<?php

/*
 * Created on Sep 7, 2006
 *
 * 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');
}

/**
 * A query action to enumerate revisions of a given page, or show top revisions of multiple pages.
 * Various pieces of information may be shown - flags, comments, and the actual wiki markup of the rev.
 * In the enumeration mode, ranges of revisions may be requested and filtered.
 *
 * @ingroup API
 */
class ApiQueryRevisions extends ApiQueryBase {

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

	private $fld_ids = false, $fld_flags = false, $fld_timestamp = false, $fld_size = false,
			$fld_comment = false, $fld_user = false, $fld_content = false;

	protected function getTokenFunctions() {
		// tokenname => function
		// function prototype is func($pageid, $title, $rev)
		// should return token or false

		// Don't call the hooks twice
		if(isset($this->tokenFunctions))
			return $this->tokenFunctions;

		// If we're in JSON callback mode, no tokens can be obtained
		if(!is_null($this->getMain()->getRequest()->getVal('callback')))
			return array();

		$this->tokenFunctions = array(
			'rollback' => array( 'ApiQueryRevisions', 'getRollbackToken' )
		);
		wfRunHooks('APIQueryRevisionsTokens', array(&$this->tokenFunctions));
		return $this->tokenFunctions;
	}

	public static function getRollbackToken($pageid, $title, $rev)
	{
		global $wgUser;
		if(!$wgUser->isAllowed('rollback'))
			return false;
		return $wgUser->editToken(array($title->getPrefixedText(),
						$rev->getUserText()));
	}

	public function execute() {
		$params = $this->extractRequestParams(false);

		// If any of those parameters are used, work in 'enumeration' mode.
		// Enum mode can only be used when exactly one page is provided.
		// Enumerating revisions on multiple pages make it extremely
		// difficult to manage continuations and require additional SQL indexes
		$enumRevMode = (!is_null($params['user']) || !is_null($params['excludeuser']) ||
				!is_null($params['limit']) || !is_null($params['startid']) ||
				!is_null($params['endid']) || $params['dir'] === 'newer' ||
				!is_null($params['start']) || !is_null($params['end']));


		$pageSet = $this->getPageSet();
		$pageCount = $pageSet->getGoodTitleCount();
		$revCount = $pageSet->getRevisionCount();

		// Optimization -- nothing to do
		if ($revCount === 0 && $pageCount === 0)
			return;

		if ($revCount > 0 && $enumRevMode)
			$this->dieUsage('The revids= parameter may not be used with the list options (limit, startid, endid, dirNewer, start, end).', 'revids');

		if ($pageCount > 1 && $enumRevMode)
			$this->dieUsage('titles, pageids or a generator was used to supply multiple pages, but the limit, startid, endid, dirNewer, user, excludeuser, start and end parameters may only be used on a single page.', 'multpages');

		if (!is_null($params['diffto'])) {
			if ($params['diffto'] == 'cur')
				$params['diffto'] = 0;
			if ((!ctype_digit($params['diffto']) || $params['diffto'] < 0) 
					&& $params['diffto'] != 'prev' && $params['diffto'] != 'next')
				$this->dieUsage('rvdiffto must be set to a non-negative number, "prev", "next" or "cur"', 'diffto');
			// Check whether the revision exists and is readable,
			// DifferenceEngine returns a rather ambiguous empty
			// string if that's not the case
			if ($params['diffto'] != 0) {
				$difftoRev = Revision::newFromID($params['diffto']);
				if (!$difftoRev)
					$this->dieUsageMsg(array('nosuchrevid', $params['diffto']));
				if (!$difftoRev->userCan(Revision::DELETED_TEXT)) {
					$this->setWarning("Couldn't diff to r{$difftoRev->getID()}: content is hidden");
					$params['diffto'] = null;
				}
			}
		}

		$this->addTables('revision');
		$this->addFields(Revision::selectFields());
		$this->addTables('page');
		$this->addWhere('page_id = rev_page');

