import {
  getDay,
  isFirstDayOfWeek,
  isAfter,
  isBefore,
  shiftDate,
  endOf,
  startOf,
  isArray,
  isSame
} from 'mirra-ui/chronos';
import { pDatepickerState } from '../reducer/p-datepicker.state';

export function getStartingDayOfCalendar(date: Date,
                                         options: { firstDayOfWeek?: number }): Date {
  if (isFirstDayOfWeek(date, options.firstDayOfWeek)) {
    return date;
  }

  const weekDay = getDay(date);
  const offset = calculateDateOffset(weekDay, options.firstDayOfWeek);

  return shiftDate(date, {day: -offset});
}

export function calculateDateOffset(weekday: number, startingDayOffset: number): number {
  if (startingDayOffset === 0) {
    return weekday;
  }

  const offset = weekday - startingDayOffset % 7;

  return offset < 0 ? offset + 7 : offset;
}

export function isMonthDisabled(date: Date, min: Date, max: Date): boolean {
  const minBound = min && isBefore(endOf(date, 'month'), min, 'day');
  const maxBound = max && isAfter(startOf(date, 'month'), max, 'day');

  return minBound || maxBound;
}

export function isYearDisabled(date: Date, min: Date, max: Date): boolean {
  const minBound = min && isBefore(endOf(date, 'year'), min, 'day');
  const maxBound = max && isAfter(startOf(date, 'year'), max, 'day');

  return minBound || maxBound;
}

export function isDisabledDate(date: Date, datesDisabled: Date[]): boolean {
  if (!datesDisabled  || !isArray(datesDisabled) || !datesDisabled.length) {
    return false;
  }

  return datesDisabled.some((dateDisabled: Date) => isSame(date, dateDisabled, 'date'));
}

export function isEnabledDate(date: Date, datesEnabled: Date[]): boolean {
  if (!datesEnabled || !isArray(datesEnabled) || !datesEnabled.length) {
    return false;
  }

  return !datesEnabled.some((enabledDate: Date) => isSame(date, enabledDate, 'date'));
}

export function getYearsCalendarInitialDate(state: pDatepickerState, calendarIndex = 0): Date {
  const model = state && state.yearsCalendarModel && state.yearsCalendarModel[calendarIndex];

  return model && model.years && model.years[0] && model.years[0][0] && model.years[0][0].date;
}