#
# Copyright (c), 2018-2020, SISSA (International School for Advanced Studies).
# All rights reserved.
# This file is distributed under the terms of the MIT License.
# See the file 'LICENSE' in the root directory of the present
# distribution, or http://opensource.org/licenses/MIT.
#
# @author Davide Brunato <brunato@sissa.it>
#
from abc import abstractmethod
import math
import operator
import re
import datetime
from calendar import isleap
from decimal import Decimal
from typing import Union

from .helpers import MONTH_DAYS_LEAP, MONTH_DAYS, DAYS_IN_4Y, \
    DAYS_IN_100Y, DAYS_IN_400Y, days_from_common_era, adjust_day, \
    normalized_seconds, months2days, round_number
from .atomic_types import AtomicTypeABCMeta, AnyAtomicType
from .untyped import UntypedAtomic


class Timezone(datetime.tzinfo):
    """
    A tzinfo implementation for XSD timezone offsets. Offsets must be specified
    between -14:00 and +14:00.

    :param offset: a timedelta instance or an XSD timezone formatted string.
    """
    _maxoffset = datetime.timedelta(hours=14, minutes=0)
    _minoffset = -_maxoffset

    def __init__(self, offset):
        super(Timezone, self).__init__()
        if not isinstance(offset, datetime.timedelta):
            raise TypeError("offset must be a datetime.timedelta")
        if offset < self._minoffset or offset > self._maxoffset:
            raise ValueError("offset must be between -14:00 and +14:00")
        self.offset = offset

    @classmethod
    def fromstring(cls, text):
        try:
            hours, minutes = text.strip().split(':')
            if hours.startswith('-'):
                return cls(datetime.timedelta(hours=int(hours), minutes=-int(minutes)))
            else:
                return cls(datetime.timedelta(hours=int(hours), minutes=int(minutes)))
        except AttributeError:
            raise TypeError("argument is not a string")
        except ValueError:
            if text.strip() == 'Z':
                return cls(datetime.timedelta(0))
            raise ValueError("%r: not an XSD timezone formatted string" % text) from None

    @classmethod
    def fromduration(cls, duration):
        if duration.seconds % 60 != 0:
            raise ValueError("{!r} has not an integral number of minutes".format(duration))
        return cls(datetime.timedelta(seconds=int(duration.seconds)))

    def __getinitargs__(self):
        return self.offset,

    def __hash__(self):
        return hash(self.offset)

    def __eq__(self, other):
        return isinstance(other, Timezone) and self.offset == other.offset

    def __ne__(self, other):
        return not isinstance(other, Timezone) or self.offset != other.offset

    def __repr__(self):
        return "%s(%r)" % (self.__class__.__name__, self.offset)

    def __str__(self):
        return self.tzname(None)

    def utcoffset(self, dt):
        if not isinstance(dt, datetime.datetime) and dt is not None:
            raise TypeError("utcoffset() argument must be a "
                            "datetime.datetime instance or None")
        return self.offset

    def tzname(self, dt):
        if not isinstance(dt, datetime.datetime) and dt is not None:
            raise TypeError("tzname() argument must be a "
                            "datetime.datetime instance or None")

        if not self.offset:
            return 'Z'
        elif self.offset < datetime.timedelta(0):
            sign, offset = '-', -self.offset
        else:
            sign, offset = '+', self.offset

        hours, minutes = offset.seconds // 3600, offset.seconds // 60 % 60
        return '{}{:02d}:{:02d}'.format(sign, hours, minutes)

    def dst(self, dt):
        if not isinstance(dt, datetime.datetime) and dt is not None:
            raise TypeError("dst() argument must be a "
                            "datetime.datetime instance or None")

    def fromutc(self, dt):
        if isinstance(dt, datetime.datetime):
            return dt + self.offset
        elif dt is not None:
            raise TypeError("fromutc() argument must be a "
                            "datetime.datetime instance or None")


class AbstractDateTime(metaclass=AtomicTypeABCMeta):
    """
    A class for representing XSD date/time objects. It uses and internal datetime.datetime
    attribute and an integer attribute for processing BCE years or for years after 9999 CE.
    """
    _utc_timezone = Timezone(datetime.timedelta(0))
    _year = None

