MT | TEC | Add shortcode to countdown to the next upcoming event

tribe_event_countdown_shortcode.php

<?php

/*
 * Shortcode that extends the existing countdown shortcode, but this ones shows 
 *  the next upcoming events rather than a specific one.
 * 
 * Example usage:
 *
 *     [tribe_event_countdown_next show_seconds="1" complete="The party is on!"]
 */
class Tribe_Custom_Countdown_Shortcode extends Tribe__Events__Pro__Shortcodes__Event_Countdown {

	public $output = '';

	/**
	 * Default arguments expected by the countdown widget.
	 *
	 * @var array
	 */
	protected $default_args = array(
		// General widget properties
		'before_widget' => '',
		'before_title'  => '',
		'title'         => '',
		'after_title'   => '',
		'after_widget'  => '',

		// Widget specific properties
		'type'         => 'next-event',
		'show_seconds' => '',
		'complete'     => '',
	);

	protected $arguments = array();

	public function __construct( $attributes ) {
		$this->arguments = shortcode_atts( $this->default_args, $attributes );

		// If the ECP CSS has not already been added lets lazily add it now
		Tribe__Events__Pro__Template_Factory::asset_package( 'events-pro-css' );

		ob_start();
		the_widget( 'Tribe__Events__Pro__Countdown_Widget', $this->arguments, $this->arguments );
		$this->output = ob_get_clean();
	}

}

function tribe_event_countdown_shortcode( $atts ) {
	$wrapper = new Tribe_Custom_Countdown_Shortcode( $atts );
	return $wrapper->output;
}
add_shortcode( 'tribe_event_countdown_next', 'tribe_event_countdown_shortcode' );