some refactoring

19 files changed, 1568 insertions, 531 deletions

diff --git a/lib/Controller/ShareController.php b/lib/Controller/ShareController.php
index 3ad41c27..a8d5c524 100644
--- a/lib/Controller/ShareController.php
+++ b/lib/Controller/ShareController.php
@@ -36,20 +36,14 @@ use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\DataResponse;
 
 use OCA\Polls\DB\Share;
-use OCA\Polls\Service\CirclesService;
-use OCA\Polls\Service\ContactsService;
 use OCA\Polls\Service\MailService;
 use OCA\Polls\Service\ShareService;
 use OCA\Polls\Service\SystemService;
+use OCA\Polls\Model\Circle;
+use OCA\Polls\Model\ContactGroup;
 
 class ShareController extends Controller {
 
-	/** @var CirclesService */
-	private $circlesService;
-
-	/** @var ContactsService */
-	private $contactsService;
-
 	/** @var MailService */
 	private $mailService;
 
@@ -63,8 +57,6 @@ class ShareController extends Controller {
 	 * ShareController constructor.
 	 * @param string $appName
 	 * @param IRequest $request
-	 * @param CirclesService $circlesService
-	 * @param ContactsService $contactsService
 	 * @param MailService $mailService
 	 * @param ShareService $shareService
 	 * @param SystemService $systemService
@@ -72,15 +64,11 @@ class ShareController extends Controller {
 	public function __construct(
 		string $appName,
 		IRequest $request,
-		CirclesService $circlesService,
-		ContactsService $contactsService,
 		MailService $mailService,
 		ShareService $shareService,
 		SystemService $systemService
 	) {
 		parent::__construct($appName, $request);
-		$this->circlesService = $circlesService;
-		$this->contactsService = $contactsService;
 		$this->mailService = $mailService;
 		$this->shareService = $shareService;
 		$this->systemService = $systemService;
@@ -212,13 +200,12 @@ class ShareController extends Controller {
 		try {
 			$share = $this->shareService->get($token);
 			if ($share->getType() === Share::TYPE_CIRCLE) {
-				foreach ($this->circlesService->getCircleMembers($share->getUserId()) as $user) {
-					\OC::$server->getLogger()->alert(json_encode($user));
-					$shares[] = $this->shareService->add($share->getPollId(), $user->getType(), $user->getUserId());
+				foreach (new Circle($share->getUserId()->getMembers()) as $member) {
+					$shares[] = $this->shareService->add($share->getPollId(), $member->getType(), $member->getId());
 				}
 			} elseif ($share->getType() === Share::TYPE_CONTACTGROUP) {
-				foreach ($this->contactsService->getContactsGroupMembers($share->getUserId()) as $member) {
-					$shares[] = $this->shareService->add($share->getPollId(), Share::TYPE_CONTACT, $member['user'], $member['emailAddress']);
+				foreach (new ContactGroup($share->getUserId()->getMembers()) as $contact) {
+					$shares[] = $this->shareService->add($share->getPollId(), Share::TYPE_CONTACT, $contact->getId(), $contact->getEmailAddress());
 				}
 			}
 
diff --git a/lib/Controller/SystemController.php b/lib/Controller/SystemController.php
index 7a18d1bb..0cd50625 100644
--- a/lib/Controller/SystemController.php
+++ b/lib/Controller/SystemController.php
@@ -26,16 +26,12 @@ namespace OCA\Polls\Controller;
 use OCP\AppFramework\Controller;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\DataResponse;
-use OCA\Polls\Service\ContactsService;
 use OCA\Polls\Service\SystemService;
 
 use OCP\IRequest;
 
 class SystemController extends Controller {
 
-	/** @var ContactsService */
-	private $contactsService;
-
 	/** @var SystemService */
 	private $systemService;
 
@@ -44,17 +40,14 @@ class SystemController extends Controller {
 	 * @param string $appName
 	 * @param IRequest $request
 	 * @param SystemService $systemService
-	 * @param ContactsService $contactsService
 	 */
 
 	public function __construct(
 		string $appName,
 		IRequest $request,
-		ContactsService $contactsService,
 		SystemService $systemService
 	) {
 		parent::__construct($appName, $request);
-		$this->contactsService = $contactsService;
 		$this->systemService = $systemService;
 	}
 
diff --git a/lib/Db/Share.php b/lib/Db/Share.php
index 13e93078..7df6df6e 100644
--- a/lib/Db/Share.php
+++ b/lib/Db/Share.php
@@ -27,7 +27,6 @@ use JsonSerializable;
 
 use OCP\IUser;
 use OCP\AppFramework\Db\Entity;
-use OCA\Polls\Model\User;
 
 /**
  * @method string getId()
@@ -44,14 +43,16 @@ use OCA\Polls\Model\User;
  * @method void setUserEmail(string $value)
  * @method int getInvitationSent()
  * @method void setInvitationSent(integer $value)
+ * @method int getDisplayName()
+ * @method void setDisplayName(string $value)
  */
 class Share extends Entity implements JsonSerializable {
-	public const TYPE_USER = User::TYPE_USER;
-	public const TYPE_EMAIL = User::TYPE_EMAIL;
-	public const TYPE_CIRCLE = User::TYPE_CIRCLE;
-	public const TYPE_GROUP = User::TYPE_GROUP;
-	public const TYPE_CONTACTGROUP = User::TYPE_CONTACTGROUP;
-	public const TYPE_CONTACT = User::TYPE_CONTACT;
+	public const TYPE_USER = 'user';
+	public const TYPE_EMAIL = 'email';
+	public const TYPE_CIRCLE = 'circle';
+	public const TYPE_GROUP = 'group';
+	public const TYPE_CONTACTGROUP = 'contactGroup';
+	public const TYPE_CONTACT = 'contact';
 	public const TYPE_PUBLIC = 'public';
 	public const TYPE_EXTERNAL = 'external';
 
@@ -85,22 +86,11 @@ class Share extends Entity implements JsonSerializable {
 			'userId' => $this->userId,
 			'userEmail' => $this->userEmail,
 			'invitationSent' => intval($this->invitationSent),
-			'displayName' => $this->getDisplayName(),
+			'displayName' => $this->displayName,
 			'externalUser' => $this->externalUser()
 		];
 	}
 
