fairnesscoop / permacoop

import {

  format as fnsFormat,

  isWeekend as fnsIsWeekend,

  getDaysInMonth as fnsGetDaysInMonth,

  eachDayOfInterval,

  addDays

} from 'date-fns';

import {IDateUtils} from 'src/Application/IDateUtils';

@Injectable()

export class DateUtilsAdapter implements IDateUtils {

  constructor(private readonly date: Date = new Date()) {}

  public format(date: Date, format: string): string {

    return fnsFormat(date, format);

  }

  public getDaysInMonth(date: Date): number {

    return fnsGetDaysInMonth(date);

  }

  public isWeekend(date: Date): boolean {

    return fnsIsWeekend(date);

  }

  public getCurrentDate(): Date {

    return this.date;

  }

  public getCurrentDateToISOString(): string {

    return this.date.toISOString();

  }

  public getWorkedDaysDuringAPeriod(start: Date, end: Date): Date[] {

    const dates: Date[] = [];

    const workedFreeDays: Date[] = [];

    for (let year = start.getFullYear(); year <= end.getFullYear(); year++) {

      workedFreeDays.push(...this.getWorkedFreeDays(year));

    }

    for (const day of eachDayOfInterval({start, end})) {

      if (

        this.isWeekend(day) ||

        workedFreeDays.filter(d => d.toISOString() === day.toISOString())

          .length > 0

      ) {

        continue;

      }

      dates.push(day);

    }

    return dates;

  }

  public getEasterDate(year: number): Date {

    const a = year % 19;

    const b = Math.floor(year / 100);

    const c = year % 100;

    const d = Math.floor(b / 4);

    const e = b % 4;

    const f = Math.floor((b + 8) / 25);

    const g = Math.floor((b - f + 1) / 3);

    const h = (19 * a + b - d - g + 15) % 30;

    const i = Math.floor(c / 4);

    const k = c % 4;

    const l = (32 + 2 * e + 2 * i - h - k) % 7;

    const m = Math.floor((a + 11 * h + 22 * l) / 451);

    const n0 = h + l + 7 * m + 114;

    const n = Math.floor(n0 / 31) - 1;

    const p = (n0 % 31) + 1;

    return new Date(year, n, p);

  }

}