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# holidays
# --------
# A fast, efficient Python library for generating country, province and state
# specific sets of holidays on the fly. It aims to make determining whether a
# specific date is a holiday as fast and flexible as possible.
#
# Authors: Vacanza Team and individual contributors (see CONTRIBUTORS file)
# dr-prodigy <dr.prodigy.github@gmail.com> (c) 2017-2023
# ryanss <ryanssdev@icloud.com> (c) 2014-2017
# Website: https://github.com/vacanza/holidays
# License: MIT (see LICENSE file)
from datetime import date
from functools import cache
from holidays.calendars.gregorian import _timedelta
MO = 1954168.050623 # Beginning of 0 ME for MMT.
SY = 1577917828.0 / 4320000.0 # Solar year (365.2587565 days).
class _BurmeseLunisolar:
"""Burmese Lunisolar calendar.
References:
* [Algorithm, Program and Calculation of Myanmar Calendar](https://web.archive.org/web/20250510011425/http://cool-emerald.blogspot.com/2013/06/algorithm-program-and-calculation-of.html)
"""
START_DATE = date(1939, 3, 20) # 1 Late Tagu 1301 Burmese Era.
START_YEAR = 1939 # 1301 Burmese Era.
END_YEAR = 2100 # 1463 Burmese Era.
LITTLE_WATAT_YEARS_GREGORIAN = {
1939,
1948,
1955,
1958,
1966,
1972,
1974,
1982,
1988,
1993,
1999,
2004,
2012,
2018,
2020,
2029,
2034,
2039,
2045,
2050,
2056,
2061,
2069,
2075,
2077,
2086,
2091,
2096,
}
BIG_WATAT_YEARS_GREGORIAN = {
1942,
1945,
1950,
1953,
1961,
1964,
1969,
1977,
1980,
1985,
1991,
1996,
2001,
2007,
2010,
2015,
2023,
2026,
2031,
2037,
2042,
2048,
2053,
2058,
2064,
2067,
2072,
2080,
2083,
2088,
2094,
2099,
}
@staticmethod
def jdn_to_gregorian(jdn: int) -> date:
"""Convert Julian Day Number to Gregorian date.
Args:
jdn: Julian Day Number.
Returns:
Gregorian date.
"""
j = jdn - 1721119
y, j = divmod(4 * j - 1, 146097)
d = j // 4
j, d = divmod(4 * d + 3, 1461)
d = (d + 4) // 4
m, d = divmod(5 * d - 3, 153)
d = (d + 5) // 5
y = 100 * y + j
if m < 10:
m += 3
else:
m -= 9
y += 1
return date(y, m, d)
@cache
def _get_start_date(self, year: int) -> date | None:
if year < self.START_YEAR or year > self.END_YEAR:
return None
delta_days = 354 * (year - self.START_YEAR)
for iter_year in range(self.START_YEAR, year):
if iter_year in self.LITTLE_WATAT_YEARS_GREGORIAN:
delta_days += 30
elif iter_year in self.BIG_WATAT_YEARS_GREGORIAN:
delta_days += 31
return _timedelta(self.START_DATE, delta_days)
def thingyan_dates(self, year: int) -> tuple[date | None, date | None]:
"""Calculate key dates of Thingyan (Myanmar New Year festival) - Akya day
and Atat day.
Args:
year:
Gregorian year.
Returns:
Akya day date, Atat day date.
"""
if year < self.START_YEAR or year > self.END_YEAR:
return None, None
ja = SY * (year - 638) + MO
jk = (ja - 2.169918982) if year >= 1950 else (ja - 2.1675)
return self.jdn_to_gregorian(round(jk)), self.jdn_to_gregorian(round(ja))
def kason_full_moon_date(self, year: int) -> date | None:
"""Calculate the Gregorian date of Full Moon Day of Kason.
15th day of 2nd month (Kason).
