<?PHP  //$Id$
//
// This file keeps track of upgrades to Moodle's
// blocks system.
//
// Sometimes, changes between versions involve
// alterations to database structures and other
// major things that may break installations.
//
// The upgrade function in this file will attempt
// to perform all the necessary actions to upgrade
// your older installtion to the current version.
//
// If there's something it cannot do itself, it
// will tell you what you need to do.
//
// Versions are defined by backup_version.php
//
// This file is tailored to PostgreSQL

function blocks_upgrade($oldversion=0) {

global $CFG;
    
    $result = true;
    
    if ($oldversion < 2004041000 and $result) {
        $result = execute_sql("
                                CREATE TABLE {$CFG->prefix}blocks 
                                (
              				    id SERIAL8 PRIMARY KEY,
  			            	    name varchar(40) NOT NULL default '',
  				                version INT8 NOT NULL default '0',
  				                cron INT8  NOT NULL default '0',
  				                lastcron INT8  NOT NULL default '0',
  				                visible int NOT NULL default '1'
                                )
			                    ") ;

    }

    if ($oldversion < 2004101900 && $result) {
        $result = execute_sql("CREATE TABLE {$CFG->prefix}block (
                        id SERIAL8 PRIMARY KEY,
                        name varchar(40) NOT NULL default '',
                        version INT8 NOT NULL default '0',
                        cron INT8 NOT NULL default '0',
                        lastcron INT8 NOT NULL default '0',
                        visible int NOT NULL default '1',
                        multiple int NOT NULL default '0'
                     ) 
                     ");

        if(!$result) {
            return false;
        }

        $records = get_records('blocks');
        if(!empty($records)) {
            foreach($records as $block) {
                $block->multiple = 0;
                unset($block->id);
                insert_record('block', $block);
            }
        }

        execute_sql("DROP TABLE {$CFG->prefix}blocks");
        
        $result = execute_sql("CREATE TABLE {$CFG->prefix}block_instance (
                        id SERIAL8 PRIMARY KEY,
                        blockid INT8 not null default '0',
                        pageid INT8 not null default '0',
                        pagetype varchar(12) not null default '',
                        position char not null check (position in ('l', 'r')) ,
                        weight int not null default '0',
                        visible int not null default '0',
                        configdata text not null default ''
                    )");

        if(!$result) {
            return false;
        }
        
        $records = get_records('course');
        if(!empty($records)) {
            foreach($records as $thiscourse) {
                // The @ suppresses a notice emitted if there is no : in the string
                @list($left, $right) = split(':', $thiscourse->blockinfo);
                if(!empty($left)) {
                    $arr = explode(',', $left);
                    foreach($arr as $weight => $blk) {
                        $instance = new stdClass;
                        $instance->blockid    = abs($blk);
                        $instance->pageid     = $thiscourse->id;
                        $instance->pagetype   = PAGE_COURSE_VIEW;
                        $instance->position   = BLOCK_POS_LEFT;
                        $instance->weight     = $weight;
                        $instance->visible    = ($blk > 0) ? 1 : 0;
                        $instance->configdata = '';
                        insert_record('block_instance', $instance);
                    }
                }
                if(!empty($right)) {
                    $arr = explode(',', $right);
                    foreach($arr as $weight => $blk) {
                        $instance = new stdClass;
                        $instance->blockid    = abs($blk);
                        $instance->pageid     = $thiscourse->id;
                        $instance->pagetype   = PAGE_COURSE_VIEW;
                        $instance->position   = BLOCK_POS_RIGHT;
                        $instance->weight     = $weight;
                        $instance->visible    = ($blk > 0) ? 1 : 0;
                        $instance->configdata = '';
                        insert_record('block_instance', $instance);
                    }
                }
            }
        }

        execute_sql("ALTER TABLE {$CFG->prefix}course DROP COLUMN blockinfo");
    }

    if ($oldversion < 2004112900 && $result) {
        $result = $result && table_column('block_instance', 'pagetype', 'pagetype', 'varchar', '20', '');
        $result = $result && table_column('block_instance', 'position', 'position', 'varchar', '10', '');
    }

    //Finally, return result
    return $result;
}
?>