'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

var convert = require('./convert.cjs');

/**
 * @copyright 2018-present commenthol
 * @license MIT
 */

const YEAR0 = 593;
const MILLISECONDS_PER_DAY = 86400000;
const monthDaysNorm = [31, 31, 31, 31, 31, 30, 30, 30, 30, 30, 30, 30];
const monthDaysLeap = [31, 31, 31, 31, 31, 30, 30, 30, 30, 30, 31, 30];

const isLeapYear = (year) => ((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0);
const UTC6 = 6; // timezone offset UTC+6
const toEpoch = year => Date.UTC(year, 3, 13, UTC6);

class CalendarBengaliRevised {
  /**
   * @constructor
   * @param {Number|String} year - bengali year
   * @param {Number|String} month - (int) 1...12
   * @param {Number|String} day - 1...31
   * @return {Object} this
   */
  constructor (year, month, day) {
    Object.assign(this, {
      year: convert.banglaToDigit(year),
      month: convert.banglaToDigit(month) || 1,
      day: convert.banglaToDigit(day) || 1
    });
  }

  /**
   * convert gregorian date to bengali calendar date
   * @param {Number} year - (int) year in Gregorian Calendar
   * @param {Number} month - (int)
   * @param {Number} day - (int)
   * @return {Object} this
   */
  fromGregorian (year, month, day) {
    const monthDays = isLeapYear(year)
      ? monthDaysLeap
      : monthDaysNorm;

    let _year = year;
    if (month < 4 || (month === 4 && day < 14)) {
      _year -= 1;
    }
    this.year = _year - YEAR0;

    const date = Date.UTC(year, month - 1, day, UTC6);
    let days = Math.floor((date - toEpoch(_year)) / MILLISECONDS_PER_DAY);

    for (let i = 0; i < monthDays.length; i++) {
      if (days <= monthDays[i]) {
        this.month = i + 1;
        break
      }
      days -= monthDays[i];
    }

    this.day = days;
    return this
  }

  /**
   * convert date to bengali calendar date
   * @param {Date} date - javascript date object - uses local date
   * @return {Object} this
   */
  fromDate (date) {
    return this.fromGregorian(date.getFullYear(), date.getMonth() + 1, date.getDate())
  }

  /**
   * convert bengali date to gregorian date
   * @return {Object} date in gregorian (preleptic) calendar
   *   {Number} year - (int)
   *   {Number} month - (int) 1...12
   *   {Number} day - (int) 1...31
   */
  toGregorian () {
    const date = this.toDate();
    return {
      year: date.getUTCFullYear(),
      month: date.getUTCMonth() + 1,
      day: date.getUTCDate()
    }
  }

  /**
   * convert bengali date to Date
   * @return {Date} javascript date object in gregorian (preleptic) calendar
   */
  toDate () {
    const year = this.year + YEAR0;
    const epoch = toEpoch(year);
    const _year = this.month > 10 ? year + 1 : year;
    const monthDays = isLeapYear(_year)
      ? monthDaysLeap
      : monthDaysNorm;

    let days = this.day;
    for (let i = 0; i < this.month - 1; i++) {
      days += monthDays[i];
    }
    const date = new Date(days * MILLISECONDS_PER_DAY + epoch);
    return date
  }

  /**
   * format date in bengali
   * @param {String} formatStr - string formatter
   *
   * | Input | Description  |
   * | ----- | ------------ |
   * | Y     | Year with any number of digits and sign |
   * | Q     | Season Name  |
   * | M     | Month number |
   * | MMMM  | Month name   |
   * | D     | Day of month |
   * | dddd  | Day name     |
   *
   * @return {String}
   */
  format (formatStr) {
    formatStr = formatStr || 'D M, Y';
    if (/dddd/.test(formatStr)) {
      const date = this.toDate();
      formatStr = formatStr.replace(/dddd/g, convert.weekDay(date.getUTCDay()));
    }
    return formatStr
      .replace(/Y/g, convert.digitToBangla(this.year))
      .replace(/Q/g, convert.seasonName(this.month))
      .replace(/MMMM/g, convert.monthName(this.month))
      .replace(/M/g, convert.digitToBangla(this.month))
      .replace(/D/g, convert.digitToBangla(this.day))
  }
}

exports.CalendarBengaliRevised = CalendarBengaliRevised;
exports["default"] = CalendarBengaliRevised;