<?php
  /**
   * ownCloud - Contact object
   *
   * @author Thomas Tanghus

   * @copyright 2012-2014 Thomas Tanghus (thomas@tanghus.net)

   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
   * License as published by the Free Software Foundation; either
   * version 3 of the License, or any later version.
   *
   * This library 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 library.  If not, see <http://www.gnu.org/licenses/>.
   *
   */
  
  namespace OCA\Contacts;
  
  use Sabre\VObject\Property,
  	OCA\Contacts\Utils\Properties;
  
  /**
   * Subclass this class or implement IPIMObject interface for PIM objects
   */
  
  class Contact extends VObject\VCard implements IPIMObject {
  
  	/**
  	 * The name of the object type in this case VCARD.
  	 *
  	 * This is used when serializing the object.
  	 *
  	 * @var string
  	 */
  	public $name = 'VCARD';
  
  	/**
  	 * @brief language object
  	 *
  	 * @var OC_L10N
  	 */
  	public static $l10n;
  
  	protected $props = array();
  
  	/**
  	 * Create a new Contact object
  	 *
  	 * @param AddressBook $parent

  	 * @param Backend\AbstractBackend $backend

  	 * @param mixed $data
  	 */
  	public function __construct($parent, $backend, $data = null) {
  		self::$l10n = $parent::$l10n;

  		//\OCP\Util::writeLog('contacts', __METHOD__ . ' , data: ' . print_r($data, true), \OCP\Util::DEBUG);

  		$this->props['parent'] = $parent;
  		$this->props['backend'] = $backend;
  		$this->props['retrieved'] = false;
  		$this->props['saved'] = false;

  		if (!is_null($data)) {
  			if ($data instanceof VObject\VCard) {
  				foreach ($data->children as $child) {

  					$this->add($child);
  				}
  				$this->setRetrieved(true);

  			} elseif (is_array($data)) {
  				foreach ($data as $key => $value) {
  					switch ($key) {

  						case 'id':
  							$this->props['id'] = $value;
  							break;

  						case 'permissions':
  							$this->props['permissions'] = $value;
  							break;

  						case 'lastmodified':
  							$this->props['lastmodified'] = $value;
  							break;
  						case 'uri':
  							$this->props['uri'] = $value;
  							break;
  						case 'carddata':
  							$this->props['carddata'] = $value;
  							$this->retrieve();
  							break;
  						case 'vcard':
  							$this->props['vcard'] = $value;
  							$this->retrieve();
  							break;
  						case 'displayname':
  						case 'fullname':
  							if(is_string($value)) {
  								$this->props['displayname'] = $value;
  								$this->FN = $value;
  								// Set it to saved again as we're not actually changing anything
  								$this->setSaved();
  							}
  							break;
  					}
  				}
  			}
  		}
  	}
  
  	/**
  	 * @return array|null
  	 */
  	public function getMetaData() {

  		if (!$this->hasPermission(\OCP\PERMISSION_READ)) {

  			throw new \Exception(self::$l10n->t('You do not have permissions to see this contact'), 403);
  		}

  		if (!isset($this->props['displayname'])) {
  			if (!$this->retrieve()) {

  				\OCP\Util::writeLog('contacts', __METHOD__.' error reading: '.print_r($this->props, true), \OCP\Util::ERROR);
  				return null;
  			}
  		}
  		return array(
  			'id' => $this->getId(),
  			'displayname' => $this->getDisplayName(),
  			'permissions' => $this->getPermissions(),
  			'lastmodified' => $this->lastModified(),
  			'owner' => $this->getOwner(),
  			'parent' => $this->getParent()->getId(),
  			'backend' => $this->getBackend()->name,
  		);
  	}
  
  	/**
  	 * Get a unique key combined of backend name, address book id and contact id.
  	 *
  	 * @return string
  	 */
  	public function combinedKey() {
  		return $this->getBackend()->name . '::' . $this->getParent()->getId() . '::' . $this->getId();
  	}
  
  	/**
  	 * @return string|null
  	 */
  	public function getOwner() {

  		return isset($this->props['owner'])
  			? $this->props['owner']
  			: $this->getParent()->getOwner();

  	}
  
  	/**
  	 * @return string|null
  	 */
  	public function getId() {
  		return isset($this->props['id']) ? $this->props['id'] : null;
  	}
  
