path: root/engine/lib/tags.php

<?php
/**
 * Elgg tags
 * Functions for managing tags and tag clouds.
 *
 * @package Elgg
 * @subpackage Core
 * @author Curverider Ltd <info@elgg.com>
 * @link http://elgg.org/
 */


/**
 * The algorithm working out the size of font based on the number of tags.
 * This is quick and dirty.
 */
function calculate_tag_size($min, $max, $number_of_tags, $buckets = 6) {

	$delta =  (($max - $min) / $buckets);
	$thresholds = array();

	for ($n=1; $n <= $buckets; $n++) {
		$thresholds[$n-1] = ($min + $n) * $delta;
	}

	// Correction
	if ($thresholds[$buckets-1]>$max) {
		$thresholds[$buckets-1] = $max;
	}

	$size = 0;
	for ($n = 0; $n < count($thresholds); $n++) {
		if ($number_of_tags >= $thresholds[$n]) {
			$size = $n;
		}
	}

	return $size;
}

/**
 * This function generates an array of tags with a weighting.
 *
 * @param array $tags The array of tags.
 * @return An associated array of tags with a weighting, this can then be mapped to a display class.
 */
function generate_tag_cloud(array $tags, $buckets = 6) {
	$cloud = array();

	$min = 65535;
	$max = 0;

	foreach ($tags as $tag) {
		$cloud[$tag]++;

		if ($cloud[$tag]>$max) {
			$max = $cloud[$tag];
		}

		if ($cloud[$tag]<$min) {
			$min = $cloud[$tag];
		}
	}

	foreach ($cloud as $k => $v) {
		$cloud[$k] = calculate_tag_size($min, $max, $v, $buckets);
	}

	return $cloud;
}

/**
 * Get an array of tags with weights for use with the output/tagcloud view.
 *
 * @param int $threshold Get the threshold of minimum number of each tags to bother with (ie only show tags where there are more than $threshold occurances)
 * @param int $limit Number of tags to return
 * @param string $metadata_name Optionally, the name of the field you want to grab for
 * @param string $entity_type Optionally, the entity type ('object' etc)
 * @param string $entity_subtype The entity subtype, optionally
 * @param int $owner_guid The GUID of the tags owner, optionally
 * @param int $site_guid Optionally, the site to restrict to (default is the current site)
 * @param int $start_ts Optionally specify a start timestamp for tags used to generate cloud.
 * @param int $ent_ts Optionally specify an end timestamp for tags used to generate cloud.
 * @return array|false Array of objects with ->tag and ->total values, or false on failure
 */

function get_tags($threshold = 1, $limit = 10, $metadata_name = "", $entity_type = "object", $entity_subtype = "", $owner_guid = "", $site_guid = -1, $start_ts = "", $end_ts = "") {
	global $CONFIG;

	$threshold = (int) $threshold;
	$limit = (int) $limit;

	if (!empty($metadata_name)) {
		$metadata_name = (int) get_metastring_id($metadata_name);
	} else {
		$metadata_name = 0;
	}
	$entity_subtype = get_subtype_id($entity_type, $entity_subtype);
	$entity_type = sanitise_string($entity_type);

	if ($owner_guid != "") {
		if (is_array($owner_guid)) {
			foreach($owner_guid as $key => $val) {
				$owner_guid[$key] = (int) $val;
			}
		} else {
			$owner_guid = (int) $owner_guid;
		}
	}

	if ($site_guid < 0) {
		$site_guid = $CONFIG->site_id;
	}

	//$access = get_access_list();

	$query = "SELECT msvalue.string as tag, count(msvalue.id) as total ";
	$query .= "FROM {$CONFIG->dbprefix}entities e join {$CONFIG->dbprefix}metadata md on md.entity_guid = e.guid ";
	if ($entity_subtype > 0) {
		$query .= " join {$CONFIG->dbprefix}entity_subtypes subtype on subtype.id = e.subtype ";
	}
	$query .= " join {$CONFIG->dbprefix}metastrings msvalue on msvalue.id = md.value_id ";