-	private function getDisplayName() {
-		if ($this->type === self::TYPE_EMAIL && !$this->userId) {
-			$user = new User($this->type, $this->userEmail, $this->userEmail, $this->displayName);
-		} elseif ($this->type === self::TYPE_CONTACT && !$this->userId) {
-			$user = new User($this->type, $this->userId, $this->userEmail, $this->displayName);
-		} else {
-			$user = new User($this->type, $this->userId);
-		}
-		return $user->getDisplayName();
-	}
-
 	private function externalUser() {
 		return (!\OC::$server->getUserManager()->get($this->userId) instanceof IUser);
 	}
diff --git a/lib/Exceptions/CirclesNotEnabled.php b/lib/Exceptions/CirclesNotEnabled.php
new file mode 100644
index 00000000..075d53c5
--- /dev/null
+++ b/lib/Exceptions/CirclesNotEnabled.php
@@ -0,0 +1,39 @@
+<?php
+/**
+ * @copyright Copyright (c) 2020 René Gieling <github@dartcafe.de>
+ *
+ * @author René Gieling <github@dartcafe.de>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\Polls\Exceptions;
+
+use OCP\AppFramework\Http;
+
+class CirclesNotEnabled extends \Exception {
+	/**
+	 * TooShortException Constructor
+	 * @param string $e exception message
+	 */
+	public function __construct($e = 'Circles is not enabled for this user') {
+		parent::__construct($e);
+	}
+	public function getStatus() {
+		return Http::STATUS_NOT_FOUND;
+	}
+}
diff --git a/lib/Exceptions/ContactGroupNotFound.php b/lib/Exceptions/ContactGroupNotFound.php
new file mode 100644
index 00000000..8b71d1d4
--- /dev/null
+++ b/lib/Exceptions/ContactGroupNotFound.php
@@ -0,0 +1,39 @@
+<?php
+/**
+ * @copyright Copyright (c) 2020 René Gieling <github@dartcafe.de>
+ *
+ * @author René Gieling <github@dartcafe.de>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\Polls\Exceptions;
+
+use OCP\AppFramework\Http;
+
+class ContactGroupNotFound extends \Exception {
+	/**
+	 * TooShortException Constructor
+	 * @param string $e exception message
+	 */
+	public function __construct($e = 'Contact Group not found') {
+		parent::__construct($e);
+	}
+	public function getStatus() {
+		return Http::STATUS_NOT_FOUND;
+	}
+}
diff --git a/lib/Exceptions/ContactsNotEnabled.php b/lib/Exceptions/ContactsNotEnabled.php
new file mode 100644
index 00000000..0a49e39f
--- /dev/null
+++ b/lib/Exceptions/ContactsNotEnabled.php
@@ -0,0 +1,39 @@
+<?php
+/**
+ * @copyright Copyright (c) 2020 René Gieling <github@dartcafe.de>
+ *
+ * @author René Gieling <github@dartcafe.de>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\Polls\Exceptions;
+
+use OCP\AppFramework\Http;
+
+class ContactsNotEnabled extends \Exception {
+	/**
+	 * TooShortException Constructor
+	 * @param string $e exception message
+	 */
+	public function __construct($e = 'Contacts is not enabled') {
+		parent::__construct($e);
+	}
+	public function getStatus() {
+		return Http::STATUS_NOT_FOUND;
+	}
+}
diff --git a/lib/Exceptions/MultipleContactsFound.php b/lib/Exceptions/MultipleContactsFound.php
new file mode 100644
index 00000000..ab91fb31
--- /dev/null
+++ b/lib/Exceptions/MultipleContactsFound.php
@@ -0,0 +1,39 @@
+<?php
+/**
+ * @copyright Copyright (c) 2020 René Gieling <github@dartcafe.de>
+ *
+ * @author René Gieling <github@dartcafe.de>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\Polls\Exceptions;
+
+use OCP\AppFramework\Http;
+
+class MultipleContactsFound extends \Exception {
+	/**
+	 * TooShortException Constructor
+	 * @param string $e exception message
+	 */
+	public function __construct($e = 'Multiple Contacts found') {
+		parent::__construct($e);
+	}
+	public function getStatus() {
+		return Http::STATUS_CONFLICT;
+	}
+}
diff --git a/lib/Interfaces/IUserObj.php b/lib/Interfaces/IUserObj.php
new file mode 100644
index 00000000..677fcbd1
--- /dev/null
+++ b/lib/Interfaces/IUserObj.php
@@ -0,0 +1,96 @@
+<?php
+/**
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ *
+ * @author Andrew Brown <andrew@casabrown.com>
+ * @author Christoph Wurst <christoph@winzerhof-wurst.at>
+ * @author Jakob Sack <mail@jakobsack.de>
+ * @author Jörn Friedrich Dreyer <jfd@butonic.de>
+ * @author Morris Jobke <hey@morrisjobke.de>
+ *
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program. If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCA\Polls\Interfaces;
+
+/**
+ * IUserObj Interface
+ */
+interface IUserObj {
+
+	/**
+	 * getId
+	 * @return string
+	 */
+	public function getId();
+
+	/**
+	 * getId
+	 * @return string
+	 */
+	public function getUser();
+
+	/**
+	 * getType
+	 * @return string
+	 */
+	public function getType();
+
+	/**
+	 * getLanguage
+	 * @return string
+	 */
+	public function getLanguage();
+
+
+	/**
+	 * getDisplayName
+	 * @return string
+	 */
+	public function getDisplayName();
+
+	/**
+	 * getDesc
+	 * @return string
+	 */
+	public function getDesc();
+
+	/**
+	 * getIcon
+	 * @return string
+	 */
+	public function getIcon();
+
+	/**
+	 * getOrganisation
+	 * @return string
+	 */
+	public function getOrganisation();
+
+	/**
+	 * getEmailAddress
+	 * @return string
+	 */
+	public function getEmailAddress();
+
+	/**
+	 * search
+	 * @param string $query
+	 * @param array $skip - list of items zu skip
+	 * @return self[]
+	 */
+	public static function search($query);
+}
diff --git a/lib/Model/Circle.php b/lib/Model/Circle.php
new file mode 100644
index 00000000..d8b0f981
--- /dev/null
+++ b/lib/Model/Circle.php
@@ -0,0 +1,234 @@
+<?php
+/**
+ * @copyright Copyright (c) 2017 Vinzenz Rosenkranz <vinzenz.rosenkranz@gmail.com>
+ *
+ * @author René Gieling <github@dartcafe.de>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+
+namespace OCA\Polls\Model;
+
+use OCP\IL10N;
+use OCA\Circles\Api\v1\Circles;
+
+use OCA\Polls\Exceptions\CirclesNotEnabled;
+use OCA\Polls\Interfaces\IUserObj;
+
+class Circle implements \JsonSerializable, IUserObj {
+	public const TYPE = 'circle';
+
+	/** @var IL10N */
+	private $l10n;
+
+	/** @var string */
+	private $id;
+
+	private $circle;
+
+	/**
+	 * Group constructor.
+	 * @param $id
+	 * @param $displayName
+	 */
+	public function __construct(
+		$id
+	) {
+		$this->id = $id;
+		$this->load();
+	}
+
+	/**
+	 * getId
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getId() {
+		return $this->id;
+	}
+
+	/**
+	 * getUser
+	 * Necessary for the avatar component
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getUser() {
+		return $this->id;
+	}
+
+	/**
+	 * getType
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getType() {
+		return self::TYPE;
+	}
+
+	/**
+	 * getlanguage
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getLanguage() {
+		return '';
+	}
+
+	/**
+	 * getDisplayName
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getDisplayName() {
+		return Circles::detailsCircle($this->id)->getName();
+	}
+
+	/**
+	 * getOrganisation
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getOrganisation() {
+		return '';
+	}
+
+	/**
+	 * getEmailAddress
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getEmailAddress() {
+		return '';
+	}
+
+	/**
+	 * getDesc
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getDesc() {
+		return Circles::detailsCircle($this->id)->gettypeLongString();
+	}
+
+	/**
+	 * getIcon
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getIcon() {
+		return 'icon-circles';
+	}
+
+	/**
+	 * load
+	 * @NoAdminRequired
+	 * @return Array
+	 * @throws CirclesNotEnabled
+	 */
+	private function load() {
+		if (\OC::$server->getAppManager()->isEnabledForUser('circles')) {
+			$this->circle = Circles::detailsCircle($this->id);
+		} else {
+			throw new CirclesNotEnabled();
+		}
+	}
+
+	/**
+	 * isEnabled
+	 * @NoAdminRequired
+	 * @return Boolean
+	 */
+	public static function isEnabled() {
+		return \OC::$server->getAppManager()->isEnabledForUser('circles');
+	}
+
+	/**
+	 * listRaw
+	 * @NoAdminRequired
+	 * @param string $query
+	 * @return Array
+	 */
+	public static function listRaw($query = '') {
+		$circles = [];
+		if (\OC::$server->getAppManager()->isEnabledForUser('circles')) {
+			$circles = Circles::listCircles(\OCA\Circles\Model\Circle::CIRCLES_ALL, $query);
+		}
+
+		return $circles;
+	}
+
+	/**
+	 * search
+	 * @NoAdminRequired
+	 * @param string $query
+	 * @param array $skip - group names to skip in return array
+	 * @return Circle[]
+	 */
+	public static function search($query = '', $skip = []) {
+		$circles = [];
+		foreach (self::listRaw($query) as $circle) {
+			if (!in_array($circle->getUniqueId(), $skip)) {
+				$circles[] = new Self($circle->getUniqueId());
+			}
+		}
+
+		return $circles;
+	}
+
+	/**
+	 * Get a list of circle members
+	 * @NoAdminRequired
+	 * @param string $query
+	 * @return User[]
+	 */
+	public function getMembers() {
+		$members = [];
+		if (\OC::$server->getAppManager()->isEnabledForUser('circles')) {
+			foreach (Circles::detailsCircle($this->id)->getMembers() as $circleMember) {
