<?php
/**
 * File deletion user interface.
 *
 * 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
 * @author Rob Church <robchur@gmail.com>
 * @ingroup Media
 */
use MediaWiki\MediaWikiServices;

/**
 * File deletion user interface
 *
 * @ingroup Media
 */
class FileDeleteForm {

	/**
	 * @var Title
	 */
	private $title = null;

	/**
	 * @var File
	 */
	private $file = null;

	/**
	 * @var File
	 */
	private $oldfile = null;
	private $oldimage = '';

	/**
	 * @param File $file File object we're deleting
	 */
	public function __construct( $file ) {
		$this->title = $file->getTitle();
		$this->file = $file;
	}

	/**
	 * Fulfil the request; shows the form or deletes the file,
	 * pending authentication, confirmation, etc.
	 */
	public function execute() {
		global $wgOut, $wgRequest, $wgUser, $wgUploadMaintenance;

		$permissionErrors = $this->title->getUserPermissionsErrors( 'delete', $wgUser );
		if ( count( $permissionErrors ) ) {
			throw new PermissionsError( 'delete', $permissionErrors );
		}

		if ( wfReadOnly() ) {
			throw new ReadOnlyError;
		}

		if ( $wgUploadMaintenance ) {
			throw new ErrorPageError( 'filedelete-maintenance-title', 'filedelete-maintenance' );
		}

		$this->setHeaders();

		$this->oldimage = $wgRequest->getText( 'oldimage', false );
		$token = $wgRequest->getText( 'wpEditToken' );
		# Flag to hide all contents of the archived revisions
		$suppress = $wgRequest->getVal( 'wpSuppress' ) && $wgUser->isAllowed( 'suppressrevision' );

		if ( $this->oldimage ) {
			$this->oldfile = RepoGroup::singleton()->getLocalRepo()->newFromArchiveName(
				$this->title,
				$this->oldimage
			);
		}

		if ( !self::haveDeletableFile( $this->file, $this->oldfile, $this->oldimage ) ) {
			$wgOut->addHTML( $this->prepareMessage( 'filedelete-nofile' ) );
			$wgOut->addReturnTo( $this->title );
			return;
		}

		// Perform the deletion if appropriate
		if ( $wgRequest->wasPosted() && $wgUser->matchEditToken( $token, $this->oldimage ) ) {
			$deleteReasonList = $wgRequest->getText( 'wpDeleteReasonList' );
			$deleteReason = $wgRequest->getText( 'wpReason' );

			if ( $deleteReasonList == 'other' ) {
				$reason = $deleteReason;
			} elseif ( $deleteReason != '' ) {
				// Entry from drop down menu + additional comment
				$reason = $deleteReasonList . wfMessage( 'colon-separator' )
					->inContentLanguage()->text() . $deleteReason;
			} else {
				$reason = $deleteReasonList;
			}

			$status = self::doDelete(
				$this->title,
				$this->file,
				$this->oldimage,
				$reason,
				$suppress,
				$wgUser
			);

			if ( !$status->isGood() ) {
				$wgOut->addHTML( '<h2>' . $this->prepareMessage( 'filedeleteerror-short' ) . "</h2>\n" );
				$wgOut->addWikiText( '<div class="error">' .
					$status->getWikiText( 'filedeleteerror-short', 'filedeleteerror-long' )
					. '</div>' );
			}
			if ( $status->isOK() ) {
				$wgOut->setPageTitle( wfMessage( 'actioncomplete' ) );
				$wgOut->addHTML( $this->prepareMessage( 'filedelete-success' ) );
				// Return to the main page if we just deleted all versions of the
				// file, otherwise go back to the description page
				$wgOut->addReturnTo( $this->oldimage ? $this->title : Title::newMainPage() );

				WatchAction::doWatchOrUnwatch( $wgRequest->getCheck( 'wpWatch' ), $this->title, $wgUser );
			}
			return;
		}

		$this->showForm();
		$this->showLogEntries();
	}

	/**
	 * Really delete the file
	 *
	 * @param Title &$title
	 * @param File &$file
	 * @param string &$oldimage Archive name
	 * @param string $reason Reason of the deletion
	 * @param bool $suppress Whether to mark all deleted versions as restricted
	 * @param User $user User object performing the request
	 * @param array $tags Tags to apply to the deletion action
	 * @throws MWException
	 * @return Status
	 */
	public static function doDelete( &$title, &$file, &$oldimage, $reason,
		$suppress, User $user = null, $tags = []
	) {
		if ( $user === null ) {
			global $wgUser;
			$user = $wgUser;
		}

		if ( $oldimage ) {
			$page = null;
			$status = $file->deleteOld( $oldimage, $reason, $suppress, $user );
			if ( $status->ok ) {
				// Need to do a log item
				$logComment = wfMessage( 'deletedrevision', $oldimage )->inContentLanguage()->text();
				if ( trim( $reason ) != '' ) {
					$logComment .= wfMessage( 'colon-separator' )
						->inContentLanguage()->text() . $reason;
				}

