Admin Menu Post List - WordPress plugin (dev)

<?php
/*
Plugin Name: Admin Menu Post List
Plugin URI:
Description: Display a simple post list in admin menu for easy access
Version: 0.2
Author: Eliot Akira
Author URI:
License: GPL2
*/


/*
 * Load CSS in header
 */

function custom_post_list_view_css() { ?>

    <style>
        .post_list_view_headline {
            padding-left: 10px !important;
            padding-right: 10px !important;
        }
        .post_list_view_post {
            margin-left:12px;
        }
        .post_current a {
            color:white !important;
        }
    </style>

<?php }
add_action( 'admin_head', 'custom_post_list_view_css' );


/*
 * Admin Menu Post List
 */


add_action('admin_menu', 'custom_post_list_view');
function custom_post_list_view() {

    /*** Get options ***/

    $post_types = array( 'post', 'page' );

    $current_post_ID = $_GET['post']; /* Get current post ID on admin screen */

    foreach ($post_types as $post_type) {

        $custom_menu_slug = $post_type;
        $output = '';

        $args = array(
            "post_type" => $post_type,
            "parent" => "0",
            "post_parent" => "0",
            "numberposts" => "-1",
            "orderby" => "menu_order",
            "order" => "ASC",
            "post_status" => "any",
            "suppress_filters" => 0
        );

        $posts = get_posts($args);

        if($posts) {

            $output .= '</a>';

            $output .= '<div class="list_view_' . $post_type . '">'
                        . '<div class="post_list_view_headline">' . '<hr>' . '</div>';
            foreach ($posts as $post) {
                $edit_link = get_edit_post_link($post->ID);
                $title = get_the_title($post->ID);
                $title = esc_html($title);
                $output .= '<div class="post_list_view_post';
                if($current_post_ID == ($post->ID)) {
                    $output .= ' post_current';
                }
                $output .= '">'
                    . '<a href="'
                    . $edit_link    . '">'
                    . $title . '</a></div>';

                /*** Search for children? ***/

            }
            $output .= '</div>';

            $output .= '<a>';

            if($post_type == 'post') {
                add_posts_page( "Title", $output, "edit_posts", $custom_menu_slug, "custom_post_list_view_page");
            } else {
                 if ($post_type == 'page') {
                    add_pages_page( "Title", $output, "edit_pages", $custom_menu_slug, "custom_post_list_view_page");
                } else {
                    if($post_type == 'attachment') {
                         add_media_page("Title", $output, "edit_posts", $custom_menu_slug, "custom_post_list_view_page");
                    } else {
                        add_submenu_page(('edit.php?post_type=' . $post_type), "Title", $output, "edit_posts", ('edit.php?post_type=' . $post_type), "custom_post_list_view_page");
                    }
                }
            }
        }
    } // End foreach post type
}

function custom_post_list_view_page() { /* Empty */ }

?>