abstract class Shortcode_Abstract implements Shortcode_Interface {
	/**
	 * Slug of the current shortcode.
	 *
	 * @since 4.7.5
	 *
	 * @var   string
	 */
	protected $slug;

	/**
	 * Default arguments to be merged into final arguments of the shortcode.
	 *
	 * @since 4.7.5
	 *
	 * @var   array
	 */
	protected $default_arguments = [];

	/**
	 * Array of callbacks for arguments validation
	 *
	 * @since 4.7.5
	 *
	 * @var   array
	 */
	protected $validate_arguments_map = [];

	/**
	 * Arguments of the current shortcode.
	 *
	 * @since 4.7.5
	 *
	 * @var   array
	 */
	protected $arguments;

	/**
	 * Content of the current shortcode.
	 *
	 * @since 4.7.5
	 *
	 * @var   string
	 */
	protected $content;

	/**
	 * {@inheritDoc}
	 */
	public function setup( array $arguments, string $content ) {
		$this->arguments = $this->parse_arguments( $arguments );
		$this->content   = $content;
	}

	/**
	 * {@inheritDoc}
	 */
	public function parse_arguments( array $arguments ) {
		$arguments = shortcode_atts( $this->get_default_arguments(), $arguments, $this->slug );
		return $this->validate_arguments( $arguments );
	}

	/**
	 * {@inheritDoc}
	 */
	public function validate_arguments( array $arguments ) {
		$validate_arguments_map = $this->get_validate_arguments_map();
		foreach ( $validate_arguments_map as $key => $callback ) {
			$arguments[ $key ] = $callback( isset( $arguments[ $key ] ) ? $arguments[ $key ] : null );
		}

		return $arguments;
	}

	/**
	 * {@inheritDoc}
	 */
	public function get_registration_slug() {
		return $this->slug;
	}

	/**
	 * {@inheritDoc}
	 */
	public function get_validate_arguments_map() {
		/**
		 * Applies a filter to instance arguments validation callbacks.
		 *
		 * @since  4.7.5
		 *
		 * @param  array  $validate_arguments_map   Current set of callbacks for arguments.
		 * @param  static $instance                 Which instance of shortcode we are dealing with.
		 */
		$validate_arguments_map = apply_filters( 'tribe_events_pro_shortcode_validate_arguments_map', $this->validate_arguments_map, $this );

		$registration_slug = $this->get_registration_slug();

		/**
		 * Applies a filter to instance arguments validation callbacks based on the registration slug of the shortcode.
		 *
		 * @since  4.7.5
		 *
		 * @param  array  $validate_arguments_map   Current set of callbacks for arguments.
		 * @param  static $instance                 Which instance of shortcode we are dealing with.
		 */
		$validate_arguments_map = apply_filters( "tribe_events_pro_shortcode_{$registration_slug}_validate_arguments_map", $validate_arguments_map, $this );

		return $validate_arguments_map;
	}

	/**
	 * {@inheritDoc}
	 */
	public function get_arguments() {
		/**
		 * Applies a filter to instance arguments.
		 *
		 * @since  4.7.5
		 *
		 * @param  array  $arguments  Current set of arguments.
		 * @param  static $instance   Which instance of shortcode we are dealing with.
		 */
		$arguments = apply_filters( 'tribe_events_pro_shortcode_arguments', $this->arguments, $this );

		$registration_slug = $this->get_registration_slug();

		/**
		 * Applies a filter to instance arguments based on the registration slug of the shortcode.
		 *
		 * @since  4.7.5
		 *
		 * @param  array  $arguments   Current set of arguments.
		 * @param  static $instance    Which instance of shortcode we are dealing with.
		 */
		$arguments = apply_filters( "tribe_events_pro_shortcode_{$registration_slug}_arguments", $arguments, $this );

		return $arguments;
	}

	/**
	 * {@inheritDoc}
	 */
	public function get_argument( $index, $default = null ) {
		$arguments = $this->get_arguments();
		$argument  = Arr::get( $arguments, $index, $default );

		/**
		 * Applies a filter to a specific shortcode argument, catch all for all shortcodes..
		 *
		 * @since  4.7.5
		 *
		 * @param  mixed  $argument   The argument.
		 * @param  array  $index      Which index we indent to fetch from the arguments.
		 * @param  array  $default    Default value if it doesnt exist.
		 * @param  static $instance   Which instance of shortcode we are dealing with.
		 */
		$argument = apply_filters( 'tribe_events_pro_shortcode_argument', $argument, $index, $default, $this );

		$registration_slug = $this->get_registration_slug();

		/**
		 * Applies a filter to a specific shortcode argument, to a particular registration slug.
		 *
		 * @since  4.7.5
		 *
		 * @param  mixed  $argument   The argument value.
		 * @param  array  $index      Which index we indent to fetch from the arguments.
		 * @param  array  $default    Default value if it doesnt exist.
		 * @param  static $instance   Which instance of shortcode we are dealing with.
		 */
		$argument = apply_filters( "tribe_events_pro_shortcode_{$registration_slug}_argument", $argument, $index, $default, $this );

		return $argument;
	}

	/**
	 * {@inheritDoc}
	 */
	public function get_default_arguments() {
		/**
		 * Applies a filter to instance default arguments.
		 *
		 * @since  4.7.5
		 *
		 * @param  array  $default_arguments  Current set of default arguments.
		 * @param  static $instance           Which instance of shortcode we are dealing with.
		 */
		$default_arguments = apply_filters( 'tribe_events_pro_shortcode_default_arguments', $this->default_arguments, $this );

		$registration_slug = $this->get_registration_slug();

		/**
		 * Applies a filter to instance default arguments based on the registration slug of the shortcode.
		 *
		 * @since  4.7.5
		 *
		 * @param  array  $default_arguments   Current set of default arguments.
		 * @param  static $instance            Which instance of shortcode we are dealing with.
		 */
		$default_arguments = apply_filters( "tribe_events_pro_shortcode_{$registration_slug}_default_arguments", $this->default_arguments, $this );

		return $default_arguments;
	}

}