<?php
/**
 * Base class for displaying a list of items in an ajaxified HTML table.
 *
 * @package WordPress
 * @subpackage List_Table
 * @since 3.1.0
 */

/**
 * Base class for displaying a list of items in an ajaxified HTML table.
 *
 * @package WordPress
 * @subpackage List_Table
 * @since 3.1.0
 * @access private
 */
class WP_List_Table {

    /**
     * The current list of items
     *
     * @since 3.1.0
     * @var array
     * @access protected
     */
    var $items;

    /**
     * Various information about the current table
     *
     * @since 3.1.0
     * @var array
     * @access private
     */
    var $_args;

    /**
     * Various information needed for displaying the pagination
     *
     * @since 3.1.0
     * @var array
     * @access private
     */
    var $_pagination_args = array();

    /**
     * The current screen
     *
     * @since 3.1.0
     * @var object
     * @access protected
     */
    var $screen;

    /**
     * Cached bulk actions
     *
     * @since 3.1.0
     * @var array
     * @access private
     */
    var $_actions;

    /**
     * Cached pagination output
     *
     * @since 3.1.0
     * @var string
     * @access private
     */
    var $_pagination;

    /**
     * Constructor. The child class should call this constructor from its own constructor
     *
     * @param array $args An associative array with information about the current table
     * @access protected
     */
    function __construct( $args = array() ) {
        $args = wp_parse_args( $args, array(
            'plural' => '',
            'singular' => '',
            'ajax' => false,
            'screen' => null,
        ) );

        $this->screen = convert_to_screen( $args['screen'] );

        add_filter( "manage_{$this->screen->id}_columns", array( $this, 'get_columns' ), 0 );

        if ( !$args['plural'] )
            $args['plural'] = $this->screen->base;

        $args['plural'] = sanitize_key( $args['plural'] );
        $args['singular'] = sanitize_key( $args['singular'] );

        $this->_args = $args;

        if ( $args['ajax'] ) {
            // wp_enqueue_script( 'list-table' );
            add_action( 'admin_footer', array( $this, '_js_vars' ) );
        }
    }

    /**
     * Checks the current user's permissions
     * @uses wp_die()
     *
     * @since 3.1.0
     * @access public
     * @abstract
     */
    function ajax_user_can() {
        die( 'function WP_List_Table::ajax_user_can() must be over-ridden in a sub-class.' );
    }

    /**
     * Prepares the list of items for displaying.
     * @uses WP_List_Table::set_pagination_args()
     *
     * @since 3.1.0
     * @access public
     * @abstract
     */
    function prepare_items() {
        die( 'function WP_List_Table::prepare_items() must be over-ridden in a sub-class.' );
    }

    /**
     * An internal method that sets all the necessary pagination arguments
     *
     * @param array $args An associative array with information about the pagination
     * @access protected
     */
    function set_pagination_args( $args ) {
        $args = wp_parse_args( $args, array(
            'total_items' => 0,
            'total_pages' => 0,
            'per_page' => 0,
        ) );

        if ( !$args['total_pages'] && $args['per_page'] > 0 )
            $args['total_pages'] = ceil( $args['total_items'] / $args['per_page'] );

        // redirect if page number is invalid and headers are not already sent
        if ( ! headers_sent() && ( ! defined( 'DOING_AJAX' ) || ! DOING_AJAX ) && $args['total_pages'] > 0 && $this->get_pagenum() > $args['total_pages'] ) {
            wp_redirect( add_query_arg( 'paged', $args['total_pages'] ) );
            exit;
        }

        $this->_pagination_args = $args;
    }

    /**
     * Access the pagination args
     *
     * @since 3.1.0
     * @access public
     *
     * @param string $key
     * @return array
     */
    function get_pagination_arg( $key ) {
        if ( 'page' == $key )
            return $this->get_pagenum();

        if ( isset( $this->_pagination_args[$key] ) )
            return $this->_pagination_args[$key];
    }