    def __init__(self, year=2000, month=1, day=1, hour=0, minute=0,
                 second=0, microsecond=0, tzinfo=None):
        if hour == 24 and minute == second == microsecond == 0:
            delta = datetime.timedelta(days=1)
            hour = 0
        else:
            delta = 0

        if 1 <= year <= 9999:
            self._dt = datetime.datetime(year, month, day, hour, minute,
                                         second, microsecond, tzinfo)
        elif year == 0:
            raise ValueError('0 is an illegal value for year')
        elif not isinstance(year, int):
            raise TypeError("invalid type %r for year" % type(year))
        elif abs(year) > 2 ** 31:
            raise OverflowError("year overflow")
        else:
            self._year = year
            if isleap(year + bool(self.xsd_version != '1.0')):
                self._dt = datetime.datetime(4, month, day, hour, minute,
                                             second, microsecond, tzinfo)
            else:
                self._dt = datetime.datetime(6, month, day, hour, minute,
                                             second, microsecond, tzinfo)

        if delta:
            self._dt += delta

    def __repr__(self):
        fields = self.pattern.groupindex.keys()
        arg_string = ', '.join(
            str(getattr(self, k))
            for k in ['year', 'month', 'day', 'hour', 'minute'] if k in fields
        )
        if 'second' in fields:
            if self.microsecond:
                arg_string += ', %d.%06d' % (self.second, self.microsecond)
            else:
                arg_string += ', %d' % self.second

        if self.tzinfo is not None:
            arg_string += ', tzinfo=%r' % self.tzinfo
        return '%s(%s)' % (self.__class__.__name__, arg_string)

    @abstractmethod
    def __str__(self):
        raise NotImplementedError()

    @property
    def year(self):
        return self._year or self._dt.year

    @property
    def bce(self):
        return self._year is not None and self._year < 0

    @property
    def iso_year(self):
        """The ISO string representation of the year field."""
        year = self.year
        if -9999 <= year < -1:
            return '{:05}'.format(year if self.xsd_version == '1.0' else year + 1)
        elif year == -1:
            return '-0001' if self.xsd_version == '1.0' else '0000'
        elif 0 <= year <= 9999:
            return '{:04}'.format(year)
        else:
            return str(year)

    @property
    def month(self):
        return self._dt.month

    @property
    def day(self):
        return self._dt.day

    @property
    def hour(self):
        return self._dt.hour

    @property
    def minute(self):
        return self._dt.minute

    @property
    def second(self):
        return self._dt.second

    @property
    def microsecond(self):
        return self._dt.microsecond

    @property
    def tzinfo(self):
        return self._dt.tzinfo

    @tzinfo.setter
    def tzinfo(self, tz):
        self._dt = self._dt.replace(tzinfo=tz)

    @classmethod
    def fromstring(cls, datetime_string, tzinfo=None):
        """
        Creates an XSD date/time instance from a string formatted value.

        :param datetime_string: a string containing an XSD formatted date/time specification.
        :param tzinfo: optional implicit timezone information, must be a `Timezone` instance.
        :return: an AbstractDateTime concrete subclass instance.
        """
        if not isinstance(datetime_string, str):
            msg = '1st argument has an invalid type {!r}'
            raise TypeError(msg.format(type(datetime_string)))
        elif tzinfo and not isinstance(tzinfo, Timezone):
            msg = '2nd argument has an invalid type {!r}'
            raise TypeError(msg.format(type(tzinfo)))

        match = cls.pattern.match(datetime_string.strip())
        if match is None:
            msg = 'Invalid datetime string {!r} for {!r}'
            raise ValueError(msg.format(datetime_string, cls))

        kwargs = {k: int(v) if k != 'tzinfo' else Timezone.fromstring(v)
                  for k, v in match.groupdict().items() if v is not None}

        if 'tzinfo' not in kwargs and tzinfo is not None:
            kwargs['tzinfo'] = tzinfo

        if 'microsecond' in kwargs:
            microseconds = match.groupdict()['microsecond']
            pow10 = 6 - len(microseconds)
            try:
                zeros = min(k for k in range(len(microseconds)) if '0' != microseconds[k])
            except ValueError:
                zeros = 0