				$logtype = $suppress ? 'suppress' : 'delete';

				$logEntry = new ManualLogEntry( $logtype, 'delete' );
				$logEntry->setPerformer( $user );
				$logEntry->setTarget( $title );
				$logEntry->setComment( $logComment );
				$logEntry->setTags( $tags );
				$logid = $logEntry->insert();
				$logEntry->publish( $logid );

				$status->value = $logid;
			}
		} else {
			$status = Status::newFatal( 'cannotdelete',
				wfEscapeWikiText( $title->getPrefixedText() )
			);
			$page = WikiPage::factory( $title );
			$dbw = wfGetDB( DB_MASTER );
			$dbw->startAtomic( __METHOD__ );
			// delete the associated article first
			$error = '';
			$deleteStatus = $page->doDeleteArticleReal( $reason, $suppress, 0, false, $error,
				$user, $tags );
			// doDeleteArticleReal() returns a non-fatal error status if the page
			// or revision is missing, so check for isOK() rather than isGood()
			if ( $deleteStatus->isOK() ) {
				$status = $file->delete( $reason, $suppress, $user );
				if ( $status->isOK() ) {
					if ( $deleteStatus->value === null ) {
						// No log ID from doDeleteArticleReal(), probably
						// because the page/revision didn't exist, so create
						// one here.
						$logtype = $suppress ? 'suppress' : 'delete';
						$logEntry = new ManualLogEntry( $logtype, 'delete' );
						$logEntry->setPerformer( $user );
						$logEntry->setTarget( clone $title );
						$logEntry->setComment( $reason );
						$logEntry->setTags( $tags );
						$logid = $logEntry->insert();
						$dbw->onTransactionPreCommitOrIdle(
							function () use ( $dbw, $logEntry, $logid ) {
								$logEntry->publish( $logid );
							},
							__METHOD__
						);
						$status->value = $logid;
					} else {
						$status->value = $deleteStatus->value; // log id
					}
					$dbw->endAtomic( __METHOD__ );
				} else {
					// Page deleted but file still there? rollback page delete
					$lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
					$lbFactory->rollbackMasterChanges( __METHOD__ );
				}
			} else {
				// Done; nothing changed
				$dbw->endAtomic( __METHOD__ );
			}
		}

		if ( $status->isOK() ) {
			Hooks::run( 'FileDeleteComplete', [ &$file, &$oldimage, &$page, &$user, &$reason ] );
		}

		return $status;
	}

	/**
	 * Show the confirmation form
	 */
	private function showForm() {
		global $wgOut, $wgUser, $wgRequest;

		$conf = RequestContext::getMain()->getConfig();
		$oldCommentSchema = $conf->get( 'CommentTableSchemaMigrationStage' ) === MIGRATION_OLD;

		if ( $wgUser->isAllowed( 'suppressrevision' ) ) {
			$suppress = "<tr id=\"wpDeleteSuppressRow\">
					<td></td>
					<td class='mw-input'><strong>" .
						Xml::checkLabel( wfMessage( 'revdelete-suppress' )->text(),
							'wpSuppress', 'wpSuppress', false, [ 'tabindex' => '3' ] ) .
					"</strong></td>
				</tr>";
		} else {
			$suppress = '';
		}

		$wgOut->addModules( 'mediawiki.action.delete.file' );

		$checkWatch = $wgUser->getBoolOption( 'watchdeletion' ) || $wgUser->isWatched( $this->title );
		$form = Xml::openElement( 'form', [ 'method' => 'post', 'action' => $this->getAction(),
			'id' => 'mw-img-deleteconfirm' ] ) .
			Xml::openElement( 'fieldset' ) .
			Xml::element( 'legend', null, wfMessage( 'filedelete-legend' )->text() ) .
			Html::hidden( 'wpEditToken', $wgUser->getEditToken( $this->oldimage ) ) .
			$this->prepareMessage( 'filedelete-intro' ) .
			Xml::openElement( 'table', [ 'id' => 'mw-img-deleteconfirm-table' ] ) .
			"<tr>
				<td class='mw-label'>" .
					Xml::label( wfMessage( 'filedelete-comment' )->text(), 'wpDeleteReasonList' ) .
				"</td>
				<td class='mw-input'>" .
					Xml::listDropDown(
						'wpDeleteReasonList',
						wfMessage( 'filedelete-reason-dropdown' )->inContentLanguage()->text(),
						wfMessage( 'filedelete-reason-otherlist' )->inContentLanguage()->text(),
						'',
						'wpReasonDropDown',
						1
					) .
				"</td>
			</tr>
			<tr>
				<td class='mw-label'>" .
					Xml::label( wfMessage( 'filedelete-otherreason' )->text(), 'wpReason' ) .
				"</td>
				<td class='mw-input'>" .
					Xml::input( 'wpReason', 60, $wgRequest->getText( 'wpReason' ), [
						'type' => 'text',
						// HTML maxlength uses "UTF-16 code units", which means that characters outside BMP
						// (e.g. emojis) count for two each. This limit is overridden in JS to instead count
						// Unicode codepoints (or 255 UTF-8 bytes for old schema).
						'maxlength' => $oldCommentSchema ? 255 : CommentStore::COMMENT_CHARACTER_LIMIT,
						'tabindex' => '2',
						'id' => 'wpReason'
					] ) .
				"</td>
			</tr>
			{$suppress}";
		if ( $wgUser->isLoggedIn() ) {
			$form .= "
			<tr>
				<td></td>
				<td class='mw-input'>" .
					Xml::checkLabel( wfMessage( 'watchthis' )->text(),
						'wpWatch', 'wpWatch', $checkWatch, [ 'tabindex' => '3' ] ) .
				"</td>
			</tr>";
		}
		$form .= "
			<tr>
				<td></td>
				<td class='mw-submit'>" .
					Xml::submitButton(
						wfMessage( 'filedelete-submit' )->text(),
						[
							'name' => 'mw-filedelete-submit',
							'id' => 'mw-filedelete-submit',
							'tabindex' => '4'
						]
					) .
				"</td>
			</tr>" .
			Xml::closeElement( 'table' ) .
			Xml::closeElement( 'fieldset' ) .
			Xml::closeElement( 'form' );