    /**
     * Whether the table has items to display or not
     *
     * @since 3.1.0
     * @access public
     *
     * @return bool
     */
    function has_items() {
        return !empty( $this->items );
    }

    /**
     * Message to be displayed when there are no items
     *
     * @since 3.1.0
     * @access public
     */
    function no_items() {
        _e( 'No items found.' );
    }

    /**
     * Display the search box.
     *
     * @since 3.1.0
     * @access public
     *
     * @param string $text The search button text
     * @param string $input_id The search input id
     */
    function search_box( $text, $input_id ) {
        if ( empty( $_REQUEST['s'] ) && !$this->has_items() )
            return;

        $input_id = $input_id . '-search-input';

        if ( ! empty( $_REQUEST['orderby'] ) )
            echo '<input type="hidden" name="orderby" value="' . esc_attr( $_REQUEST['orderby'] ) . '" />';
        if ( ! empty( $_REQUEST['order'] ) )
            echo '<input type="hidden" name="order" value="' . esc_attr( $_REQUEST['order'] ) . '" />';
        if ( ! empty( $_REQUEST['post_mime_type'] ) )
            echo '<input type="hidden" name="post_mime_type" value="' . esc_attr( $_REQUEST['post_mime_type'] ) . '" />';
        if ( ! empty( $_REQUEST['detached'] ) )
            echo '<input type="hidden" name="detached" value="' . esc_attr( $_REQUEST['detached'] ) . '" />';
        ?>
        <p class="search-box">
            <label class="screen-reader-text" for="<?php echo $input_id ?>"><?php echo $text; ?>:</label>
            <input type="search" id="<?php echo $input_id ?>" name="s" value="<?php _admin_search_query(); ?>" />
            <?php submit_button( $text, 'button', false, false, array('id' => 'search-submit') ); ?>
        </p>
        <?php
    }

    /**
     * Get an associative array ( id => link ) with the list
     * of views available on this table.
     *
     * @since 3.1.0
     * @access protected
     *
     * @return array
     */
    function get_views() {
        return array();
    }

    /**
     * Display the list of views available on this table.
     *
     * @since 3.1.0
     * @access public
     */
    function views() {
        $views = $this->get_views();
        /**
         * Filter the list of available list table views.
         *
         * The dynamic portion of the hook name, $this->screen->id, refers
         * to the ID of the current screen, usually a string.
         *
         * @since 3.5.0
         *
         * @param array $views An array of available list table views.
         */
        $views = apply_filters( "views_{$this->screen->id}", $views );

        if ( empty( $views ) )
            return;

        echo "<ul class='subsubsub'>\n";
        foreach ( $views as $class => $view ) {
            $views[ $class ] = "\t<li class='$class'>$view";
        }
        echo implode( " |</li>\n", $views ) . "</li>\n";
        echo "</ul>";
    }

    /**
     * Get an associative array ( option_name => option_title ) with the list
     * of bulk actions available on this table.
     *
     * @since 3.1.0
     * @access protected
     *
     * @return array
     */
    function get_bulk_actions() {
        return array();
    }

    /**
     * Display the bulk actions dropdown.
     *
     * @since 3.1.0
     * @access public
     */
    function bulk_actions() {
        if ( is_null( $this->_actions ) ) {
            $no_new_actions = $this->_actions = $this->get_bulk_actions();
            /**
             * Filter the list table Bulk Actions drop-down.
             *
             * The dynamic portion of the hook name, $this->screen->id, refers
             * to the ID of the current screen, usually a string.
             *
             * This filter can currently only be used to remove bulk actions.
             *
             * @since 3.5.0
             *
             * @param array $actions An array of the available bulk actions.
             */
            $this->_actions = apply_filters( "bulk_actions-{$this->screen->id}", $this->_actions );
            $this->_actions = array_intersect_assoc( $this->_actions, $no_new_actions );
            $two = '';
        } else {
            $two = '2';
        }

        if ( empty( $this->_actions ) )
            return;

        echo "<select name='action$two'>\n";
        echo "<option value='-1' selected='selected'>" . __( 'Bulk Actions' ) . "</option>\n";

        foreach ( $this->_actions as $name => $title ) {
            $class = 'edit' == $name ? ' class="hide-if-no-js"' : '';

            echo "\t<option value='$name'$class>$title</option>\n";
        }

        echo "</select>\n";

        submit_button( __( 'Apply' ), 'action', false, false, array( 'id' => "doaction$two" ) );
        echo "\n";
    }