+				if ($circleMember->getType() === Circles::TYPE_USER) {
+					$members[] = new User($circleMember->getUserId());
+				} elseif ($circleMember->getType() === Circles::TYPE_MAIL) {
+					$members[] = new Email($circleMember->getUserId());
+				} elseif ($circleMember->getType() === Circles::TYPE_CONTACT) {
+					$members[] = new Contact($circleMember->getUserId());
+				} else {
+					continue;
+				}
+			}
+		}
+		return $members;
+	}
+
+	/**
+	 * @return array
+	 */
+	public function jsonSerialize(): array {
+		return	[
+			'id'        	=> $this->id,
+			'user'          => $this->id,
+			'type'       	=> $this->getType(),
+			'displayName'	=> $this->getDisplayName(),
+			'organisation'	=> $this->getOrganisation(),
+			'emailAddress'	=> $this->getEmailAddress(),
+			'desc' 			=> $this->getDesc(),
+			'icon'			=> $this->getIcon(),
+			'isNoUser'		=> true,
+		];
+	}
+}
diff --git a/lib/Model/Contact.php b/lib/Model/Contact.php
new file mode 100644
index 00000000..1609b52b
--- /dev/null
+++ b/lib/Model/Contact.php
@@ -0,0 +1,261 @@
+<?php
+/**
+ * @copyright Copyright (c) 2017 Vinzenz Rosenkranz <vinzenz.rosenkranz@gmail.com>
+ *
+ * @author René Gieling <github@dartcafe.de>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\Polls\Model;
+
+use OCP\IL10N;
+use OCA\Polls\Exceptions\MultipleContactsFound;
+use OCA\Polls\Exceptions\ContactsNotEnabled;
+use OCA\Polls\Interfaces\IUserObj;
+
+class Contact implements \JsonSerializable, IUserObj {
+	public const TYPE = 'contact';
+
+	/** @var IL10N */
+	private $l10n;
+
+	/** @var string */
+	private $id;
+
+	/** @var string */
+	private $type;
+
+	/** @var string */
+	private $displayName = '';
+
+	/** @var string */
+	private $desc = '';
+
+	/** @var array */
+	private $contact;
+
+	/**
+	 * User constructor.
+	 * @param $type
+	 * @param $id
+	 * @param $displayName
+	 */
+	public function __construct(
+		$id,
+		$displayName = ''
+	) {
+		$this->id = $id;
+		$this->displayName = $displayName;
+
+		$this->l10n = \OC::$server->getL10N('polls');
+		$this->load();
+	}
+
+	/**
+	 * Get id
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getId() {
+		return $this->id;
+	}
+
+	/**
+	 * getUser
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getUser() {
+		return $this->id;
+	}
+
+	/**
+	 * Get user type
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getType() {
+		return self::TYPE;
+	}
+
+	/**
+	 * Get language of user, if type = TYPE_USER
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getLanguage() {
+		return '';
+	}
+
+	/**
+	 * Get displayName
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getDisplayName() {
+		return isset($this->contact['FN']) ? $this->contact['FN'] : $this->displayName;
+	}
+
+	/**
+	 * Get additional description, if available
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getDesc() {
+		$desc = $this->getCategories();
+		if (isset($this->contact['ORG'])) {
+			array_unshift($desc, $this->getOrganisation());
+		}
+		if (count($desc) > 0) {
+			return implode(", ", $desc);
+		} else {
+			return \OC::$server->getL10N('polls')->t('Contact');
+		}
+	}
+
+	/**
+	 * Get email address
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getEmailAddress() {
+		return isset($this->contact['EMAIL'][0]) ? $this->contact['EMAIL'][0] : '';
+	}
+
+	/**
+	 * Get organisation, if type = TYPE_CONTACT
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getOrganisation() {
+		return isset($this->contact['ORG']) ? $this->contact['ORG'] : '';
+	}
+
+	/**
+	 * getCategories
+	 * @NoAdminRequired
+	 * @return Array
+	 */
+	public function getCategories() {
+		if (isset($this->contact['CATEGORIES'])) {
+			return explode(',', $this->contact['CATEGORIES']);
+		} else {
+			return [];
+		}
+	}
+
+	/**
+	 * Get icon class
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getIcon() {
+		return 'icon-mail';
+	}
+
+	/**
+	 * Load contact, if type = TYPE_CONTACT
+	 * @NoAdminRequired
+	 * @return String
+	 * @throws MultipleContactsFound
+	 * @throws ContactsNotEnabled
+	 */
+	private function load() {
+		$this->contact = [];
+		$parts = explode(":", $this->id);
+		$this->id = end($parts);
+		if (\OC::$server->getAppManager()->isEnabledForUser('contacts')) {
+			// Search for UID and FN
+			// Before this implementation contacts where stored with their FN property
+			// From now on, the contact's UID is used as identifier
+			// TODO: Remove FN as search range for loading a contact in a polls version later than 1.6
+			$contacts = \OC::$server->getContactsManager()->search($this->id, ['UID', 'FN']);
+
+			if (count($contacts) === 1) {
+				$this->contact = $contacts[0];
+				$this->id = $this->contact['UID'];
+			} elseif (count($contacts) > 1) {
+				throw new MultipleContactsFound('Multiple contacts found for id '. $this->id);
+			}
+		} else {
+			throw new ContactsNotEnabled();
+		}
+	}
+
+	/**
+	 * isEnabled
+	 * @NoAdminRequired
+	 * @return Boolean
+	 */
+	public static function isEnabled() {
+		return \OC::$server->getAppManager()->isEnabledForUser('contacts');
+	}
+
+	/**
+	 * listRaw
+	 * @NoAdminRequired
+	 * @param string $query
+	 * @return Array
+	 */
+	public static function listRaw($query = '', $queryRange = ['FN', 'EMAIL', 'ORG', 'CATEGORIES']) {
+		$contacts = [];
+		if (\OC::$server->getAppManager()->isEnabledForUser('contacts')) {
+			foreach (\OC::$server->getContactsManager()->search($query, $queryRange) as $contact) {
+				if (!array_key_exists('isLocalSystemBook', $contact) && array_key_exists('EMAIL', $contact)) {
+					$contacts[] = $contact;
+				}
+			}
+		}
+		return $contacts;
+	}
+
+	/**
+	 * list
+	 * @NoAdminRequired
+	 * @param string $query
+	 * @param array $queryRange
+	 * @return self[]
+	 */
+	public static function search($query = '', $queryRange = ['FN', 'EMAIL', 'ORG', 'CATEGORIES']) {
+		$contacts = [];
+		foreach (self::listRaw($query, $queryRange) as $contact) {
+			$contacts[] = new Self($contact['UID']);
+		}
+		return $contacts;
+	}
+
+
+	/**
+	 * @return array
+	 */
+	public function jsonSerialize(): array {
+		return	[
+			'id'        	=> $this->getId(),
+			'user'          => $this->id,
+			'type'       	=> $this->getType(),
+			'displayName'	=> $this->getDisplayName(),
+			'organisation'	=> $this->getOrganisation(),
+			'emailAddress'	=> $this->getEmailAddress(),
+			'desc' 			=> $this->getDesc(),
+			'icon'			=> $this->getIcon(),
+			'categories'	=> $this->getCategories(),
+			'isNoUser'		=> true,
+			'isGuest'		=> true,
+		];
+	}
+}
diff --git a/lib/Model/ContactGroup.php b/lib/Model/ContactGroup.php
new file mode 100644
index 00000000..24a81aca
--- /dev/null
+++ b/lib/Model/ContactGroup.php
@@ -0,0 +1,225 @@
+<?php
+/**
+ * @copyright Copyright (c) 2017 Vinzenz Rosenkranz <vinzenz.rosenkranz@gmail.com>
+ *
+ * @author René Gieling <github@dartcafe.de>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+
+namespace OCA\Polls\Model;
+
+use OCP\IL10N;
+use OCA\Polls\Interfaces\IUserObj;
+
+class ContactGroup implements \JsonSerializable, IUserObj {
+	public const TYPE = 'contactGroup';
+
+	/** @var IL10N */
+	private $l10n;
+
+	/** @var string */
+	private $id;
+
+	/** @var string */
+	private $displayName = '';
+
+	private $group;
+
+	/**
+	 * Group constructor.
+	 * @param $id
+	 * @param $displayName
+	 */
+	public function __construct(
+		$id,
+		$displayName = ''
+	) {
+		$this->id = $id;
+		$this->displayName = $displayName;
+	}
+
+	/**
+	 * getId
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getId() {
+		return $this->id;
+	}
+
+	/**
+	 * getType
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getType() {
+		return self::TYPE;
+	}
+
+	/**
+	 * getUser
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getUser() {
+		return $this->id;
+	}
+
+	/**
+	 * getlanguage
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getLanguage() {
+		return '';
+	}
+
+	/**
+	 * getDisplayName
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getDisplayName() {
+		return $this->id;
+	}
+
+	/**
+	 * getOrganisation
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getOrganisation() {
+		return '';
+	}
+
+	/**
+	 * getEmailAddress
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getEmailAddress() {
+		return '';
+	}
+
+	/**
+	 * getDesc
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getDesc() {
+		return \OC::$server->getL10N('polls')->t('Contact group');
+	}
+
+	/**
+	 * getIcon
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getIcon() {
+		return 'icon-group';
+	}
+
+	/**
+	 * listRaw
+	 * @NoAdminRequired
+	 * @param string $query
+	 * @return Array
+	 */
+	public static function listRaw($query = '') {
+		$contactGroups = [];
+		if (\OC::$server->getContactsManager()->isEnabled()) {
+			// find contact, which are member of the requested Group
+			foreach (\OC::$server->getContactsManager()->search($query, ['CATEGORIES']) as $contact) {
