class ComposerValidator

final class ComposerValidator implements EventSubscriberInterface {
    use BaseRequirementValidatorTrait;
    use StringTranslationTrait;
    public function __construct(ComposerInspector $composerInspector, PathLocator $pathLocator, ModuleHandlerInterface $moduleHandler) {
    }
    
    /**
     * Validates that the Composer executable is the correct version.
     */
    public function validate(PreOperationStageEvent $event) : void {
        // If we can't stat processes, there's nothing else we can possibly do here.
        // @see \Symfony\Component\Process\Process::__construct()
        if (!\function_exists('proc_open')) {
            $message = $this->t('Composer cannot be used because the <code>proc_open()</code> function is disabled.');
            if ($this->moduleHandler
                ->moduleExists('help')) {
                $message = $this->t('@message See <a href=":package-manager-help">the help page</a> for information on how to resolve the problem.', [
                    '@message' => $message,
                    ':package-manager-help' => self::getHelpUrl('package-manager-composer-related-faq'),
                ]);
            }
            $event->addError([
                $message,
            ]);
            return;
        }
        $messages = [];
        $dir = $event instanceof PreApplyEvent ? $event->stage
            ->getStageDirectory() : $this->pathLocator
            ->getProjectRoot();
        try {
            $this->composerInspector
                ->validate($dir);
        } catch (\Throwable $e) {
            if ($this->moduleHandler
                ->moduleExists('help')) {
                $message = $this->t('@message See <a href=":package-manager-help">the help page</a> for information on how to resolve the problem.', [
                    '@message' => $e->getMessage(),
                    ':package-manager-help' => self::getHelpUrl('package-manager-composer-related-faq'),
                ]);
                $event->addError([
                    $message,
                ]);
            }
            else {
                $event->addErrorFromThrowable($e);
            }
            return;
        }
        $settings = [];
        foreach ([
            'disable-tls',
            'secure-http',
        ] as $key) {
            try {
                $settings[$key] = json_decode($this->composerInspector
                    ->getConfig($key, $dir));
            } catch (\Throwable $e) {
                $event->addErrorFromThrowable($e, $this->t('Unable to determine Composer <code>@key</code> setting.', [
                    '@key' => $key,
                ]));
                return;
            }
        }
        // If disable-tls is enabled, it overrides secure-http and sets its value to
        // FALSE, even if secure-http is set to TRUE explicitly.
        if ($settings['disable-tls'] === TRUE) {
            $message = $this->t('TLS must be enabled for HTTPS Composer downloads.');
            // If the Help module is installed, link to our help page, which displays
            // the commands for configuring Composer correctly. Otherwise, direct
            // users straight to the Composer documentation, which is a little less
            // helpful.
            if ($this->moduleHandler
                ->moduleExists('help')) {
                $messages[] = $this->t('@message See <a href=":url">the help page</a> for more information on how to configure Composer to download packages securely.', [
                    '@message' => $message,
                    ':url' => self::getHelpUrl('package-manager-requirements'),
                ]);
            }
            else {
                $messages[] = $this->t('@message See <a href=":url">the Composer documentation</a> for more information.', [
                    '@message' => $message,
                    ':url' => 'https://getcomposer.org/doc/06-config.md#disable-tls',
                ]);
            }
            $messages[] = $this->t('You should also check the value of <code>secure-http</code> and make sure that it is set to <code>true</code> or not set at all.');
        }
        elseif ($settings['secure-http'] !== TRUE) {
            $message = $this->t('HTTPS must be enabled for Composer downloads.');
            if ($this->moduleHandler
                ->moduleExists('help')) {
                $messages[] = $this->t('@message See <a href=":url">the help page</a> for more information on how to configure Composer to download packages securely.', [
                    '@message' => $message,
                    ':url' => self::getHelpUrl('package-manager-requirements'),
                ]);
            }
            else {
                $messages[] = $this->t('@message See <a href=":url">the Composer documentation</a> for more information.', [
                    '@message' => $message,
                    ':url' => 'https://getcomposer.org/doc/06-config.md#secure-http',
                ]);
            }
        }
        if ($messages) {
            $event->addError($messages, $this->t("Composer settings don't satisfy Package Manager's requirements."));
        }
    }
    
    /**
     * Returns a URL to a specific fragment of Package Manager's online help.
     *
     * @param string $fragment
     *   The fragment to link to.
     *
     * @return string
     *   A URL to Package Manager's online help.
     */
    private static function getHelpUrl(string $fragment) : string {
        return Url::fromRoute('help.page', [
            'name' => 'package_manager',
        ])->setOption('fragment', $fragment)
            ->toString();
    }

}