    /**
     * Get the current action selected from the bulk actions dropdown.
     *
     * @since 3.1.0
     * @access public
     *
     * @return string|bool The action name or False if no action was selected
     */
    function current_action() {
        if ( isset( $_REQUEST['action'] ) && -1 != $_REQUEST['action'] )
            return $_REQUEST['action'];

        if ( isset( $_REQUEST['action2'] ) && -1 != $_REQUEST['action2'] )
            return $_REQUEST['action2'];

        return false;
    }

    /**
     * Generate row actions div
     *
     * @since 3.1.0
     * @access protected
     *
     * @param array $actions The list of actions
     * @param bool $always_visible Whether the actions should be always visible
     * @return string
     */
    function row_actions( $actions, $always_visible = false ) {
        $action_count = count( $actions );
        $i = 0;

        if ( !$action_count )
            return '';

        $out = '<div class="' . ( $always_visible ? 'row-actions visible' : 'row-actions' ) . '">';
        foreach ( $actions as $action => $link ) {
            ++$i;
            ( $i == $action_count ) ? $sep = '' : $sep = ' | ';
            $out .= "<span class='$action'>$link$sep</span>";
        }
        $out .= '</div>';

        return $out;
    }

    /**
     * Display a monthly dropdown for filtering items
     *
     * @since 3.1.0
     * @access protected
     */
    function months_dropdown( $post_type ) {
        global $wpdb, $wp_locale;

        $months = $wpdb->get_results( $wpdb->prepare( "
			SELECT DISTINCT YEAR( post_date ) AS year, MONTH( post_date ) AS month
			FROM $wpdb->posts
			WHERE post_type = %s
			ORDER BY post_date DESC
		", $post_type ) );

        /**
         * Filter the 'Months' drop-down results.
         *
         * @since 3.7.0
         *
         * @param object $months    The months drop-down query results.
         * @param string $post_type The post type.
         */
        $months = apply_filters( 'months_dropdown_results', $months, $post_type );

        $month_count = count( $months );

        if ( !$month_count || ( 1 == $month_count && 0 == $months[0]->month ) )
            return;

        $m = isset( $_GET['m'] ) ? (int) $_GET['m'] : 0;
        ?>
        <select name='m'>
            <option<?php selected( $m, 0 ); ?> value='0'><?php _e( 'Show all dates', 'wp-mail-logging' ); ?></option>
            <?php
            foreach ( $months as $arc_row ) {
                if ( 0 == $arc_row->year )
                    continue;

                $month = zeroise( $arc_row->month, 2 );
                $year = $arc_row->year;

                printf( "<option %s value='%s'>%s</option>\n",
                    selected( $m, $year . $month, false ),
                    esc_attr( $arc_row->year . $month ),
                    /* translators: 1: month name, 2: 4-digit year */
                    sprintf( __( '%1$s %2$d' ), $wp_locale->get_month( $month ), $year )
                );
            }
            ?>
        </select>
        <?php
    }

    /**
     * Display a view switcher
     *
     * @since 3.1.0
     * @access protected
     */
    function view_switcher( $current_mode ) {
        $modes = array(
            'list'    => __( 'List View' ),
            'excerpt' => __( 'Excerpt View', 'wp-mail-logging' )
        );

