class ComposerValidator

final class ComposerValidator implements EventSubscriberInterface {
  use BaseRequirementValidatorTrait;
  use StringTranslationTrait;
  public function __construct(private readonly ComposerInspector $composerInspector, private readonly PathLocator $pathLocator, private readonly ModuleHandlerInterface $moduleHandler) {
  }
  
  /**
   * Validates that the Composer executable is the correct version.
   */
  public function validate(SandboxValidationEvent $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->sandboxManager
      ->getSandboxDirectory() : $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();
  }

}