  	/**
  	 * @return string|null
  	 */

  	public function getDisplayName() {
  		if (!$this->hasPermission(\OCP\PERMISSION_READ)) {

  			throw new \Exception(self::$l10n->t('You do not have permissions to see this contact'), 403);
  		}
  		return isset($this->props['displayname'])
  			? $this->props['displayname']
  			: (isset($this->FN) ? $this->FN : null);
  	}
  
  	/**
  	 * @return string|null
  	 */
  	public function getURI() {
  		return isset($this->props['uri']) ? $this->props['uri'] : null;
  	}
  
  	/**
  	 * @return string|null
  	 * TODO: Cache result.
  	 */
  	public function getETag() {
  		$this->retrieve();
  		return md5($this->serialize());
  	}
  
  	/**
  	 * If this object is part of a collection return a reference
  	 * to the parent object, otherwise return null.
  	 * @return IPIMObject|null
  	 */
  	public function getParent() {
  		return $this->props['parent'];
  	}
  
  	public function getBackend() {
  		return $this->props['backend'];
  	}
  
  	/** CRUDS permissions (Create, Read, Update, Delete, Share)
  	 *
  	 * @return integer
  	 */
  	public function getPermissions() {

  		return isset($this->props['permissions'])
  			? $this->props['permissions']
  			: $this->getParent()->getPermissions();

  	}
  
  	/**
  	 * @param integer $permission
  	 * @return bool
  	 */
  	public function hasPermission($permission) {
  		return $this->getPermissions() & $permission;
  	}
  
  	/**
  	 * Save the address book data to backend
  	 * FIXME
  	 *
  	 * @param array $data
  	 * @return bool
  	 */
  /*	public function update(array $data) {
  
  		foreach($data as $key => $value) {
  			switch($key) {
  				case 'displayname':
  					$this->addressBookInfo['displayname'] = $value;
  					break;
  				case 'description':
  					$this->addressBookInfo['description'] = $value;
  					break;
  			}
  		}
  		return $this->props['backend']->updateContact(
  			$this->getParent()->getId(),
  			$this->getId(),
  			$this
  		);
  	}
  */
  	/**
  	 * Delete the data from backend
  	 *
  	 * FIXME: Should be removed as it could leave the parent with a dataless object.
  	 *
  	 * @return bool
  	 */
  	public function delete() {

  		if (!$this->hasPermission(\OCP\PERMISSION_DELETE)) {

  			throw new \Exception(self::$l10n->t('You do not have permissions to delete this contact'), 403);
  		}
  		return $this->props['backend']->deleteContact(
  			$this->getParent()->getId(),
  			$this->getId()
  		);
  	}
  
  	/**
  	 * Save the contact data to backend
  	 *
  	 * @return bool
  	 */
  	public function save($force = false) {

  		if (!$this->hasPermission(\OCP\PERMISSION_UPDATE)) {

  			throw new \Exception(self::$l10n->t('You do not have permissions to update this contact'), 403);
  		}

  		if ($this->isSaved() && !$force) {

  			\OCP\Util::writeLog('contacts', __METHOD__.' Already saved: ' . print_r($this->props, true), \OCP\Util::DEBUG);
  			return true;
  		}

  
  		if (isset($this->FN)) {

  			$this->props['displayname'] = (string)$this->FN;
  		}

  
  		if ($this->getId()) {
  			if (!$this->getBackend()->hasContactMethodFor(\OCP\PERMISSION_UPDATE)) {

  				throw new \Exception(self::$l10n->t('The backend for this contact does not support updating it'), 501);
  			}

  			if ($this->getBackend()

  				->updateContact(
  					$this->getParent()->getId(),
  					$this->getId(),
  					$this
  				)
  			) {
  				$this->props['lastmodified'] = time();
  				$this->setSaved(true);
  				return true;
  			} else {
  				return false;
  			}
  		} else {

  			if (!$this->getBackend()->hasContactMethodFor(\OCP\PERMISSION_CREATE)) {
  				throw new \Exception(self::$l10n->t('This backend does not support adding contacts'), 501);

  			}
  			$this->props['id'] = $this->getBackend()->createContact(
  				$this->getParent()->getId(), $this
  			);
  			$this->setSaved(true);
  			return $this->getId() !== false;
  		}
  	}
  
  	/**
  	 * Get the data from the backend
  	 * FIXME: Clean this up and make sure the logic is OK.

