Magento : programmatically add custom options for products

I’ve found plenty of places on magento forums and websites that mention adding custom options to products : none of them seemed to work on my installation (1.5) so I suppose each version has its own tweaks. The technique below catches a specific event that is fired when the product is being saved from the admin. A good tutorial on Magento events can be found here, pseudo official list of events can also be found on Magento’s wiki, probably outdated though. What I need now is to find the appropriate code to delete options from a product. not simple either… Anyone tried?

The way I did is the following

• create a custom module PoleOuest_CustomOptions_Model_Observer 
  app/local/PoleOuest/CustomOptions/Model/Observer.php

  
  

  
  

  
  

   class PoleOuest_CustomOptions_Model_Observer
   {
  
        public function Add_CustomOptions_Automatically($observer) {
  
              $event = $observer->getEvent();
      $product = $event->getProduct();
  
     // if ($product->getDecodirect())
       //   {
          $optionData = array(
    'is_delete'         => 0,
      'is_require'        => false,
      'previous_group'    => '',
      'title'             => 'want to preorder ? ',
      'type'              => 'checkbox',
      'price_type'        => 'fixed',
      'price'             => '20.0000',
      'sort_order'        => 0,
  
             'values'            => array(
          array(
              'is_delete'     => 0,
              'title'         => 'preorder',
              'price_type'    => 'percent',
              'price'         => -20,
              'sku'           => 'product sku',
              'option_type_id'=> -1,
          ))
  
          );
          $product->setHasOptions(1);
  
         $opt = Mage::getModel('catalog/product_option');
          $opt->setProduct($product);
          $opt->addOption($optionData);
          $opt->saveOptions();      
  
                 Mage::log("option should be added now");
       // }
        }
  
   }

• catch product save before event in app/local/PoleOuest/CustomOptions/etc/config.xml

  <?xml version="1.0" encoding="utf-8"?>
  <config>
      <modules>
          <PoleOuest_CustomOptions>
              <version>0.0.1</version>
          </PoleOuest_CustomOptions>
      </modules>
      <global>
          <events>
              <catalog_product_save_before>
                  <observers>
                      <custom_options>
                          <type>singleton</type>
                          <class>PoleOuest_CustomOptions_Model_Observer</class>
                          <method>Add_CustomOptions_Automatically</method>
                      </custom_options>
                  </observers>
              </catalog_product_save_before>
          </events>
      </global>
  </config>