+				// get all groups from the found contact and explode to array
+				$temp = explode(',', $contact['CATEGORIES']);
+				foreach ($temp as $contactGroup) {
+					if (stripos($contactGroup, $query) === 0) {
+						$contactGroups[] = $contactGroup;
+					}
+				}
+			}
+		}
+		return array_unique($contactGroups);
+	}
+
+	/**
+	 * Get a list of contact groups
+	 * @NoAdminRequired
+	 * @param string $query
+	 * @return Array
+	 */
+	public static function search($query = '') {
+		if (\OC::$server->getContactsManager()->isEnabled() && $query) {
+			$contactGroups = [];
+			foreach (self::listRaw($query) as $contactGroup) {
+				$contactGroups[] = new self($contactGroup);
+			}
+		}
+		return $contactGroups;
+	}
+
+	/**
+	 * Get a list of contacts group members
+	 * @NoAdminRequired
+	 * @param string $query
+	 * @return Contact[]
+	 */
+	public function getMembers() {
+		if (\OC::$server->getContactsManager()->isEnabled()) {
+			$contacts = [];
+			foreach (\OC::$server->getContactsManager()->search($this->id, ['CATEGORIES']) as $contact) {
+				if (!array_key_exists('isLocalSystemBook', $contact)
+					&& array_key_exists('EMAIL', $contact)
+					&& in_array($query, explode(',', $contact['CATEGORIES']))
+				) {
+					$emailAdresses = $contact['EMAIL'];
+
+					if (!is_array($emailAdresses)) {
+						$emailAdress = $emailAdresses;
+					} else {
+						// take the first eMail address for now
+						$emailAdress = $emailAdresses[0];
+					}
+					$contacts[] = new Contact($contact['UID']);
+				}
+			}
+			return $contacts;
+		}
+		return [];
+	}
+
+
+	/**
+	 * @return array
+	 */
+	public function jsonSerialize(): array {
+		return	[
+			'id'        	=> $this->id,
+			'user'          => $this->id,
+			'type'       	=> $this->getType(),
+			'displayName'	=> $this->getDisplayName(),
+			'organisation'	=> $this->getOrganisation(),
+			'emailAddress'	=> $this->getEmailAddress(),
+			'desc' 			=> $this->getDesc(),
+			'icon'			=> $this->getIcon(),
+			'isNoUser'		=> true,
+			'isGuest'		=> true,
+		];
+	}
+}
diff --git a/lib/Model/Email.php b/lib/Model/Email.php
new file mode 100644
index 00000000..51e5af03
--- /dev/null
+++ b/lib/Model/Email.php
@@ -0,0 +1,182 @@
+<?php
+/**
+ * @copyright Copyright (c) 2017 Vinzenz Rosenkranz <vinzenz.rosenkranz@gmail.com>
+ *
+ * @author René Gieling <github@dartcafe.de>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+
+namespace OCA\Polls\Model;
+
+use OCP\IL10N;
+use OCA\Polls\Interfaces\IUserObj;
+
+class Email implements \JsonSerializable, IUserObj {
+	public const TYPE = 'email';
+
+	/** @var IL10N */
+	private $l10n;
+
+	/** @var string */
+	private $id;
+
+	/** @var string */
+	private $type;
+
+	/** @var string */
+	private $displayName = '';
+
+	/** @var string */
+	private $desc = '';
+
+	/** @var string */
+	private $emailAddress = '';
+
+	/** @var array */
+	private $contact;
+
+	/**
+	 * User constructor.
+	 * @param $type
+	 * @param $id
+	 * @param $emailAddress
+	 * @param $displayName
+	 */
+	public function __construct(
+		$id,
+		$emailAddress = '',
+		$displayName = ''
+	) {
+		$this->id = $id;
+		$this->emailAddress = $emailAddress;
+		$this->displayName = $displayName;
+
+		$this->l10n = \OC::$server->getL10N('polls');
+	}
+
+	/**
+	 * Get id
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getId() {
+		return $this->id;
+	}
+
+	/**
+	 * getUser
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getUser() {
+		return $this->id;
+	}
+
+	/**
+	 * Get user type
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getType() {
+		return self::TYPE;
+	}
+
+	/**
+	 * Get language of user, if type = TYPE_USER
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getLanguage() {
+		return '';
+	}
+
+	/**
+	 * Get displayName
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getDisplayName() {
+		if ($this->displayName) {
+			return $this->displayName;
+		}
+		return $this->id;
+	}
+
+	/**
+	 * Get additional description, if available
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getDesc() {
+		return \OC::$server->getL10N('polls')->t('External Email');
+	}
+
+	/**
+	 * Get email address
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getEmailAddress() {
+		if ($this->emailAddress) {
+			return $this->emailAddress;
+		}
+		return $this->id;
+	}
+
+	/**
+	 * Get organisation, if type = TYPE_CONTACT
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getOrganisation() {
+		return '';
+	}
+
+	/**
+	 * Get icon class
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getIcon() {
+		return 'icon-mail';
+	}
+
+	// no search right now
+	public static function search($query) {
+		return [];
+	}
+
+	/**
+	 * @return array
+	 */
+	public function jsonSerialize(): array {
+		return	[
+			'id'        	=> $this->id,
+			'user'          => $this->id,
+			'type'       	=> $this->getType(),
+			'displayName'	=> $this->getDisplayName(),
+			'organisation'	=> $this->getOrganisation(),
+			'emailAddress'	=> $this->getEmailAddress(),
+			'desc' 			=> $this->getDesc(),
+			'icon'			=> $this->getIcon(),
+			'isNoUser'		=> true,
+			'isGuest'		=> true,
+		];
+	}
+}
diff --git a/lib/Model/Group.php b/lib/Model/Group.php
new file mode 100644
index 00000000..12d0f34b
--- /dev/null
+++ b/lib/Model/Group.php
@@ -0,0 +1,204 @@
+<?php
+/**
+ * @copyright Copyright (c) 2017 Vinzenz Rosenkranz <vinzenz.rosenkranz@gmail.com>
+ *
+ * @author René Gieling <github@dartcafe.de>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+
+namespace OCA\Polls\Model;
+
+use OCP\IL10N;
+use OCA\Polls\Interfaces\IUserObj;
+
+class Group implements \JsonSerializable, IUserObj {
+	public const TYPE = 'group';
+
+	/** @var IL10N */
+	private $l10n;
+
+	/** @var string */
+	private $id;
+
+	/** @var IGroup */
+	private $group;
+
+	/**
+	 * Group constructor.
+	 * @param $id
+	 * @param $displayName
+	 */
+	public function __construct(
+		$id
+	) {
+		$this->id = $id;
+		$this->load();
+	}
+
+	/**
+	 * getId
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getId() {
+		return $this->id;
+	}
+
+	/**
+	 * getUser
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getUser() {
+		return $this->id;
+	}
+
+	/**
+	 * getType
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getType() {
+		return self::TYPE;
+	}
+
+	/**
+	 * getlanguage
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getLanguage() {
+		return '';
+	}
+
+	/**
+	 * getDisplayName
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getDisplayName() {
+		try {
+			// since NC19
+			return $this->group->getDisplayName();
+		} catch (\Exception $e) {
+			// until NC18
+			return $this->id;
+		}
+	}
+
+	/**
+	 * getOrganisation
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getOrganisation() {
+		return '';
+	}
+
+	/**
+	 * getEmailAddress
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getEmailAddress() {
+		return '';
+	}
+
+	/**
+	 * getDesc
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getDesc() {
+		return \OC::$server->getL10N('polls')->t('Group');
+	}
+
+	/**
+	 * getIcon
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getIcon() {
+		return 'icon-group';
+	}
+
+	private function load() {
+		$this->group = \OC::$server->getGroupManager()->get($this->id);
+	}
+
+	/**
+	 * listRaw
+	 * @NoAdminRequired
+	 * @param string $query
+	 * @return Array
+	 */
+	public static function listRaw($query = '') {
+		return \OC::$server->getGroupManager()->search($query);
+	}
+
+	/**
+	 * search
+	 * @NoAdminRequired
+	 * @param string $query
+	 * @param array $skip - group names to skip in return array
+	 * @return Group[]
+	 */
+	public static function search($query = '', $skip = []) {
+		$groups = [];
+		foreach (self::listRaw($query) as $group) {
+			if (!in_array($group->getGID(), $skip)) {
+				$groups[] = new Self($group->getGID());
+			}
+		}
+		return $groups;
+	}
+
+	/**
+	 * Get a list of circle members
+	 * @NoAdminRequired
+	 * @param string $query
+	 * @return User[]
+	 */
+	public function getMembers() {
+		$members = [];
+		foreach (array_keys(\OC::$server->getGroupManager()->displayNamesInGroup($this->id)) as $member) {
+			$members[] = new user($member);
+		}
+		return $members;
+	}
+
+
+
+	/**
+	 * @return array
+	 */
+	public function jsonSerialize(): array {
+		return	[
+			'id'        	=> $this->id,
+			'user'          => $this->id,
+			'type'       	=> $this->getType(),
+			'displayName'	=> $this->getDisplayName(),
+			'organisation'	=> $this->getOrganisation(),
+			'emailAddress'	=> $this->getEmailAddress(),
+			'desc' 			=> $this->getDesc(),
+			'icon'			=> $this->getIcon(),
+			'isNoUser'		=> true,
+		];
+	}
+}
diff --git a/lib/Model/User.php b/lib/Model/User.php
index 98513a0b..154cea9e 100644
--- a/lib/Model/User.php
+++ b/lib/Model/User.php
@@ -25,8 +25,10 @@
 namespace OCA\Polls\Model;
 
