<?php
/**
 * 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
 */

namespace MediaWiki\Linter;

use Html;
use HTMLForm;
use MalformedTitleException;
use MediaWiki\MediaWikiServices;
use OutputPage;
use SpecialPage;

class SpecialLintErrors extends SpecialPage {

	/**
	 * @var string|null
	 */
	private $category;

	public function __construct() {
		parent::__construct( 'LintErrors' );
	}

	/**
	 * @param int|null $ns
	 * @param bool $invert
	 * @param string $titleLabel
	 */
	protected function showFilterForm( $ns, $invert, $titleLabel ) {
		$selectOptions = [
			(string)$this->msg( 'linter-form-exact-match' )->escaped() => true,
			(string)$this->msg( 'linter-form-prefix-match' )->escaped() => false,
		];
		$fields = [
			'namespace' => [
				'type' => 'namespaceselect',
				'name' => 'namespace',
				'label-message' => 'linter-form-namespace',
				'default' => $ns,
				'id' => 'namespace',
				'all' => '',
				'cssclass' => 'namespaceselector'
			],
			'invertnamespace' => [
				'type' => 'check',
				'name' => 'invert',
				'label-message' => 'invert',
				'default' => $invert,
				'tooltip' => 'invert'
			],
			'titlefield' => [
				'type' => 'title',
				'name' => $titleLabel,
				'label-message' => 'linter-form-title-prefix',
				'exists' => true,
				'required' => false
			],
			'exactmatchradio' => [
				'type' => 'radio',
				'name' => 'exactmatch',
				'options' => $selectOptions,
				'label-message' => 'linter-form-exact-or-prefix',
				'default' => true
			]
		];
		$form = HTMLForm::factory( 'ooui', $fields, $this->getContext() );
		$form->setWrapperLegend( true );
		if ( $this->category !== null ) {
			$form->addHeaderHtml( $this->msg( "linter-category-{$this->category}-desc" )->parse() );
		}
		$form->setMethod( 'get' );
		$form->prepareForm()->displayForm( false );
	}

	/**
	 * cleanTitle parses a title and handles a malformed titles, namespaces that are mismatched
	 * and exact title searches that find no matching records, and produce appropriate error messages
	 *
	 * @param string $title
	 * @param int|null $namespace
	 * @param bool $invert
	 * @return array
	 */
	public function cleanTitle( $title, $namespace, $invert ) {
		// Check all titles for malformation regardless of exact match or prefix match
		try {
			$titleElements = MediaWikiServices::getInstance()->getTitleParser()->parseTitle( $title );
		} catch ( MalformedTitleException  $e ) {
			return [ 'titlefield' => null, 'error' => 'linter-invalid-title' ];
		}

		// The drop-down namespace defaults to 'all' which is returned as a null, indicating match all namespaces.
		// If 'main' is selected in the drop-down, int 0 is returned. Other namespaces are returned as int values > 0.
		//
		// If the user does not specify a namespace in the title text box, parseTitle sets it to int 0 as the default.
		// If the user entered ':' (main) namespace as the namespace prefix of a title such as ":MyPageTitle",
		// parseTitle will also return int 0 as the namespace. Other valid system namespaces entered as prefixes
		// in the title text box are returned by parseTitle as int values > 0.
		// To determine if the user entered the ':' (main) namespace when int 0 is returned, a separate check for
		// the substring ':' at offset 0 must be performed.

		$titleNamespace = $titleElements->getNamespace();
		// Determine if the user entered ':' (resolves to main) as the namespace part of the title,
		// or was it was set by default by parseTitle() to 0, but the user intended to search across 'all' namespaces.
		if ( $titleNamespace === 0 && $title[0] !== ':' ) {
			$titleNamespace = null;
		}

		if ( $namespace === null && $titleNamespace === null ) {
			// if invert checkbox is set while the namespace drop-down is set to 'all' and no namespace was set in the
			// title text box, then the invert check box being set is invalid as it would exclude all namespaces.
			if ( $invert ) {
				return [ 'titlefield' => null, 'error' => 'linter-namespace-invert-error' ];
			}
		}

		if ( $namespace !== null && $titleNamespace !== null ) {
			// Show the namespace mismatch error if the namespaces specified in drop-down and title text do not match.
			if ( $namespace !== $titleNamespace ) {
				return [ 'titlefield' => null, 'error' => 'linter-namespace-mismatch' ];
			}
		}

		// If the namespace drop-down selection is 'all' (null), return the namespace from the title text
		$ns = ( $namespace === null ) ? $titleNamespace : $namespace;

		return [ 'titlefield' => $titleElements->getDBkey(), 'namespace' => $ns ];
	}

	/**
	 * @param OutputPage $out
	 * @param string|null $message
	 */
	private function displayError( $out, $message ) {
		$out->addHTML(
			Html::element( 'span', [ 'class' => 'error' ],
				$this->msg( $message )->text() )
		);
	}

	/**
	 * @param string|null $par
	 */
	public function execute( $par ) {
		$request = $this->getRequest();
		$out = $this->getOutput();

		$params = $request->getQueryValues();

		$this->setHeaders();
		$this->outputHeader( $par || isset( $params[ 'titlesearch' ] ) ? 'disable-summary' : '' );

