public function calendars_option_page()
    {
        $sAllCalendarsUrl = esc_url(add_query_arg(array('page' => 'uni-events-calendars'), admin_url('admin.php')));
        $sAddNewCalendarUrl = esc_url(add_query_arg(array('page' => 'uni-events-calendars', 'action' => 'add-new'), admin_url('admin.php')));
        ?>

        <div id="uni-calendar-wrapper" class="wrap">
            <div id="icon-tools" class="icon32"></div>
            <?php 
        if (!isset($_GET['action']) || $_GET['action'] != 'add-new' && $_GET['action'] != 'edit' && $_GET['action'] != 'edit-events') {
            ?>
                <h2><?php 
            _e('Uni Events Calendars Manager', 'uni-calendar');
            ?>
 <a href="<?php 
            echo $sAddNewCalendarUrl;
            ?>
" class="add-new-h2"><?php 
            _e('Add New', 'uni-calendar');
            ?>
</a></h2>
            <?php 
        } else {
            if (!empty($_GET['action']) && $_GET['action'] == 'edit-events') {
                if (!empty($_GET['cal_id'])) {
                    $oPost = get_post($_GET['cal_id']);
                }
                ?>
                <h2><?php 
                echo $oPost->post_title;
                ?>
 <a href="<?php 
                echo $sAllCalendarsUrl;
                ?>
" class="add-new-h2"><?php 
                _e('Back to all calendars list', 'uni-calendar');
                ?>
</a></h2>
            <?php 
            } else {
                if (!empty($_GET['action']) && $_GET['action'] == 'add-new') {
                    ?>
                <h2><?php 
                    _e('Add a new calendar', 'uni-calendar');
                    ?>
 <a href="<?php 
                    echo $sAllCalendarsUrl;
                    ?>
" class="add-new-h2"><?php 
                    _e('Back to all calendars list', 'uni-calendar');
                    ?>
</a></h2>
            <?php 
                } else {
                    if (!empty($_GET['action']) && $_GET['action'] == 'edit') {
                        if (!empty($_GET['cal_id'])) {
                            $oPost = get_post($_GET['cal_id']);
                        }
                        ?>
                <h2><?php 
                        _e('Edit calendar', 'uni-calendar');
                        ?>
 <a href="<?php 
                        echo $sAllCalendarsUrl;
                        ?>
" class="add-new-h2"><?php 
                        _e('Back to all calendars list', 'uni-calendar');
                        ?>
</a></h2>
            <?php 
                    }
                }
            }
        }
        ?>

            <div id="ajax-messages">
            </div>

            <?php 
        if (!isset($_GET['action']) || $_GET['action'] != 'add-new' && $_GET['action'] != 'edit' && $_GET['action'] != 'edit-events') {
            $this->prepare_items();
            $this->display();
        } else {
            if (!empty($_GET['action']) && $_GET['action'] == 'edit-events') {
                include UniCalendar()->plugin_path() . '/includes/views/single-calendar-admin.php';
            } else {
                if (!empty($_GET['action']) && $_GET['action'] == 'add-new') {
                    include UniCalendar()->plugin_path() . '/includes/views/single-calendar-admin-add.php';
                } else {
                    if (!empty($_GET['action']) && $_GET['action'] == 'edit') {
                        include UniCalendar()->plugin_path() . '/includes/views/single-calendar-admin-edit.php';
                    }
                }
            }
        }
        ?>

        </div>
        <?php 
    }
                <form name="post" action="<?php 
echo UniCalendar()->ajax_url();
?>
" method="post" id="post">
                    <input type="hidden" name="action" value="uni_add_calendar" />
                    <input type="hidden" name="uni_auth_nonce" value="<?php 
echo wp_create_nonce('uni_authenticate_nonce');
?>
" />

                    <div id="poststuff">
                        <div id="post-body" class="metabox-holder columns-2">
                            <div id="post-body-content">

                                <div id="uni_calendar_title_wrap">
                                    <div id="uni_calendar_title_inside">
		                                <label class="screen-reader-text" id="uni_input_title_label" for="uni_input_title"><?php 
_e('Enter title here', 'uni-calendar');
?>
</label>
	                                    <input type="text" name="uni_input_title" size="30" value="" id="uni_input_title" spellcheck="true" autocomplete="off" data-parsley-required="true" data-parsley-trigger="change focusout submit" />
                                    </div>
                                </div>

                                <div id="uni_calendar_options_wrap" class="postbox">
                                    <h3><span><?php 
_e('Calendar settings', 'uni-calendar');
?>
</span></h3>
                                    <div class="uni_calendar_options_inside">
 /**
  * calendar_shortcode()
  */
 public function calendar_shortcode($atts, $content = null)
 {
     $aAttr = shortcode_atts(array('id' => null), $atts);
     if ($aAttr['id'] != null) {
         ob_start();
         include UniCalendar()->plugin_path() . '/includes/views/single-calendar.php';
         return ob_get_clean();
     } else {
         return;
     }
 }