[PLUGIN] Automatic Unpublish

<?php //<-Delete the php open tag
/*
* Automatic Unpublish Plugin 
*
* Sets unpub_date using another date field as reference.
*
* Written By Jay Gilmore - June 6, 2009
* With assistance of Susan Otwell (sottwell) and Shane Sponagle (dev_cw)
*
* Version 1.0.1-alpha
*
* Events: OnDocFormSave
*
*/

if(!$fieldName){
    return;   
}

if (!$fieldType){
    $fieldType = 'Document Variable';
}

if($fieldType == 'Template Variable'){
    $fieldPrefix = 'tv'; 
}
else{
    $fieldPrefix = '';
}

if(!$offsetQ){
    $offsetQ = '1';   
}

if(!$offsetU){
    $offsetU = 'Day';
}

if($offsetQ){
    $offset = '+'.$offsetQ . ' ' . $offsetU;
}

else {
    $offset = $offsetU;
}

$postfield = $fieldPrefix . $fieldName;

if($_POST[$postfield]  ){

    $e = &$modx->Event;
    switch ($e->name) {
        case "OnDocFormSave":
            $ud = strtotime($_POST[$postfield]. $offset);
            $unpub_date = $ud;
            $table = $modx->getFullTableName( 'site_content' );
            $fields = array('unpub_date' => $unpub_date);

            // Check to see if there is an unpub_date set and skip the update if it is.
            if($_POST['unpub_date'] != $ud){
                // Update the db with the field value
                $modx->db->update( $fields, $table, 'id = "'.$id.'"' );
            }
            break;
        default :
            return; 
            break;
    }
}

&fieldName=Field Name;text; &fieldType=Field Type;list;Template Variable, Document Variable; &offsetQ=Offset Quantity;text; &offsetU=Offset Unit;list;Day, Week, Month, Year;