        ?>
        <input type="hidden" name="mode" value="<?php echo esc_attr( $current_mode ); ?>" />
        <div class="view-switch">
            <?php
            foreach ( $modes as $mode => $title ) {
                $class = ( $current_mode == $mode ) ? 'class="current"' : '';
                echo "<a href='" . esc_url( add_query_arg( 'mode', $mode, $_SERVER['REQUEST_URI'] ) ) . "' $class><img id='view-switch-$mode' src='" . esc_url( includes_url( 'images/blank.gif' ) ) . "' width='20' height='20' title='$title' alt='$title' /></a>\n";
            }
            ?>
        </div>
        <?php
    }

    /**
     * Display a comment count bubble
     *
     * @since 3.1.0
     * @access protected
     *
     * @param int $post_id
     * @param int $pending_comments
     */
    function comments_bubble( $post_id, $pending_comments ) {
        $pending_phrase = sprintf( __( '%s pending', 'wp-mail-logging' ), number_format( $pending_comments ) );

        if ( $pending_comments )
            echo '<strong>';

        echo "<a href='" . esc_url( add_query_arg( 'p', $post_id, admin_url( 'edit-comments.php' ) ) ) . "' title='" . esc_attr( $pending_phrase ) . "' class='post-com-count'><span class='comment-count'>" . number_format_i18n( get_comments_number() ) . "</span></a>";

        if ( $pending_comments )
            echo '</strong>';
    }

    /**
     * Get the current page number
     *
     * @since 3.1.0
     * @access protected
     *
     * @return int
     */
    function get_pagenum() {
        $pagenum = isset( $_REQUEST['paged'] ) ? absint( $_REQUEST['paged'] ) : 0;

        if( isset( $this->_pagination_args['total_pages'] ) && $pagenum > $this->_pagination_args['total_pages'] )
            $pagenum = $this->_pagination_args['total_pages'];

        return max( 1, $pagenum );
    }

    /**
     * Get number of items to display on a single page
     *
     * @since 3.1.0
     * @access protected
     *
     * @return int
     */
    function get_items_per_page( $option, $default = 20 ) {
        $per_page = (int) get_user_option( $option );
        if ( empty( $per_page ) || $per_page < 1 )
            $per_page = $default;

        /**
         * Filter the number of items to be displayed on each page of the list table.
         *
         * The dynamic hook name, $option, refers to the per page option depending
         * on the type of list table in use. Possible values may include:
         * 'edit_comments_per_page', 'sites_network_per_page', 'site_themes_network_per_page',
         * 'themes_netework_per_page', 'users_network_per_page', 'edit_{$post_type}', etc.
         *
         * @since 2.9.0
         *
         * @param int $per_page Number of items to be displayed. Default 20.
         */
        return (int) apply_filters( $option, $per_page );
    }

    /**
     * Display the pagination.
     *
     * @since 3.1.0
     * @access protected
     */
    function pagination( $which ) {
        if ( empty( $this->_pagination_args ) )
            return;

        extract( $this->_pagination_args, EXTR_SKIP );

        $output = '<span class="displaying-num">' . sprintf( _n( '1 item', '%s items', $total_items, 'wp-mail-logging' ), number_format_i18n( $total_items ) ) . '</span>';

        $current = $this->get_pagenum();

        $current_url = set_url_scheme( 'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'] );

        $current_url = remove_query_arg( array( 'hotkeys_highlight_last', 'hotkeys_highlight_first' ), $current_url );

        $page_links = array();

        $disable_first = $disable_last = '';
        if ( $current == 1 )
            $disable_first = ' disabled';
        if ( $current == $total_pages )
            $disable_last = ' disabled';

        $page_links[] = sprintf( "<a class='%s' title='%s' href='%s'>%s</a>",
            'first-page' . $disable_first,
            esc_attr__( 'Go to the first page', 'wp-mail-logging' ),
            esc_url( remove_query_arg( 'paged', $current_url ) ),
            '&laquo;'
        );