  	 *
  	 * @return bool

  	 */
  	public function retrieve() {

  		if ($this->isRetrieved() || count($this->children) > 1) {

  			//\OCP\Util::writeLog('contacts', __METHOD__. ' children', \OCP\Util::DEBUG);
  			return true;
  		} else {
  			$data = null;
  			if(isset($this->props['vcard'])
  				&& $this->props['vcard'] instanceof VObject\VCard) {
  				foreach($this->props['vcard']->children() as $child) {
  					$this->add($child);
  					if($child->name === 'FN') {
  						$this->props['displayname']
  							= strtr($child->value, array('\,' => ',', '\;' => ';', '\\\\' => '\\'));
  					}
  				}
  				$this->setRetrieved(true);
  				$this->setSaved(true);
  				//$this->children = $this->props['vcard']->children();
  				unset($this->props['vcard']);
  				return true;

  			} elseif (!isset($this->props['carddata'])) {

  				$result = $this->props['backend']->getContact(
  					$this->getParent()->getId(),
  					$this->getId()
  				);

  				if ($result) {
  					if (isset($result['vcard'])

  						&& $result['vcard'] instanceof VObject\VCard) {

  						foreach ($result['vcard']->children() as $child) {

  							$this->add($child);
  						}
  						$this->setRetrieved(true);
  						return true;

  					} elseif (isset($result['carddata'])) {

  						// Save internal values
  						$data = $result['carddata'];
  						$this->props['carddata'] = $result['carddata'];
  						$this->props['lastmodified'] = isset($result['lastmodified'])
  							? $result['lastmodified']
  							: null;
  						$this->props['displayname'] = $result['displayname'];
  						$this->props['permissions'] = $result['permissions'];
  					} else {
  						\OCP\Util::writeLog('contacts', __METHOD__
  							. ' Could not get vcard or carddata: '
  							. $this->getId()
  							. print_r($result, true), \OCP\Util::DEBUG);
  						return false;
  					}
  				} else {
  					\OCP\Util::writeLog('contacts', __METHOD__.' Error getting contact: ' . $this->getId(), \OCP\Util::DEBUG);
  				}

  			} elseif (isset($this->props['carddata'])) {

  				$data = $this->props['carddata'];
  			}
  			try {
  				$obj = \Sabre\VObject\Reader::read(
  					$data,
  					\Sabre\VObject\Reader::OPTION_IGNORE_INVALID_LINES
  				);

  				if ($obj) {
  					foreach ($obj->children as $child) {

  						$this->add($child);
  					}
  					$this->setRetrieved(true);
  					$this->setSaved(true);
  				} else {
  					\OCP\Util::writeLog('contacts', __METHOD__.' Error reading: ' . print_r($data, true), \OCP\Util::DEBUG);
  					return false;
  				}
  			} catch (\Exception $e) {
  				\OCP\Util::writeLog('contacts', __METHOD__ .
  					' Error parsing carddata  for: ' . $this->getId() . ' ' . $e->getMessage(),
  						\OCP\Util::ERROR);
  				return false;
  			}
  		}
  		return true;
  	}
  
  	/**

  	 * Get the PHOTO or LOGO
  	 *
  	 * @return \OCP\Image|null
  	 */
  	public function getPhoto() {
  		$image = new \OCP\Image();
  
  		if (isset($this->PHOTO) && $image->loadFromBase64((string)$this->PHOTO)) {
  			return $image;
  		} elseif (isset($this->LOGO) && $image->loadFromBase64((string)$this->LOGO)) {
  			return $image;
  		}
  	}
  
  	/**
  	 * Set the contact photo.
  	 *
  	 * @param \OCP\Image $photo
  	 */
  	public function setPhoto(\OCP\Image $photo) {
  		// For vCard 3.0 the type must be e.g. JPEG or PNG
  		// For version 4.0 the full mimetype should be used.
  		// https://tools.ietf.org/html/rfc2426#section-3.1.4
  		if (strval($this->VERSION) === '4.0') {
  			$type = $photo->mimeType();
  		} else {
  			$type = explode('/', $photo->mimeType());
  			$type = strtoupper(array_pop($type));
  		}
  		if (isset($this->PHOTO)) {
  			$property = $this->PHOTO;
  			if (!$property) {
  				return false;
  			}
  			$property->setValue(strval($photo));
  			$property->parameters = array();
  			$property->parameters[]
  				= new \Sabre\VObject\Parameter('ENCODING', 'b');
  			$property->parameters[]
  				= new \Sabre\VObject\Parameter('TYPE', $photo->mimeType());
  			$this->PHOTO = $property;
  		} else {
  			$this->add('PHOTO',
  				strval($photo), array('ENCODING' => 'b',
  				'TYPE' => $type));
  			// TODO: Fix this hack
  			$this->setSaved(false);
  		}
  
  		return true;
  
