<?php

/**
 * @class ElggGroup Class representing a container for other elgg entities.
 */
class ElggGroup extends ElggEntity
	implements Friendable {

	protected function initialise_attributes() {
		parent::initialise_attributes();

		$this->attributes['type'] = "group";
		$this->attributes['name'] = "";
		$this->attributes['description'] = "";
		$this->attributes['tables_split'] = 2;
	}

	/**
	 * Construct a new user entity, optionally from a given id value.
	 *
	 * @param mixed $guid If an int, load that GUID.
	 * 	If a db row then will attempt to load the rest of the data.
	 * @throws Exception if there was a problem creating the user.
	 */
	function __construct($guid = null) {
		$this->initialise_attributes();

		if (!empty($guid)) {
			// Is $guid is a DB row - either a entity row, or a user table row.
			if ($guid instanceof stdClass) {
				// Load the rest
				if (!$this->load($guid->guid)) {
					throw new IOException(sprintf(elgg_echo('IOException:FailedToLoadGUID'), get_class(), $guid->guid));
				}
			}
			// Is $guid is an ElggGroup? Use a copy constructor
			else if ($guid instanceof ElggGroup) {
				elgg_deprecated_notice('This type of usage of the ElggGroup constructor was deprecated. Please use the clone method.', 1.7);

				foreach ($guid->attributes as $key => $value) {
					$this->attributes[$key] = $value;
				}
			}
			// Is this is an ElggEntity but not an ElggGroup = ERROR!
			else if ($guid instanceof ElggEntity) {
				throw new InvalidParameterException(elgg_echo('InvalidParameterException:NonElggGroup'));
			}
			// We assume if we have got this far, $guid is an int
			else if (is_numeric($guid)) {
				if (!$this->load($guid)) {
					throw new IOException(sprintf(elgg_echo('IOException:FailedToLoadGUID'), get_class(), $guid));
				}
			}

			else {
				throw new InvalidParameterException(elgg_echo('InvalidParameterException:UnrecognisedValue'));
			}
		}
	}

	/**
	 * Add an ElggObject to this group.
	 *
	 * @param ElggObject $object The object.
	 * @return bool
	 */
	public function addObjectToGroup(ElggObject $object) {
		return add_object_to_group($this->getGUID(), $object->getGUID());
	}

	/**
	 * Remove an object from the containing group.
	 *
	 * @param int $guid The guid of the object.
	 * @return bool
	 */
	public function removeObjectFromGroup($guid) {
		return remove_object_from_group($this->getGUID(), $guid);
	}

	public function get($name) {
		if ($name == 'username') {
			return 'group:' . $this->getGUID();
		}
		return parent::get($name);
	}

/**
 * Start friendable compatibility block:
 *
 * 	public function addFriend($friend_guid);
	public function removeFriend($friend_guid);
	public function isFriend();
	public function isFriendsWith($user_guid);
	public function isFriendOf($user_guid);
	public function getFriends($subtype = "", $limit = 10, $offset = 0);
	public function getFriendsOf($subtype = "", $limit = 10, $offset = 0);
	public function getObjects($subtype="", $limit = 10, $offset = 0);
	public function getFriendsObjects($subtype = "", $limit = 10, $offset = 0);
	public function countObjects($subtype = "");
 */

	/**
	 * For compatibility with Friendable
	 */
	public function addFriend($friend_guid) {
		return $this->join(get_entity($friend_guid));
	}

	/**
	 * For compatibility with Friendable
	 */
	public function removeFriend($friend_guid) {
		return $this->leave(get_entity($friend_guid));
	}

	/**
	 * For compatibility with Friendable
	 */
	public function isFriend() {
		return $this->isMember();
	}

	/**
	 * For compatibility with Friendable
	 */
	public function isFriendsWith($user_guid) {
		return $this->isMember($user_guid);
	}

	/**
	 * For compatibility with Friendable
	 */
	public function isFriendOf($user_guid) {
		return $this->isMember($user_guid);
	}