		$prop = array_flip($params['prop']);

		// Optional fields
		$this->fld_ids = isset ($prop['ids']);
		// $this->addFieldsIf('rev_text_id', $this->fld_ids); // should this be exposed?
		$this->fld_flags = isset ($prop['flags']);
		$this->fld_timestamp = isset ($prop['timestamp']);
		$this->fld_comment = isset ($prop['comment']);
		$this->fld_size = isset ($prop['size']);
		$this->fld_user = isset ($prop['user']);
		$this->token = $params['token'];
		$this->diffto = $params['diffto'];

		if ( !is_null($this->token) || $pageCount > 0) {
			$this->addFields( Revision::selectPageFields() );
		}

		if (isset ($prop['content'])) {

			// For each page we will request, the user must have read rights for that page
			foreach ($pageSet->getGoodTitles() as $title) {
				if( !$title->userCanRead() )
					$this->dieUsage(
						'The current user is not allowed to read ' . $title->getPrefixedText(),
						'accessdenied');
			}

			$this->addTables('text');
			$this->addWhere('rev_text_id=old_id');
			$this->addFields('old_id');
			$this->addFields(Revision::selectTextFields());

			$this->fld_content = true;

			$this->expandTemplates = $params['expandtemplates'];
			$this->generateXML = $params['generatexml'];
			if(isset($params['section']))
				$this->section = $params['section'];
			else
				$this->section = false;
		}

		$userMax = ( $this->fld_content ? ApiBase::LIMIT_SML1 : ApiBase::LIMIT_BIG1 );
		$botMax  = ( $this->fld_content ? ApiBase::LIMIT_SML2 : ApiBase::LIMIT_BIG2 );
		$limit = $params['limit'];
		if( $limit == 'max' ) {
			$limit = $this->getMain()->canApiHighLimits() ? $botMax : $userMax;
			$this->getResult()->addValue( 'limits', $this->getModuleName(), $limit );
		}

		if ($enumRevMode) {

			// This is mostly to prevent parameter errors (and optimize SQL?)
			if (!is_null($params['startid']) && !is_null($params['start']))
				$this->dieUsage('start and startid cannot be used together', 'badparams');

			if (!is_null($params['endid']) && !is_null($params['end']))
				$this->dieUsage('end and endid cannot be used together', 'badparams');

			if(!is_null($params['user']) && !is_null($params['excludeuser']))
				$this->dieUsage('user and excludeuser cannot be used together', 'badparams');

			// This code makes an assumption that sorting by rev_id and rev_timestamp produces
			// the same result. This way users may request revisions starting at a given time,
			// but to page through results use the rev_id returned after each page.
			// Switching to rev_id removes the potential problem of having more than
			// one row with the same timestamp for the same page.
			// The order needs to be the same as start parameter to avoid SQL filesort.

			if (is_null($params['startid']) && is_null($params['endid']))
				$this->addWhereRange('rev_timestamp', $params['dir'],
					$params['start'], $params['end']);
			else {
				$this->addWhereRange('rev_id', $params['dir'],
					$params['startid'], $params['endid']);
				// One of start and end can be set
				// If neither is set, this does nothing
				$this->addWhereRange('rev_timestamp', $params['dir'],
					$params['start'], $params['end'], false);
			}

			// must manually initialize unset limit
			if (is_null($limit))
				$limit = 10;
			$this->validateLimit('limit', $limit, 1, $userMax, $botMax);