  	}
  
  	/**

  	* Get a property index in the contact by the checksum of its serialized value
  	*
  	* @param string $checksum An 8 char m5d checksum.
  	* @return \Sabre\VObject\Property Property by reference
  	* @throws An exception with error code 404 if the property is not found.
  	*/
  	public function getPropertyIndexByChecksum($checksum) {
  		$this->retrieve();
  		$idx = 0;

  		foreach ($this->children as $i => &$property) {
  			if (substr(md5($property->serialize()), 0, 8) == $checksum ) {

  				return $idx;
  			}
  			$idx += 1;
  		}
  		throw new \Exception(self::$l10n->t('Property not found'), 404);
  	}
  
  	/**
  	* Get a property by the checksum of its serialized value
  	*
  	* @param string $checksum An 8 char m5d checksum.
  	* @return \Sabre\VObject\Property Property by reference
  	* @throws An exception with error code 404 if the property is not found.
  	*/
  	public function getPropertyByChecksum($checksum) {
  		$this->retrieve();

  		foreach ($this->children as $i => &$property) {
  			if (substr(md5($property->serialize()), 0, 8) == $checksum ) {

  				return $property;
  			}
  		}
  		throw new \Exception(self::$l10n->t('Property not found'), 404);
  	}
  
  	/**
  	* Delete a property by the checksum of its serialized value
  	* It is up to the caller to call ->save()
  	*
  	* @param string $checksum An 8 char m5d checksum.
  	* @throws @see getPropertyByChecksum
  	*/
  	public function unsetPropertyByChecksum($checksum) {
  		$idx = $this->getPropertyIndexByChecksum($checksum);
  		unset($this->children[$idx]);
  		$this->setSaved(false);
  	}
  
  	/**
  	* Set a property by the checksum of its serialized value
  	* It is up to the caller to call ->save()
  	*
  	* @param string $checksum An 8 char m5d checksum.
  	* @param string $name Property name
  	* @param mixed $value
  	* @param array $parameters
  	* @throws @see getPropertyByChecksum
  	* @return string new checksum
  	*/
  	public function setPropertyByChecksum($checksum, $name, $value, $parameters=array()) {

  		if ($checksum === 'new') {

  			$property = Property::create($name);
  			$this->add($property);
  		} else {
  			$property = $this->getPropertyByChecksum($checksum);
  		}

  		switch ($name) {

  			case 'EMAIL':
  				$value = strtolower($value);
  				$property->setValue($value);
  				break;
  			case 'ADR':
  				if(is_array($value)) {
  					$property->setParts($value);
  				} else {
  					$property->setValue($value);
  				}
  				break;
  			case 'IMPP':

  				if (is_null($parameters) || !isset($parameters['X-SERVICE-TYPE'])) {

  					throw new \InvalidArgumentException(self::$l10n->t(' Missing IM parameter for: ') . $name. ' ' . $value, 412);
  				}
  				$serviceType = $parameters['X-SERVICE-TYPE'];

  				if (is_array($serviceType)) {

  					$serviceType = $serviceType[0];
  				}
  				$impp = Utils\Properties::getIMOptions($serviceType);

  				if (is_null($impp)) {

  					throw new \UnexpectedValueException(self::$l10n->t('Unknown IM: ') . $serviceType, 415);
  				}
  				$value = $impp['protocol'] . ':' . $value;
  				$property->setValue($value);
  				break;
  			default:
  				\OCP\Util::writeLog('contacts', __METHOD__.' adding: '.$name. ' ' . $value, \OCP\Util::DEBUG);
  				$property->setValue($value);
  				break;
  		}
  		$this->setParameters($property, $parameters, true);
  		$this->setSaved(false);
  		return substr(md5($property->serialize()), 0, 8);
  	}
  
  	/**
  	* Set a property by the property name.
  	* It is up to the caller to call ->save()
  	*
  	* @param string $name Property name
  	* @param mixed $value
  	* @param array $parameters
  	* @return bool
  	*/
  	public function setPropertyByName($name, $value, $parameters=array()) {
  		// TODO: parameters are ignored for now.

