import MathUtil from "./MathUtil";

export default class ImmutablePrioritySet<E> extends Set<E> {
  constructor(private _values: E[]) {
    super(_values);
  }

  public static of<E>(values: E[]): ImmutablePrioritySet<E> {
    return new ImmutablePrioritySet<E>(values);
  }

  public compare(a: E, b: E): number {
    if (!this.has(a) || !this.has(b)) {
      throw new Error("No such element");
    }
    return MathUtil.compare(this._values.indexOf(a), this._values.indexOf(b));
  }

  public iterator(): IterableIterator<E> {
    return this[Symbol.iterator]();
  }
}