			// There is only one ID, use it
			$this->addWhereFld('rev_page', reset(array_keys($pageSet->getGoodTitles())));

			if(!is_null($params['user'])) {
				$this->addWhereFld('rev_user_text', $params['user']);
			} elseif (!is_null($params['excludeuser'])) {
				$this->addWhere('rev_user_text != ' .
					$this->getDB()->addQuotes($params['excludeuser']));
			}
			if(!is_null($params['user']) || !is_null($params['excludeuser'])) {
				// Paranoia: avoid brute force searches (bug 17342)
				$this->addWhere('rev_deleted & ' . Revision::DELETED_USER . ' = 0');
			}
		}
		elseif ($revCount > 0) {
			$max = $this->getMain()->canApiHighLimits() ? $botMax : $userMax;
			$revs = $pageSet->getRevisionIDs();
			if(self::truncateArray($revs, $max))
				$this->setWarning("Too many values supplied for parameter 'revids': the limit is $max"); 

			// Get all revision IDs
			$this->addWhereFld('rev_id', array_keys($revs));

			if(!is_null($params['continue']))
				$this->addWhere("rev_id >= '" . intval($params['continue']) . "'");
			$this->addOption('ORDER BY', 'rev_id');

			// assumption testing -- we should never get more then $revCount rows.
			$limit = $revCount;
		}
		elseif ($pageCount > 0) {
			$max = $this->getMain()->canApiHighLimits() ? $botMax : $userMax;
			$titles = $pageSet->getGoodTitles();
			if(self::truncateArray($titles, $max))
				$this->setWarning("Too many values supplied for parameter 'titles': the limit is $max");
			
			// When working in multi-page non-enumeration mode,
			// limit to the latest revision only
			$this->addWhere('page_id=rev_page');
			$this->addWhere('page_latest=rev_id');
			
			// Get all page IDs
			$this->addWhereFld('page_id', array_keys($titles));
			// Every time someone relies on equality propagation, god kills a kitten :)
			$this->addWhereFld('rev_page', array_keys($titles));
			
			if(!is_null($params['continue']))
			{
				$cont = explode('|', $params['continue']);
				if(count($cont) != 2)
					$this->dieUsage("Invalid continue param. You should pass the original " .
							"value returned by the previous query", "_badcontinue");
				$pageid = intval($cont[0]);
				$revid = intval($cont[1]);
				$this->addWhere("rev_page > '$pageid' OR " .
						"(rev_page = '$pageid' AND " .
						"rev_id >= '$revid')");
			}
			$this->addOption('ORDER BY', 'rev_page, rev_id');

			// assumption testing -- we should never get more then $pageCount rows.
			$limit = $pageCount;
		} else
			ApiBase :: dieDebug(__METHOD__, 'param validation?');

		$this->addOption('LIMIT', $limit +1);

		$data = array ();
		$count = 0;
		$res = $this->select(__METHOD__);

		$db = $this->getDB();
		while ($row = $db->fetchObject($res)) {

			if (++ $count > $limit) {
				// We've reached the one extra which shows that there are additional pages to be had. Stop here...
				if (!$enumRevMode)
					ApiBase :: dieDebug(__METHOD__, 'Got more rows then expected'); // bug report
				$this->setContinueEnumParameter('startid', intval($row->rev_id));
				break;
			}
			$revision = new Revision( $row );
			//
			$fit = $this->addPageSubItem($revision->getPage(), $this->extractRowInfo($revision), 'rev');
			if(!$fit)
			{
				if($enumRevMode)
					$this->setContinueEnumParameter('startid', intval($row->rev_id));
				else if($revCount > 0)
					$this->setContinueEnumParameter('continue', intval($row->rev_id));
				else
					$this->setContinueEnumParameter('continue', intval($row->rev_page) .
						'|' . intval($row->rev_id));
				break;
			}
		}
		$db->freeResult($res);
	}

	private function extractRowInfo( $revision ) {
		$title = $revision->getTitle();
		$vals = array ();

		if ($this->fld_ids) {
			$vals['revid'] = intval($revision->getId());
			// $vals['oldid'] = intval($row->rev_text_id);	// todo: should this be exposed?
		}

		if ($this->fld_flags && $revision->isMinor())
			$vals['minor'] = '';

