Tools\Model\Table\Table::validateDateTime PHP Method

    public function validateDateTime($value, $options = [], array $context = [])
    {
        if (!$value) {
            if (!empty($options['allowEmpty'])) {
                return true;
            }
            return false;
        }
        $format = !empty($options['dateFormat']) ? $options['dateFormat'] : 'ymd';
        if (!is_object($value)) {
            $value = new Time($value);
        }
        $pieces = $value->format(FORMAT_DB_DATETIME);
        $dateTime = explode(' ', $pieces, 2);
        $date = $dateTime[0];
        $time = !empty($dateTime[1]) ? $dateTime[1] : '';
        if (!empty($options['allowEmpty']) && (empty($date) && empty($time))) {
            return true;
        }
        if (Validation::date($date, $format) && Validation::time($time)) {
            // after/before?
            $seconds = isset($options['min']) ? $options['min'] : 1;
            if (!empty($options['after'])) {
                if (!is_object($options['after']) && isset($context['data'][$options['after']])) {
                    $options['after'] = $context['data'][$options['after']];
                    if (!is_object($options['after'])) {
                        $options['after'] = new Time($options['after']);
                    }
                } elseif (!is_object($options['after'])) {
                    return false;
                }
            }
            if (!empty($options['before'])) {
                if (!is_object($options['before']) && isset($context['data'][$options['before']])) {
                    $options['before'] = $context['data'][$options['before']];
                    if (!is_object($options['before'])) {
                        $options['before'] = new Time($options['before']);
                    }
                } elseif (!is_object($options['before'])) {
                    return false;
                }
            }
            // We need this for those not using immutable objects just yet
            $compareValue = clone $value;
            if (!empty($options['after'])) {
                $compare = $compareValue->subSeconds($seconds);
                if ($options['after']->gt($compare)) {
                    return false;
                }
                if (!empty($options['max'])) {
                    $after = $options['after']->addSeconds($options['max']);
                    if ($value->gt($after)) {
                        return false;
                    }
                }
            }
            if (!empty($options['before'])) {
                $compare = $compareValue->addSeconds($seconds);
                if ($options['before']->lt($compare)) {
                    return false;
                }
                if (!empty($options['max'])) {
                    $after = $options['before']->subSeconds($options['max']);
                    if ($value->lt($after)) {
                        return false;
                    }
                }
            }
            return true;
        }
        return false;
    }