        $page_links[] = sprintf( "<a class='%s' title='%s' href='%s'>%s</a>",
            'prev-page' . $disable_first,
            esc_attr__( 'Go to the previous page', 'wp-mail-logging' ),
            esc_url( add_query_arg( 'paged', max( 1, $current-1 ), $current_url ) ),
            '&lsaquo;'
        );

        if ( 'bottom' == $which )
            $html_current_page = $current;
        else
            $html_current_page = sprintf( "<input class='current-page' title='%s' type='text' name='paged' value='%s' size='%d' />",
                esc_attr__( 'Current page' ),
                $current,
                strlen( $total_pages )
            );

        $html_total_pages = sprintf( "<span class='total-pages'>%s</span>", number_format_i18n( $total_pages ) );
        $page_links[] = '<span class="paging-input">' . sprintf( _x( '%1$s of %2$s', 'paging' ), $html_current_page, $html_total_pages ) . '</span>';

        $page_links[] = sprintf( "<a class='%s' title='%s' href='%s'>%s</a>",
            'next-page' . $disable_last,
            esc_attr__( 'Go to the next page', 'wp-mail-logging' ),
            esc_url( add_query_arg( 'paged', min( $total_pages, $current+1 ), $current_url ) ),
            '&rsaquo;'
        );

        $page_links[] = sprintf( "<a class='%s' title='%s' href='%s'>%s</a>",
            'last-page' . $disable_last,
            esc_attr__( 'Go to the last page', 'wp-mail-logging' ),
            esc_url( add_query_arg( 'paged', $total_pages, $current_url ) ),
            '&raquo;'
        );

        $pagination_links_class = 'pagination-links';
        if ( ! empty( $infinite_scroll ) )
            $pagination_links_class = ' hide-if-js';
        $output .= "\n<span class='$pagination_links_class'>" . join( "\n", $page_links ) . '</span>';

        if ( $total_pages )
            $page_class = $total_pages < 2 ? ' one-page' : '';
        else
            $page_class = ' no-pages';

        $this->_pagination = "<div class='tablenav-pages{$page_class}'>$output</div>";

        echo $this->_pagination;
    }

    /**
     * Get a list of columns. The format is:
     * 'internal-name' => 'Title'
     *
     * @since 3.1.0
     * @access protected
     * @abstract
     *
     * @return array
     */
    function get_columns() {
        die( 'function WP_List_Table::get_columns() must be over-ridden in a sub-class.' );
    }

    /**
     * Get a list of sortable columns. The format is:
     * 'internal-name' => 'orderby'
     * or
     * 'internal-name' => array( 'orderby', true )
     *
     * The second format will make the initial sorting order be descending
     *
     * @since 3.1.0
     * @access protected
     *
     * @return array
     */
    function get_sortable_columns() {
        return array();
    }

    /**
     * Get a list of all, hidden and sortable columns, with filter applied
     *
     * @since 3.1.0
     * @access protected
     *
     * @return array
     */
    function get_column_info() {
        if ( isset( $this->_column_headers ) )
            return $this->_column_headers;

        $columns = get_column_headers( $this->screen );
        $hidden = get_hidden_columns( $this->screen );

        $sortable_columns = $this->get_sortable_columns();
        /**
         * Filter the list table sortable columns for a specific screen.
         *
         * The dynamic portion of the hook name, $this->screen->id, refers
         * to the ID of the current screen, usually a string.
         *
         * @since 3.5.0
         *
         * @param array $sortable_columns An array of sortable columns.
         */
        $_sortable = apply_filters( "manage_{$this->screen->id}_sortable_columns", $sortable_columns );

        $sortable = array();
        foreach ( $_sortable as $id => $data ) {
            if ( empty( $data ) )
                continue;

            $data = (array) $data;
            if ( !isset( $data[1] ) )
                $data[1] = false;

            $sortable[$id] = $data;
        }

        $this->_column_headers = array( $columns, $hidden, $sortable );

        return $this->_column_headers;
    }

    /**
     * Return number of visible columns
     *
     * @since 3.1.0
     * @access public
     *
     * @return int
     */
    function get_column_count() {
        list ( $columns, $hidden ) = $this->get_column_info();
        $hidden = array_intersect( array_keys( $columns ), array_filter( $hidden ) );
        return count( $columns ) - count( $hidden );
    }

