/**
     * Gets the rules for all contact fields that are require by the client group
     *
     * @param int $client_id The ID of the client this contact is associated with
     * @param bool $edit Whether this data is being validated for an edit (optional, default false)
     * @return array A list of rules with the addition of the client groups required fields
     */
    private function getRequiredFieldRules($client_id, $edit = false)
    {
        Loader::loadModels($this, ['ClientGroups']);

        $required_fields = [];
        $client = $this->Record->select('client_group_id')
            ->from('clients')
            ->where('id', '=', $client_id)
            ->fetch();

        if ($client) {
            $required_contact_fields = $this->ClientGroups->getSetting(
                $client->client_group_id,
                'required_contact_fields'
            );

            if ($required_contact_fields) {
                $required_fields = unserialize(base64_decode($required_contact_fields->value));
            }
        }

        $rules = [];
        foreach ($required_fields as $field) {
            $rules[$field]['empty'] = [
                'if_set' => $edit,
                'rule' => 'isEmpty',
                'negate' => true,
                'message' => $this->_('Contacts.!error.' . $field . '.empty')
            ];
        }

        return $rules;
    }