public function actionCleanup()
    {
        $delete = [];
        $this->output("Blocks to delete:");
        foreach (Block::find()->all() as $block) {
            if (!$block->getFileExists()) {
                $this->outputInfo("{$block->class} (id: {$block->id}) used {$block->usageCount} times.");
                $delete[] = $block;
            }
        }
        
        if (!empty($delete) && $this->confirm('Are you sure to delete those blocks with its content? This can not be undone!')) {
            foreach ($delete as $deleteBlock) {
                if ($deleteBlock->delete()) {
                    $this->outputSuccess('Deleted ' . $deleteBlock->class);
                } else {
                    $this->outputError('Error while deleting ' . $deleteBlock->class);
                }
            }
            
            return $this->outputSuccess("Clean has been finished successful.");
        } elseif (empty($delete)) {
            return $this->outputSuccess("Nothing to cleanup.");
        }
        
        return $this->outputError("Abort by user.");
    }