import { WeekdaySet } from './WeekdaySet';
import { MonthlyRecurrencePattern } from './MonthlyRecurrencePattern';
import { RacingDomainValidationError } from '../errors/RacingDomainError';

export type WeeklyRecurrenceStrategy = {
  kind: 'weekly';
  weekdays: WeekdaySet;
};

export type EveryNWeeksRecurrenceStrategy = {
  kind: 'everyNWeeks';
  weekdays: WeekdaySet;
  intervalWeeks: number;
};

export type MonthlyNthWeekdayRecurrenceStrategy = {
  kind: 'monthlyNthWeekday';
  monthlyPattern: MonthlyRecurrencePattern;
};

export type RecurrenceStrategy =
  | WeeklyRecurrenceStrategy
  | EveryNWeeksRecurrenceStrategy
  | MonthlyNthWeekdayRecurrenceStrategy;

export class RecurrenceStrategyFactory {
  static weekly(weekdays: WeekdaySet): RecurrenceStrategy {
    if (weekdays.getAll().length === 0) {
      throw new RacingDomainValidationError('weekdays are required for weekly recurrence');
    }

    return {
      kind: 'weekly',
      weekdays,
    };
  }

  static everyNWeeks(intervalWeeks: number, weekdays: WeekdaySet): RecurrenceStrategy {
    if (!Number.isInteger(intervalWeeks) || intervalWeeks <= 0) {
      throw new RacingDomainValidationError('intervalWeeks must be a positive integer');
    }
    if (weekdays.getAll().length === 0) {
      throw new RacingDomainValidationError('weekdays are required for everyNWeeks recurrence');
    }

    return {
      kind: 'everyNWeeks',
      weekdays,
      intervalWeeks,
    };
  }

  static monthlyNthWeekday(pattern: MonthlyRecurrencePattern): RecurrenceStrategy {
    return {
      kind: 'monthlyNthWeekday',
      monthlyPattern: pattern,
    };
  }
}