/* eslint no-use-before-define: "off", no-param-reassign: "off" */

/*
 * Based on a code from https://github.com/omid/Persian-Calendar-for-Gnome-Shell
 */

export const PersianDate = class PersianDate extends Date {
    constructor(...args) {
        super(...args);
        this._createPersianDate();
    }

    getPersianDate() {
        return this.pDate.day;
    }

    getPersianMonth() {
        return this.pDate.month;
    }

    getPersianFullYear() {
        return this.pDate.year;
    }

    _createPersianDate() {
        let persianDate = toJalaali(this);
        this.pDate = {year: persianDate.jy, month: persianDate.jm - 1, day: persianDate.jd};
    }

    setPersianDate(year, month, day) {
        let gDate = toGregorian(year, month, day);
        this.setGregorianDate(gDate.gy, gDate.gm - 1, gDate.gd);
    }

    setDate(date) {
        super.setDate(date);
        this._createPersianDate();
    }

    setMonth(month) {
        super.setMonth(month);
        this._createPersianDate();
    }

    setFullYear(year) {
        super.setFullYear(year);
        this._createPersianDate();
    }

    setGregorianDate(year, month, date) {
        super.setDate(date);
        super.setMonth(month);
        super.setFullYear(year);
        this._createPersianDate();
    }

    toPersianString(option) {
        // or can use 'fa-ir-u-nu-latn' to replace latin number with persian
        return this.toLocaleDateString('fa-ir', option);
    }
};

/* https://github.com/jalaali/jalaali-js/ */

/*
  Jalaali years starting the 33-year rule.
*/
const breaks = [-61, 9, 38, 199, 426, 686, 756, 818, 1111, 1181, 1210,
    1635, 2060, 2097, 2192, 2262, 2324, 2394, 2456, 3178];

/*
    Converts a Gregorian date to Jalaali.
  */
function toJalaali(gy, gm, gd) {
    if (Object.prototype.toString.call(gy) === '[object Date]') {
        gd = gy.getDate();
        gm = gy.getMonth() + 1;
        gy = gy.getFullYear();
    }
    return d2j(g2d(gy, gm, gd));
}

/*
    Converts a Jalaali date to Gregorian.
  */
function toGregorian(jy, jm, jd) {
    return d2g(j2d(jy, jm, jd));
}

/*
    Checks whether a Jalaali date is valid or not.
  */
// eslint-disable-next-line no-unused-vars
function isValidJalaaliDate(jy, jm, jd) {
    return jy >= -61 && jy <= 3177 &&
            jm >= 1 && jm <= 12 &&
            jd >= 1 && jd <= jalaaliMonthLength(jy, jm);
}

/*
    Is this a leap year or not?
  */
function isLeapJalaaliYear(jy) {
    return jalCalLeap(jy) === 0;
}

/*
    Number of days in a given month in a Jalaali year.
  */
function jalaaliMonthLength(jy, jm) {
    if (jm <= 6)
        return 31;
    if (jm <= 11)
        return 30;
    if (isLeapJalaaliYear(jy))
        return 30;
    return 29;
}

/*
      This function determines if the Jalaali (Persian) year is
      leap (366-day long) or is the common year (365 days)

      @param jy Jalaali calendar year (-61 to 3177)
      @returns number of years since the last leap year (0 to 4)
   */
function jalCalLeap(jy) {
    let bl = breaks.length,
        jp = breaks[0],
        jm,
        jump,
        leap,
        n,
        i;

    if (jy < jp || jy >= breaks[bl - 1])
        throw new Error(`Invalid Jalaali year ${jy}`);

    for (i = 1; i < bl; i += 1) {
        jm = breaks[i];
        jump = jm - jp;
        if (jy < jm)
            break;
        jp = jm;
    }
    n = jy - jp;

    if (jump - n < 6)
        n = n - jump + div(jump + 4, 33) * 33;
    leap = mod(mod(n + 1, 33) - 1, 4);
    if (leap === -1)
        leap = 4;


    return leap;
}

/*
    This function determines if the Jalaali (Persian) year is
    leap (366-day long) or is the common year (365 days), and
    finds the day in March (Gregorian calendar) of the first
    day of the Jalaali year (jy).

    @param jy Jalaali calendar year (-61 to 3177)
    @param withoutLeap when don't need leap (true or false) default is false
    @return
      leap: number of years since the last leap year (0 to 4)
      gy: Gregorian year of the beginning of Jalaali year
      march: the March day of Farvardin the 1st (1st day of jy)
    @see: http://www.astro.uni.torun.pl/~kb/Papers/EMP/PersianC-EMP.htm
    @see: http://www.fourmilab.ch/documents/calendar/
  */
function jalCal(jy, withoutLeap) {
    let bl = breaks.length,
        gy = jy + 621,
        leapJ = -14,
        jp = breaks[0],
        jm,
        jump,
        leap,
        leapG,
        march,
        n,
        i;

    if (jy < jp || jy >= breaks[bl - 1])
        throw new Error(`Invalid Jalaali year ${jy}`);

    // Find the limiting years for the Jalaali year jy.
    for (i = 1; i < bl; i += 1) {
        jm = breaks[i];
        jump = jm - jp;
        if (jy < jm)
            break;
        leapJ = leapJ + div(jump, 33) * 8 + div(mod(jump, 33), 4);
        jp = jm;
    }
    n = jy - jp;

    // Find the number of leap years from AD 621 to the beginning
    // of the current Jalaali year in the Persian calendar.
    leapJ = leapJ + div(n, 33) * 8 + div(mod(n, 33) + 3, 4);
    if (mod(jump, 33) === 4 && jump - n === 4)
        leapJ += 1;

    // And the same in the Gregorian calendar (until the year gy).
    leapG = div(gy, 4) - div((div(gy, 100) + 1) * 3, 4) - 150;

    // Determine the Gregorian date of Farvardin the 1st.
    march = 20 + leapJ - leapG;

    // return with gy and march when we don't need leap
    if (withoutLeap)
        return {gy, march};


    // Find how many years have passed since the last leap year.
    if (jump - n < 6)
        n = n - jump + div(jump + 4, 33) * 33;
    leap = mod(mod(n + 1, 33) - 1, 4);
    if (leap === -1)
        leap = 4;

    return {
        leap,
        gy,
        march,
    };
}

/*
    Converts a date of the Jalaali calendar to the Julian Day number.

