import type { Weekday } from './Weekday';
import { weekdayToIndex } from './Weekday';

export class WeekdaySet {
  private readonly days: Weekday[];

  constructor(days: Weekday[]) {
    if (!Array.isArray(days) || days.length === 0) {
      throw new Error('WeekdaySet requires at least one weekday');
    }

    const unique = Array.from(new Set(days));
    this.days = unique.sort((a, b) => weekdayToIndex(a) - weekdayToIndex(b));
  }

  getAll(): Weekday[] {
    return [...this.days];
  }

  includes(day: Weekday): boolean {
    return this.days.includes(day);
  }
}