<?php

/*
 * Created on Monday, January 28, 2008
 *
 * API for MediaWiki 1.8+
 *
 * Copyright (C) 2008 Brent Garber
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 * http://www.gnu.org/copyleft/gpl.html
 */

if (!defined('MEDIAWIKI')) {
	// Eclipse helper - will be ignored in production
	require_once ('ApiQueryBase.php');
}

/**
 * Query module to get list of random pages
 * 
 * @addtogroup API
 */
 
 class ApiQueryRandom extends ApiQueryBase {

	private $namespace = NS_MAIN;

	public function __construct($query, $moduleName) {
		parent :: __construct($query, $moduleName, 'rn');
	}

	public function execute() {
		/* Initialize vars */
		$limit = $namespace = null;
		/* Get the parameters of the request */
		extract($this->extractRequestParams());

		$randstr = wfRandom();

		$data = array();
	
		/* Build Basic Query (Yea it really sucks) */
		$result = $this->getResult();
		$pageSet = $this->getPageSet();
		$titles = $pageSet->getTitles();

		$data = array();

		$this->addTables('page');
		$this->addFields('*');
		$this->addOption('LIMIT', $limit);
		$this->addWhereFld('page_namespace', $namespace);
		$this->addWhereRange('page_random','newer',$randstr,null);
		$this->addWhereIf('page_is_redirect != 0', true);
		$this->addOption('LIMIT', $limit + 1);
		$this->addOption('USE INDEX', 'page_random');
		$this->addOption('ORDER BY', 'page_random');
		$count = 0;
		$db = $this->getDB();
		$res = $this->select(__METHOD__);
		while($row = $db->fetchObject($res)) {
			$vals = $this->extractRowInfo($row);
			if($vals)
				$data[] = $vals;
		}
		$db->freeResult($res);

		$result->setIndexedTagName($data, 'rn');
		$result->addValue('query', $this->getModuleName(), $data);		
	}

	private function wfRandom() {
		# The maximum random value is "only" 2^31-1, so get two random
		# values to reduce the chance of dupes
		$max = mt_getrandmax() + 1;
		$rand = number_format( (mt_rand() * $max + mt_rand())
			/ $max / $max, 12, '.', '' );
		return $rand;
	}

	private function extractRowInfo($row) {
		$title = Title :: makeTitle($row->page_namespace, $row->page_title);
		$vals = array();
		$vals['title'] = $title;
		$vals['ns'] = $row->page_namespace;
		$vals['id'] = $row->page_id;

		return $vals;
	}
		
	protected function getAllowedParams() {
		return array (
			'namespace' => array(
				ApiBase :: PARAM_TYPE => 'namespace',
				ApiBase :: PARAM_ISMULTI => true
			),
			'limit' => array (
				ApiBase :: PARAM_TYPE => 'limit',
				ApiBase :: PARAM_MIN => 1,
				ApiBase :: PARAM_MAX => 10,
				ApiBase :: PARAM_MAX2 => 20
			),
		);
	}

	protected function getParamDescription() {
		return array (
			'namespace' => "Return pagess in (this|these) namespace(s) only",
			'limit' => 'limit how many random pages will be returned'
		);
	}

	protected function getDescription() {
		return 'Get a set of Random Pages';
	}

	protected function getExamples() {
		return 'api.php?action=query&list=random&rnnamespace=0&rnlimit=2';
	}

	public function getVersion() {
		return __CLASS__ . ': $Id: ApiQueryRandom.php overlordq$';
	}
}