = 0;
            $balance = 0;

            foreach ($client->credits as $credit) {
                $amount += $credit->amount;
                $balance += $credit->balance;
            }

            if (! $amount && ! $balance) {
                continue;
            }

            $row = [
                $this->isExport ? $client->getDisplayName() : $client->present()->link,
                $account->formatMoney($amount, $client),
                $account->formatMoney($balance, $client),
            ];

            $this->data[] = $row;

            $this->addToTotals($client->currency_id, 'amount', $amount);
            $this->addToTotals($client->currency_id, 'balance', $balance);
        }
    }
}