  		switch ($name) {

  			case 'BDAY':
  				try {
  					$date = New \DateTime($value);
  				} catch(\Exception $e) {
  					\OCP\Util::writeLog('contacts',
  						__METHOD__.' DateTime exception: ' . $e->getMessage(),
  						\OCP\Util::ERROR
  					);
  					return false;
  				}
  				$value = $date->format('Y-m-d');
  				$this->BDAY = $value;
  				$this->BDAY->add('VALUE', 'DATE');
  				//\OCP\Util::writeLog('contacts', __METHOD__.' BDAY: '.$this->BDAY->serialize(), \OCP\Util::DEBUG);
  				break;
  			case 'CATEGORIES':
  			case 'N':
  			case 'ORG':
  				$property = $this->select($name);

  				if (count($property) === 0) {

  					$property = \Sabre\VObject\Property::create($name);
  					$this->add($property);
  				} else {
  					// Actually no idea why this works
  					$property = array_shift($property);
  				}

  				if (is_array($value)) {

  					$property->setParts($value);
  				} else {
  					$this->{$name} = $value;
  				}
  				break;
  			default:
  				\OCP\Util::writeLog('contacts', __METHOD__.' adding: '.$name. ' ' . $value, \OCP\Util::DEBUG);
  				$this->{$name} = $value;
  				break;
  		}
  		$this->setSaved(false);
  		return true;
  	}
  
  	protected function setParameters($property, $parameters, $reset = false) {

  		if (!$parameters) {

  			return;
  		}

  		if ($reset) {

  			$property->parameters = array();
  		}
  		//debug('Setting parameters: ' . print_r($parameters, true));

  		foreach ($parameters as $key => $parameter) {

  			//debug('Adding parameter: ' . $key);

  			if (is_array($parameter)) {
  				foreach ($parameter as $val) {
  					if (is_array($val)) {
  						foreach ($val as $val2) {
  							if (trim($key) && trim($val2)) {

  								//debug('Adding parameter: '.$key.'=>'.print_r($val2, true));
  								$property->add($key, strip_tags($val2));
  							}
  						}
  					} else {

  						if (trim($key) && trim($val)) {

  							//debug('Adding parameter: '.$key.'=>'.print_r($val, true));
  							$property->add($key, strip_tags($val));
  						}
  					}
  				}
  			} else {

  				if (trim($key) && trim($parameter)) {

  					//debug('Adding parameter: '.$key.'=>'.print_r($parameter, true));
  					$property->add($key, strip_tags($parameter));
  				}
  			}
  		}
  	}
  
  	public function lastModified() {

  		if (!isset($this->props['lastmodified']) && !$this->isRetrieved()) {

  			$this->retrieve();
  		}
  		return isset($this->props['lastmodified'])
  			? $this->props['lastmodified']
  			: null;
  	}
  
  	/**
  	 * Merge in data from a multi-dimentional array
  	 *
  	 * NOTE: The data has actually already been merged client side!
  	 * NOTE: The only properties coming from the web client are the ones

  	 * defined in \OCA\Contacts\Utils\Properties::$indexProperties and

  	 * UID is skipped for obvious reasons, and PHOTO is currently not updated.
  	 * The data array has this structure:
  	 *
  	 * array(
  	 * 	'EMAIL' => array(array('value' => 'johndoe@example.com', 'parameters' = array('TYPE' => array('HOME','VOICE'))))
  	 * );
  	 * @param array $data
  	 * @return bool
  	 */
  	public function mergeFromArray(array $data) {

  		foreach ($data as $name => $properties) {
  			if (in_array($name, array('PHOTO', 'UID'))) {

  				continue;
  			}

  			if (!is_array($properties)) {

  				\OCP\Util::writeLog('contacts', __METHOD__.' not an array?: ' .$name. ' '.print_r($properties, true), \OCP\Util::DEBUG);
  			}

  			if (in_array($name, Utils\Properties::$multiProperties)) {

  				unset($this->{$name});
  			}

  			foreach ($properties as $parray) {

  				\OCP\Util::writeLog('contacts', __METHOD__.' adding: ' .$name. ' '.print_r($parray['value'], true) . ' ' . print_r($parray['parameters'], true), \OCP\Util::DEBUG);

  				if (in_array($name, Utils\Properties::$multiProperties)) {

  					// TODO: wrap in try/catch, check return value
  					$this->setPropertyByChecksum('new', $name, $parray['value'], $parray['parameters']);
  				} else {
  					// TODO: Check return value

  					if (!isset($this->{$name})) {

  						$this->setPropertyByName($name, $parray['value'], $parray['parameters']);
  					}
  				}
  			}
  		}
  		$this->setSaved(false);
  		return true;
  	}
  
