/**
 * Given an ID of an instance of this module,
 * this function will permanently delete the instance
 * and any data that depends on it.
 *
 * @global object
 * @param int $id glossary id
 * @return bool success
 */
function glossary_delete_instance($id) {
    global $DB, $CFG;

    if (!$glossary = $DB->get_record('glossary', array('id'=>$id))) {
        return false;
    }

    if (!$cm = get_coursemodule_from_instance('glossary', $id)) {
        return false;
    }

    if (!$context = get_context_instance(CONTEXT_MODULE, $cm->id)) {
        return false;
    }

    $fs = get_file_storage();

    if ($glossary->mainglossary) {
        // unexport entries
        $sql = "SELECT ge.id, ge.sourceglossaryid, cm.id AS sourcecmid
                  FROM {glossary_entries} ge
                  JOIN {modules} m ON m.name = 'glossary'
                  JOIN {course_modules} cm ON (cm.module = m.id AND cm.instance = ge.sourceglossaryid)
                 WHERE ge.glossaryid = ? AND ge.sourceglossaryid > 0";

        if ($exported = $DB->get_records_sql($sql, array($id))) {
            foreach ($exported as $entry) {
                $entry->glossaryid = $entry->sourceglossaryid;
                $entry->sourceglossaryid = 0;
                $newcontext = get_context_instance(CONTEXT_MODULE, $entry->sourcecmid);
                if ($oldfiles = $fs->get_area_files($context->id, 'mod_glossary', 'attachment', $entry->id)) {
                    foreach ($oldfiles as $oldfile) {
                        $file_record = new stdClass();
                        $file_record->contextid = $newcontext->id;
                        $fs->create_file_from_storedfile($file_record, $oldfile);
                    }
                    $fs->delete_area_files($context->id, 'mod_glossary', 'attachment', $entry->id);
                    $entry->attachment = '1';
                } else {
                    $entry->attachment = '0';
                }
                $DB->update_record('glossary_entries', $entry);
            }
        }
    } else {
        // move exported entries to main glossary
        $sql = "UPDATE {glossary_entries}
                   SET sourceglossaryid = 0
                 WHERE sourceglossaryid = ?";
        $DB->execute($sql, array($id));
    }

    // Delete any dependent records
    $entry_select = "SELECT id FROM {glossary_entries} WHERE glossaryid = ?";
    $DB->delete_records_select('comments', "contextid=? AND commentarea=? AND itemid IN ($entry_select)", array($id, 'glossary_entry', $context->id));
    $DB->delete_records_select('glossary_alias',    "entryid IN ($entry_select)", array($id));

    $category_select = "SELECT id FROM {glossary_categories} WHERE glossaryid = ?";
    $DB->delete_records_select('glossary_entries_categories', "categoryid IN ($category_select)", array($id));
    $DB->delete_records('glossary_categories', array('glossaryid'=>$id));
    $DB->delete_records('glossary_entries', array('glossaryid'=>$id));

    // delete all files
    $fs->delete_area_files($context->id);

    glossary_grade_item_delete($glossary);

    return $DB->delete_records('glossary', array('id'=>$id));
}

function glossary_delete_instance($id)
{
    /// Given an ID of an instance of this module,
    /// this function will permanently delete the instance
    /// and any data that depends on it.
    if (!($glossary = get_record("glossary", "id", "{$id}"))) {
        return false;
    }
    $result = true;
    # Delete any dependent records here #
    if (!delete_records("glossary", "id", "{$glossary->id}")) {
        $result = false;
    } else {
        if ($categories = get_records("glossary_categories", "glossaryid", $glossary->id)) {
            $cats = "";
            foreach ($categories as $cat) {
                $cats .= "{$cat->id},";
            }
            $cats = substr($cats, 0, -1);
            if ($cats) {
                delete_records_select("glossary_entries_categories", "categoryid in ({$cats})");
                delete_records("glossary_categories", "glossaryid", $glossary->id);
            }
        }
        if ($entries = get_records("glossary_entries", "glossaryid", $glossary->id)) {
            $ents = "";
            foreach ($entries as $entry) {
                if ($entry->sourceglossaryid) {
                    $entry->glossaryid = $entry->sourceglossaryid;
                    $entry->sourceglossaryid = 0;
                    update_record("glossary_entries", $entry);
                } else {
                    $ents .= "{$entry->id},";
                }
            }
            $ents = substr($ents, 0, -1);
            if ($ents) {
                delete_records_select("glossary_comments", "entryid in ({$ents})");
                delete_records_select("glossary_alias", "entryid in ({$ents})");
                delete_records_select("glossary_ratings", "entryid in ({$ents})");
            }
        }
        glossary_delete_attachments($glossary);
        delete_records("glossary_entries", "glossaryid", "{$glossary->id}");
    }
    glossary_grade_item_delete($glossary);
    return $result;
}