/**
 * Set the tags assigned to a record.  This overwrites the current tags.
 * 
 * This function is meant to be fed the string coming up from the user 
 * interface, which contains all tags assigned to a record.
 *
 * @param string $record_type the type of record to tag ('post' for blogs, 
 *     'user' for users, 'tag' for tags, etc.
 * @param int $record_id the id of the record to tag
 * @param array $tags the array of tags to set on the record. If 
 *     given an empty array, all tags will be removed.
 * @return void 
 */
function tag_set($record_type, $record_id, $tags)
{
    static $in_recursion_semaphore = false;
    // this is to prevent loops when tagging a tag
    if ($record_type == 'tag' && !$in_recursion_semaphore) {
        $current_tagged_tag_name = tag_get_name($record_id);
    }
    $tags_ids = tag_get_id($tags, TAG_RETURN_ARRAY);
    // force an array, even if we only have one tag.
    $cleaned_tags = tag_normalize($tags);
    //echo 'tags-in-tag_set'; var_dump($tags); var_dump($tags_ids); var_dump($cleaned_tags);
    $current_ids = tag_get_tags_ids($record_type, $record_id);
    //var_dump($current_ids);
    // for data coherence reasons, it's better to remove deleted tags
    // before adding new data: ordering could be duplicated.
    foreach ($current_ids as $current_id) {
        if (!in_array($current_id, $tags_ids)) {
            tag_delete_instance($record_type, $record_id, $current_id);
            if ($record_type == 'tag' && !$in_recursion_semaphore) {
                // if we are removing a tag-on-a-tag (manually related tag),
                // we need to remove the opposite relationship as well.
                tag_delete_instance('tag', $current_id, $record_id);
            }
        }
    }
    foreach ($tags as $ordering => $tag) {
        $tag = trim($tag);
        if (!$tag) {
            continue;
        }
        $clean_tag = $cleaned_tags[$tag];
        $tag_current_id = $tags_ids[$clean_tag];
        if (is_null($tag_current_id)) {
            // create new tags
            //echo "call to add tag $tag\n";
            $new_tag = tag_add($tag);
            $tag_current_id = $new_tag[$clean_tag];
        }
        tag_assign($record_type, $record_id, $tag_current_id, $ordering);
        // if we are tagging a tag (adding a manually-assigned related tag), we
        // need to create the opposite relationship as well.
        if ($record_type == 'tag' && !$in_recursion_semaphore) {
            $in_recursion_semaphore = true;
            tag_set_add('tag', $tag_current_id, $current_tagged_tag_name);
            $in_recursion_semaphore = false;
        }
    }
}

/**
 * Stores a tag for a course for a user
 *
 * @uses $CFG
 * @param array $tags simple array of keywords to be stored
 * @param integer $courseid
 * @param integer $userid
 * @param string $tagtype official or default only
 * @param string $myurl optional for logging creation of course tags
 */
function coursetag_store_keywords($tags, $courseid, $userid=0, $tagtype='official', $myurl='') {

    global $CFG;

    if (is_array($tags) and !empty($tags)) {
        foreach($tags as $tag) {
            $tag = trim($tag);
            if (strlen($tag) > 0) {
                //tag_set_add('course', $courseid, $tag, $userid); //deletes official tags

                //add tag if does not exist
                if (!$tagid = tag_get_id($tag)) {
                    $tag_id_array = tag_add(array($tag), $tagtype);
                    $tagid = $tag_id_array[moodle_strtolower($tag)];
                }
                //ordering
                $ordering = 0;
                if ($current_ids = tag_get_tags_ids('course', $courseid)) {
                    end($current_ids);
                    $ordering = key($current_ids) + 1;
                }
                //set type
                tag_type_set($tagid, $tagtype);

                //tag_instance entry
                tag_assign('course', $courseid, $tagid, $ordering, $userid);

                //logging - note only for user added tags
                if ($tagtype == 'default' and $myurl != '') {
                    $url = $myurl.'?query='.urlencode($tag);
                    add_to_log($courseid, 'coursetags', 'add', $url, 'Course tagged');
                }
            }
        }
    }

}

/**
 * Stores a tag for a course for a user
 *
 * @package  core_tag
 * @category tag
 * @param    array  $tags     simple array of keywords to be stored
 * @param    int    $courseid the id of the course we wish to store a tag for
 * @param    int    $userid   the id of the user we wish to store a tag for
 * @param    string $tagtype  official or default only
 * @param    string $myurl    (optional) for logging creation of course tags
 */
function coursetag_store_keywords($tags, $courseid, $userid = 0, $tagtype = 'official', $myurl = '')
{
    global $CFG;
    if (is_array($tags) and !empty($tags)) {
        foreach ($tags as $tag) {
            $tag = trim($tag);
            if (strlen($tag) > 0) {
                //tag_set_add('course', $courseid, $tag, $userid); //deletes official tags
                //add tag if does not exist
                if (!($tagid = tag_get_id($tag))) {
                    $tag_id_array = tag_add(array($tag), $tagtype);
                    $tagid = $tag_id_array[core_text::strtolower($tag)];
                }
                //ordering
                $ordering = 0;
                if ($current_ids = tag_get_tags_ids('course', $courseid)) {
                    end($current_ids);
                    $ordering = key($current_ids) + 1;
                }
                //set type
                tag_type_set($tagid, $tagtype);
                //tag_instance entry
                tag_assign('course', $courseid, $tagid, $ordering, $userid, 'core', context_course::instance($courseid)->id);
            }
        }
    }
}

/**
 * Stores a tag for a course for a user
 *
 * @deprecated since 3.0
 * @package  core_tag
 * @category tag
 * @param    array  $tags     simple array of keywords to be stored
 * @param    int    $courseid the id of the course we wish to store a tag for
 * @param    int    $userid   the id of the user we wish to store a tag for
 * @param    string $tagtype  official or default only
 * @param    string $myurl    (optional) for logging creation of course tags
 */
function coursetag_store_keywords($tags, $courseid, $userid = 0, $tagtype = 'official', $myurl = '')
{
    debugging('Function coursetag_store_keywords() is deprecated. Userid is no longer used for tagging courses.', DEBUG_DEVELOPER);
    global $CFG;
    require_once $CFG->dirroot . '/tag/lib.php';
    if (is_array($tags) and !empty($tags)) {
        foreach ($tags as $tag) {
            $tag = trim($tag);
            if (strlen($tag) > 0) {
                //tag_set_add('course', $courseid, $tag, $userid); //deletes official tags
                //add tag if does not exist
                if (!($tagid = tag_get_id($tag))) {
                    $tag_id_array = tag_add(array($tag), $tagtype);
                    $tagid = $tag_id_array[core_text::strtolower($tag)];
                }
                //ordering
                $ordering = 0;
                if ($current_ids = tag_get_tags_ids('course', $courseid)) {
                    end($current_ids);
                    $ordering = key($current_ids) + 1;
                }
                //set type
                tag_type_set($tagid, $tagtype);
                //tag_instance entry
                tag_assign('course', $courseid, $tagid, $ordering, $userid, 'core', context_course::instance($courseid)->id);
            }
        }
    }
}