    /**
     * Print column headers, accounting for hidden and sortable columns.
     *
     * @since 3.1.0
     * @access protected
     *
     * @param bool $with_id Whether to set the id attribute or not
     */
    function print_column_headers( $with_id = true ) {
        list( $columns, $hidden, $sortable ) = $this->get_column_info();

        $current_url = set_url_scheme( 'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'] );
        $current_url = remove_query_arg( 'paged', $current_url );

        if ( isset( $_GET['orderby'] ) )
            $current_orderby = $_GET['orderby'];
        else
            $current_orderby = '';

        if ( isset( $_GET['order'] ) && 'desc' == $_GET['order'] )
            $current_order = 'desc';
        else
            $current_order = 'asc';

        if ( ! empty( $columns['cb'] ) ) {
            static $cb_counter = 1;
            $columns['cb'] = '<label class="screen-reader-text" for="cb-select-all-' . $cb_counter . '">' . __( 'Select All' ) . '</label>'
                . '<input id="cb-select-all-' . $cb_counter . '" type="checkbox" />';
            $cb_counter++;
        }

        foreach ( $columns as $column_key => $column_display_name ) {
            $class = array( 'manage-column', "column-$column_key" );

            $style = '';
            if ( in_array( $column_key, $hidden ) )
                $style = 'display:none;';

            $style = ' style="' . $style . '"';

            if ( 'cb' == $column_key )
                $class[] = 'check-column';
            elseif ( in_array( $column_key, array( 'posts', 'comments', 'links' ) ) )
                $class[] = 'num';

            if ( isset( $sortable[$column_key] ) ) {
                list( $orderby, $desc_first ) = $sortable[$column_key];

                if ( $current_orderby == $orderby ) {
                    $order = 'asc' == $current_order ? 'desc' : 'asc';
                    $class[] = 'sorted';
                    $class[] = $current_order;
                } else {
                    $order = $desc_first ? 'desc' : 'asc';
                    $class[] = 'sortable';
                    $class[] = $desc_first ? 'asc' : 'desc';
                }

                $column_display_name = '<a href="' . esc_url( add_query_arg( compact( 'orderby', 'order' ), $current_url ) ) . '"><span>' . $column_display_name . '</span><span class="sorting-indicator"></span></a>';
            }

            $id = $with_id ? "id='$column_key'" : '';

            if ( !empty( $class ) )
                $class = "class='" . join( ' ', $class ) . "'";

            echo "<th scope='col' $id $class $style>$column_display_name</th>";
        }
    }

    /**
     * Display the table
     *
     * @since 3.1.0
     * @access public
     */
    function display() {
        extract( $this->_args );

        $this->display_tablenav( 'top' );

        ?>
        <table class="wp-list-table <?php echo implode( ' ', $this->get_table_classes() ); ?>" cellspacing="0">
            <thead>
            <tr>
                <?php $this->print_column_headers(); ?>
            </tr>
            </thead>

            <tfoot>
            <tr>
                <?php $this->print_column_headers( false ); ?>
            </tr>
            </tfoot>

            <tbody id="the-list"<?php if ( $singular ) echo " data-wp-lists='list:$singular'"; ?>>
            <?php $this->display_rows_or_placeholder(); ?>
            </tbody>
        </table>
        <?php
        $this->display_tablenav( 'bottom' );
    }

    /**
     * Get a list of CSS classes for the <table> tag
     *
     * @since 3.1.0
     * @access protected
     *
     * @return array
     */
    function get_table_classes() {
        return array( 'widefat', 'fixed', $this->_args['plural'] );
    }

    /**
     * Generate the table navigation above or below the table
     *
     * @since 3.1.0
     * @access protected
     */
    function display_tablenav( $which ) {
        if ( 'top' == $which )
            wp_nonce_field( 'bulk-' . $this->_args['plural'] );
        ?>
        <div class="tablenav <?php echo esc_attr( $which ); ?>">