		$ns = $request->getIntOrNull( 'namespace' );
		$invert = $request->getBool( 'invert' );
		$exactMatch = $request->getBool( 'exactmatch', true );

		// If the request contains a 'titlesearch' parameter, then the user entered a page title
		// or just the first few characters of the title. They also may have entered the first few characters
		// of a custom namespace (just text before a :) to search for and pressed the associated Submit button.
		if ( $par === null && isset( $params[ 'titlesearch' ] ) ) {
			$out->addBacklinkSubtitle( $this->getPageTitle() );

			$title = $request->getText( 'titlesearch' );
			$titleSearch = $this->cleanTitle( $title, $ns, $invert );

			if ( $titleSearch[ 'titlefield' ] !== null ) {
				$out->setPageTitle( $this->msg( 'linter-prefix-search-subpage', $titleSearch[ 'titlefield' ] ) );

				$catManager = new CategoryManager();
				$pager = new LintErrorsPager(
					$this->getContext(), null, $this->getLinkRenderer(),
					$catManager, $titleSearch[ 'namespace' ], $invert, $exactMatch,
					$titleSearch[ 'titlefield' ]
				);
				$out->addParserOutput( $pager->getFullOutput() );
			} else {
				$this->displayError( $out, $titleSearch[ 'error' ] );
			}
			return;
		}

		$catManager = new CategoryManager();
		if ( in_array( $par, $catManager->getVisibleCategories() ) ) {
			$this->category = $par;
		}

		if ( !$this->category ) {
			$this->addHelpLink( 'Help:Extension:Linter' );
			$this->showCategoryListings( $catManager );
		} else {
			$this->addHelpLink( "Help:Extension:Linter/{$this->category}" );
			$out->setPageTitle(
				$this->msg( 'linterrors-subpage',
					$this->msg( "linter-category-{$this->category}" )->text()
				)
			);
			$out->addBacklinkSubtitle( $this->getPageTitle() );

			$title = $request->getText( 'titlecategorysearch' );
			// For category based searches, allow an undefined title to display all records
			if ( $title === '' ) {
				$titleCategorySearch = [ 'titlefield' => '', 'namespace' => $ns, 'pageid' => null ];
			} else {
				$titleCategorySearch = $this->cleanTitle( $title, $ns, $invert );
			}

			if ( $titleCategorySearch[ 'titlefield' ] !== null ) {
				$this->showFilterForm( null, $invert, 'titlecategorysearch' );
				$pager = new LintErrorsPager(
					$this->getContext(), $this->category, $this->getLinkRenderer(),
					$catManager, $titleCategorySearch[ 'namespace' ], $invert, $exactMatch,
					$titleCategorySearch[ 'titlefield' ]
				);
				$out->addParserOutput( $pager->getFullOutput() );
			} else {
				$this->displayError( $out, $titleCategorySearch[ 'error' ] );
			}
		}
	}

	/**
	 * @param string $priority
	 * @param int[] $totals name => count
	 * @param string[] $categories
	 */
	private function displayList( $priority, $totals, array $categories ) {
		$out = $this->getOutput();
		$msgName = 'linter-heading-' . $priority . '-priority';
		$out->addHTML( Html::element( 'h2', [], $this->msg( $msgName )->text() ) );
		$out->addHTML( $this->buildCategoryList( $categories, $totals ) );
	}

	/**
	 */
	private function displaySearchPage() {
		$out = $this->getOutput();
		$out->addHTML( Html::element( 'h2', [],
			$this->msg( "linter-lints-prefix-search-page-desc" )->text() ) );
		$this->showFilterForm( null, false, 'titlesearch' );
	}

	/**
	 * @param CategoryManager $catManager
	 */
	private function showCategoryListings( CategoryManager $catManager ) {
		$lookup = new TotalsLookup(
			$catManager,
			MediaWikiServices::getInstance()->getMainWANObjectCache()
		);
		$totals = $lookup->getTotals();

		// Display lint issues by priority
		$this->displayList( 'high', $totals, $catManager->getHighPriority() );
		$this->displayList( 'medium', $totals, $catManager->getMediumPriority() );
		$this->displayList( 'low', $totals, $catManager->getLowPriority() );

		$this->displaySearchPage();
	}

	/**
	 * @param string[] $cats
	 * @param int[] $totals name => count
	 * @return string
	 */
	private function buildCategoryList( array $cats, array $totals ) {
		$linkRenderer = $this->getLinkRenderer();
		$html = Html::openElement( 'ul' ) . "\n";
		foreach ( $cats as $cat ) {
			$html .= Html::rawElement( 'li', [], $linkRenderer->makeKnownLink(
				$this->getPageTitle( $cat ),
				$this->msg( "linter-category-$cat" )->text()
			) . ' ' . Html::element( 'bdi', [],
				$this->msg( "linter-numerrors" )->numParams( $totals[$cat] )->text()
			) ) . "\n";
		}
		$html .= Html::closeElement( 'ul' );

		return $html;
	}

	/** @inheritDoc */
	public function getGroupName() {
		return 'maintenance';
	}

	/**
	 * @return string[]
	 */
	protected function getSubpagesForPrefixSearch() {
		return ( new CategoryManager() )->getVisibleCategories();
	}

}