            if pow10 == 0:
                pass
            elif pow10 > 0:
                kwargs['microsecond'] = kwargs['microsecond'] * 10**pow10
            elif (kwargs['microsecond'] // 1 ** zeros) > 999999:
                msg = "Invalid value {} for microsecond"
                raise OverflowError(msg.format(kwargs['microsecond']))
            else:
                kwargs['microsecond'] = int(match.groupdict()['microsecond'][:6])

        if 'year' in kwargs:
            year_digits = match.groupdict()['year'].lstrip('-')
            if year_digits.startswith('0') and len(year_digits) > 4:
                msg = "Invalid datetime string {!r} for {!r} (when year " \
                      "exceeds 4 digits leading zeroes are not allowed)"
                raise ValueError(msg.format(datetime_string, cls))

            if cls.xsd_version == '1.0':
                if kwargs['year'] == 0:
                    raise ValueError("year '0000' is an illegal value for XSD 1.0")
            elif kwargs['year'] <= 0:
                kwargs['year'] -= 1

        return cls(**kwargs)

    @classmethod
    def fromdatetime(cls, dt, year=None):
        """
        Creates an XSD date/time instance from a datetime.datetime/date/time instance.

        :param dt: the datetime, date or time instance that stores the XSD Date/Time value.
        :param year: if an year is provided the created instance refers to it and the \
        possibly present *dt.year* part is ignored.
        :return: an AbstractDateTime concrete subclass instance.
        """
        if not isinstance(dt, (datetime.datetime, datetime.date, datetime.time)):
            raise TypeError('1st argument has an invalid type %r' % type(dt))
        elif year is not None and not isinstance(year, int):
            raise TypeError('2nd argument has an invalid type %r' % type(year))

        kwargs = {k: getattr(dt, k) for k in cls.pattern.groupindex.keys() if hasattr(dt, k)}
        if year is not None:
            kwargs['year'] = year
        return cls(**kwargs)

    # Python can't compares offset-naive and offset-aware datetimes
    def _get_operands(self, other):
        if isinstance(other, (self.__class__, datetime.datetime)) or \
                isinstance(self, other.__class__):
            dt = getattr(other, '_dt', other)
            if self._dt.tzinfo is dt.tzinfo:
                return self._dt, dt
            elif self.tzinfo is None:
                return self._dt.replace(tzinfo=self._utc_timezone), dt
            elif dt.tzinfo is None:
                return self._dt, dt.replace(tzinfo=self._utc_timezone)
            else:
                return self._dt, dt
        else:
            raise TypeError("wrong type %r for operand %r" % (type(other), other))

    def __hash__(self):
        return hash((self._dt, self._year))

    def __eq__(self, other):
        try:
            return operator.eq(*self._get_operands(other)) and self.year == other.year
        except TypeError:
            return False

    def __ne__(self, other):
        try:
            return operator.ne(*self._get_operands(other)) or self.year != other.year
        except TypeError:
            return True


class OrderedDateTime(AbstractDateTime):

    @abstractmethod
    def __str__(self):
        raise NotImplementedError()

    @classmethod
    def fromdelta(cls, delta, adjust_timezone=False):
        """
        Creates an XSD dateTime/date instance from a datetime.timedelta related to
        0001-01-01T00:00:00 CE. In case of a date the time part is not counted.

        :param delta: a datetime.timedelta instance.
        :param adjust_timezone: if `True` adjusts the timezone of Date objects \
        with eventually present hours and minutes.
        """
        try:
            dt = datetime.datetime(1, 1, 1) + delta
        except OverflowError:
            days = delta.days
            if days > 0:
                y400, days = divmod(days, DAYS_IN_400Y)
                y100, days = divmod(days, DAYS_IN_100Y)
                y4, days = divmod(days, DAYS_IN_4Y)
                y1, days = divmod(days, 365)
                year = y400 * 400 + y100 * 100 + y4 * 4 + y1 + 1
                if y1 == 4 or y100 == 4:
                    year -= 1
                    days = 365

                td = datetime.timedelta(days=days, seconds=delta.seconds,
                                        microseconds=delta.microseconds)
                dt = datetime.datetime(4 if isleap(year) else 6, 1, 1) + td

            elif days >= -366:
                year = -1
                td = datetime.timedelta(days=days, seconds=delta.seconds,
                                        microseconds=delta.microseconds)
                dt = datetime.datetime(5, 1, 1) + td