    @param jy Jalaali year (1 to 3100)
    @param jm Jalaali month (1 to 12)
    @param jd Jalaali day (1 to 29/31)
    @return Julian Day number
  */
function j2d(jy, jm, jd) {
    let r = jalCal(jy, true);
    return g2d(r.gy, 3, r.march) + (jm - 1) * 31 - div(jm, 7) * (jm - 7) + jd - 1;
}

/*
    Converts the Julian Day number to a date in the Jalaali calendar.

    @param jdn Julian Day number
    @return
      jy: Jalaali year (1 to 3100)
      jm: Jalaali month (1 to 12)
      jd: Jalaali day (1 to 29/31)
  */
function d2j(jdn) {
    let gy = d2g(jdn).gy, // Calculate Gregorian year (gy).
        jy = gy - 621,
        r = jalCal(jy, false),
        jdn1f = g2d(gy, 3, r.march),
        jd,
        jm,
        k;

    // Find number of days that passed since 1 Farvardin.
    k = jdn - jdn1f;
    if (k >= 0) {
        if (k <= 185) {
        // The first 6 months.
            jm = 1 + div(k, 31);
            jd = mod(k, 31) + 1;
            return {
                jy,
                jm,
                jd,
            };
        }
        // The remaining months.
        k -= 186;
    } else {
        // Previous Jalaali year.
        jy -= 1;
        k += 179;
        if (r.leap === 1)
            k += 1;
    }
    jm = 7 + div(k, 30);
    jd = mod(k, 30) + 1;
    return {
        jy,
        jm,
        jd,
    };
}

/*
    Calculates the Julian Day number from Gregorian or Julian
    calendar dates. This integer number corresponds to the noon of
    the date (i.e. 12 hours of Universal Time).
    The procedure was tested to be good since 1 March, -100100 (of both
    calendars) up to a few million years into the future.

    @param gy Calendar year (years BC numbered 0, -1, -2, ...)
    @param gm Calendar month (1 to 12)
    @param gd Calendar day of the month (1 to 28/29/30/31)
    @return Julian Day number
  */
function g2d(gy, gm, gd) {
    let d = div((gy + div(gm - 8, 6) + 100100) * 1461, 4) +
        div(153 * mod(gm + 9, 12) + 2, 5) +
        gd - 34840408;
    d = d - div(div(gy + 100100 + div(gm - 8, 6), 100) * 3, 4) + 752;
    return d;
}

/*
    Calculates Gregorian and Julian calendar dates from the Julian Day number
    (jdn) for the period since jdn=-34839655 (i.e. the year -100100 of both
    calendars) to some millions years ahead of the present.

    @param jdn Julian Day number
    @return
      gy: Calendar year (years BC numbered 0, -1, -2, ...)
      gm: Calendar month (1 to 12)
      gd: Calendar day of the month M (1 to 28/29/30/31)
  */
function d2g(jdn) {
    let j,
        i,
        gd,
        gm,
        gy;
    j = 4 * jdn + 139361631;
    j = j + div(div(4 * jdn + 183187720, 146097) * 3, 4) * 4 - 3908;
    i = div(mod(j, 1461), 4) * 5 + 308;
    gd = div(mod(i, 153), 5) + 1;
    gm = mod(div(i, 153), 12) + 1;
    gy = div(j, 1461) - 100100 + div(8 - gm, 6);
    return {
        gy,
        gm,
        gd,
    };
}

/**
 * Return Saturday and Friday day of current week(week start in Saturday)
 *
 * @param {number} jy jalaali year
 * @param {number} jm jalaali month
 * @param {number} jd jalaali day
 * @returns Saturday and Friday of current week
 */
// eslint-disable-next-line no-unused-vars
function jalaaliWeek(jy, jm, jd) {
    let dayOfWeek = jalaaliToDateObject(jy, jm, jd).getDay();

    let startDayDifference = dayOfWeek === 6 ? 0 : -(dayOfWeek + 1);
    let endDayDifference = 6 + startDayDifference;

    return {
        saturday: d2j(j2d(jy, jm, jd + startDayDifference)),
        friday: d2j(j2d(jy, jm, jd + endDayDifference)),
    };
}

/**
 * Convert Jalaali calendar dates to javascript Date object
 *
 * @param {number} jy jalaali year
 * @param {number} jm jalaali month
 * @param {number} jd jalaali day
 * @param {number} [h] hours
 * @param {number} [m] minutes
 * @param {number} [s] seconds
 * @param {number} [ms] milliseconds
 * @returns Date object of the jalaali calendar dates
 */
function jalaaliToDateObject(
    jy,
    jm,
    jd,
    h,
    m,
    s,
    ms
) {
    let gregorianCalenderDate = toGregorian(jy, jm, jd);

    return new Date(
        gregorianCalenderDate.gy,
        gregorianCalenderDate.gm - 1,
        gregorianCalenderDate.gd,
        h || 0,
        m || 0,
        s || 0,
        ms || 0
    );
}

/*
    Utility helper functions.
  */

function div(a, b) {
    return ~~(a / b);
}

function mod(a, b) {
    return a - ~~(a / b) * b;
}
