<?php
/**
 * Copyright © 2007 Roan Kattouw "<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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 */

use MediaWiki\MainConfigNames;
use MediaWiki\Page\DeletePage;
use MediaWiki\Page\DeletePageFactory;
use MediaWiki\Page\File\FileDeleteForm;
use MediaWiki\User\UserOptionsLookup;
use MediaWiki\Watchlist\WatchlistManager;
use Wikimedia\ParamValidator\ParamValidator;

/**
 * API module that facilitates deleting pages. The API equivalent of action=delete.
 * Requires API write mode to be enabled.
 *
 * @ingroup API
 */
class ApiDelete extends ApiBase {

	use ApiWatchlistTrait;

	/** @var RepoGroup */
	private $repoGroup;

	/** @var DeletePageFactory */
	private $deletePageFactory;

	/**
	 * @param ApiMain $mainModule
	 * @param string $moduleName
	 * @param RepoGroup $repoGroup
	 * @param WatchlistManager $watchlistManager
	 * @param UserOptionsLookup $userOptionsLookup
	 * @param DeletePageFactory $deletePageFactory
	 */
	public function __construct(
		ApiMain $mainModule,
		$moduleName,
		RepoGroup $repoGroup,
		WatchlistManager $watchlistManager,
		UserOptionsLookup $userOptionsLookup,
		DeletePageFactory $deletePageFactory
	) {
		parent::__construct( $mainModule, $moduleName );
		$this->repoGroup = $repoGroup;
		$this->deletePageFactory = $deletePageFactory;

		// Variables needed in ApiWatchlistTrait trait
		$this->watchlistExpiryEnabled = $this->getConfig()->get( MainConfigNames::WatchlistExpiry );
		$this->watchlistMaxDuration =
			$this->getConfig()->get( MainConfigNames::WatchlistExpiryMaxDuration );
		$this->watchlistManager = $watchlistManager;
		$this->userOptionsLookup = $userOptionsLookup;
	}

	/**
	 * Extracts the title and reason from the request parameters and invokes
	 * the local delete() function with these as arguments. It does not make use of
	 * the delete function specified by Article.php. If the deletion succeeds, the
	 * details of the article deleted and the reason for deletion are added to the
	 * result object.
	 */
	public function execute() {
		$this->useTransactionalTimeLimit();

		$params = $this->extractRequestParams();

		$pageObj = $this->getTitleOrPageId( $params, 'fromdbmaster' );
		$titleObj = $pageObj->getTitle();
		$this->getErrorFormatter()->setContextTitle( $titleObj );
		if ( !$pageObj->exists() &&
			// @phan-suppress-next-line PhanUndeclaredMethod
			!( $titleObj->getNamespace() === NS_FILE && self::canDeleteFile( $pageObj->getFile() ) )
		) {
			$this->dieWithError( 'apierror-missingtitle' );
		}

		$reason = $params['reason'];
		$user = $this->getUser();

		$tags = $params['tags'] ?: [];

		if ( $titleObj->getNamespace() === NS_FILE ) {
			$status = $this->deleteFile(
				$pageObj,
				$params['oldimage'],
				$reason,
				false,
				$tags,
				$params['deletetalk']
			);
			// TODO What kind of non-fatal errors should we expect here?
			$wasScheduled = $status->isOK() && $status->getValue() === false;
		} else {
			$status = $this->delete( $pageObj, $reason, $tags, $params['deletetalk'] );
			$wasScheduled = $status->isGood() && $status->getValue() === false;
		}

		if ( !$status->isOK() ) {
			$this->dieStatus( $status );
		}

		if ( $wasScheduled ) {
			$this->addWarning( [ 'delete-scheduled', $titleObj->getPrefixedText() ] );
		}

		// Deprecated parameters
		if ( $params['watch'] ) {
			$watch = 'watch';
		} elseif ( $params['unwatch'] ) {
			$watch = 'unwatch';
		} else {
			$watch = $params['watchlist'];
		}

		$watchlistExpiry = $this->getExpiryFromParams( $params );
		$this->setWatch( $watch, $titleObj, $user, 'watchdeletion', $watchlistExpiry );

		$r = [
			'title' => $titleObj->getPrefixedText(),
			'reason' => $reason,
		];

		// TODO: We could expose additional information (scheduled and log ID) about the status of the talk page
		// deletion.
		if ( $wasScheduled ) {
			$r['scheduled'] = true;
		} else {
			// Scheduled deletions don't currently have a log entry available at this point
			$r['logid'] = $status->value;
		}
		$this->getResult()->addValue( null, $this->getModuleName(), $r );
	}

	/**
	 * We have our own delete() function, since Article.php's implementation is split in two phases
	 *
	 * @param WikiPage $page WikiPage object to work on
	 * @param string|null &$reason Reason for the deletion. Autogenerated if null
	 * @param string[] $tags Tags to tag the deletion with
	 * @param bool $deleteTalk
	 * @return StatusValue Same as DeletePage::deleteIfAllowed, but if the status is good, then:
	 *  - For immediate deletions, the value is the ID of the deletion
	 *  - For scheduled deletions, the value is false
	 *   If $deleteTalk is set, no information about the deletion of the talk page is included in the returned Status.
	 */
	private function delete( WikiPage $page, &$reason, array $tags, bool $deleteTalk ): StatusValue {
		$title = $page->getTitle();