            else:
                days = -days - 366
                y400, days = divmod(days, DAYS_IN_400Y)
                y100, days = divmod(days, DAYS_IN_100Y)
                y4, days = divmod(days, DAYS_IN_4Y)
                y1, days = divmod(days, 365)
                year = -y400 * 400 - y100 * 100 - y4 * 4 - y1 - 2
                if y1 == 4 or y100 == 4:
                    year += 1
                    days = 365

                td = datetime.timedelta(days=-days, seconds=delta.seconds,
                                        microseconds=delta.microseconds)
                if not td:
                    dt = datetime.datetime(4 if isleap(year + 1) else 6, 1, 1)
                    year += 1
                else:
                    dt = datetime.datetime(5 if isleap(year + 1) else 7, 1, 1) + td
        else:
            year = dt.year

        if issubclass(cls, Date10):
            if adjust_timezone and (dt.hour or dt.minute):
                assert dt.tzinfo is None
                hour, minute = dt.hour, dt.minute

                if hour < 14 or hour == 14 and minute == 0:
                    tz = Timezone(datetime.timedelta(hours=-hour, minutes=-minute))
                    dt = dt.replace(tzinfo=tz)
                else:
                    tz = Timezone(datetime.timedelta(hours=-dt.hour + 24, minutes=-minute))
                    dt = dt.replace(tzinfo=tz)
                    dt += datetime.timedelta(days=1)

            return cls(year, dt.month, dt.day, tzinfo=dt.tzinfo)
        return cls(year, dt.month, dt.day, dt.hour, dt.minute,
                   dt.second, dt.microsecond, dt.tzinfo)

    def todelta(self):
        """Returns the datetime.timedelta from 0001-01-01T00:00:00 CE."""
        if self._year is None:
            return operator.sub(*self._get_operands(datetime.datetime(1, 1, 1)))

        year, dt = self.year, self._dt
        tzinfo = None if dt.tzinfo is None else self._utc_timezone

        if year > 0:
            m_days = MONTH_DAYS_LEAP if isleap(year) else MONTH_DAYS
            days = days_from_common_era(year - 1) + sum(m_days[m] for m in range(1, dt.month))
        else:
            m_days = MONTH_DAYS_LEAP if isleap(year + 1) else MONTH_DAYS
            days = days_from_common_era(year) + sum(m_days[m] for m in range(1, dt.month))

        delta = (dt - datetime.datetime(dt.year, dt.month, day=1, tzinfo=tzinfo))
        return datetime.timedelta(days=days, seconds=delta.total_seconds())

    def _date_operator(self, op, other):
        if isinstance(other, self.__class__):
            dt1, dt2 = self._get_operands(other)
            if self._year is None and other._year is None:
                return DayTimeDuration.fromtimedelta(dt1 - dt2)
            return DayTimeDuration.fromtimedelta(self.todelta() - other.todelta())

        elif isinstance(other, datetime.timedelta):
            delta = op(self.todelta(), other)
            return type(self).fromdelta(delta, adjust_timezone=True)

        elif isinstance(other, DayTimeDuration):
            delta = op(self.todelta(), other.get_timedelta())
            if self._dt.tzinfo is None:
                return type(self).fromdelta(delta)

            value = type(self).fromdelta(delta + self._dt.tzinfo.offset)
            value.tzinfo = self._dt.tzinfo
            return value

        elif isinstance(other, YearMonthDuration):
            month = op(self._dt.month - 1, other.months) % 12 + 1
            year = self.year + op(self._dt.month - 1, other.months) // 12
            day = adjust_day(year, month, self._dt.day)

            if year > 0:
                dt = self._dt.replace(year=year, month=month, day=day)
            elif isleap(year):
                dt = self._dt.replace(year=4, month=month, day=day)
            else:
                dt = self._dt.replace(year=6, month=month, day=day)

            kwargs = {k: getattr(dt, k) for k in self.pattern.groupindex.keys()}
            if year <= 0:
                kwargs['year'] = year
            return type(self)(**kwargs)

        else:
            raise TypeError("wrong type %r for operand %r" % (type(other), other))

    def __lt__(self, other):
        dt1, dt2 = self._get_operands(other)
        y1, y2 = self.year, other.year
        return y1 < y2 or y1 == y2 and dt1 < dt2

