python-minari-date/minari_date/__init__.py

from datetime import datetime, timedelta
from math import ceil
from typing import Optional


class MinariDateTime:
    DAY_NAMES = (
        'Mirdu',
        'Hëmi',
        'Drak',
        'Þodon',
        'Charm',
        'Ro’unn',
    )

    MONTH_NAMES = (
        'Mëbel',
        'Dirann',
        'Ma’uþ',
        'Gerub',
        'Þrei',
        'Dimoc',
        'Xentor',
        'Mëðir',
        'Draþ',
        'Quaden',
        'Ridïmel',
        'Rodom',
    )

    SPECIAL_NAMES = (
        'Hëður',
        'Rideyy',
        'Morkh',
        'Khmerd',
        'Chamog',
    )

    ENTITIES = {
        'Hëður': {
            'entity': 'Garquon',
            'element': 'Meren'
        },
        'Mëbel': {
            'entity': 'Þoraðrin',
            'element': 'Aðun'
        },
        'Dirann': {
            'entity': 'Detërien',
            'element': 'Merðen'
        },
        'Ma’uþ': {
            'entity': 'Elin',
            'element': 'Fronn'
        },
        'Rideyy': {
            'entity': 'Hëriel',
            'element': 'Enðir'
        },
        'Gerub': {
            'entity': 'Iliþon',
            'element': 'Miþon'
        },
        'Þrei': {
            'entity': 'Amenar',
            'element': None
        },
        'Dimoc': {
            'entity': 'Iminiru',
            'element': 'Sëdur'
        },
        'Morkh': {
            'entity': 'Luminar',
            'element': 'Holar'
        },
        'Xentor': {
            'entity': 'Motimor',
            'element': 'Rort'
        },
        'Mëðïr': {
            'entity': 'Mirian',
            'element': 'Ilšir'
        },
        'Draþ': {
            'entity': 'Heloor',
            'element': None
        },
        'Khmerd': {
            'entity': 'Zuþeron',
            'element': 'Gord'
        },
        'Quaden': {
            'entity': 'Umonar',
            'element': 'Ulquon'
        },
        'Ridïmel': {
            'entity': 'Feiriamen',
            'element': 'Reina'
        },
        'Rodom': {
            'entity': 'Nozoru',
            'element': 'Zima'
        },
        'Chamog': {
            'entity': 'Ketirai',
            'element': 'Loar'
        }
    }

    def __init__(self, timestamp: datetime):
        self.set_timestamp(timestamp.replace(hour=0, minute=0, second=0, microsecond=0))
        self._minari_year = None
        self._minari_month = None
        self._minari_day = None
        self._special_day = None
        self._minari_weekday = None

    def set_timestamp(self, timestamp: datetime):
        self._timestamp = timestamp + timedelta(days=11)
        self._calculated = False

    @staticmethod
    def _get_doy(timestamp: datetime) -> int:
        onejan = datetime(timestamp.year, 1, 1)
        time_diff = timestamp - onejan

        return ceil(time_diff.total_seconds() / 86400)

    @staticmethod
    def _is_leap(timestamp: datetime) -> bool:
        year = timestamp.year

        if year % 400 == 0:
            return True

        if year % 100 == 0:
            return False

        if year % 4 == 0:
            return True

        return False

    def _calculate_minari_parts(self):
        if self._calculated:
            return

        minari_leap = self._is_leap(self._timestamp)
        doy = self._get_doy(self._timestamp)
        self._minari_year = self._timestamp.year - 1873
        self._minari_month = None
        self._minari_day = None

        special_days = (
            (0, None, 0),
            (91, None, 1),
            (182, None, 2),
            (183, True, 2),
            (273, False, 3),
            (274, True, 3),
            (364, False, 4),
            (365, True, 4),
        )

        for special_doy, leap_only, special_num in special_days:
            if doy == special_doy and (leap_only is None or leap_only == minari_leap):
                self._special_day = special_num
                break

        if self._special_day is None:
            decr = 0
            minari_doy = doy

            for special_doy, leap_only, _ in special_days:
                if minari_doy > special_doy and (leap_only is None or leap_only == minari_leap):
                    decr += 1

            minari_doy -= decr - 1
            self._minari_month = ceil(minari_doy / 30)
            self._minari_day = minari_doy % 30

            if self._minari_day == 0:
                self._minari_day = 30

            self._minari_weekday = self._minari_day % 6

        self._calculated = True

    @property
    def minari_year(self):
        if not self._calculated:
            self._calculate_minari_parts()

        return self._minari_year

    @property
    def minari_month(self):
        if not self._calculated:
            self._calculate_minari_parts()

        return self._minari_month

    @property
    def minari_day(self):
        """Return the current Minari calendar day
        """

        if not self._calculated:
            self._calculate_minari_parts()

        return self._minari_day

    @property
    def minari_special(self):
        """Return the name of the current special day, if any
        """

        if not self._calculated:
            self._calculate_minari_parts()

        return self._special_day

    def __str__(self):
        output = f'{self.minari_year} '

        if self.minari_special is not None:
            output += self.SPECIAL_NAMES[self.minari_special]
        else:
            weekday = self._minari_weekday - 1

            if weekday == -1:
                weekday = 5

            month_name = self.MONTH_NAMES[self.minari_month - 1]
            weekday_name = self.DAY_NAMES[weekday]
            output += f'{month_name} {self.minari_day} ({weekday_name})'

        return output