 use OCP\IL10N;
+use OCA\Polls\Interfaces\IUserObj;
 
-class User implements \JsonSerializable {
+class User implements \JsonSerializable, IUserObj {
+	public const TYPE = 'user';
 	public const TYPE_USER = 'user';
 	public const TYPE_GROUP = 'group';
 	public const TYPE_CONTACTGROUP = 'contactGroup';
@@ -34,185 +36,159 @@ class User implements \JsonSerializable {
 	public const TYPE_EMAIL = 'email';
 	public const TYPE_CIRCLE = 'circle';
 	public const TYPE_EXTERNAL = 'external';
+	public const TYPE_INVALID = 'invalid';
 
 	/** @var IL10N */
 	private $l10n;
 
 	/** @var string */
-	private $userId;
+	private $id;
 
-	/** @var string */
-	private $type;
-
-	/** @var string */
-	private $displayName = '';
-
-	/** @var string */
-	private $desc = '';
-
-	/** @var string */
-	private $emailAddress = '';
-
-	private $contact;
-	private $circlesEnabled = false;
-	private $contactsEnabled = false;
+	/** @var IUser */
+	private $user;
 
 	/**
 	 * User constructor.
 	 * @param $type
-	 * @param $userId
+	 * @param $id
 	 * @param $emailAddress
 	 * @param $displayName
 	 */
 	public function __construct(
-		$type,
-		$userId,
-		$emailAddress = '',
-		$displayName = ''
+		$id
 	) {
-		$this->l10n = \OC::$server->getL10N('polls');
-		$this->type = $type;
-		$this->userId = $userId;
-		$this->emailAddress = $emailAddress;
-		$this->displayName = $displayName;
-		$this->loadContact();
-		$this->circlesEnabled = \OC::$server->getAppManager()->isEnabledForUser('circles') &&
-			(version_compare(\OC::$server->getAppManager()->getAppVersion('circles'), '0.17.1') >= 0);
-		$this->contactsEnabled = \OC::$server->getContactsManager()->isEnabled();
+		$this->id = $id;
+		$this->load();
 	}
 
-
-	public function setDisplayName($displayName) {
-		$this->displayName = $displayName;
+	/**
+	 * Get userId
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getUserId() {
+		return $this->id;
 	}
 
-	public function setEmailAddress($emailAddress) {
-		$this->emailAddress = $emailAddress;
+	/**
+	 * Get userId
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getId() {
+		return $this->id;
 	}
 
-	public function getUserId() {
-		return $this->userId;
+	/**
+	 * getUser
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getUser() {
+		return $this->id;
 	}
 
+	/**
+	 * Get user type
+	 * @NoAdminRequired
+	 * @return String
+	 */
 	public function getType() {
-		return $this->type;
+		return self::TYPE;
 	}
 
+	/**
+	 * Get language of user, if type = TYPE_USER
+	 * @NoAdminRequired
+	 * @return String
+	 */
 	public function getLanguage() {
-		if ($this->type === self::TYPE_USER) {
-			// Variant: $this->config->getUserValue($this->userId, 'core', 'lang')
-			return \OC::$server->getConfig()->getUserValue($this->userId, 'core', 'lang');
-		} else {
-			return '';
-		}
+		return \OC::$server->getConfig()->getUserValue($this->id, 'core', 'lang');
 	}
 
+	/**
+	 * Get displayName
+	 * @NoAdminRequired
+	 * @return String
+	 */
 	public function getDisplayName() {
-		if ($this->type === self::TYPE_USER) {
-			return \OC::$server->getUserManager()->get($this->userId)->getDisplayName();
-		} elseif ($this->type === self::TYPE_GROUP) {
-			try {
-				// since NC19
-				return \OC::$server->getGroupManager()->get($this->userId)->getDisplayName();
-			} catch (\Exception $e) {
-				// until NC18
-				return $this->userId;
-			}
-		} elseif ($this->type === self::TYPE_CONTACTGROUP && $this->contactsEnabled) {
-			return $this->userId;
-		} elseif ($this->type === self::TYPE_CIRCLE && $this->circlesEnabled) {
-			return \OCA\Circles\Api\v1\Circles::detailsCircle($this->userId)->getName();
-		} elseif ($this->type === self::TYPE_CONTACT && $this->contactsEnabled) {
-			return isset($this->contact['FN']) ? $this->contact['FN'] : '';
-		} elseif ($this->displayName) {
-			return $this->displayName;
-		} else {
-			return $this->userId;
-		}
+		return \OC::$server->getUserManager()->get($this->id)->getDisplayName();
 	}
 
+	/**
+	 * Get organisation, if type = TYPE_CONTACT
+	 * @NoAdminRequired
+	 * @return String
+	 */
 	public function getOrganisation() {
-		if ($this->type === self::TYPE_CONTACT && $this->contactsEnabled) {
-			return isset($this->contact['ORG']) ? $this->contact['ORG'] : '';
-		} else {
-			return '';
-		}
+		return '';
 	}
 
+	/**
+	 * Get email address
+	 * @NoAdminRequired
+	 * @return String
+	 */
 	public function getEmailAddress() {
-		if ($this->type === self::TYPE_USER) {
-			// Variant: \OC::$server->getConfig()->getUserValue($this->userId, 'settings', 'email'),
-			return \OC::$server->getUserManager()->get($this->userId)->getEMailAddress();
-		} elseif ($this->type === self::TYPE_CONTACT && $this->contactsEnabled) {
-			return isset($this->contact['EMAIL'][0]) ? $this->contact['EMAIL'][0] : '';
-		} elseif ($this->type === self::TYPE_EMAIL) {
-			return $this->userId;
-		} else {
-			return $this->emailAddress;
-		}
+		return $this->user->getEMailAddress();
 	}
 
+	/**
+	 * Get additional description, if available
+	 * @NoAdminRequired
+	 * @return String
+	 */
 	public function getDesc() {
-		if ($this->type === self::TYPE_USER) {
-			return $this->l10n->t('User');
-		} elseif ($this->type === self::TYPE_GROUP) {
-			return $this->l10n->t('Group');
-		} elseif ($this->type === self::TYPE_CONTACT && $this->contactsEnabled) {
-			$this->desc = $this->l10n->t('Contact');
-			if (isset($this->contact['ORG'])) {
-				// Add organisation to description
-				$this->desc = $this->contact['ORG'];
-			}
-
-			if (isset($this->contact['CATEGORIES'])) {
-				// Add contact groups to description
-				// Add aspace before each comma
-				if ($this->desc === $this->l10n->t('Contact')) {
-					$this->desc = $this->contact['CATEGORIES'];
-				} else {
-					$this->desc = $this->desc . ', ' . $this->contact['CATEGORIES'];
-				}
-			}
-			return $this->desc;
-		} elseif ($this->type === self::TYPE_CONTACTGROUP && $this->contactsEnabled) {
-			return $this->l10n->t('Contact group');
-		} elseif ($this->type === self::TYPE_CIRCLE && $this->circlesEnabled) {
-			return \OCA\Circles\Api\v1\Circles::detailsCircle($this->userId)->gettypeLongString();
-		} elseif ($this->type === self::TYPE_EMAIL) {
-			return $this->l10n->t('External email');
-		} else {
-			return '';
-		}
+		return \OC::$server->getL10N('polls')->t('User');
 	}
 
