Change User Role Upon Product Purchase

woo-change-user-role.php

<?php

// Single Product - Only Use One Snippet or the Other!!

function woo_change_role_after_purchase( $order_id ) {

  // Get order object and items
  $order = new WC_Order( $order_id );
  $items = $order->get_items();

  $product_id = 10; // Change Product ID

  foreach ( $items as $item ) {

    if( $product_id == $item['product_id'] && $order->user_id ) {
    $user = new WP_User( $order->user_id );

    // Remove old Role
    $user->remove_role( 'customer' ); 

    // Add new Role
    $user->add_role( 'editor' );
    }
  }
}

add_action( 'woocommerce_order_status_completed', 'woo_change_role_after_purchase' );

// Multiple Products - Only Use One Snippet or the Other!!

function woo_change_role_after_purchase( $order_id ) {

  // Get order object and items
  $order = wc_get_order( $order_id );
  $items = $order->get_items();

  $products_to_check = array( '20', '21' ); // Add Product IDs Here

  foreach ( $items as $item ) {
    if ( $order->user_id > 0 && in_array( $item['product_id'], $products_to_check ) ) {
    $user = new WP_User( $order->user_id );

    // Remove old Role
    $user->remove_role( 'customer' ); 

    // Add new Role
    $user->add_role( 'editor' );

    // Exit the loop
    break;
    }
  }
}

add_action( 'woocommerce_order_status_completed', 'woo_change_role_after_purchase' );