Migrating Content to WordPress with a Custom Plug-in

/*
Plugin Name: Generic Content Import Tool
Description: One Time Import of Old Drupal Content
*/

// standard wordpress meny hook
add_action( 'admin_menu', 'drupal_import_menu' );

/**
 * A standard WordPress plugin menu item
 */
function drupal_import_menu()
{
    add_menu_page( "Drupal Import", "Drupal Import", 'import', 'drupal-import', show_drupal_import_menu );
}

/**
 * A standard WordPress plugin menu page
 * This has an "if is a POST, process the form"
 * and then shows the form through normal echo of HTML
 */
function show_drupal_import_menu()
{
    if ( !current_user_can( 'import' ) )  {
        wp_die( __( 'You do not have sufficient permissions to access this page.' ) );
    }

     if( isset($_POST[ 'drupal_import_hidden' ]) && $_POST[ 'drupal_import_hidden' ] == 'Y' ) {

        // the bulk of the logic goes here
     }

    echo '<form method="post" style="padding: 50px">';
    echo '<input type="hidden" name="drupal_import_hidden" value="Y" />';
    echo '<input type="submit" value="Process" />';
    echo '</form>';
}

function load_data($db, $limit = 10)
{
    // get X nodes where X is the passed in limit
    $sql = sprintf("select n.nid, n.uid, nr.title, nr.body, nr.teaser, nr.timestamp, n.status from node_revisions nr join node n on n.nid = nr.nid and n.vid = nr.vid and n.type = 'story' left join drupal_import_nid_map m on nr.nid = m.drupal_nid where m.wordpress_post_id is null order by n.created limit %d", $limit);
    $rows = $db->get_results($sql);
    $data = [];
    foreach ($rows as $obj) {

        // grab the categories associated with this node and
        // store them in an array of categoryIDs
        $categories = [];
        $get_categories_sql = sprintf("select name from term_data d join term_node n on n.tid = d.tid and n.nid = %d", $obj->nid);
        $cats = $db->get_results($get_categories_sql);
        foreach ($cats as $catObj) {
            $categories[] = get_wp_cat_id($catObj->name);
        }

        $data[] = [
            'ID' => 0,
            'post_author' => get_wp_user_id($obj->uid), // maps drupal UID to WP User ID
            'post_date' => date('Y-m-d', $obj->timestamp), // Formats Drupal Timestamp to standard date
            'post_content' => $obj->body, // HTML
            'post_title' => $obj->title,
            'post_excerpt' => $obj->teaser,
            'post_status' => $obj->status == 1 ? 'publish' : 'draft',
            'post_type' => 'post', // I only have one type, but helper function could be used if you have more
            'comment_status' => 'closed',
            'post_category' => $categories, // see above
            'drupal_nid' => $obj->nid // only used by a later function, ignored by WordPress
        ];
    }
    return $data;
}

function get_wp_cat_id($drupal_cat_name)
{
    switch ($drupal_cat_name) {
        case 'Old Category Name':
            return 2; // New Category ID
            break;
        default:
            return 1; // uncategorized
            break;
    }
}

function get_wp_user_id($drupal_uid)
{
    switch ($drupal_uid) {
        case 301:
            return 2; // New User ID
            break;
        default:
            return 1; // Admin
            break;
    }
}