    def __le__(self, other):
        dt1, dt2 = self._get_operands(other)
        y1, y2 = self.year, other.year
        return y1 < y2 or y1 == y2 and dt1 <= dt2

    def __gt__(self, other):
        dt1, dt2 = self._get_operands(other)
        y1, y2 = self.year, other.year
        return y1 > y2 or y1 == y2 and dt1 > dt2

    def __ge__(self, other):
        dt1, dt2 = self._get_operands(other)
        y1, y2 = self.year, other.year
        return y1 > y2 or y1 == y2 and dt1 >= dt2

    def __add__(self, other):
        if isinstance(other, OrderedDateTime):
            raise TypeError("wrong type %r for operand %r" % (type(other), other))
        return self._date_operator(operator.add, other)

    def __sub__(self, other):
        return self._date_operator(operator.sub, other)


class DateTime10(OrderedDateTime):
    """XSD 1.0 xs:dateTime builtin type"""
    name = 'dateTime'
    pattern = re.compile(
        r'^(?P<year>(?:-)?[0-9]*[0-9]{4})-(?P<month>[0-9]{2})-(?P<day>[0-9]{2})'
        r'(T(?P<hour>[0-9]{2}):(?P<minute>[0-9]{2}):'
        r'(?P<second>[0-9]{2})(?:\.(?P<microsecond>[0-9]+))?)'
        r'(?P<tzinfo>Z|[+-](?:(?:0[0-9]|1[0-3]):[0-5][0-9]|14:00))?$')

    def __init__(self, year, month, day, hour=0, minute=0, second=0, microsecond=0, tzinfo=None):
        super(DateTime10, self).__init__(
            year, month, day, hour, minute, second, microsecond, tzinfo
        )

    def __str__(self):
        if self.microsecond:
            return '{}-{:02}-{:02}T{:02}:{:02}:{:02}.{}{}'.format(
                self.iso_year, self.month, self.day, self.hour, self.minute, self.second,
                '{:06}'.format(self.microsecond).rstrip('0'), str(self.tzinfo or '')
            ).rstrip('0')
        return '{}-{:02}-{:02}T{:02}:{:02}:{:02}{}'.format(
            self.iso_year, self.month, self.day, self.hour,
            self.minute, self.second, str(self.tzinfo or '')
        )


class DateTime(DateTime10):
    """XSD 1.1 xs:dateTime builtin type"""
    name = 'dateTime'
    xsd_version = '1.1'


class DateTimeStamp(DateTime):
    """XSD 1.1 xs:dateTimeStamp builtin type"""
    name = 'dateTimeStamp'
    pattern = re.compile(
        r'^(?P<year>(?:-)?[0-9]*[0-9]{4})-(?P<month>[0-9]{2})-(?P<day>[0-9]{2})'
        r'(T(?P<hour>[0-9]{2}):(?P<minute>[0-9]{2}):'
        r'(?P<second>[0-9]{2})(?:\.(?P<microsecond>[0-9]+))?)'
        r'(?P<tzinfo>Z|[+-](?:(?:0[0-9]|1[0-3]):[0-5][0-9]|14:00))$')


class Date10(OrderedDateTime):
    """XSD 1.0 xs:date builtin type"""
    name = 'date'
    pattern = re.compile(r'^(?P<year>(?:-)?[0-9]*[0-9]{4})-(?P<month>[0-9]{2})-(?P<day>[0-9]{2})'
                         r'(?P<tzinfo>Z|[+-](?:(?:0[0-9]|1[0-3]):[0-5][0-9]|14:00))?$')

    def __init__(self, year, month, day, tzinfo=None):
        super(Date10, self).__init__(year, month, day, tzinfo=tzinfo)

    def __str__(self):
        return '{}-{:02}-{:02}{}'.format(
            self.iso_year, self.month, self.day, str(self.tzinfo or '')
        )


class Date(Date10):
    """XSD 1.1 xs:date builtin type"""
    name = 'date'
    xsd_version = '1.1'


class GregorianDay(OrderedDateTime):
    """XSD xs:gDay builtin type"""
    name = 'gDay'
    pattern = re.compile(r'^---(?P<day>[0-9]{2})'
                         r'(?P<tzinfo>Z|[+-](?:(?:0[0-9]|1[0-3]):[0-5][0-9]|14:00))?$')