+	/**
+	 * Get icon class
+	 * @NoAdminRequired
+	 * @return String
+	 */
 	public function getIcon() {
-		if ($this->type === self::TYPE_USER) {
-			return 'icon-user';
-		} elseif ($this->type === self::TYPE_GROUP) {
-			return 'icon-group';
-		} elseif ($this->type === self::TYPE_CONTACT && $this->contactsEnabled) {
-			return 'icon-mail';
-		} elseif ($this->type === self::TYPE_EMAIL) {
-			return 'icon-mail';
-		} elseif ($this->type === self::TYPE_CONTACTGROUP && $this->contactsEnabled) {
-			return 'icon-group';
-		} elseif ($this->type === self::TYPE_CIRCLE && $this->circlesEnabled) {
-			return 'icon-circle';
-		} else {
-			return '';
-		}
+		return 'icon-user';
 	}
 
-	private function loadContact() {
-		if ($this->type === self::TYPE_CONTACT && \OC::$server->getContactsManager()->isEnabled()) {
-			// TODO: remove FN in a later version than 1.5
-			$contacts = \OC::$server->getContactsManager()->search($this->userId, ['UID', 'FN']);
-			if (!$contacts) {
-				$this->contact = [];
-			} else {
-				$this->contact = $contacts[0];
+	/**
+	 * Get icon class
+	 * @NoAdminRequired
+	 * @return String
+	 */
+	public function getUserIsDisabled() {
+		return !\OC::$server->getUserManager()->get($user)->isEnabled();
+	}
+
+	/**
+	 * listRaw
+	 * @NoAdminRequired
+	 * @param string $query
+	 * @return Array
+	 */
+	public static function listRaw($query = '') {
+		return \OC::$server->getUserManager()->search($query);
+	}
+
+	/**
+	 * search
+	 * @NoAdminRequired
+	 * @param string $query
+	 * @param array $skip - group names to skip in return array
+	 * @return Group[]
+	 */
+	public static function search($query = '', $skip = []) {
+		$users = [];
+		foreach (self::listRaw($query) as $user) {
+			if (!in_array($user->getUID(), $skip)) {
+				$users[] = new Self($user->getUID());
 			}
 		}
+		return $users;
+	}
+
+	private function load() {
+		$this->user = \OC::$server->getUserManager()->get($this->id);
 	}
 
 	/**
@@ -220,15 +196,15 @@ class User implements \JsonSerializable {
 	 */
 	public function jsonSerialize(): array {
 		return	[
-			'userId'        => $this->userId,
-			'type'       	=> $this->type,
-			'user'          => $this->userId,
+			'user'          => $this->id,
+			'id'        	=> $this->id,
+			'userId'        => $this->id,
+			'type'       	=> $this->getType(),
 			'displayName'	=> $this->getDisplayName(),
-			'Organisation'	=> $this->getOrganisation(),
+			'organisation'	=> $this->getOrganisation(),
 			'emailAddress'	=> $this->getEmailAddress(),
 			'desc' 			=> $this->getDesc(),
 			'icon'			=> $this->getIcon(),
-			'contact'		=> $this->contact,
 		];
 	}
 }
diff --git a/lib/Service/CirclesService.php b/lib/Service/CirclesService.php
deleted file mode 100644
index 372c970b..00000000
--- a/lib/Service/CirclesService.php
+++ /dev/null
@@ -1,111 +0,0 @@
-<?php
-/**
- * @copyright Copyright (c) 2017 Vinzenz Rosenkranz <vinzenz.rosenkranz@gmail.com>
- *
- * @author René Gieling <github@dartcafe.de>
- *
- * @license GNU AGPL version 3 or any later version
- *
- *  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 <http://www.gnu.org/licenses/>.
- *
- */
-
-namespace OCA\Polls\Service;
-
-use OCA\Polls\Model\User;
-use \OCA\Circles\Api\v1\Circles;
-
-class CirclesService {
-	public function __construct(
-	) {
-		$this->enabled = \OC::$server->getAppManager()->isEnabledForUser('circles');
-	}
-
-	/**
-	 * Get a list of avaiable circles
-	 * @NoAdminRequired
-	 * @param string $query
-	 * @param array $skip - circle names to skip in return array
-	 * @return Array
-	 */
-	public function getCircles($query = '', $skip = []) {
-		if (!$this->enabled || $query === '') {
-			return [];
-		}
-
-		$circles = [];
-
-
-		foreach (\OCA\Circles\Api\v1\Circles::listCircles(\OCA\Circles\Model\Circle::CIRCLES_ALL, $query) as $circle) {
-			if (!in_array($circle->getId(), $skip)) {
-				$displayName = $circle->getName();
-
-				$circles[] = new User(User::TYPE_CIRCLE, $circle->getUniqueId());
-			}
-		}
-		return $circles;
-	}
-
-
-	/**
-	 * Get circle details
-	 * @NoAdminRequired
-	 * @param string $circleId
-	 * @return String
-	 */
-	public function getDisplayName($circleId = 0) {
-		if (!$this->enabled) {
-			return 'NixCircle';
-		}
-		return \OCA\Circles\Api\v1\Circles::detailsCircle($circleId)->getName();
-	}
-
-	/**
-	 * Get circle details
-	 * @NoAdminRequired
-	 * @param string $circleId
-	 * @return Array
-	 */
-	public function getDetails($circleId = 0) {
-		if (!$this->enabled) {
-			return 'Unknown circle';
-		}
-		return \OCA\Circles\Api\v1\Circles::detailsCircle($circleId);
-	}
-
-	/**
-	 * Get a list of contacts
-	 * @NoAdminRequired
-	 * @param string $query
-	 * @return User[]
-	 */
-	public function getCircleMembers($circleId) {
-		if (!$this->enabled) {
-			return [];
-		}
-		$members = [];
-		foreach (\OCA\Circles\Api\v1\Circles::detailsCircle($circleId)->getMembers() as $circleMember) {
-			if ($circleMember->getType() === Circles::TYPE_USER) {
-				$members[] = new User(User::TYPE_USER, $circleMember->getUserId());
-			} elseif ($circleMember->getType() === Circles::TYPE_GROUP) {
-				$members[] = new User(User::TYPE_GROUP, $circleMember->getUserId());
-			} elseif ($circleMember->getType() === Circles::TYPE_MAIL) {
-				$members[] = new User(User::TYPE_EMAIL, $circleMember->getUserId());
-			} elseif ($circleMember->getType() === Circles::TYPE_CONTACT) {
-				$members[] = new User(User::TYPE_CONTACT, $circleMember->getUserId());
-			}
-		}
-		return $members;
-	}
-}
diff --git a/lib/Service/ContactsService.php b/lib/Service/ContactsService.php
deleted file mode 100644
index a344aeac..00000000
--- a/lib/Service/ContactsService.php
+++ /dev/null
@@ -1,112 +0,0 @@
-<?php
-/**
- * @copyright Copyright (c) 2017 Vinzenz Rosenkranz <vinzenz.rosenkranz@gmail.com>
- *
- * @author René Gieling <github@dartcafe.de>
- *
- * @license GNU AGPL version 3 or any later version
- *
- *  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 <http://www.gnu.org/licenses/>.
- *
- */
-
-namespace OCA\Polls\Service;
-
-use OCA\Polls\Model\User;
-
-class ContactsService {
-	public function __construct(
-	) {
-		$this->enabled = \OC::$server->getContactsManager()->isEnabled();
-	}
-
-	/**
-	 * Get a list of contacts
-	 * @NoAdminRequired
-	 * @param string $query
-	 * @return User[]
-	 */
-	public function getContacts($query = '', $queryRange = ['FN', 'EMAIL', 'ORG', 'CATEGORIES']) {
-		if (!$this->enabled || $query === '') {
-			return [];
-		}
-
-		$contacts = [];
-
-		foreach (\OC::$server->getContactsManager()->search($query, $queryRange) as $contact) {
-			if (!array_key_exists('isLocalSystemBook', $contact) && array_key_exists('EMAIL', $contact)) {
-				$contacts[] = new User(User::TYPE_CONTACT, $contact['UID']);
-			}
-		}
-		return $contacts;
-	}
-
-	/**
-	 * Get a list of contacts
-	 * @NoAdminRequired
-	 * @param string $query
-	 * @return User[]
-	 */
-	public function getContactsGroupMembers($query = '') {
-		if (!$this->enabled || $query === '') {
-			return [];
-		}
-
-		$contacts = [];
-		foreach (\OC::$server->getContactsManager()->search($query, ['CATEGORIES']) as $contact) {
-			if (!array_key_exists('isLocalSystemBook', $contact)
-				&& array_key_exists('EMAIL', $contact)
-				&& in_array($query, explode(',', $contact['CATEGORIES']))
-			) {
-				$emailAdresses = $contact['EMAIL'];
-
-				if (!is_array($emailAdresses)) {
-					$emailAdresses = [$emailAdresses];
-				} else {
-					// take the first eMail address for now
-					$emailAdresses = [$emailAdresses[0]];
-				}
-
-				foreach ($emailAdresses as $emailAddress) {
-					$contacts[] = new User(User::TYPE_CONTACT, $contact['UID']);
-				}
-			}
-		}
-		return $contacts;
-	}
-
-	/**
-	 * Get a list of contact groups
-	 * @NoAdminRequired
-	 * @param string $query
-	 * @return Array
-	 */
-	public function getContactsGroups($query = '') {
-		if (!$this->enabled || $query === '') {
-			return [];
-		}
-
-		$contactGroups = [];
-		$foundContacts = [];
-		foreach (\OC::$server->getContactsManager()->search($query, ['CATEGORIES']) as $contact) {
-			foreach (explode(',', $contact['CATEGORIES']) as $contactGroup) {
-				if (strpos($contactGroup, $query) === 0 && !in_array($contactGroup, $foundContacts)) {
-					$foundContacts[] = $contactGroup;
-					$contactGroups[] = new User(User::TYPE_CONTACTGROUP, $contactGroup);
-				};
-			}
-		}
-		return $contactGroups;
-	}
-}
diff --git a/lib/Service/MailService.php b/lib/Service/MailService.php
index bc36e3c8..9d6c91c9 100644
--- a/lib/Service/MailService.php
+++ b/lib/Service/MailService.php
@@ -40,6 +40,9 @@ use OCA\Polls\Db\PollMapper;
 use OCA\Polls\Db\ShareMapper;
 use OCA\Polls\Db\Share;
 use OCA\Polls\Db\LogMapper;
+use OCA\Polls\Model\User;
+use OCA\Polls\Model\Contact;
+use OCA\Polls\Model\Group;
 
