compareLanguageConverterOutput.php

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<?php
use MediaWiki\Content\TextContent;
use MediaWiki\Parser\ParserOutput;
use MediaWiki\Rest\Handler\Helper\HtmlOutputRendererHelper;
use MediaWiki\Revision\SlotRecord;
use MediaWiki\Title\Title;
use MediaWiki\User\User;
use Wikimedia\Bcp47Code\Bcp47Code;
use Wikimedia\Diff\ArrayDiffFormatter;
use Wikimedia\Diff\ComplexityException;
use Wikimedia\Diff\Diff;
 
require_once __DIR__ . '/Maintenance.php';
 
class CompareLanguageConverterOutput extends Maintenance {
    public function __construct() {
        parent::__construct();
        $this->addDescription( 'Compares variant conversion output between Parser and HtmlOutputRendererHelper' );
        $this->addArg(
            'page-title',
            'Name of the page to be parsed and compared',
            true
        );
        $this->addArg(
            'target-variant',
            'Target variant language code to transform the content to',
            true
        );
    }
 
    public function execute() {
        $mwInstance = $this->getServiceContainer();
 
        $pageName = $this->getArg( 'page-title' );
        $pageTitle = Title::newFromText( $pageName );
 
        if ( !$pageTitle || !$pageTitle->exists() ) {
            $this->fatalError( "Title with name $pageName not found" );
        }
 
        $targetVariantCode = $this->getArg( 'target-variant' );
        $languageNameUtils = $mwInstance->getLanguageNameUtils();
        if ( !$languageNameUtils->isValidBuiltInCode( $targetVariantCode ) ) {
            $this->fatalError( "$targetVariantCode is not a supported variant" );
        }
        $targetVariant = $mwInstance->getLanguageFactory()->getLanguage(
            $targetVariantCode
        );
 
        $user = User::newSystemUser( User::MAINTENANCE_SCRIPT_USER, [ 'steal' => true ] );
        $baseLanguage = $pageTitle->getPageLanguage();
 
        $parserOutput = $this->getParserOutput( $pageTitle, $baseLanguage, $targetVariant );
        $parsoidOutput = $this->getParsoidOutput( $pageTitle, $targetVariant, $user );
        $converterUsed = $this->getConverterUsed( $parsoidOutput );
 
        $this->compareOutput( $parserOutput, $parsoidOutput, $converterUsed );
 
        return true;
    }
 
    private function newHtmlOutputRendererHelper(): HtmlOutputRendererHelper {
        $services = $this->getServiceContainer();
 
        $helper = new HtmlOutputRendererHelper(
            $services->getParsoidOutputStash(),
            new NullStatsdDataFactory(),
            $services->getParsoidOutputAccess(),
            $services->getHtmlTransformFactory(),
            $services->getContentHandlerFactory(),
            $services->getLanguageFactory()
        );
        return $helper;
    }
 
    private function getParserOptions( Language $language ): ParserOptions {
        $parserOpts = ParserOptions::newFromAnon();
        $parserOpts->setTargetLanguage( $language );
        $parserOpts->disableContentConversion( false );
        $parserOpts->disableTitleConversion( false );
 
        return $parserOpts;
    }
 
    private function getParserOutput(
        Title $pageTitle,
        Language $baseLanguage,
        Language $targetVariant
    ): ParserOutput {
        // We update the default language variant because we want Parser to
        // perform variant conversion to it.
        global $wgDefaultLanguageVariant;
        $wgDefaultLanguageVariant = $targetVariant->getCode();
 
        $mwInstance = $this->getServiceContainer();
 
        $languageFactory = $mwInstance->getLanguageFactory();
        $parser = $mwInstance->getParser();
        $parserOptions = $this->getParserOptions(
            $languageFactory->getParentLanguage( $baseLanguage )
        );
 
        $content = $mwInstance->getRevisionLookup()
            ->getRevisionByTitle( $pageTitle )
            ->getContent( SlotRecord::MAIN );
        $wikiContent = ( $content instanceof TextContent ) ? $content->getText() : '';
 
        return $parser->parse( $wikiContent, $pageTitle, $parserOptions );
    }
 
    private function getParsoidOutput(
        Title $pageTitle,
        Bcp47Code $targetVariant,
        User $user
    ): ParserOutput {
        $htmlOutputRendererHelper = $this->newHtmlOutputRendererHelper();
        $htmlOutputRendererHelper->init( $pageTitle, [
            'stash' => false,
            'flavor' => 'view',
        ], $user );
        $htmlOutputRendererHelper->setVariantConversionLanguage( $targetVariant );
 
        return $htmlOutputRendererHelper->getHtml();
    }
 
    private function getWords( string $output ): array {
        $tagsRemoved = strip_tags( $output );
        $words = preg_split( '/\s+/', trim( $tagsRemoved ), -1, PREG_SPLIT_NO_EMPTY );
        return $words;
    }
 
