/**
     * Extra controls to be displayed before pagination, which
     * includes our Filters: Customers, Event Types, Event Dates
     *
     * @see WP_List_Table::extra_tablenav();
     * @since 1.0
     * @param string $which the placement, one of 'top' or 'bottom'
     */
    public function extra_tablenav($which)
    {
        global $woocommerce;
        if ('top' == $which) {
            echo '<div class="alignleft actions">';
            // Customers, products
            ?>
			<select id="dropdown_customers" name="_customer_user">
				<option value=""><?php 
            _e('Show All Customers', 'wc_points_rewards');
            ?>
</option>
				<?php 
            if (!empty($_GET['_customer_user'])) {
                $user = get_user_by('id', absint($_GET['_customer_user']));
                echo '<option value="' . absint($user->ID) . '" ';
                selected(1, 1);
                echo '>' . esc_html($user->display_name) . ' (#' . absint($user->ID) . ' &ndash; ' . esc_html($user->user_email) . ')</option>';
            }
            ?>
			</select>

			<select id="dropdown_event_types" name="_event_type">
				<option value=""><?php 
            _e('Show All Event Types', 'wc_points_rewards');
            ?>
</option>
				<?php 
            foreach (WC_Points_Rewards_Points_Log::get_event_types() as $event_type) {
                echo '<option value="' . esc_attr($event_type->type) . '" ' . selected($event_type->type, isset($_GET['_event_type']) ? $_GET['_event_type'] : null, false) . '>' . esc_html(sprintf("%s (%d)", $event_type->name, $event_type->count)) . '</option>';
            }
            ?>
			</select>
			<?php 
            $this->render_dates_dropdown();
            submit_button(__('Filter'), 'button', false, false, array('id' => 'post-query-submit'));
            echo '</div>';
            // javascript
            $js = "\n\t\t\t\t// Ajax Chosen Product Selectors\n\t\t\t\t\$('select#dropdown_dates').css('width', '250px').chosen();\n\n\t\t\t\t\$('select#dropdown_event_types').css('min-width', '190px').chosen();\n\n\t\t\t\t\$('select#dropdown_customers').css('width', '250px').ajaxChosen({\n\t\t\t\t\tmethod:         'GET',\n\t\t\t\t\turl:            '" . admin_url('admin-ajax.php') . "',\n\t\t\t\t\tdataType:       'json',\n\t\t\t\t\tafterTypeDelay: 100,\n\t\t\t\t\tminTermLength:  1,\n\t\t\t\t\tdata: {\n\t\t\t\t\t\taction:   'woocommerce_json_search_customers',\n\t\t\t\t\t\tsecurity: '" . wp_create_nonce("search-customers") . "',\n\t\t\t\t\t\tdefault:  '" . esc_js(__('Show All Customers', 'wc_points_rewards')) . "'\n\t\t\t\t\t}\n\t\t\t\t}, function (data) {\n\n\t\t\t\t\tvar terms = {};\n\n\t\t\t\t\t\$.each(data, function (i, val) {\n\t\t\t\t\t\tterms[i] = val;\n\t\t\t\t\t});\n\n\t\t\t\t\treturn terms;\n\t\t\t\t});\n\t\t\t";
            if (function_exists('wc_enqueue_js')) {
                wc_enqueue_js($js);
            } else {
                $woocommerce->add_inline_js($js);
            }
        }
    }