    def __init__(self, day, tzinfo=None):
        super(GregorianDay, self).__init__(day=day, tzinfo=tzinfo)

    def __str__(self):
        return '---{:02}{}'.format(self.day, str(self.tzinfo or ''))


class GregorianMonth(OrderedDateTime):
    """XSD xs:gMonth builtin type"""
    name = 'gMonth'
    pattern = re.compile(r'^--(?P<month>[0-9]{2})'
                         r'(?P<tzinfo>Z|[+-](?:(?:0[0-9]|1[0-3]):[0-5][0-9]|14:00))?$')

    def __init__(self, month, tzinfo=None):
        super(GregorianMonth, self).__init__(month=month, tzinfo=tzinfo)

    def __str__(self):
        return '--{:02}{}'.format(self.month, str(self.tzinfo or ''))


class GregorianMonthDay(OrderedDateTime):
    """XSD xs:gMonthDay builtin type"""
    name = 'gMonthDay'
    pattern = re.compile(r'^--(?P<month>[0-9]{2})-(?P<day>[0-9]{2})'
                         r'(?P<tzinfo>Z|[+-](?:(?:0[0-9]|1[0-3]):[0-5][0-9]|14:00))?$')

    def __init__(self, month, day, tzinfo=None):
        super(GregorianMonthDay, self).__init__(month=month, day=day, tzinfo=tzinfo)

    def __str__(self):
        return '--{:02}-{:02}{}'.format(self.month, self.day, str(self.tzinfo or ''))


class GregorianYear10(OrderedDateTime):
    """XSD 1.0 xs:gYear builtin type"""
    name = 'gYear'
    pattern = re.compile(r'^(?P<year>(?:-)?[0-9]*[0-9]{4})'
                         r'(?P<tzinfo>Z|[+-](?:(?:0[0-9]|1[0-3]):[0-5][0-9]|14:00))?$')

    def __init__(self, year, tzinfo=None):
        super(GregorianYear10, self).__init__(year, tzinfo=tzinfo)

    def __str__(self):
        return '{}{}'.format(self.iso_year, str(self.tzinfo or ''))


class GregorianYear(GregorianYear10):
    """XSD 1.1 xs:gYear builtin type"""
    name = 'gYear'
    xsd_version = '1.1'


class GregorianYearMonth10(OrderedDateTime):
    """XSD 1.0 xs:gYearMonth builtin type"""
    name = 'gYearMonth'
    pattern = re.compile(r'^(?P<year>(?:-)?[0-9]*[0-9]{4})-(?P<month>[0-9]{2})'
                         r'(?P<tzinfo>Z|[+-](?:(?:0[0-9]|1[0-3]):[0-5][0-9]|14:00))?$')

    def __init__(self, year, month, tzinfo=None):
        super(GregorianYearMonth10, self).__init__(year, month, tzinfo=tzinfo)

    def __str__(self):
        return '{}-{:02}{}'.format(self.iso_year, self.month, str(self.tzinfo or ''))


class GregorianYearMonth(GregorianYearMonth10):
    """XSD 1.1 xs:gYearMonth builtin type"""
    name = 'gYearMonth'
    xsd_version = '1.1'


class Time(AbstractDateTime):
    """XSD xs:time builtin type"""
    name = 'time'
    pattern = re.compile(
        r'^(?P<hour>[0-9]{2}):(?P<minute>[0-9]{2}):'
        r'(?P<second>[0-9]{2})(?:\.(?P<microsecond>[0-9]+))?'
        r'(?P<tzinfo>Z|[+-](?:(?:0[0-9]|1[0-3]):[0-5][0-9]|14:00))?$')

    def __init__(self, hour=0, minute=0, second=0, microsecond=0, tzinfo=None):
        if hour == 24 and minute == second == microsecond == 0:
            hour = 0
        super(Time, self).__init__(
            hour=hour, minute=minute, second=second, microsecond=microsecond, tzinfo=tzinfo
        )

    def __str__(self):
        if self.microsecond:
            return '{:02}:{:02}:{:02}.{}{}'.format(
                self.hour, self.minute, self.second,
                '{:06}'.format(self.microsecond).rstrip('0'),
                str(self.tzinfo or '')
            )
        return '{:02}:{:02}:{:02}{}'.format(
            self.hour, self.minute, self.second, str(self.tzinfo or '')
        )

