How to use a switch statement in a controller


    $action = filter_input(INPUT_POST, 'action');

    if ($action == NULL) {

      $action = filter_input(INPUT_GET, 'action');

      if ($action == NULL) {

        $action = 'list_products';

      }
}

    switch ($action) {

      case 'list_products':

        $category_id = filter_input(INPUT_GET, 'category_id', FILTER_VALIDATE_INT);

        if ($category_id == NULL || $category_id == FALSE) {

          $category_id = 1;

        }

        $category_name = get_category_name($category_id);

        $categories = get_categories();

        $products = get_products_by_category($category_id);

        include('product_list.php');

        break;

      case 'delete_products':

        $product_id = filter_input(INPUT_POST, 'product_id', FILTER_VALIDATE_INT);

        $category_id = filter_input(INPUT_POST, 'category_id', FILTER_VALIDATE_INT);

        if ($category_id == NULL || $category_id == FALSE || $product_id == NULL || $product_id == FALSE) {

          $error = "Missing or incorrect product id or category id.";

          include('../errors/error.php');

        } else {

          delete_product($product_id);

          header("Location: .?category_id=$category_id");

        } break;

      case 'show_add_form':

        $categories = get_categories();

        include('product_add.php');

        break;

      case 'add_product':

        $category_id = filter_input(INPUT_POST, 'category_id', FILTER_VALIDATE_INT);

        $code = filter_input(INPUT_POST, 'code');

        $name = filter_input(INPUT_POST, 'name');

        $price = filter_input(INPUT_POST, 'price');

        if ($category_id == NULL || $category_id == FALSE || $code == NULL || $name == NULL || $price == NULL || $price == FALSE) {

          $error = "Invalid product data. Check all fields and try again.";

          include('../errors/error.php');

        } else {

          add_product($category_id, $code, $name, $price);

          header("Location: .?category_id=$category_id");

        }

        break;

    }