<?php
/**
 * Implements Special:Mostlinkedtemplates
 *
 * 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
 * @ingroup SpecialPage
 * @author Rob Church <robchur@gmail.com>
 */

use MediaWiki\Cache\LinkBatchFactory;
use MediaWiki\Html\Html;
use MediaWiki\Linker\Linker;
use MediaWiki\Linker\LinksMigration;
use MediaWiki\Title\Title;
use Wikimedia\Rdbms\IDatabase;
use Wikimedia\Rdbms\ILoadBalancer;
use Wikimedia\Rdbms\IResultWrapper;

/**
 * Special page lists templates with a large number of
 * transclusion links, i.e. "most used" templates
 *
 * @ingroup SpecialPage
 */
class SpecialMostLinkedTemplates extends QueryPage {

	/** @var LinksMigration */
	private $linksMigration;

	/**
	 * @param ILoadBalancer $loadBalancer
	 * @param LinkBatchFactory $linkBatchFactory
	 * @param LinksMigration $linksMigration
	 */
	public function __construct(
		ILoadBalancer $loadBalancer,
		LinkBatchFactory $linkBatchFactory,
		LinksMigration $linksMigration
	) {
		parent::__construct( 'Mostlinkedtemplates' );
		$this->setDBLoadBalancer( $loadBalancer );
		$this->setLinkBatchFactory( $linkBatchFactory );
		$this->linksMigration = $linksMigration;
	}

	/**
	 * Is this report expensive, i.e should it be cached?
	 *
	 * @return bool
	 */
	public function isExpensive() {
		return true;
	}

	/**
	 * Is there a feed available?
	 *
	 * @return bool
	 */
	public function isSyndicated() {
		return false;
	}

	/**
	 * Sort the results in descending order?
	 *
	 * @return bool
	 */
	public function sortDescending() {
		return true;
	}

	public function getQueryInfo() {
		$queryInfo = $this->linksMigration->getQueryInfo( 'templatelinks' );
		[ $ns, $title ] = $this->linksMigration->getTitleFields( 'templatelinks' );
		return [
			'tables' => $queryInfo['tables'],
			'fields' => [
				'namespace' => $ns,
				'title' => $title,
				'value' => 'COUNT(*)'
			],
			'options' => [ 'GROUP BY' => [ $ns, $title ] ],
			'join_conds' => $queryInfo['joins']
		];
	}

	/**
	 * Pre-cache page existence to speed up link generation
	 *
	 * @param IDatabase $db
	 * @param IResultWrapper $res
	 */
	public function preprocessResults( $db, $res ) {
		$this->executeLBFromResultWrapper( $res );
	}

	/**
	 * Format a result row
	 *
	 * @param Skin $skin
	 * @param stdClass $result Result row
	 * @return string
	 */
	public function formatResult( $skin, $result ) {
		$title = Title::makeTitleSafe( $result->namespace, $result->title );
		if ( !$title ) {
			return Html::element(
				'span',
				[ 'class' => 'mw-invalidtitle' ],
				Linker::getInvalidTitleDescription(
					$this->getContext(),
					$result->namespace,
					$result->title
				)
			);
		}

		return $this->getLanguage()->specialList(
			$this->getLinkRenderer()->makeLink( $title ),
			$this->makeWlhLink( $title, $result )
		);
	}

	/**
	 * Make a "what links here" link for a given title
	 *
	 * @param Title $title Title to make the link for
	 * @param stdClass $result Result row
	 * @return string
	 */
	private function makeWlhLink( $title, $result ) {
		$wlh = SpecialPage::getTitleFor( 'Whatlinkshere', $title->getPrefixedText() );
		$label = $this->msg( 'ntransclusions' )->numParams( $result->value )->text();

		return $this->getLinkRenderer()->makeLink( $wlh, $label );
	}

	protected function getGroupName() {
		return 'highuse';
	}
}