 class MailService {
 
@@ -76,9 +79,6 @@ class MailService {
 	/** @var LogMapper */
 	private $logMapper;
 
-	/** @var ContactsService */
-	private $contactsService;
-
 	/**
 	 * MailService constructor.
 	 * @param IUserManager $userManager
@@ -92,7 +92,6 @@ class MailService {
 	 * @param ShareMapper $shareMapper
 	 * @param PollMapper $pollMapper
 	 * @param LogMapper $logMapper
-	 * @param ContactsService $contactsService
 	 */
 
 	public function __construct(
@@ -106,8 +105,7 @@ class MailService {
 		ShareMapper $shareMapper,
 		SubscriptionMapper $subscriptionMapper,
 		PollMapper $pollMapper,
-		LogMapper $logMapper,
-		ContactsService $contactsService
+		LogMapper $logMapper
 	) {
 		$this->config = $config;
 		$this->userManager = $userManager;
@@ -120,7 +118,6 @@ class MailService {
 		$this->subscriptionMapper = $subscriptionMapper;
 		$this->pollMapper = $pollMapper;
 		$this->logMapper = $logMapper;
-		$this->contactsService = $contactsService;
 	}
 
 
@@ -205,7 +202,7 @@ class MailService {
 		);
 
 		if ($share->getType() === Share::TYPE_USER) {
-			$user = new User(User::TYPE_USER, $share->getUserId());
+			$user = new User($share->getUserId());
 			$recipients[] = [
 				'userId' => $user->getUserId(),
 				'eMailAddress' => $user->getEmailAddress(),
@@ -214,7 +211,8 @@ class MailService {
 				'link' => $internalLink,
 			];
 		} elseif ($share->getType() === Share::TYPE_EMAIL) {
-			$user = new User(User::TYPE_EMAIL, $share->getUserId());
+			$user = new Email($share->getUserId());
+
 			$recipients[] = [
 				'userId' => $user->getUserId(),
 				'eMailAddress' => $user->getEmailAddress(),
@@ -223,20 +221,15 @@ class MailService {
 				'link' => $tokenLink,
 			];
 		} elseif ($share->getType() === Share::TYPE_CONTACT) {
-			$contacts = $this->contactsService->getContacts($share->getUserId(), ['FN', 'UID']);
-			if (count($contacts)) {
-				$user = $contacts[0];
+			$user = new Contact($share->getUserId());
 
-				$recipients[] = [
-					'userId' => $user->getUserId(),
-					'eMailAddress' => $user->getEmailAddress(),
-					'displayName' => $user->getDisplayname(),
-					'language' => $defaultLang,
-					'link' => $tokenLink,
-				];
-			} else {
-				return;
-			}
+			$recipients[] = [
+				'userId' => $user->getUserId(),
+				'eMailAddress' => $user->getEmailAddress(),
+				'displayName' => $user->getDisplayname(),
+				'language' => $defaultLang,
+				'link' => $tokenLink,
+			];
 		} elseif ($share->getType() === Share::TYPE_EXTERNAL) {
 			$recipients[] = [
 				'userId' => $share->getUserId(),
@@ -246,16 +239,13 @@ class MailService {
 				'link' => $tokenLink,
 			];
 		} elseif ($share->getType() === Share::TYPE_GROUP) {
-			$groupMembers = array_keys($this->groupManager->displayNamesInGroup($share->getUserId()));
-
-			foreach ($groupMembers as $user) {
-				if ($skipUser === $user || !$this->userManager->get($user)->isEnabled()) {
+			foreach ((new Group($share->getUserId()))->getMembers() as $user) {
+				if ($skipUser === $user->getId() || !$user->isUserDisabled()) {
 					continue;
 				}
-				$user = new User(User::TYPE_USER, $user->getUserId());
 
 				$recipients[] = [
-					'userId' => $user->getUserId(),
+					'userId' => $user->getId(),
 					'eMailAddress' => $user->getEmailAddress(),
 					'displayName' => $user->getDisplayName(),
 					'language' => $user->getLanguage(),
diff --git a/lib/Service/ShareService.php b/lib/Service/ShareService.php
index 3404f882..f94fd136 100644
--- a/lib/Service/ShareService.php
+++ b/lib/Service/ShareService.php
@@ -31,6 +31,11 @@ use OCP\Security\ISecureRandom;
 use OCA\Polls\Db\ShareMapper;
 use OCA\Polls\Db\Share;
 use OCA\Polls\Model\Acl;
+use OCA\Polls\Model\Circle;
+use OCA\Polls\Model\Contact;
+use OCA\Polls\Model\ContactGroup;
+use OCA\Polls\Model\Email;
+use OCA\Polls\Model\Group;
 use OCA\Polls\Model\User;
 
 class ShareService {
@@ -114,14 +119,27 @@ class ShareService {
 		if (!$this->acl->set($pollId)->getAllowEdit()) {
 			throw new NotAuthorizedException;
 		}
-		$user = new User($type, $userId, $emailAddress);
+		if ($type === Group::TYPE) {
+			$share = new Group($userId);
+		} elseif ($type === Circle::TYPE) {
+			$share = new Circle($userId);
+		} elseif ($type === Contact::TYPE) {
+			$share = new Contact($userId);
+		} elseif ($type === ContactGroup::TYPE) {
+			$share = new ContactGroup($userId);
+		} elseif ($type === User::TYPE) {
+			$share = new User($userId);
+		} elseif ($type === Email::TYPE) {
+			$share = new Email($userId);
+		}
+		\OC::$server->getLogger()->alert(json_encode($share));
 
 		$this->share = new Share();
 		$this->share->setPollId($pollId);
-		$this->share->setType($user->getType());
-		$this->share->setUserId($user->getUserId());
-		$this->share->setDisplayName($user->getDisplayName());
-		$this->share->setUserEmail($user->getEmailAddress());
+		$this->share->setType($share->getType());
+		$this->share->setUserId($share->getId());
+		$this->share->setDisplayName($share->getDisplayName());
+		$this->share->setUserEmail($share->getEmailAddress());
 		$this->share->setInvitationSent(0);
 		$this->share->setToken(\OC::$server->getSecureRandom()->generate(
 			16,
diff --git a/lib/Service/SystemService.php b/lib/Service/SystemService.php
index ab02cead..9e6b479c 100644
--- a/lib/Service/SystemService.php
+++ b/lib/Service/SystemService.php
@@ -28,27 +28,18 @@ use OCA\Polls\Exceptions\TooShortException;
 use OCA\Polls\Exceptions\InvalidUsernameException;
 use OCA\Polls\Exceptions\InvalidEmailAddress;
 
