<nav class="menu-widget">

    <ul>
    <?php
    if(isset($categories)) {
        $prevLevel = 1;
        $i=0;

        foreach ($categories as $category) {
            $level = $category->level;

            $prefix = '</li>'."\n";
            if($i==0) $prefix = '';

            $sufix  = '';

            if($level>$prevLevel) {
                $prefix = "\n".'<ul>'."\n";
            } else if($level<$prevLevel) {
                $prefix .= '</ul>'."\n".'</li>'."\n";
            }

            if($category->parent_id == 0) {
                //$href = '/section'.$category->id;
                $href = Yii::app()->createUrl(
                            'page/list',
                            array(
                                'section'=>$category->id
                            )
                        );
            } else {
                //$href = '/section'.$category->parent_id.'/subsection'.$category->id;
                $href = Yii::app()->createUrl(
                            'page/list',
                            array(
                                'section' => $category->parent_id,
                                'subsection' => $category->id,
                            )
                        );
            }

            echo $prefix.'<li><a href="'. Yii::app()->baseUrl . $href .'">'.$category->name.'</a>'.$sufix;


            $prevLevel = $level;
            $i++;
        }

        if($level>1) {
            $level -= 1;
            while($level--) { echo '</li></ul>'; }
        }
    }

    ?>

    </ul>
</nav>