';
        print_r($report);
        exit;


        $balance      = new Balance;
        $header       = new BalanceHeader;
        $budgetLimits = $this->budgetRepository->getAllBudgetLimits($start, $end);
        foreach ($accounts as $account) {
            Log::debug(sprintf('Add account %s to headers.', $account->name));
            $header->addAccount($account);
        }

        /** @var BudgetLimit $budgetLimit */
        foreach ($budgetLimits as $budgetLimit) {
            if (null !== $budgetLimit->budget) {
                $line = $this->createBalanceLine($budgetLimit, $accounts);
                $balance->addBalanceLine($line);
            }
        }
        $noBudgetLine = $this->createNoBudgetLine($accounts, $start, $end);

        $balance->addBalanceLine($noBudgetLine);
        $balance->setBalanceHeader($header);

        Log::debug('Clear unused budgets.');
        // remove budgets without expenses from balance lines:
        $balance = $this->removeUnusedBudgets($balance);

        Log::debug('Return report.');

        return $balance;
    }

    /**
     * Create one balance line.
     *
     * @param BudgetLimit $budgetLimit
     * @param Collection  $accounts
     *
     * @return BalanceLine
     */
    private function createBalanceLine(BudgetLimit $budgetLimit, Collection $accounts): BalanceLine
    {
        $line = new BalanceLine;
        $line->setBudget($budgetLimit->budget);
        $line->setBudgetLimit($budgetLimit);

        // loop accounts:
        foreach ($accounts as $account) {
            $balanceEntry = new BalanceEntry;
            $balanceEntry->setAccount($account);
            $spent = $this->budgetRepository->spentInPeriod(
                new Collection([$budgetLimit->budget]),
                new Collection([$account]),
                $budgetLimit->start_date,
                $budgetLimit->end_date
            );
            $balanceEntry->setSpent($spent);
            $line->addBalanceEntry($balanceEntry);
        }

        return $line;
    }

    /**
     * Create a line for transactions without a budget.
     *
     * @param Collection $accounts
     * @param Carbon     $start
     * @param Carbon     $end
     *
     * @return BalanceLine
     */
    private function createNoBudgetLine(Collection $accounts, Carbon $start, Carbon $end): BalanceLine
    {
        $empty = new BalanceLine;

        foreach ($accounts as $account) {
            $spent = $this->budgetRepository->spentInPeriodWoBudget(new Collection([$account]), $start, $end);
            // budget
            $budgetEntry = new BalanceEntry;
            $budgetEntry->setAccount($account);
            $budgetEntry->setSpent($spent);
            $empty->addBalanceEntry($budgetEntry);
        }

        return $empty;
    }

    /**
     * Remove unused budgets from the report.
     *
     * @SuppressWarnings(PHPMD.CyclomaticComplexity)
     * @param Balance $balance
     *
     * @return Balance
     */
    private function removeUnusedBudgets(Balance $balance): Balance
    {
        $set    = $balance->getBalanceLines();
        $newSet = new Collection;
        /** @var BalanceLine $entry */
        foreach ($set as $entry) {
            if (null !== $entry->getBudget()->id) {
                $sum = '0';
                /** @var BalanceEntry $balanceEntry */
                foreach ($entry->getBalanceEntries() as $balanceEntry) {
                    $sum = bcadd($sum, $balanceEntry->getSpent());
                }
                if (bccomp($sum, '0') === -1) {
                    $newSet->push($entry);
                }
                continue;
            }
            $newSet->push($entry);
        }

        $balance->setBalanceLines($newSet);

        return $balance;
    }
}