Move first method from pdfexport module into the hook

It made little sense that we ask a concrete hook implementation for the
first implementation of a hook. It essentially limited us to exactly one
possible pdfexport extension (our own), which is not how hooks are
supposed to work.

Author: TheSyscall

library/Icinga/Application/Hook/PdfexportHook.php

@@ -5,11 +5,41 @@
 
 namespace Icinga\Application\Hook;
 
+use Icinga\Application\Hook;
+use Icinga\Application\Logger;
+use Icinga\Exception\IcingaException;
+use RuntimeException;
+use Throwable;
+
 /**
  * Base class for the PDF Export Hook
  */
 abstract class PdfexportHook
 {
+    /**
+     * Get the first hook
+     *
+     * @return static
+     */
+    public static function first()
+    {
+        foreach (Hook::all('Pdfexport') as $exporter) {
+            try {
+                if ($exporter->isSupported()) {
+                    return $exporter;
+                }
+            } catch (Throwable $e) {
+                Logger::error(
+                    "PDF exporter reported an error during support check: %s\n%s",
+                    $e,
+                    IcingaException::getConfidentialTraceAsString($e),
+                );
+            }
+        }
+
+        throw new RuntimeException('No supported PDF exporter available');
+    }
+
     /**
      * Get whether PDF export is supported
      *

library/Icinga/Common/PdfExport.php

@@ -5,6 +5,7 @@
 
 namespace Icinga\Common;
 
+use Icinga\Application\Hook\PdfexportHook;
 use Icinga\Application\Icinga;
 use Icinga\Date\DateFormatter;
 use Icinga\Exception\ConfigurationError;
@@ -26,7 +27,8 @@ trait PdfExport
      * Export the requested action to PDF and send it
      *
      * @return never
-     * @throws ConfigurationError If the pdfexport module is not available
+     *
+     * @throws ConfigurationError If no pdfexport module is available
      */
     protected function sendAsPdf()
     {
@@ -71,7 +73,7 @@ protected function sendAsPdf()
             $doc->getAttributes()->add('class', 'icinga-module module-' . $moduleName);
         }
 
-        \Icinga\Module\Pdfexport\ProvidedHook\Pdfexport::first()->streamPdfFromHtml($doc, sprintf(
+        PdfexportHook::first()->streamPdfFromHtml($doc, sprintf(
             '%s-%s',
             $this->view->title ?: $this->getRequest()->getActionName(),
             $time