<?php
/**
 * ARC2 RDF Store Query Handler.
 *
 * @author Benjamin Nowack
 * @license W3C Software License and GPL
 * @homepage <https://github.com/semsol/arc2>
 *
 * @version 2010-11-16
 */
ARC2::inc('Class');

class ARC2_StoreQueryHandler extends ARC2_Class
{
    public function __construct($a, &$caller)
    {
        parent::__construct($a, $caller);
    }

    public function __init()
    {
        parent::__init();
        $this->xsd = 'http://www.w3.org/2001/XMLSchema#';
        $this->allow_extension_functions = $this->v('store_allow_extension_functions', 1, $this->a);
        $this->keep_time_limit = $this->v('keep_time_limit', 0, $this->a);
        $this->handler_type = '';
    }

    public function getTermID($val, $term = '', $dont_cache = false)
    {
        return $this->store->getTermID($val, $term, $dont_cache);
    }

    public function hasHashColumn($tbl)
    {
        return $this->store->hasHashColumn($tbl);
    }

    public function getValueHash($val)
    {
        return $this->store->getValueHash($val);
    }

    public function getTripleTable()
    {
        $r = $this->store->getTablePrefix().'triple';

        return $r;
    }

    public function createMergeTable()
    {
        $split_ps = $this->store->getSetting('split_predicates', []);
        if (!$split_ps) {
            return 1;
        }
        $this->mrg_table_id = 'MRG_'.$this->store->getTablePrefix().crc32(uniqid(rand()));
        $this->getDBObject()->query('FLUSH TABLES');
        $indexes = $this->v('store_indexes', ['sp (s,p)', 'os (o,s)', 'po (p,o)'], $this->a);
        $index_code = $indexes ? 'KEY '.implode(', KEY ', $indexes).', ' : '';
        $prefix = $this->store->getTablePrefix();
        $sql = '
      CREATE TEMPORARY TABLE IF NOT EXISTS '.$prefix.'triple_all (
        t mediumint UNSIGNED NOT NULL,
        s mediumint UNSIGNED NOT NULL,
        p mediumint UNSIGNED NOT NULL,
        o mediumint UNSIGNED NOT NULL,
        o_lang_dt mediumint UNSIGNED NOT NULL,
        o_comp char(35) NOT NULL,                   /* normalized value for ORDER BY operations */
        s_type tinyint(1) NOT NULL default 0,       /* uri/bnode => 0/1 */
        o_type tinyint(1) NOT NULL default 0,       /* uri/bnode/literal => 0/1/2 */
        misc tinyint(1) NOT NULL default 0,         /* temporary flags */
        UNIQUE KEY (t), '.$index_code.' KEY (misc)
      )
    ';
        $v = $this->store->getDBVersion();
        $sql .= (($v < '04-01-00') && ($v >= '04-00-18')) ? 'ENGINE' : (($v >= '04-01-02') ? 'ENGINE' : 'TYPE');
        $sql .= '=MERGE UNION=('.$prefix.'triple';
        foreach ($split_ps as $pos => $p) {
            $sql .= ','.$prefix.'triple_'.abs(crc32($p));
        }
        $sql .= ')';
        // TODO whats about that?
        //$sql .= ($v >= '04-00-00') ? " CHARACTER SET utf8" : "";
        //$sql .= ($v >= '04-01-00') ? " COLLATE utf8_unicode_ci" : "";
        //echo $sql;
        return $this->getDBObject()->query($sql);
    }

    public function dropMergeTable()
    {
        return 1;
        // TODO triple_all table seems not used anymore, therefore this function can be removed?
        $sql = 'DROP TABLE IF EXISTS '.$this->store->getTablePrefix().'triple_all';
        //echo $sql;
        //return $this->queryDB($sql, $this->store->getDBCon());
    }
}