  	/**
  	 * Merge in data from another VCard
  	 * Used on import if a matching UID is found. Returns true if any updates
  	 * take place, otherwise false.
  	 *
  	 * @param VCard $vcard
  	 * @return bool
  	 */
  	public function mergeFromVCard(VCard $vcard) {
  		$updated = false;

  		foreach ($vcard->children as $property) {
  			if (in_array($property->name, array('REV', 'UID'))) {

  				continue;
  			}
  			\OCP\Util::writeLog('contacts', __METHOD__.' merging: ' .$property->name, \OCP\Util::DEBUG);

  			if (in_array($property->name, Utils\Properties::$multiProperties)) {

  				$ownproperties = $this->select($property->name);

  				if (count($ownproperties) === 0) {

  					// We don't have any instances of this property, so just add it.
  					$this->add($property);
  					$updated = true;
  					continue;
  				} else {

  					foreach ($ownproperties as $ownproperty) {
  						if (strtolower($property->value) === strtolower($ownproperty->value)) {

  							// We already have this property, so skip both loops
  							continue 2;
  						}
  					}
  					$this->add($property);
  					$updated = true;
  				}
  			} else {

  				if(!isset($this->{$property->name})) {

  					$this->add($property);
  					$updated = true;
  				} else {
  					$this->setPropertyByName($property->name, $property->value, $property->parameters);
  				}
  			}
  		}
  
  		$this->setSaved(!$updated);
  
  		return $updated;
  	}

  	public function __get($key) {
  		if (!$this->isRetrieved()) {

  			$this->retrieve();
  		}
  
  		return parent::__get($key);
  	}

  	public function __isset($key) {
  		if (!$this->isRetrieved()) {

  			$this->retrieve();
  		}
  
  		return parent::__isset($key);
  	}
  
  	public function __set($key, $value) {

  		if (!$this->isRetrieved()) {

  			$this->retrieve();
  		}
  		parent::__set($key, $value);

  		if ($key === 'FN') {

  			$this->props['displayname'] = $value;
  		}
  		$this->setSaved(false);
  	}
  
  	public function __unset($key) {

  		if (!$this->isRetrieved()) {

  			$this->retrieve();
  		}
  		parent::__unset($key);

  		if ($key === 'PHOTO') {

  			Properties::cacheThumbnail(
  				$this->getBackend()->name,
  				$this->getParent()->getId(),
  				$this->getId(),
  				null,

  				$this,

  				array('remove' => true)
  			);
  		}
  		$this->setSaved(false);
  	}
  
  	public function setRetrieved($state) {
  		$this->props['retrieved'] = $state;
  	}
  
  	public function isRetrieved() {
  		return $this->props['retrieved'];
  	}
  
  	public function setSaved($state = true) {
  		$this->props['saved'] = $state;
  	}
  
  	public function isSaved() {
  		return $this->props['saved'];
  	}
  
  	/**
  	 * Generate an event to show in the calendar
  	 *
  	 * @return \Sabre\VObject\Component\VCalendar|null
  	 */
  	public function getBirthdayEvent() {

  		if (!isset($this->BDAY)) {

  			return;
  		}
  		$birthday = $this->BDAY;
  		if ((string)$birthday) {
  			$title = str_replace('{name}',
  				strtr((string)$this->FN, array('\,' => ',', '\;' => ';')),
  				App::$l10n->t('{name}\'s Birthday')
  			);
  			try {
  				$date = new \DateTime($birthday);
  			} catch(\Exception $e) {
  				return;
  			}
  			$vevent = \Sabre\VObject\Component::create('VEVENT');
  			$vevent->add('DTSTART');
  			$vevent->DTSTART->setDateTime(
  				$date,
  				\Sabre\VObject\Property\DateTime::DATE
  			);
  			$vevent->add('DURATION', 'P1D');
  			$vevent->{'UID'} = $this->UID;
  			$vevent->{'RRULE'} = 'FREQ=YEARLY';
  			$vevent->{'SUMMARY'} = $title . ' (' . $date->format('Y') . ')';
  			$vcal = \Sabre\VObject\Component::create('VCALENDAR');
  			$vcal->VERSION = '2.0';
  			$appinfo = \OCP\App::getAppInfo('contacts');
  			$appversion = \OCP\App::getAppVersion('contacts');
  			$vcal->PRODID = '-//ownCloud//NONSGML '.$appinfo['name'].' '.$appversion.'//EN';
  			$vcal->add($vevent);
  			return $vcal;
  		}
  	}
  
  }