# 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 (c) 2017-2023 # ryanss (c) 2014-2017 # Website: https://github.com/vacanza/holidays # License: MIT (see LICENSE file) from datetime import date from functools import cache from typing import Optional 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) -> Optional[date]: 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[Optional[date], Optional[date]]: """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) -> Optional[date]: """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) -> Optional[date]: """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) -> Optional[date]: """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) -> Optional[date]: """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) -> Optional[date]: """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) -> Optional[date]: """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) -> Optional[date]: """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)