To calculate, we use the following time delta:
* All years:
29 [1] + 15 - 1 = 43.
Args:
year:
Gregorian year.
Returns:
Gregorian date of Full Moon Day of Kason.
`None` if the Gregorian year is out of supported range.
"""
if not (start_date := self._get_start_date(year)):
return None
return _timedelta(start_date, +43)
def waso_full_moon_date(self, year: int) -> date | None:
"""Calculate the Gregorian date of Full Moon Day of Waso.
15th day of 4th month (Waso).
To calculate, we use the following time delta:
* All years:
Year_length - 266 [4-12] + 15 - 1 = Year_length - 252.
Args:
year:
Gregorian year.
Returns:
Gregorian date of Full Moon Day of Waso.
`None` if the Gregorian year is out of supported range.
"""
if not (next_year_start_date := self._get_start_date(year + 1)):
return None
return _timedelta(next_year_start_date, -252)
def thadingyut_full_moon_date(self, year: int) -> date | None:
"""Calculate the Gregorian date of Full Moon Day of Thadingyut.
15th day of 7th month (Thadingyut).
To calculate, we use the following time delta:
* All years:
Year_length - 177 [7-12] + 15 - 1 = Year_length - 163.
Args:
year:
Gregorian year.
Returns:
Gregorian date of Full Moon Day of Thadingyut.
`None` if the Gregorian year is out of supported range.
"""
if not (next_year_start_date := self._get_start_date(year + 1)):
return None
return _timedelta(next_year_start_date, -163)
def tazaungmon_waxing_moon_date(self, year: int) -> date | None:
"""Calculate the Gregorian date of 1st Waxing Day of Tazaungmon.
1st day of 8th month (Tazaungmon).
To calculate, we use the following time delta:
* All years:
Year_length - 148 [8-12] + 1 - 1 = Year_length - 148.
Args:
year:
Gregorian year.
Returns:
Gregorian date of 1st Waxing Day of Tazaungmon.
`None` if the Gregorian year is out of supported range.
"""
if not (next_year_start_date := self._get_start_date(year + 1)):
return None
return _timedelta(next_year_start_date, -148)
def tazaungmon_full_moon_date(self, year: int) -> date | None:
"""Calculate the Gregorian date of Full Moon Day of Tazaungmon.
15th day of 8th month (Tazaungmon).
To calculate, we use the following time delta:
* All years:
Year_length - 148 [8-12] + 15 - 1 = Year_length - 134.
Args:
year:
Gregorian year.
Returns:
Gregorian date of Full Moon Day of Tazaungmon.
`None` if the Gregorian year is out of supported range.
"""
if not (next_year_start_date := self._get_start_date(year + 1)):
return None
return _timedelta(next_year_start_date, -134)
def pyatho_waxing_moon_date(self, year: int) -> date | None:
"""Calculate the Gregorian date of 1st Waxing Day of Pyatho.
1st day of 10th month (Pyatho).
To calculate, we use the following time delta:
* All years:
Year_length - 89 [10-12] + 1 - 1 = Year_length - 89.
Args:
year:
Gregorian year.
Returns:
Gregorian date of 1st Waxing Day of Pyatho.
`None` if the Gregorian year is out of supported range.
"""
if not (next_year_start_date := self._get_start_date(year + 1)):
return None
return _timedelta(next_year_start_date, -89)
def tabaung_full_moon_date(self, year: int) -> date | None:
"""Calculate the Gregorian date of Full Moon Day of Tabaung.
15th day of 12th month (Tabaung).
To calculate, we use the following time delta:
* All years:
Year_length - 30 [12] + 15 - 1 = Year_length - 16.
Args:
year:
Gregorian year.
Returns:
Gregorian date of Full Moon Day of Tabaung.
`None` if the Gregorian year is out of supported range.
"""
if not (next_year_start_date := self._get_start_date(year + 1)):
return None
return _timedelta(next_year_start_date, -16)
|
