export interface SettingsSpec extends Spec {
  /**
   * A compare function or an object of compare functions to sort
   * series in a different part of the chart like tooltip, legend and
   * the rendering order on the screen. To assign the same compare function.
   *  @defaultValue the series are sorted in order of appearance in the chart configuration
   */
  sortSeriesBy?: SeriesCompareFn | SortSeriesByConfig;
}


/**
 * An object of compare functions to sort
 * series in different part of the chart like tooltip, legend and rendering order.
 */
export interface SortSeriesByConfig {
  /**
   * A SeriesSortFn to sort the legend values (top-bottom)
   * It has precedence over the general one
   */
  legend?: SeriesCompareFn;
  /**
   * A SeriesSortFn to sort tooltip values (top-bottom)
   * It has precedence over the general one
   */
  tooltip?: SeriesCompareFn;
  /**
   * A SeriesSortFn to sort the rendering order of series.
   * Left/right for cluster, bottom-up for stacked.
   * It has precedence over the general one
   * Currently available only on XY charts
   */
  rendering?: SeriesCompareFn;
  /**
   * The default SeriesSortFn in case no other specific sorting fn are used.
   * The rendering sorting is applied only to XY charts at the moment
   */
  default?: SeriesCompareFn;
}

export type SeriesCompareFn = (siA: SeriesIdentifier, siB: SeriesIdentifier) => number;