<?php

/*
 * Created on July 7, 2007
 *
 * API for MediaWiki 1.8+
 *
 * Copyright (C) 2006 Yuri Astrakhan <Firstname><Lastname>@gmail.com
 *
 * 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 enumerate links from all pages together.
 *
 * @ingroup API
 */
class ApiQueryAllLinks extends ApiQueryGeneratorBase {

	public function __construct( $query, $moduleName ) {
		parent :: __construct( $query, $moduleName, 'al' );
	}

	public function execute() {
		$this->run();
	}

	public function getCacheMode( $params ) {
		return 'public';
	}

	public function executeGenerator( $resultPageSet ) {
		$this->run( $resultPageSet );
	}

	private function run( $resultPageSet = null ) {

		$db = $this->getDB();
		$params = $this->extractRequestParams();

		$prop = array_flip( $params['prop'] );
		$fld_ids = isset( $prop['ids'] );
		$fld_title = isset( $prop['title'] );

		if ( $params['unique'] ) {
			if ( !is_null( $resultPageSet ) )
				$this->dieUsage( $this->getModuleName() . ' cannot be used as a generator in unique links mode', 'params' );
			if ( $fld_ids )
				$this->dieUsage( $this->getModuleName() . ' cannot return corresponding page ids in unique links mode', 'params' );
			$this->addOption( 'DISTINCT' );
		}

		$this->addTables( 'pagelinks' );
		$this->addWhereFld( 'pl_namespace', $params['namespace'] );
		
		if ( !is_null( $params['from'] ) && !is_null( $params['continue'] ) )
			$this->dieUsage( 'alcontinue and alfrom cannot be used together', 'params' );
		if ( !is_null( $params['continue'] ) )
		{
			$arr = explode( '|', $params['continue'] );
			if ( count( $arr ) != 2 )
				$this->dieUsage( "Invalid continue parameter", 'badcontinue' );
			$from = $this->getDB()->strencode( $this->titleToKey( $arr[0] ) );
			$id = intval( $arr[1] );
			$this->addWhere( "pl_title > '$from' OR " .
					"(pl_title = '$from' AND " .
					"pl_from > $id)" );
		}

		if ( !is_null( $params['from'] ) )
			$this->addWhere( 'pl_title>=' . $db->addQuotes( $this->titlePartToKey( $params['from'] ) ) );
		if ( isset ( $params['prefix'] ) )
			$this->addWhere( 'pl_title' . $db->buildLike( $this->titlePartToKey( $params['prefix'] ), $db->anyString() ) );

		$this->addFields( array (
			'pl_title',
		) );
		$this->addFieldsIf( 'pl_from', !$params['unique'] );

		$this->addOption( 'USE INDEX', 'pl_namespace' );
		$limit = $params['limit'];
		$this->addOption( 'LIMIT', $limit + 1 );
		if ( $params['unique'] )
			$this->addOption( 'ORDER BY', 'pl_title' );
		else
			$this->addOption( 'ORDER BY', 'pl_title, pl_from' );

		$res = $this->select( __METHOD__ );

		$pageids = array ();
		$count = 0;
		$result = $this->getResult();
		while ( $row = $db->fetchObject( $res ) ) {
			if ( ++ $count > $limit ) {
				// We've reached the one extra which shows that there are additional pages to be had. Stop here...
				// TODO: Security issue - if the user has no right to view next title, it will still be shown
				if ( $params['unique'] )
					$this->setContinueEnumParameter( 'from', $this->keyToTitle( $row->pl_title ) );
				else
					$this->setContinueEnumParameter( 'continue', $this->keyToTitle( $row->pl_title ) . "|" . $row->pl_from );
				break;
			}

			if ( is_null( $resultPageSet ) ) {
				$vals = array();
				if ( $fld_ids )
					$vals['fromid'] = intval( $row->pl_from );
				if ( $fld_title ) {
					$title = Title :: makeTitle( $params['namespace'], $row->pl_title );
					ApiQueryBase::addTitleInfo( $vals, $title );
				}
				$fit = $result->addValue( array( 'query', $this->getModuleName() ), null, $vals );
				if ( !$fit )
				{
					if ( $params['unique'] )
						$this->setContinueEnumParameter( 'from', $this->keyToTitle( $row->pl_title ) );
					else
						$this->setContinueEnumParameter( 'continue', $this->keyToTitle( $row->pl_title ) . "|" . $row->pl_from );
					break;
				}
			} else {
				$pageids[] = $row->pl_from;
			}
		}
		$db->freeResult( $res );

		if ( is_null( $resultPageSet ) ) {
			$result->setIndexedTagName_internal( array( 'query', $this->getModuleName() ), 'l' );
		} else {
			$resultPageSet->populateFromPageIDs( $pageids );
		}
	}

	public function getAllowedParams() {
		return array (
			'continue' => null,
			'from' => null,
			'prefix' => null,
			'unique' => false,
			'prop' => array (
				ApiBase :: PARAM_ISMULTI => true,
				ApiBase :: PARAM_DFLT => 'title',
				ApiBase :: PARAM_TYPE => array (
					'ids',
					'title'
				)
			),
			'namespace' => array (
				ApiBase :: PARAM_DFLT => 0,
				ApiBase :: PARAM_TYPE => 'namespace'
			),
			'limit' => array (
				ApiBase :: PARAM_DFLT => 10,
				ApiBase :: PARAM_TYPE => 'limit',
				ApiBase :: PARAM_MIN => 1,
				ApiBase :: PARAM_MAX => ApiBase :: LIMIT_BIG1,
				ApiBase :: PARAM_MAX2 => ApiBase :: LIMIT_BIG2
			)
		);
	}

	public function getParamDescription() {
		return array (
			'from' => 'The page title to start enumerating from.',
			'prefix' => 'Search for all page titles that begin with this value.',
			'unique' => 'Only show unique links. Cannot be used with generator or prop=ids',
			'prop' => 'What pieces of information to include',
			'namespace' => 'The namespace to enumerate.',
			'limit' => 'How many total links to return.',
			'continue' => 'When more results are available, use this to continue.',
		);
	}

	public function getDescription() {
		return 'Enumerate all links that point to a given namespace';
	}
	
	public function getPossibleErrors() {
		return array_merge( parent::getPossibleErrors(), array(
			array( 'code' => 'params', 'info' => $this->getModuleName() . ' cannot be used as a generator in unique links mode' ),
			array( 'code' => 'params', 'info' => $this->getModuleName() . ' cannot return corresponding page ids in unique links mode' ),
			array( 'code' => 'params', 'info' => 'alcontinue and alfrom cannot be used together' ),
			array( 'code' => 'badcontinue', 'info' => 'Invalid continue parameter' ),
		) );
	}

	protected function getExamples() {
		return array (
			'api.php?action=query&list=alllinks&alunique&alfrom=B',
		);
	}

	public function getVersion() {
		return __CLASS__ . ': $Id: ApiQueryAllLinks.php 69932 2010-07-26 08:03:21Z tstarling $';
	}
}