		if ($this->fld_user) {
			if ($revision->isDeleted(Revision::DELETED_USER)) {
				$vals['userhidden'] = '';
			} else {
				$vals['user'] = $revision->getUserText();
				if (!$revision->getUser())
					$vals['anon'] = '';
			}
		}

		if ($this->fld_timestamp) {
			$vals['timestamp'] = wfTimestamp(TS_ISO_8601, $revision->getTimestamp());
		}

		if ($this->fld_size && !is_null($revision->getSize())) {
			$vals['size'] = intval($revision->getSize());
		}

		if ($this->fld_comment) {
			if ($revision->isDeleted(Revision::DELETED_COMMENT)) {
				$vals['commenthidden'] = '';
			} else {
				$comment = $revision->getComment();
				if (strval($comment) !== '')
					$vals['comment'] = $comment;
			}
		}	

		if(!is_null($this->token))
		{
			$tokenFunctions = $this->getTokenFunctions();
			foreach($this->token as $t)
			{
				$val = call_user_func($tokenFunctions[$t], $title->getArticleID(), $title, $revision);
				if($val === false)
					$this->setWarning("Action '$t' is not allowed for the current user");
				else
					$vals[$t . 'token'] = $val;
			}
		}
		
		if ($this->fld_content && !$revision->isDeleted(Revision::DELETED_TEXT)) {
			global $wgParser;
			$text = $revision->getText();
			# Expand templates after getting section content because
			# template-added sections don't count and Parser::preprocess()
			# will have less input
			if ($this->section !== false) {
				$text = $wgParser->getSection( $text, $this->section, false);
				if($text === false)
					$this->dieUsage("There is no section {$this->section} in r".$revision->getId(), 'nosuchsection');
			}
			if ($this->generateXML) {
				$wgParser->startExternalParse( $title, new ParserOptions(), OT_PREPROCESS );
				$dom = $wgParser->preprocessToDom( $text );
				if ( is_callable( array( $dom, 'saveXML' ) ) ) {
					$xml = $dom->saveXML();
				} else {
					$xml = $dom->__toString();
				}
				$vals['parsetree'] = $xml;
				
			}
			if ($this->expandTemplates) {
				$text = $wgParser->preprocess( $text, $title, new ParserOptions() );
			}
			ApiResult :: setContent($vals, $text);
		} else if ($this->fld_content) {
			$vals['texthidden'] = '';
		}

		if (!is_null($this->diffto)) {
			global $wgAPIMaxUncachedDiffs;
			static $n = 0; // Numer of uncached diffs we've had
			if($n< $wgAPIMaxUncachedDiffs) {
				$engine = new DifferenceEngine($title, $revision->getID(), $this->diffto);
				$difftext = $engine->getDiffBody();
				$vals['diff']['from'] = $engine->getOldid();
				$vals['diff']['to'] = $engine->getNewid();
				ApiResult::setContent($vals['diff'], $difftext);
				if(!$engine->wasCacheHit())
					$n++;
			} else {
				$vals['diff']['notcached'] = '';
			}
		}
		return $vals;
	}

	public function getAllowedParams() {
		return array (
			'prop' => array (
				ApiBase :: PARAM_ISMULTI => true,
				ApiBase :: PARAM_DFLT => 'ids|timestamp|flags|comment|user',
				ApiBase :: PARAM_TYPE => array (
					'ids',
					'flags',
					'timestamp',
					'user',
					'size',
					'comment',
					'content',
				)
			),
			'limit' => array (
				ApiBase :: PARAM_TYPE => 'limit',
				ApiBase :: PARAM_MIN => 1,
				ApiBase :: PARAM_MAX => ApiBase :: LIMIT_BIG1,
				ApiBase :: PARAM_MAX2 => ApiBase :: LIMIT_BIG2
			),
			'startid' => array (
				ApiBase :: PARAM_TYPE => 'integer'
			),
			'endid' => array (
				ApiBase :: PARAM_TYPE => 'integer'
			),
			'start' => array (
				ApiBase :: PARAM_TYPE => 'timestamp'
			),
			'end' => array (
				ApiBase :: PARAM_TYPE => 'timestamp'
			),
			'dir' => array (
				ApiBase :: PARAM_DFLT => 'older',
				ApiBase :: PARAM_TYPE => array (
					'newer',
					'older'
				)
			),
			'user' => array(
				ApiBase :: PARAM_TYPE => 'user'
			),
			'excludeuser' => array(
				ApiBase :: PARAM_TYPE => 'user'
			),
			'expandtemplates' => false,
			'generatexml' => false,
			'section' => null,
			'token' => array(
				ApiBase :: PARAM_TYPE => array_keys($this->getTokenFunctions()),
				ApiBase :: PARAM_ISMULTI => true
			),
			'continue' => null,
			'diffto' => null,
		);
	}