    private function getBody( string $output ): string {
        $dom = new DOMDocument();
        // phpcs:disable Generic.PHP.NoSilencedErrors.Discouraged
        @$dom->loadHTML( $output );
        $body = $dom->getElementsByTagName( 'body' )->item( 0 );
        if ( $body === null ) {
            // Body element not present
            return $output;
        }
 
        return $body->textContent;
    }
 
    private function compareOutput(
        ParserOutput $parserOutput,
        ParserOutput $parsoidOutput,
        string $converterUsed
    ): void {
        $parsoidText = $parsoidOutput->getText( [ 'deduplicateStyles' => false ] );
        $parserText = $parserOutput->getText( [ 'deduplicateStyles' => false ] );
 
        $parsoidWords = $this->getWords( $this->getBody( $parsoidText ) );
        $parserWords = $this->getWords( $parserText );
 
        $parserWordCount = count( $parserWords );
        $parsoidWordCount = count( $parsoidWords );
        $this->output( "Word count: Parsoid: $parsoidWordCount; Parser: $parserWordCount\n" );
 
        $this->outputSimilarity( $parsoidWords, $parserWords );
        $this->output( "\n" );
        $this->outputDiff( $parsoidWords, $parserWords, $converterUsed );
    }
 
    private function getConverterUsed( ParserOutput $parsoidOutput ): string {
        $isCoreConverterUsed = strpos(
            $parsoidOutput->getRawText(),
            'Variant conversion performed using the core LanguageConverter'
        );
 
        if ( $isCoreConverterUsed ) {
            return 'Core LanguageConverter';
        } else {
            return 'Parsoid LanguageConverter';
        }
    }
 
    // Inspired from: https://stackoverflow.com/a/55927237/903324
    private function mb_sprintf( string $format, ...$args ): string {
        $params = $args;
 
        return sprintf(
            preg_replace_callback(
                '/(?<=%|%-)\d+(?=s)/',
                static function ( array $matches ) use ( &$params ) {
                    $value = array_shift( $params );
 
                    return (string)( strlen( $value ) - mb_strlen( $value ) + $matches[0] );
                },
                $format
            ),
            ...$args
        );
    }
 
    private function outputSimilarity( array $parsoidWords, array $parserWords ): void {
        $parsoidOutput = implode( ' ', $parsoidWords );
        $parserOutput = implode( ' ', $parserWords );
        $this->output(
            'Total characters: Parsoid: ' . strlen( $parsoidOutput ) .
            '; Parser: ' . strlen( $parserOutput ) . "\n"
        );
 
        $similarityPercent = 0;
        $similarCharacters = similar_text( $parsoidOutput, $parserOutput, $similarityPercent );
        $similarityPercent = round( $similarityPercent, 2 );
 
        $this->output(
            "Similarity via similar_text(): $similarityPercent%; Similar characters: $similarCharacters"
        );
    }
 
    private function outputDiff( array $parsoidWords, array $parserWords, string $converterUsed ): void {
        $out = str_repeat( '-', 96 ) . "\n";
        $out .= sprintf( "| %5s | %-35s | %-35s | %-8s |\n", 'Line', 'Parsoid', 'Parser', 'Diff' );
        $out .= sprintf( "| %5s | %-35s | %-35s | %-8s |\n", '', "($converterUsed)", '', '' );
        $out .= str_repeat( '-', 96 ) . "\n";
 
        try {
            $diff = new Diff( $parsoidWords, $parserWords );
        } catch ( ComplexityException $e ) {
            $this->output( $e->getMessage() );
            $this->error( 'Encountered ComplexityException while computing diff' );
        }
 
        // Print the difference between the words
        $wordDiffFormat = ( new ArrayDiffFormatter() )->format( $diff );
        foreach ( $wordDiffFormat as $index => $wordDiff ) {
            $action = $wordDiff['action'];
            $old = $wordDiff['old'] ?? null;
            $new = $wordDiff['new'] ?? null;
 
            $out .= $this->mb_sprintf(
                "| %5s | %-35s | %-35s | %-8s |\n",
                str_pad( (string)( $index + 1 ), 5, ' ', STR_PAD_LEFT ),
                mb_strimwidth( $old ?? '- N/A -', 0, 35, '…' ),
                mb_strimwidth( $new ?? '- N/A -', 0, 35, '…' ),
                $action
            );
        }
 
        // Print the footer.
        $out .= str_repeat( '-', 96 ) . "\n";
        $this->output( "\n" . $out );
    }
}
 
$maintClass = CompareLanguageConverterOutput::class;
require_once RUN_MAINTENANCE_IF_MAIN;