WordPress Uploads Metabox

/**
 * Meta Box class
 */
class RW_Meta_Box {

    protected $_meta_box;
    protected $_fields;

    // Create meta box based on given data
    function __construct($meta_box) {
        if (!is_admin()) return;

        // assign meta box values to local variables and add it's missed values
        $this->_meta_box = $meta_box;
        $this->_fields = & $this->_meta_box['fields'];
        $this->add_missed_values();

        add_action('admin_menu', array(&$this, 'add')); // add meta box
        add_action('save_post', array(&$this, 'save')); // save meta box's data

        // check for some special fields and add needed actions for them
        $this->check_field_upload();
        $this->check_field_color();
        $this->check_field_date();
        $this->check_field_time();
    }

    /******************** BEGIN UPLOAD **********************/

    // Check field upload and add needed actions
    function check_field_upload() {
        if ($this->has_field('image') || $this->has_field('file')) {
            add_action('post_edit_form_tag', array(&$this, 'add_enctype'));             // add data encoding type for file uploading

            wp_enqueue_script('jquery-ui-core');
            wp_enqueue_script('jquery-ui-sortable');
            add_action('admin_head-post.php', array(&$this, 'add_script_upload'));      // add scripts for handling add/delete images
            add_action('admin_head-post-new.php', array(&$this, 'add_script_upload'));

            add_action('delete_post', array(&$this, 'delete_attachments'));             // delete all attachments when delete post
            add_action('wp_ajax_rw_delete_file', array(&$this, 'delete_file'));         // ajax delete files
            add_action('wp_ajax_rw_reorder_images', array(&$this, 'reorder_images'));   // ajax reorder images
        }
    }

    // Add data encoding type for file uploading
    function add_enctype() {
        echo ' enctype="multipart/form-data"';
    }

    // Add scripts for handling add/delete images
    function add_script_upload() {
        global $post;
        echo '
        <style type="text/css">
        .rw-images li {margin: 0 10px 10px 0; float: left; width: 150px; height: 100px; text-align: center; border: 3px solid #ccc; cursor: move; position: relative}
        .rw-images img {width: 150px; height: 100px}
        .rw-images a {position: absolute; bottom: 0; right: 0; color: #fff; background: #000; font-weight: bold; padding: 5px}
        </style>
        ';

        echo '
        <script type="text/javascript">
        jQuery(document).ready(function($) {
        ';

        echo '
            // add more file
            $(".rw-add-file").click(function(){
                var $first = $(this).parent().find(".file-input:first");
                $first.clone().insertAfter($first).show();
                return false;
            });
        ';

        echo '
            // delete file
            $(".rw-delete-file").click(function(){
                var $parent = $(this).parent(),
                    data = $(this).attr("rel");
                $.post(ajaxurl, {action: \'rw_delete_file\', data: data}, function(response){
                    if (response == "0") {
                        alert("' . __('File has been successfully deleted.') . '");
                        $parent.remove();
                    }
                    if (response == "1") {
                        alert("' . __("You don't have permission to delete this file.") . '");
                    }
                });
                return false;
            });
        ';

        foreach ($this->_fields as $field) {
            if ('image' != $field['type']) continue;

            $id = $field['id'];
            $nonce_delete = wp_create_nonce('rw_ajax_delete_file');
            echo "
            // thickbox upload
            $('#rw_upload_$id').click(function(){
                backup = window.send_to_editor;
                window.send_to_editor = function(html) {
                    var el = $(html).is('a') ? $('img', html) : $(html),
                        img_url = el.attr('src'),
                        img_id = el.attr('class');

                    img_id = img_id.slice((img_id.search(/wp-image-/) + 9));

                    html = '<li id=\"item_' + img_id + '\">';
                    html += '<img src=\"' + img_url + '\" />';
                    html += '<a title=\"" . __('Delete this image') . "\" class=\"rw-delete-file\" href=\"#\" rel=\"{$post->ID}!$id!' + img_id + '!$nonce_delete\">" . __('Delete') . "</a>';
                    html += '<input type=\"hidden\" name=\"{$id}[]\" value=\"' + img_id + '\" />';
                    html += '</li>';

                    $('#rw-images-$id').append($(html));

                    tb_remove();
                    window.send_to_editor = backup;
                }
                tb_show('', 'media-upload.php?post_id={$post->ID}; ?>&type=image&TB_iframe=true');

                return false;
            });
            ";

            echo "
            // sort
            $('#rw-images-$id').sortable({
                placeholder: 'ui-state-highlight',
                update: function (){
                    var order = $('#rw-images-$id').sortable('serialize'),
                        data = order + '!' + $('#rw-data-$id').val();
                    $.post(ajaxurl, {action: 'rw_reorder_images', data: data}, function(response){
                        if (response == '0') {
                            alert('" . __('Order saved.') . "');
                        }
                        if (response == '1') {
                            alert(\"" . __("You don't have permission to reorder images.") . "\");
                        }
                    });
                }
            });
            ";
        }

        echo '});
        </script>
        ';
    }

    // Delete all attachments when delete post
    function delete_attachments($post_id) {
        $attachments = get_posts(array(
            'numberposts' => -1,
            'post_type' => 'attachment',
            'post_parent' => $post_id
        ));
        if (!empty($attachments)) {
            foreach ($attachments as $att) {
                wp_delete_attachment($att->ID);
            }
        }
    }

    // Ajax callback for deleting files. Modified from a function used by "Verve Meta Boxes" plugin (http://goo.gl/LzYSq)
    function delete_file() {
        if (!isset($_POST['data'])) die();

        list($post_id, $key, $attach_id, $nonce) = explode('!', $_POST['data']);

        if (!wp_verify_nonce($nonce, 'rw_ajax_delete_file')) {
            die('1');
        }

        wp_delete_attachment($attach_id);
        delete_post_meta($post_id, $key, $attach_id);

        die('0');
    }

    // Ajax callback for reordering images
    function reorder_images() {
        if (!isset($_POST['data'])) die();

        list($order, $post_id, $key, $nonce) = explode('!',$_POST['data']);

        if (!wp_verify_nonce($nonce, 'rw_ajax_sort_file')) {
            die('1');
        }

        parse_str($order, $items);
        $items = $items['item'];
        $order = 0;
        $meta = array();
        foreach ($items as $item) {
            wp_update_post(array(
                'ID' => $item,
                'post_parent' => $post_id,
                'menu_order' => $order
            ));
            $order++;
            $meta[] = $item;
        }
        delete_post_meta($post_id, $key);
        foreach ($meta as $value) {
            add_post_meta($post_id, $key, $value);
        }

        die('0');
    }

    /******************** END UPLOAD **********************/