<?php
    /**
    * Global Search Engine for Moodle
    *
    * @package search
    * @category core
    * @subpackage search_engine
    * @author Michael Champanis (mchampan) [cynnical@gmail.com], Valery Fremaux [valery.fremaux@club-internet.fr] > 1.8
    * @date 2008/03/31
    * @license http://www.gnu.org/copyleft/gpl.html GNU Public License
    *
    * Index asynchronous updator
    *
    * Major chages in this review is passing the xxxx_db_names return to
    * multiple arity to handle multiple document types modules
    */

    /**
    * includes and requires
    */
    require_once('../config.php');
    require_once("$CFG->dirroot/search/lib.php");
    require_once("$CFG->dirroot/search/indexlib.php");

/// makes inclusions of the Zend Engine more reliable
    $separator = (array_key_exists('WINDIR', $_SERVER)) ? ';' : ':' ;
    ini_set('include_path', $CFG->dirroot.'/search'.$separator.ini_get('include_path'));require_login();

/// checks global search activation

    require_login();

    if (empty($CFG->enableglobalsearch)) {
        print_error('globalsearchdisabled', 'search');
    }

    if (!has_capability('moodle/site:doanything', get_context_instance(CONTEXT_SYSTEM))) {
        print_error('beadmin', 'search', "$CFG->wwwroot/login/index.php");
    }

    try {
        $index = new Zend_Search_Lucene(SEARCH_INDEX_PATH);
    } catch(LuceneException $e) {
        mtrace("Could not construct a valid index. Maybe the first indexation was never made, or files might be corrupted. Run complete indexation again.");
        return;
    }
    $dbcontrol = new IndexDBControl();
    $update_count = 0;
    $indexdate = $CFG->search_indexer_update_date;
    $startupdatedate = time();

/// indexing changed resources

    mtrace("Starting index update (updates)...\n");

    if ($mods = get_records_select('modules')) {
        $mods = array_merge($mods, search_get_additional_modules());

        foreach ($mods as $mod) {
            $class_file = $CFG->dirroot.'/search/documents/'.$mod->name.'_document.php';
            $get_document_function = $mod->name.'_single_document';
            $delete_function = $mod->name.'_delete';
            $db_names_function = $mod->name.'_db_names';
            $updates = array();

            if (file_exists($class_file)) {
                require_once($class_file);

                //if both required functions exist
                if (function_exists($delete_function) and function_exists($db_names_function) and function_exists($get_document_function)) {
                    mtrace("Checking $mod->name module for updates.");
                    $valuesArray = $db_names_function();
                    if ($valuesArray){
                        foreach($valuesArray as $values){

                            $where = (isset($values[5])) ? 'AND ('.$values[5].')' : '';
                            $itemtypes = ($values[4] != '*' && $values[4] != 'any') ? " AND itemtype = '{$values[4]}' " : '' ;

                            //TODO: check 'in' syntax with other RDBMS' (add and update.php as well)
                            $table = SEARCH_DATABASE_TABLE;
                            $query = "
                                SELECT
                                    docid,
                                    itemtype
                                FROM
                                    {$CFG->prefix}{$table}
                                WHERE
                                    doctype = ?
                                    $itemtypes
                            ";
                            $docIds = $DB->get_records_sql_menu($query, array($mod->name));
                            $docIdList = ($docIds) ? implode("','", array_keys($docIds)) : '' ;

                            $query = "
                                SELECT
                                    id,
                                    {$values[0]} as docid
                                FROM
                                    {$CFG->prefix}{$values[1]}
                                WHERE
                                    {$values[3]} > {$indexdate} AND
                                    id IN ('{$docIdList}')
                                    $where
                            ";
                            $records = get_records_sql($query);
                            if (is_array($records)) {
                                foreach($records as $record) {
                                    $updates[] = $delete_function($record->docid, $docIds[$record->docid]);
                                }
                            }
                        }

                        foreach ($updates as $update) {
                            ++$update_count;

                            //delete old document
                            $doc = $index->find("+docid:{$update->id} +doctype:{$mod->name} +itemtype:{$update->itemtype}");

                            //get the record, should only be one
                            foreach ($doc as $thisdoc) {
                                mtrace("  Delete: $thisdoc->title (database id = $thisdoc->dbid, index id = $thisdoc->id, moodle instance id = $thisdoc->docid)");
                                $dbcontrol->delDocument($thisdoc);
                                $index->delete($thisdoc->id);
                            }

                            //add new modified document back into index
                            $add = $get_document_function($update->id, $update->itemtype);

                            //object to insert into db
                            $dbid = $dbcontrol->addDocument($add);

                            //synchronise db with index
                            $add->addField(Zend_Search_Lucene_Field::Keyword('dbid', $dbid));
                            mtrace("  Add: $add->title (database id = $add->dbid, moodle instance id = $add->docid)");
                            $index->addDocument($add);
                        }
                    }
                    else{
                        mtrace("No types to update.\n");
                    }
                    mtrace("Finished $mod->name.\n");
                }
            }
        }
    }

    //commit changes
    $index->commit();

    //update index date
    set_config("search_indexer_update_date", $startupdatedate);

    mtrace("Finished $update_count updates");

?>