		// Auto-generate a summary, if necessary
		if ( $reason === null ) {
			$reason = $page->getAutoDeleteReason();
			if ( $reason === false ) {
				// Should be reachable only if the page has no revisions
				return Status::newFatal( 'cannotdelete', $title->getPrefixedText() ); // @codeCoverageIgnore
			}
		}

		$deletePage = $this->deletePageFactory->newDeletePage( $page, $this->getAuthority() );
		if ( $deleteTalk ) {
			$checkStatus = $deletePage->canProbablyDeleteAssociatedTalk();
			if ( !$checkStatus->isGood() ) {
				foreach ( $checkStatus->getErrors() as $error ) {
					$this->addWarning( $error );
				}
			} else {
				$deletePage->setDeleteAssociatedTalk( true );
			}
		}
		$deletionStatus = $deletePage->setTags( $tags )->deleteIfAllowed( $reason );
		if ( $deletionStatus->isGood() ) {
			$deletionStatus->value = $deletePage->deletionsWereScheduled()[DeletePage::PAGE_BASE]
				? false
				: $deletePage->getSuccessfulDeletionsIDs()[DeletePage::PAGE_BASE];
		}
		return $deletionStatus;
	}

	/**
	 * @param File $file
	 * @return bool
	 */
	protected static function canDeleteFile( File $file ) {
		return $file->exists() && $file->isLocal() && !$file->getRedirected();
	}

	/**
	 * @param WikiPage $page Object to work on
	 * @param string $oldimage Archive name
	 * @param string|null &$reason Reason for the deletion. Autogenerated if null.
	 * @param bool $suppress Whether to mark all deleted versions as restricted
	 * @param string[] $tags Tags to tag the deletion with
	 * @param bool $deleteTalk
	 * @return StatusValue
	 */
	private function deleteFile(
		WikiPage $page,
		$oldimage,
		&$reason,
		bool $suppress,
		array $tags,
		bool $deleteTalk
	) {
		$title = $page->getTitle();

		// @phan-suppress-next-line PhanUndeclaredMethod There's no right typehint for it
		$file = $page->getFile();
		if ( !self::canDeleteFile( $file ) ) {
			return $this->delete( $page, $reason, $tags, $deleteTalk );
		}

		// Check that the user is allowed to carry out the deletion
		$this->checkTitleUserPermissions( $page->getTitle(), 'delete' );
		if ( $tags ) {
			// If change tagging was requested, check that the user is allowed to tag,
			// and the tags are valid
			$tagStatus = ChangeTags::canAddTagsAccompanyingChange( $tags, $this->getAuthority() );
			if ( !$tagStatus->isOK() ) {
				$this->dieStatus( $tagStatus );
			}
		}

		if ( $oldimage ) {
			if ( !FileDeleteForm::isValidOldSpec( $oldimage ) ) {
				return Status::newFatal( 'invalidoldimage' );
			}
			$oldfile = $this->repoGroup->getLocalRepo()->newFromArchiveName( $title, $oldimage );
			if ( !$oldfile->exists() || !$oldfile->isLocal() || $oldfile->getRedirected() ) {
				return Status::newFatal( 'nodeleteablefile' );
			}
		}

		if ( $reason === null ) { // Log and RC don't like null reasons
			$reason = '';
		}

		return FileDeleteForm::doDelete(
			$title,
			$file,
			$oldimage,
			$reason,
			$suppress,
			$this->getUser(),
			$tags,
			$deleteTalk
		);
	}

	public function mustBePosted() {
		return true;
	}

	public function isWriteMode() {
		return true;
	}

	public function getAllowedParams() {
		$params = [
			'title' => null,
			'pageid' => [
				ParamValidator::PARAM_TYPE => 'integer'
			],
			'reason' => null,
			'tags' => [
				ParamValidator::PARAM_TYPE => 'tags',
				ParamValidator::PARAM_ISMULTI => true,
			],
			'deletetalk' => false,
			'watch' => [
				ParamValidator::PARAM_DEFAULT => false,
				ParamValidator::PARAM_DEPRECATED => true,
			],
		];

		// Params appear in the docs in the order they are defined,
		// which is why this is here and not at the bottom.
		$params += $this->getWatchlistParams();

		return $params + [
			'unwatch' => [
				ParamValidator::PARAM_DEFAULT => false,
				ParamValidator::PARAM_DEPRECATED => true,
			],
			'oldimage' => null,
		];
	}

	public function needsToken() {
		return 'csrf';
	}

	protected function getExamplesMessages() {
		return [
			'action=delete&title=Main%20Page&token=123ABC'
				=> 'apihelp-delete-example-simple',
			'action=delete&title=Main%20Page&token=123ABC&reason=Preparing%20for%20move'
				=> 'apihelp-delete-example-reason',
		];
	}

	public function getHelpUrls() {
		return 'https://www.mediawiki.org/wiki/Special:MyLanguage/API:Delete';
	}
}