            <div class="alignleft actions bulkactions">
                <?php $this->bulk_actions(); ?>
            </div>
            <?php
            $this->extra_tablenav( $which );
            $this->pagination( $which );
            ?>

            <br class="clear" />
        </div>
        <?php
    }

    /**
     * Extra controls to be displayed between bulk actions and pagination
     *
     * @since 3.1.0
     * @access protected
     */
    function extra_tablenav( $which ) {}

    /**
     * Generate the <tbody> part of the table
     *
     * @since 3.1.0
     * @access protected
     */
    function display_rows_or_placeholder() {
        if ( $this->has_items() ) {
            $this->display_rows();
        } else {
            list( $columns, $hidden ) = $this->get_column_info();
            echo '<tr class="no-items"><td class="colspanchange" colspan="' . $this->get_column_count() . '">';
            $this->no_items();
            echo '</td></tr>';
        }
    }

    /**
     * Generate the table rows
     *
     * @since 3.1.0
     * @access protected
     */
    function display_rows() {
        foreach ( $this->items as $item )
            $this->single_row( $item );
    }

    /**
     * Generates content for a single row of the table
     *
     * @since 3.1.0
     * @access protected
     *
     * @param object $item The current item
     */
    function single_row( $item ) {
        static $row_class = '';
        $row_class = ( $row_class == '' ? ' class="alternate"' : '' );

        echo '<tr' . $row_class . '>';
        $this->single_row_columns( $item );
        echo '</tr>';
    }

    /**
     * Generates the columns for a single row of the table
     *
     * @since 3.1.0
     * @access protected
     *
     * @param object $item The current item
     */
    function single_row_columns( $item ) {
        list( $columns, $hidden ) = $this->get_column_info();

        foreach ( $columns as $column_name => $column_display_name ) {
            $class = "class='$column_name column-$column_name'";

            $style = '';
            if ( in_array( $column_name, $hidden ) )
                $style = ' style="display:none;"';

            $attributes = "$class$style";

            if ( 'cb' == $column_name ) {
                echo '<th scope="row" class="check-column">';
                echo $this->column_cb( $item );
                echo '</th>';
            }
            elseif ( method_exists( $this, 'column_' . $column_name ) ) {
                echo "<td $attributes>";
                echo call_user_func( array( $this, 'column_' . $column_name ), $item );
                echo "</td>";
            }
            else {
                echo "<td $attributes>";
                echo $this->column_default( $item, $column_name );
                echo "</td>";
            }
        }
    }

    /**
     * Handle an incoming ajax request (called from admin-ajax.php)
     *
     * @since 3.1.0
     * @access public
     */
    function ajax_response() {
        $this->prepare_items();

        extract( $this->_args );
        extract( $this->_pagination_args, EXTR_SKIP );

        ob_start();
        if ( ! empty( $_REQUEST['no_placeholder'] ) )
            $this->display_rows();
        else
            $this->display_rows_or_placeholder();

        $rows = ob_get_clean();

        $response = array( 'rows' => $rows );

        if ( isset( $total_items ) )
            $response['total_items_i18n'] = sprintf( _n( '1 item', '%s items', $total_items, 'wp-mail-logging' ), number_format_i18n( $total_items ) );

        if ( isset( $total_pages ) ) {
            $response['total_pages'] = $total_pages;
            $response['total_pages_i18n'] = number_format_i18n( $total_pages );
        }

        die( json_encode( $response ) );
    }

    /**
     * Send required variables to JavaScript land
     *
     * @access private
     */
    function _js_vars() {
        $args = array(
            'class'  => get_class( $this ),
            'screen' => array(
                'id'   => $this->screen->id,
                'base' => $this->screen->base,
            )
        );

        printf( "<script type='text/javascript'>list_args = %s;</script>\n", json_encode( $args ) );
    }
}