	/**
	 * For compatibility with Friendable
	 */
	public function getFriends($subtype = "", $limit = 10, $offset = 0) {
		return get_group_members($this->getGUID(), $limit, $offset);
	}

	/**
	 * For compatibility with Friendable
	 */
	public function getFriendsOf($subtype = "", $limit = 10, $offset = 0) {
		return get_group_members($this->getGUID(), $limit, $offset);
	}

	/**
	 * Get objects contained in this group.
	 *
	 * @param string $subtype
	 * @param int $limit
	 * @param int $offset
	 * @return mixed
	 */
	public function getObjects($subtype="", $limit = 10, $offset = 0) {
		return get_objects_in_group($this->getGUID(), $subtype, 0, 0, "", $limit, $offset, false);
	}

	/**
	 * For compatibility with Friendable
	 */
	public function getFriendsObjects($subtype = "", $limit = 10, $offset = 0) {
		return get_objects_in_group($this->getGUID(), $subtype, 0, 0, "", $limit, $offset, false);
	}

	/**
	 * For compatibility with Friendable
	 */
	public function countObjects($subtype = "") {
		return get_objects_in_group($this->getGUID(), $subtype, 0, 0, "", 10, 0, true);
	}

/**
 * End friendable compatibility block
 */

	/**
	 * Get a list of group members.
	 *
	 * @param int $limit
	 * @param int $offset
	 * @return mixed
	 */
	public function getMembers($limit = 10, $offset = 0, $count = false) {
		return get_group_members($this->getGUID(), $limit, $offset, 0 , $count);
	}

	/**
	 * Returns whether the current group is public membership or not.
	 * @return bool
	 */
	public function isPublicMembership() {
		if ($this->membership == ACCESS_PUBLIC) {
			return true;
		}

		return false;
	}

	/**
	 * Return whether a given user is a member of this group or not.
	 *
	 * @param ElggUser $user The user
	 * @return bool
	 */
	public function isMember($user = 0) {
		if (!($user instanceof ElggUser)) {
			$user = get_loggedin_user();
		}
		if (!($user instanceof ElggUser)) {
			return false;
		}
		return is_group_member($this->getGUID(), $user->getGUID());
	}

	/**
	 * Join an elgg user to this group.
	 *
	 * @param ElggUser $user
	 * @return bool
	 */
	public function join(ElggUser $user) {
		return join_group($this->getGUID(), $user->getGUID());
	}

	/**
	 * Remove a user from the group.
	 *
	 * @param ElggUser $user
	 */
	public function leave(ElggUser $user) {
		return leave_group($this->getGUID(), $user->getGUID());
	}

	/**
	 * Override the load function.
	 * This function will ensure that all data is loaded (were possible), so
	 * if only part of the ElggGroup is loaded, it'll load the rest.
	 *
	 * @param int $guid
	 */
	protected function load($guid) {
		// Test to see if we have the generic stuff
		if (!parent::load($guid)) {
			return false;
		}

		// Check the type
		if ($this->attributes['type']!='group') {
			throw new InvalidClassException(sprintf(elgg_echo('InvalidClassException:NotValidElggStar'), $guid, get_class()));
		}

		// Load missing data
		$row = get_group_entity_as_row($guid);
		if (($row) && (!$this->isFullyLoaded())) {
			// If $row isn't a cached copy then increment the counter
			$this->attributes['tables_loaded'] ++;
		}

		// Now put these into the attributes array as core values
		$objarray = (array) $row;
		foreach($objarray as $key => $value) {
			$this->attributes[$key] = $value;
		}

		return true;
	}

	/**
	 * Override the save function.
	 */
	public function save() {
		// Save generic stuff
		if (!parent::save()) {
			return false;
		}

		// Now save specific stuff
		return create_group_entity($this->get('guid'), $this->get('name'), $this->get('description'));
	}

	// EXPORTABLE INTERFACE ////////////////////////////////////////////////////////////

	/**
	 * Return an array of fields which can be exported.
	 */
	public function getExportableValues() {
		return array_merge(parent::getExportableValues(), array(
			'name',
			'description',
		));
	}
}