firefly-iii/app/Rules/ValidRecurrenceRepetitionValue.php

<?php

/**
 * ValidRecurrenceRepetitionValue.php
 * Copyright (c) 2019 james@firefly-iii.org
 *
 * This file is part of Firefly III (https://github.com/firefly-iii).
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

declare(strict_types=1);

namespace FireflyIII\Rules;

use Carbon\Carbon;
use Illuminate\Contracts\Validation\ValidationRule;

/**
 * Class ValidRecurrenceRepetitionValue
 */
class ValidRecurrenceRepetitionValue implements ValidationRule
{
    /**
     * @SuppressWarnings("PHPMD.UnusedFormalParameter")
     */
    public function validate(string $attribute, mixed $value, \Closure $fail): void
    {
        $value = (string) $value;

        if ('daily' === $value) {
            return;
        }

        if (str_starts_with($value, 'monthly') && $this->validateMonthly($value)) {
            return;
        }

        // Value is like: ndom,3,7
        // nth x-day of the month.
        if (str_starts_with($value, 'ndom') && $this->validateNdom($value)) {
            return;
        }

        // Value is like: weekly,7
        if (str_starts_with($value, 'weekly') && $this->validateWeekly($value)) {
            return;
        }

        // Value is like: yearly,2018-01-01
        if (str_starts_with($value, 'yearly') && $this->validateYearly($value)) {
            return;
        }

        $fail('validation.valid_recurrence_rep_type')->translate();
    }

    private function validateMonthly(string $value): bool
    {
        $dayOfMonth = (int) substr($value, 8);

        return $dayOfMonth > 0 && $dayOfMonth < 32;
    }

    private function validateNdom(string $value): bool
    {
        $parameters = explode(',', substr($value, 5));
        if (2 !== count($parameters)) {
            return false;
        }
        $nthDay     = (int) $parameters[0];
        $dayOfWeek  = (int) $parameters[1];
        if ($nthDay < 1 || $nthDay > 5) {
            return false;
        }

        return $dayOfWeek > 0 && $dayOfWeek < 8;
    }

    private function validateWeekly(string $value): bool
    {
        $dayOfWeek = (int) substr($value, 7);

        return $dayOfWeek > 0 && $dayOfWeek < 8;
    }

    private function validateYearly(string $value): bool
    {
        // rest of the string must be valid date:
        $dateString = substr($value, 7);

        try {
            Carbon::createFromFormat('Y-m-d', $dateString);
        } catch (\InvalidArgumentException $e) {
            app('log')->debug(sprintf('Could not parse date %s: %s', $dateString, $e->getMessage()));

            return false;
        }

        return true;
    }
}