public function parseJsonFileToIssues($filename)
 {
     $data = json_decode(file_get_contents($filename), true);
     /*
      * parse issues
      */
     $issues = [];
     foreach ($data['issues'] as $issueData) {
         $issue = new Issue($issueData['title'], $issueData['content'], $this->getUser($issueData['assignee']));
         $issue->parseAndSetState($issueData['status']);
         $issue->setCreatedOn($issueData['created_on']);
         $issue->setReporter($this->getUser($issueData['reporter']));
         if (isset($issueData['priority'])) {
             $issue->addLabel($issueData['priority']);
         }
         if (isset($issueData['kind'])) {
             $issue->addLabel($issueData['kind']);
         }
         $issues[$issueData['id']] = $issue;
     }
     /*
      * Parse comments
      */
     foreach ($data['comments'] as $commentData) {
         if (!empty($commentData['content'])) {
             $issueId = $commentData['issue'];
             $comment = new Comment($commentData['content'], $this->getUser($commentData['user']), $commentData['created_on']);
             /** @var Issue $issue */
             $issue = $issues[$issueId];
             $issue->addComment($comment);
         }
     }
     ksort($issues);
     return $issues;
 }