-use OCP\IGroupManager;
-use OCP\IUserManager;
 use OCA\Polls\Db\Share;
 use OCA\Polls\Db\ShareMapper;
 use OCA\Polls\Db\VoteMapper;
+use OCA\Polls\Model\Circle;
+use OCA\Polls\Model\Contact;
+use OCA\Polls\Model\ContactGroup;
+use OCA\Polls\Model\Email;
+use OCA\Polls\Model\Group;
 use OCA\Polls\Model\User;
 
 class SystemService {
 
-	/** @var IGroupManager */
-	private $groupManager;
-
-	/** @var IUserManager */
-	private $userManager;
-
-	/** @var CirclesService */
-	private $circlesService;
-
-	/** @var ContactsService */
-	private $contactsService;
-
 	/** @var VoteMapper */
 	private $voteMapper;
 
@@ -57,26 +48,14 @@ class SystemService {
 
 	/**
 	 * SystemService constructor.
-	 * @param IGroupManager $groupManager
-	 * @param IUserManager $userManager
-	 * @param CirclesService $circlesService,
-	 * @param ContactsService $contactsService,
 	 * @param VoteMapper $voteMapper
 	 * @param ShareMapper $shareMapper
 	 */
 	public function __construct(
-		IGroupManager $groupManager,
-		IUserManager $userManager,
 		VoteMapper $voteMapper,
-		CirclesService $circlesService,
-		ContactsService $contactsService,
 		ShareMapper $shareMapper
 	) {
-		$this->groupManager = $groupManager;
-		$this->userManager = $userManager;
 		$this->voteMapper = $voteMapper;
-		$this->circlesService = $circlesService;
-		$this->contactsService = $contactsService;
 		$this->shareMapper = $shareMapper;
 	}
 
@@ -90,43 +69,39 @@ class SystemService {
 		return (!preg_match('/^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/', $emailAddress)) ? false : true;
 	}
 
-
 	/**
-	 * Get a list of users
+	 * Validate email address and throw an exception
+	 * return true, if email address is a valid
 	 * @NoAdminRequired
-	 * @param string $query
-	 * @param array $skip - usernames to skip in return array
-	 * @return User[]
+	 * @return Boolean
+	 * @throws InvalidEmailAddress
 	 */
-	public function getSiteUsers($query = '', $skip = []) {
-		$users = [];
-		foreach ($this->userManager->searchDisplayName($query) as $user) {
-			if (!in_array($user->getUID(), $skip) && $user->isEnabled()) {
-				$users[] = new User(User::TYPE_USER, $user->getUID());
-			}
+	public static function validateEmailAddress($emailAddress) {
+		if (!self::isValidEmail($emailAddress)) {
+			throw new InvalidEmailAddress;
 		}
-		return $users;
+		return true;
 	}
 
 	/**
-	 * Get a list of user groups
+	 * Get a list of users
 	 * @NoAdminRequired
 	 * @param string $query
-	 * @param array $skip - group names to skip in return array
+	 * @param array $skip - usernames to skip in return array
 	 * @return User[]
 	 */
-	public function getSiteGroups($query = '', $skip = []) {
-		$groups = [];
-		foreach ($this->groupManager->search($query) as $group) {
-			if (!in_array($group->getGID(), $skip)) {
-				$groups[] = new User(User::TYPE_GROUP, $group->getGID());
+	public static function getSiteUsers($query = '', $skip = []) {
+		$users = [];
+		foreach (\OC::$server->getUserManager()->searchDisplayName($query) as $user) {
+			if (!in_array($user->getUID(), $skip) && $user->isEnabled()) {
+				$users[] = new User($user->getUID());
 			}
 		}
-		return $groups;
+		return $users;
 	}
 
 	/**
-	 * Get a combined list of NC users, groups and contacts
+	 * Get a combined list of users, groups, circles, contact groups and contacts
 	 * @NoAdminRequired
 	 * @param string $query
 	 * @param bool $getGroups - search in groups
@@ -135,7 +110,7 @@ class SystemService {
 	 * @param bool $getContactGroups - search in contacs
 	 * @param array $skipGroups - group names to skip in return array
 	 * @param array $skipUsers - user names to skip in return array
-	 * @return Array
+	 * @return User[]
 	 */
 	public function getSiteUsersAndGroups(
 		$query = '',
@@ -149,26 +124,26 @@ class SystemService {
 	) {
 		$list = [];
 		if ($query !== '') {
-			if ($getMail && $this->isValidEmail($query)) {
-				$list[] = new User(User::TYPE_EMAIL, $query);
+			if ($getMail && self::isValidEmail($query)) {
+				$list[] = new Email($query);
 			}
 
 			if ($getGroups) {
-				$list = array_merge($list, $this->getSiteGroups($query, $skipGroups));
+				$list = array_merge($list, Group::search($query, $skipGroups));
 			}
 
 			if ($getUsers) {
-				$list = array_merge($list, $this->getSiteUsers($query, $skipUsers));
+				$list = array_merge($list, User::search($query, $skipUsers));
 			}
 
 			if ($getContacts) {
-				$list = array_merge($list, $this->contactsService->getContacts($query));
+				$list = array_merge($list, Contact::search($query));
 			}
 
 			if ($getContacts) {
-				$list = array_merge($list, $this->contactsService->getContactsGroups($query));
+				$list = array_merge($list, ContactGroup::search($query));
 			}
-			$list = array_merge($list, $this->circlesService->getCircles($query));
+			$list = array_merge($list, Circle::search($query));
 		}
 
 		return $list;
@@ -180,22 +155,6 @@ class SystemService {
 	 * a participant of the poll
 	 * @NoAdminRequired
 	 * @return Boolean
-	 * @throws InvalidEmailAddress
-	 */
-	public function validateEmailAddress($emailAddress) {
-		if (!$this->isValidEmail($emailAddress)) {
-			throw new InvalidEmailAddress;
-		}
-		return true;
-	}
-
-
-	/**
-	 * Validate it the user name is reservrd
-	 * return false, if this username already exists as a user or as
-	 * a participant of the poll
-	 * @NoAdminRequired
-	 * @return Boolean
 	 * @throws NotAuthorizedException
 	 * @throws TooShortException
 	 * @throws InvalidUsernameException
@@ -212,32 +171,27 @@ class SystemService {
 		if (strlen($userName) < 3) {
 			return new TooShortException('Username must have at least 3 characters');
 		}
-		$list = [];
 
 		// get all groups
-		foreach ($this->getSiteGroups() as $user) {
-			if ($userName === strtolower(trim($user->getUserId()))
-				|| $userName === strtolower(trim($user->getDisplayName()))) {
+		foreach (Group::search() as $group) {
+			if ($userName === strtolower(trim($group->getId()))
+				|| $userName === strtolower(trim($group->getDisplayName()))) {
 				throw new InvalidUsernameException;
 			}
-			$list[] = $user;
 		}
 
 		// get all users
-		foreach ($this->getSiteUsers() as $user) {
+		foreach (User::search() as $user) {
 			if ($userName === strtolower(trim($user->getUserId()))
 				|| $userName === strtolower(trim($user->getDisplayName()))) {
 				throw new InvalidUsernameException;
 			}
-			$list[] = $user;
 		}
 
 		// get all participants
 		foreach ($this->voteMapper->findParticipantsByPoll($pollId) as $vote) {
-			if ($vote->getUserId() !== '' && $vote->getUserId() !== null) {
-				$list[] = new User(User::TYPE_USER, $vote->getUserId());
-				if ($userName === strtolower(trim(end($list)->getUserId()))
-					|| $userName === strtolower(trim(end($list)->getDisplayName()))) {
+			if ($vote->getUserId()) {
+				if ($userName === strtolower(trim($vote->getUserId()))) {
 					throw new InvalidUsernameException;
 				}
 			}
@@ -245,17 +199,11 @@ class SystemService {
 
 		// get all shares for this poll
 		foreach ($this->shareMapper->findByPoll($pollId) as $share) {
-			if ($share->getUserId() !== ''
-				&& $share->getUserId() !== null
-				&& $share->getType() !== User::TYPE_CIRCLE) {
-				$user = new User($share->getType(), $share->getUserId());
-				\OC::$server->getLogger()->alert(json_encode($user));
-				if ($userName === strtolower(trim($user->getUserId()))
-					|| $userName === strtolower(trim($share->getDisplayName()))
-					|| $userName === strtolower(trim($user->getDisplayName()))) {
+			if ($share->getUserId() && $share->getType() !== User::TYPE_CIRCLE) {
+				if ($userName === strtolower(trim($share->getUserId()))
+					|| $userName === strtolower(trim($share->getDisplayName()))) {
 					throw new InvalidUsernameException;
 				}
-				$list[] = new User($share->getType(), $share->getUserId());
 			}
 		}
 		// return true, if username is allowed