public function changePost($post_id, $categories, $is_add = false)
{
$categories = array_map('intval', $categories);
$current_categories = array_keys($this->getByField('post_id', $post_id, 'category_id'));
if ($new_categories = array_diff($categories, $current_categories)) {
foreach ($new_categories as $key => $id) {
$this->insert(array('post_id' => $post_id, 'category_id' => $id), 2);
}
}
if ($excluded_categories = array_diff($current_categories, $categories)) {
$this->deleteByField(array('post_id' => $post_id, 'category_id' => $excluded_categories));
}
if ($updated = array_merge($excluded_categories, $new_categories, $current_categories)) {
$category_model = new blogCategoryModel();
$category_model->recalculate($updated);
}
}