.-.-.-.-.-

<?php

class yoothemeInstallerScript
{
    protected $db;
    protected $tmp;
    protected $name;
    protected $dest;

public function __construct($parent)
    {
        $this->db = JFactory::getDBO();
        $this->tmp = JFactory::getApplication()->getCfg('tmp_path');
        $this->name = $parent->getName();
        $this->dest = $parent->getParent()->getPath('extension_root');
    }

public function preflight($type, $parent)
    {
        if ($type == 'update') {

// backup theme*.css
            $files = glob("{$this->dest}/css/theme*.css");

foreach ($files as $file) {

$filename = basename($file);

if (strpos($file, 'update.css')) {
                    continue;
                }

if (JFile::exists($file)) {
                    JFile::move($file, "{$this->tmp}/{$filename}");
                }
            }

// clean folders
            foreach (array('less', 'vendor', 'templates') as $path) {
                JFolder::delete("{$this->dest}/{$path}");
            }
        }
    }

public function postflight($type, $parent)
    {
        if ($type == 'update') {

// restore theme*.css
            $files = glob("{$this->tmp}/theme*.css");

foreach ($files as $file) {

$filename = basename($file);

if (JFile::exists($file)) {
                    JFile::move($file, "{$this->dest}/css/{$filename}");
                }
            }

// Check child theme's "theme.js" for jQuery
            foreach ($this->loadTemplateStyles() as $id => $params) {

$params = json_decode($params, true);

if ($params
                    AND isset($params['config'])
                    AND $config = json_decode($params['config'], true)
                    AND isset($config['child_theme'])
                    AND $config['child_theme']
                    AND JFile::exists($path = JPATH_ROOT."/templates/{$this->name}_{$config['child_theme']}/js/theme.js")
                    AND $contents = JFile::read($path)
                    AND strpos($contents, 'jQuery') !== false
                ) {
                    $config['jquery'] = true;
                    $params['config'] = json_encode($config);
                    $this->updateTemplateStyle($id, json_encode($params));
                }
            }
        }
    }

protected function loadTemplateStyles()
    {
        $query = "SELECT id, params FROM #__template_styles WHERE template=".$this->db->quote($this->name);
        return $this->db->setQuery($query)->loadAssocList('id', 'params');
    }

protected function updateTemplateStyle($id, $params)
    {
        $query = "UPDATE #__template_styles SET params=".$this->db->quote($params)." WHERE id={$id}";
        $this->db->setQuery($query);
        $this->db->execute();
    }
}

/home/poliximo/public_html/templates/yootheme/script.php