<?php
  //Category Id
  $saleid = 1180;


  if (!isset($_SERVER['TERM']) && !empty($_SERVER['REMOTE_ADDR'])) {
    echo 'Must be run from command line ('.$_SERVER['REMOTE_ADDR'].')';
    exit;
  } 
  
  require_once 'app/Mage.php';
  umask(0);
  Mage::app('admin');

  $categoryApi = new Mage_Catalog_Model_Category_Api();
  $category = Mage::getModel('catalog/category')->load($saleid);
  $productRef = Mage::getModel('catalog/product');
  $todayDate = $productRef->getResource()->formatDate(time());

  //Get all products which are valid sales
  $products = $productRef->getCollection()
    ->addAttributeToFilter('special_to_date', array('date'=>true, 'from'=> $todayDate));
  foreach ($products as $product) {
    $categories = $product->getCategoryIds();
    if (array_search($saleid, $product->getCategoryIds())===FALSE) {
      //Not set so assign the product
      $categoryApi->assignProduct($saleid, $product->getId());
      echo $product->getSku().'(A) ';
    }
  }

  //Get all products which are expired
  $products = $productRef->getCollection()
    ->addAttributeToFilter('special_to_date', array('date'=>true, 'to'=> $todayDate));
  foreach ($products as $product) {
    $categories = $product->getCategoryIds();
    if (array_search($saleid, $product->getCategoryIds())!==FALSE) {
      //Expired so remove the product
      $categoryApi->removeProduct($saleid, $product->getId());
      echo $product->getSku().'(E) ';
    }
  }

  //Get all products which are invalid
  $products = $productRef->getCollection()
    ->addCategoryFilter($category)
    ->addAttributeToFilter('special_to_date', array('is' => new Zend_Db_Expr('null')));
  foreach ($products as $product) {
    $categories = $product->getCategoryIds();
    if (array_search($saleid, $product->getCategoryIds())!==FALSE) {
      //Expired so remove the product
      $categoryApi->removeProduct($saleid, $product->getId());
      echo $product->getSku().'(I) ';
    }
  }
?>