Answered Can Modx create a new menu-index TV?

$tvid = 8; //the ID of the TV thats the rank
$eventName = $modx->event->name;
$thisid = $resource->get('id');

//--------------------
if(!function_exists('getranks')){
    function getranks($tvid){
        global $modx;
        $c = $modx->newQuery('modTemplateVarResource');
        $c->sortby('value', 'ASC');
        $c->where(array('tmplvarid' => $tvid));
        $tvs = $modx->getCollection('modTemplateVarResource', $c);
        usort($tvs, 'sortByValue');
        return $tvs;
    }
}

if(!function_exists('sortByValue')){
    function sortByValue($a, $b){
        return (int)$a->get('value') - (int)$b->get('value');
    }
}
//--------------------------------------
if(!function_exists('getrank')){
    function getrank($contentid){
        global $modx;
        $c = $modx->newQuery('modTemplateVarResource');
        $c->where(array('contentid' => $contentid));
        $tv = $modx->getObject('modTemplateVarResource', $c);
        return $tv;
    }
}

//-----------------------------------
if(!function_exists('reorder')){
    //move one indexed item to new index
    function reorder(&$a, $old, $new = null, $thisid = null){
        if($old < $new){
            foreach ($a as $tv) {
                $v = $tv->get('value');
                if($v > $old && $v <= $new){
                    $v--;
                }
                $tv->set('value', $v);
                $tv->save();
            }
        } elseif($old > $new) {
            foreach ($a as $tv) {
                $v = $tv->get('value');
                if($v < $old && $v >= $new){
                    $v++;
                }
                $tv->set('value', $v);
                $tv->save();
            }
        } else {
            foreach ($a as $tv) {
                $v = $tv->get('value');
                if($v > $old){
                    $v--;
                }
                $tv->set('value', $v);
                $tv->save();
            }

        }
    }
}

//--------------------
if(!function_exists('removeElementWithValue')){
    function removeElementWithValue($array, $key, $value){
        foreach ($array as $subKey => $subArray) {
            if($subArray[$key] == $value){
                unset($array[$subKey]);
            }
        }
        return $array;
    }
}

//----------------------------------------
if (!function_exists('reindex')) {
    /* orderby value, renumber indices to 0 till max, re-sequence indices */
    function reindex($tvs)
    {
        $order = array();
        foreach ($tvs as $tv) {
            $order[(int)$tv->get('value')] = $tv;
        }
        ksort($order);
        $order = array_values($order);
        foreach ($order as $key => &$tv) {
            $tv->set('value', $key + 1);
            $tv->save();
        }
        return $order;
    }
}

switch ($eventName) {
    case 'OnBeforeDocFormSave':
        $field = $_POST['tv' . $tvid];
        $value = $resource->getTVValue($tvid);
        if(!empty($field) && empty($value)){
            $modx->rankaction = 'new';
        }
        if(empty($field) && !empty($value)){
            $modx->rankaction = 'remove';
        }
        if(!empty($field) && !empty($value)){
            $modx->rankaction = 'update';
        }
        if($field != $value){
            $modx->rankold = $value;
            // get all tvvalues, order by value and revalue them sequentionaly 1 to n
            $tvs = getranks($tvid);
            $i = 0;
            foreach ($tvs as $tv) {
                $i++;
                $tv->set('value', $i);
                $tv->save();
            }
        }
        break;

    case 'OnDocFormSave':
        if($modx->rankaction){
            $new = $resource->getTVValue($tvid);
            $tvs = getranks($tvid);
            switch ($modx->rankaction) {
                case 'new':
                    $amt = count($tvs);
                    $new = ($amt < $new) ? $amt : $new;
                    $old = ($modx->rankold) ? $old = $modx->rankold : count($tvs);
                    reorder($tvs, $old, $new, $thisid);
                    $resource->setTVValue($tvid, $new);
                    break;

                case 'update':
                    $amt = count($tvs);
                    $new = ($amt < $new) ? $amt : $new;
                    $old = ($modx->rankold) ? $old = $modx->rankold : count($tvs);
                    reorder($tvs, $old, $new, $thisid);
                    $resource->setTVValue($tvid, $new);
                    break;

                case 'remove':
                    reindex($tvs);
                    break;
            }
            unset($modx->rankold);
            unset($modx->rankaction);
        }
        break;
}

return '';