	public function getParamDescription() {
		return array (
			'prop' => 'Which properties to get for each revision.',
			'limit' => 'limit how many revisions will be returned (enum)',
			'startid' => 'from which revision id to start enumeration (enum)',
			'endid' => 'stop revision enumeration on this revid (enum)',
			'start' => 'from which revision timestamp to start enumeration (enum)',
			'end' => 'enumerate up to this timestamp (enum)',
			'dir' => 'direction of enumeration - towards "newer" or "older" revisions (enum)',
			'user' => 'only include revisions made by user',
			'excludeuser' => 'exclude revisions made by user',
			'expandtemplates' => 'expand templates in revision content',
			'generatexml' => 'generate XML parse tree for revision content',
			'section' => 'only retrieve the content of this section',
			'token' => 'Which tokens to obtain for each revision',
			'continue' => 'When more results are available, use this to continue',
			'diffto' => array('Revision ID to diff each revision to.',
				'Use "prev", "next" and "cur" for the previous, next and current revision respectively.'),
		);
	}

	public function getDescription() {
		return array (
			'Get revision information.',
			'This module may be used in several ways:',
			' 1) Get data about a set of pages (last revision), by setting titles or pageids parameter.',
			' 2) Get revisions for one given page, by using titles/pageids with start/end/limit params.',
			' 3) Get data about a set of revisions by setting their IDs with revids parameter.',
			'All parameters marked as (enum) may only be used with a single page (#2).'
		);
	}

	protected function getExamples() {
		return array (
			'Get data with content for the last revision of titles "API" and "Main Page":',
			'  api.php?action=query&prop=revisions&titles=API|Main%20Page&rvprop=timestamp|user|comment|content',
			'Get last 5 revisions of the "Main Page":',
			'  api.php?action=query&prop=revisions&titles=Main%20Page&rvlimit=5&rvprop=timestamp|user|comment',
			'Get first 5 revisions of the "Main Page":',
			'  api.php?action=query&prop=revisions&titles=Main%20Page&rvlimit=5&rvprop=timestamp|user|comment&rvdir=newer',
			'Get first 5 revisions of the "Main Page" made after 2006-05-01:',
			'  api.php?action=query&prop=revisions&titles=Main%20Page&rvlimit=5&rvprop=timestamp|user|comment&rvdir=newer&rvstart=20060501000000',
			'Get first 5 revisions of the "Main Page" that were not made made by anonymous user "127.0.0.1"',
			'  api.php?action=query&prop=revisions&titles=Main%20Page&rvlimit=5&rvprop=timestamp|user|comment&rvexcludeuser=127.0.0.1',
			'Get first 5 revisions of the "Main Page" that were made by the user "MediaWiki default"',
			'  api.php?action=query&prop=revisions&titles=Main%20Page&rvlimit=5&rvprop=timestamp|user|comment&rvuser=MediaWiki%20default',
		);
	}

	public function getVersion() {
		return __CLASS__ . ': $Id: ApiQueryRevisions.php 48642 2009-03-20 20:21:38Z midom $';
	}
}