	$query .= " where msvalue.string != '' ";

	if ($metadata_name > 0) {
		$query .= " and md.name_id = {$metadata_name} ";
	}
	if ($site_guid > 0) {
		$query .= " and e.site_guid = {$site_guid} ";
	}
	if ($entity_subtype > 0) {
		$query .= " and e.subtype = {$entity_subtype} ";
	}
	if ($entity_type != "") {
		$query .= " and e.type = '{$entity_type}' ";
	}
	if (is_array($owner_guid)) {
		$query .= " and e.container_guid in (".implode(",",$owner_guid).")";
	} else if (is_int($owner_guid)) {
		$query .= " and e.container_guid = {$owner_guid} ";
	}
	if ($start_ts) {
		$start_ts = (int)$start_ts;
		$query .= " and e.time_created>=$start_ts";
	}

	if ($end_ts) {
		$end_ts = (int)$end_ts;
		$query .= " and e.time_created<=$end_ts";
	}

	//$userid = get_loggedin_userid();
	//$query .= " and (e.access_id in {$access} or (e.access_id = " . ACCESS_PRIVATE . " and e.owner_guid = {$userid}))";
	$query .= ' and ' . get_access_sql_suffix("e"); // Add access controls

	$query .= " group by msvalue.string having total > {$threshold} order by total desc limit {$limit} ";

	return get_data($query);
}

/**
 * Loads and displays a tagcloud given particular criteria.
 *
 * @param int $threshold Get the threshold of minimum number of each tags to bother with (ie only show tags where there are more than $threshold occurances)
 * @param int $limit Number of tags to return
 * @param string $metadata_name Optionally, the name of the field you want to grab for
 * @param string $entity_type Optionally, the entity type ('object' etc)
 * @param string $entity_subtype The entity subtype, optionally
 * @param int $owner_guid The GUID of the tags owner, optionally
 * @param int $site_guid Optionally, the site to restrict to (default is the current site)
 * @return string THe HTML (or other, depending on view type) of the tagcloud.
 */

function display_tagcloud($threshold = 1, $limit = 10, $metadata_name = "", $entity_type = "object", $entity_subtype = "", $owner_guid = "", $site_guid = -1) {
	return elgg_view("output/tagcloud",array('value' => get_tags($threshold, $limit, $metadata_name, $entity_type, $entity_subtype, $owner_guid, $site_guid),'object' => $entity_type, 'subtype' => $entity_subtype));
}



/**
 * Return default results for searches on groups.
 *
 * @param unknown_type $hook
 * @param unknown_type $type
 * @param unknown_type $value
 * @param unknown_type $params
 * @return unknown_type
 */
function tags_search_hook($hook, $type, $value, $params) {
	global $CONFIG;

	$query = $params['query'];

	$params['metadata_name_value_pair'] = array ('name' => 'tags', 'value' => $query, 'case_sensitive' => FALSE);

	$entities = elgg_get_entities_from_metadata($params);
	$params['count'] = TRUE;
	$count = elgg_get_entities_from_metadata($params);

	// no need to continue if nothing here.
	if (!$count) {
		return array('entities' => array(), 'count' => $count);
	}

	// add the volatile data for why these entities have been returned.
	foreach ($entities as $entity) {
		$tags = implode(',', $entity->tags);
		$tags_str = search_get_relevant_substring($tags, $query, '<strong class="searchMatch">', '</strong>');
		$entity->setVolatileData('search_matched_tags', $tags_str);
	}

	return array(
		'entities' => $entities,
		'count' => $count,
	);
}

/**
 * Register tags as a custom search type.
 *
 * @param unknown_type $hook
 * @param unknown_type $type
 * @param unknown_type $value
 * @param unknown_type $params
 * @return unknown_type
 */
function tags_search_custom_types_hook($hook, $type, $value, $params) {
	$value[] = 'tags';
	return $value;
}


register_plugin_hook('search', 'tags', 'tags_search_hook');
register_plugin_hook('search_types', 'get_types', 'tags_search_custom_types_hook');