app\models\Client::addContact PHP Method

    public function addContact($data, $isPrimary = false)
    {
        $publicId = isset($data['public_id']) ? $data['public_id'] : (isset($data['id']) ? $data['id'] : false);
        if ($publicId && $publicId != '-1') {
            $contact = Contact::scope($publicId)->firstOrFail();
        } else {
            $contact = Contact::createNew();
            $contact->send_invoice = true;
        }
        if (Utils::hasFeature(FEATURE_CLIENT_PORTAL_PASSWORD) && $this->account->enable_portal_password) {
            if (!empty($data['password']) && $data['password'] != '-%unchanged%-') {
                $contact->password = bcrypt($data['password']);
            } else {
                if (empty($data['password'])) {
                    $contact->password = null;
                }
            }
        }
        $contact->fill($data);
        $contact->is_primary = $isPrimary;
        return $this->contacts()->save($contact);
    }