			if ( $wgUser->isAllowed( 'editinterface' ) ) {
				$title = wfMessage( 'filedelete-reason-dropdown' )->inContentLanguage()->getTitle();
				$linkRenderer = MediaWikiServices::getInstance()->getLinkRenderer();
				$link = $linkRenderer->makeKnownLink(
					$title,
					wfMessage( 'filedelete-edit-reasonlist' )->text(),
					[],
					[ 'action' => 'edit' ]
				);
				$form .= '<p class="mw-filedelete-editreasons">' . $link . '</p>';
			}

		$wgOut->addHTML( $form );
	}

	/**
	 * Show deletion log fragments pertaining to the current file
	 */
	private function showLogEntries() {
		global $wgOut;
		$deleteLogPage = new LogPage( 'delete' );
		$wgOut->addHTML( '<h2>' . $deleteLogPage->getName()->escaped() . "</h2>\n" );
		LogEventsList::showLogExtract( $wgOut, 'delete', $this->title );
	}

	/**
	 * Prepare a message referring to the file being deleted,
	 * showing an appropriate message depending upon whether
	 * it's a current file or an old version
	 *
	 * @param string $message Message base
	 * @return string
	 */
	private function prepareMessage( $message ) {
		global $wgLang;
		if ( $this->oldimage ) {
			# Message keys used:
			# 'filedelete-intro-old', 'filedelete-nofile-old', 'filedelete-success-old'
			return wfMessage(
				"{$message}-old",
				wfEscapeWikiText( $this->title->getText() ),
				$wgLang->date( $this->getTimestamp(), true ),
				$wgLang->time( $this->getTimestamp(), true ),
				wfExpandUrl( $this->file->getArchiveUrl( $this->oldimage ), PROTO_CURRENT ) )->parseAsBlock();
		} else {
			return wfMessage(
				$message,
				wfEscapeWikiText( $this->title->getText() )
			)->parseAsBlock();
		}
	}

	/**
	 * Set headers, titles and other bits
	 */
	private function setHeaders() {
		global $wgOut;
		$wgOut->setPageTitle( wfMessage( 'filedelete', $this->title->getText() ) );
		$wgOut->setRobotPolicy( 'noindex,nofollow' );
		$wgOut->addBacklinkSubtitle( $this->title );
	}

	/**
	 * Is the provided `oldimage` value valid?
	 *
	 * @param string $oldimage
	 * @return bool
	 */
	public static function isValidOldSpec( $oldimage ) {
		return strlen( $oldimage ) >= 16
			&& strpos( $oldimage, '/' ) === false
			&& strpos( $oldimage, '\\' ) === false;
	}

	/**
	 * Could we delete the file specified? If an `oldimage`
	 * value was provided, does it correspond to an
	 * existing, local, old version of this file?
	 *
	 * @param File &$file
	 * @param File &$oldfile
	 * @param File $oldimage
	 * @return bool
	 */
	public static function haveDeletableFile( &$file, &$oldfile, $oldimage ) {
		return $oldimage
			? $oldfile && $oldfile->exists() && $oldfile->isLocal()
			: $file && $file->exists() && $file->isLocal();
	}

	/**
	 * Prepare the form action
	 *
	 * @return string
	 */
	private function getAction() {
		$q = [];
		$q['action'] = 'delete';

		if ( $this->oldimage ) {
			$q['oldimage'] = $this->oldimage;
		}

		return $this->title->getLocalURL( $q );
	}

	/**
	 * Extract the timestamp of the old version
	 *
	 * @return string
	 */
	private function getTimestamp() {
		return $this->oldfile->getTimestamp();
	}
}
