Move Craft Content Between Element Types

migrate.php

<?php
namespace Craft;
// This file could be placed into your public_html folder and visited to import a cheese product.
$craft = require '../craft/app/bootstrap.php';
$craft->plugins->loadPlugins();


$criteria = craft()->elements->getCriteria(ElementType::Entry);

$criteria->section = 'books';
$criteria->order   = 'postDate desc';
$criteria->limit   = 5;

foreach ($criteria as $entry)
{
  // load product and varient
  $newProduct = new Commerce_ProductModel();
  $newProduct->typeId = 4; // Replace with product type ID;
  $newProduct->enabled = true;
  $newProduct->promotable = true;
  $newProduct->freeShipping = 0;
  $newProduct->postDate = $entry->postDate;
  $newProduct->taxCategoryId = craft()->commerce_taxCategories->getDefaultTaxCategoryId();
  $newProduct->getContent()->title =   $entry->getContent()->title ;
  $newProduct->slug = StringHelper::toKebabCase($entry->getContent()->title);


  $newProduct->setContent($entry->getContent());

  $variant = new Commerce_VariantModel();
  $variant->setProduct($newProduct);
  $variant->sortOrder = 1;
  $variant->getContent()->title = $entry->getContent()->title;
  $variant->sku = $entry->slug.'1';
  $variant->price = "0";
  $variant->unlimitedStock = true;
  $newProduct->setVariants([$variant]);

  if(craft()->commerce_products->saveProduct($newProduct)){
      echo "done";

    // get all the relations fields from entry and move over
    $fields = $entry->fieldLayout->fields;

    foreach ($fields as $fieldModel) {

      $field = $fieldModel->getField();

      if ($field->type ==  'Assets' || $field->type ==  'Entries' || $field->type ==  'Categories') {
        craft()->relations->saveRelations($field, $newProduct, $entry->{$field->handle}->ids());
      } else if ( $field->type ==  'Matrix') {
        foreach ($entry->{$field->handle} as $block) {
          $block->ownerId = $newProduct->id;
          craft()->matrix->saveBlock($block);
        }

      }
    }

  } else {
      $errors = $newProduct->getAllErrors();
      foreach ($errors as $error) {
          echo $error;
          echo "<br>";
      }
      foreach ($newProduct->getVariants() as $variant) {
          $errors = $variant->getAllErrors();
          foreach ($errors as $error) {
              echo $error;
              echo "<br>";
          }
      }
  };

}



$craft->end();