/**
 * Handles document upload preview
 */
function bpfb_documents_ajax_preview_document()
{
    $dir = BPFB_PLUGIN_BASE_DIR . '/img/';
    if (!class_exists('qqFileUploader')) {
        require_once BPFB_PLUGIN_BASE_DIR . '/lib/external/file_uploader.php';
    }
    $uploader = new qqFileUploader(array_map('trim', explode(',', BPFB_DOCUMENTS_ALLOWED_EXTENSIONS)));
    $result = $uploader->handleUpload(BPFB_TEMP_IMAGE_DIR);
    if ($result['file']) {
        $doc_obj = new BP_Group_Documents();
        $doc_obj->file = $result['file'];
        $result['icon'] = $doc_obj->get_icon();
    }
    echo htmlspecialchars(json_encode($result), ENT_NOQUOTES);
    exit;
}