gistfile1.txt

 add_action('save_post', 'myweb_duplicate_product', 10, 3);
 function myweb_duplicate_product($post_id, $post, $update) {
	 $new_or_existing = '';
	 // only sync products from child sites, do nothing if its the parent site
	 if(get_current_blog_id() != 1){
		// check if the post is new or if it is being updated
		$myPost = get_post($post_id);
		if( $myPost->post_modified_gmt == $myPost->post_date_gmt ){
		  // new product
		  $new_or_existing = 'new';
		}else{
		  //echo 'update';
		}
	}
	copy_post_to_blog($post_id, 1, $new_or_existing);
 }
  

function copy_post_to_blog($post_id, $target_blog_id, $new_or_existing) {
	
	$posttocopy = get_post($post_id); // get the post to copy
	$posttocopy = get_object_vars($posttocopy);
	$childblog_id = get_current_blog_id();
	$mymeta = get_post_meta($post_id);
	
    // retrieve all the product variations for the product we are copying across to the parent
	// if there are any
	$args = array(
		'post_type'       => 'product_variation',
		'posts_per_page'  => -1,
		'post_parent'     => $posttocopy[ID],
	);
	$child_product_variations = get_posts( $args );
	if ( ! empty( $child_product_variations ) ) {
			foreach ( $child_product_variations as $child_product_variation ) {
				  $child_product_variation_postmeta = get_post_meta($child_product_variation->ID);
				  // build an array of all post meta.
				  //$child_product_variation_postmeta_all[] = $child_product_variation_postmeta;
			}
			//var_dump($child_product_variation_postmeta);
		}
	
	unset($posttocopy[ID]); // empty id field, to tell wordpress that this will be a new post
	switch_to_blog($target_blog_id); // switch to target blog
	remove_action('save_post', 'myweb_duplicate_product');
	
	// if this is a new post, create it in the parent network site
	//echo $product_update;
	if($new_or_existing == 'new'){
		// insert the post,. true means it returns the post ID on complete 
		// so $inserted_post_id will equal the new post id
	   $inserted_post_id = wp_insert_post($posttocopy, true); 
	
	   foreach($mymeta as $key=>$value) {
		 update_post_meta($inserted_post_id,$key,$value[0]);
	   }
	   // now add blog id & post id of the product in the child site that the product came from so we can handle updates to it
	   update_post_meta($inserted_post_id,'_myweb_childblog_id',$childblog_id);
	   update_post_meta($inserted_post_id,'_myweb_childblog_post_id',$post_id);
	   
	   
	   if ( ! empty( $child_product_variations ) ) {
			// loop through all product variations
			wp_set_object_terms ($inserted_post_id,'variable','product_type');
			foreach ( $child_product_variations as $child_product_variation ) {
				  // then set the parent id of variations to the new parent site product.
				  $child_product_variation->post_parent = $inserted_post_id;
				  //var_dump($child_product_variation);
				  $new_parent_variation_post_id = wp_insert_post($child_product_variation, true); // insert the post
				  update_post_meta($new_parent_variation_post_id->ID,'_myweb_childblog_id',$childblog_id);
				  update_post_meta($new_parent_variation_post_id->ID,'_myweb_childblog_post_id',$post_id);
				  //
				  // THIS NEEDS TO BE DONE BEFORE SWITCHING BLOGS
				  // now get the post meta for the child site variations
				  // 
				  // and then update this to the new parent variations
				  foreach($child_product_variation_postmeta as $key=>$value) {
					 update_post_meta($new_parent_variation_post_id,$key,$value[0]);
					 //echo 'key: ' . $key . ' value: ' . $value[0] . '<br />';
				  }
			}
		}

	}
	// else if we are updating the post, dont create a new post - just update
	else{
		// find the product to update in the parent site
		$args = array(
			'post_type'  => 'product',
			'posts_per_page' => 1,
			'fields' 	=> 'ids',
			'meta_query' => array(
				'relation' => 'AND',
				array(
					'key'     => '_myweb_childblog_id',
					'value'   => $childblog_id,
					'compare' => '=',
				),
				array(
					'key'     => '_myweb_childblog_post_id',
					'compare' => '=',
					'value'   => $post_id,    
				),
			)
		);
		// load the post from the parent site we are going to update
		$producttoupdate = new WP_Query($args);
		if ($producttoupdate->have_posts()):
			foreach( $producttoupdate->posts as $id ):
				// update the parent with new child post details.
				//print_r($posttocopy);
				// now set the id of the child site product to the id of the parent
				$posttocopy[ID] = $id;
				wp_update_post( $posttocopy);
				//$parent_post = get_post($id);
				//$parent_post = $posttocopy; // now we've set the update
				//wp_update_post( $parent_post);// update the post
				// update all parent post meta
				foreach($mymeta as $key=>$value) {
					update_post_meta($id,$key,$value[0]);
				}
			endforeach;
		endif;
	}
   
   restore_current_blog(); // return to original blog
}