    def __lt__(self, other):
        return operator.lt(*self._get_operands(other))

    def __le__(self, other):
        return operator.le(*self._get_operands(other))

    def __gt__(self, other):
        return operator.gt(*self._get_operands(other))

    def __ge__(self, other):
        return operator.ge(*self._get_operands(other))

    def __add__(self, other):
        if isinstance(other, DayTimeDuration):
            dt = self._dt + other.get_timedelta()
        elif isinstance(other, datetime.timedelta):
            dt = self._dt + other
        else:
            raise TypeError("wrong type %r for operand %r" % (type(other), other))
        return Time(dt.hour, dt.minute, dt.second, dt.microsecond, dt.tzinfo)

    def __sub__(self, other):
        if isinstance(other, self.__class__):
            delta = operator.sub(*self._get_operands(other))
            return DayTimeDuration.fromtimedelta(delta)
        elif isinstance(other, DayTimeDuration):
            dt = self._dt - other.get_timedelta()
            return Time(dt.hour, dt.minute, dt.second, dt.microsecond, dt.tzinfo)
        elif isinstance(other, datetime.timedelta):
            dt = self._dt - other
            return Time(dt.hour, dt.minute, dt.second, dt.microsecond, dt.tzinfo)
        else:
            raise TypeError("wrong type %r for operand %r" % (type(other), other))


class Duration(AnyAtomicType):
    """
    Base class for the XSD duration types.

    :param months: an integer value that represents years and months.
    :param seconds: a decimal or an integer instance that represents \
    days, hours, minutes, seconds and fractions of seconds.
    """
    name = 'duration'
    pattern = re.compile(
        r'^(-)?P(?=(?:[0-9]|T))(?:([0-9]+)Y)?(?:([0-9]+)M)?(?:([0-9]+)D)?'
        r'(?:T(?=[0-9])(?:([0-9]+)H)?(?:([0-9]+)M)?(?:([0-9]+(?:\.[0-9]+)?)S)?)?$'
    )

    def __init__(self, months: int = 0, seconds: Union[Decimal, int] = 0):
        if seconds < 0 < months or months < 0 < seconds:
            raise ValueError('signs differ: (months=%d, seconds=%d)' % (months, seconds))
        elif abs(months) > 2 ** 31:
            raise OverflowError("months duration overflow")
        elif abs(seconds) > 2 ** 63:
            raise OverflowError("seconds duration overflow")

        self.months = months
        self.seconds = Decimal(seconds).quantize(Decimal('1.000000'))

    def __repr__(self):
        return '{}(months={!r}, seconds={})'.format(
            self.__class__.__name__, self.months, normalized_seconds(self.seconds)
        )

    def __str__(self):
        m = abs(self.months)
        years, months = m // 12, m % 12
        s = self.seconds.copy_abs()
        days = int(s // 86400)
        hours = int(s // 3600 % 24)
        minutes = int(s // 60 % 60)
        seconds = s % 60

        value = '-P' if self.sign else 'P'
        if years or months or days:
            if years:
                value += '%dY' % years
            if months:
                value += '%dM' % months
            if days:
                value += '%dD' % days

        if hours or minutes or seconds:
            value += 'T'
            if hours:
                value += '%dH' % hours
            if minutes:
                value += '%dM' % minutes
            if seconds:
                value += '%sS' % normalized_seconds(seconds)

        elif value[-1] == 'P':
            value += 'T0S'
        return value

    @classmethod
    def fromstring(cls, text):
        """
        Creates a Duration instance from a formatted XSD duration string.

        :param text: an ISO 8601 representation without week fragment and an optional decimal part \
        only for seconds fragment.
        """
        if not isinstance(text, str):
            msg = 'argument has an invalid type {!r}'
            raise TypeError(msg.format(type(text)))

        match = cls.pattern.match(text.strip())
        if match is None:
            raise ValueError('%r is not an xs:duration value' % text)

        sign, years, months, days, hours, minutes, seconds = match.groups()
        seconds = Decimal(seconds or 0)
        minutes = int(minutes or 0) + int(seconds // 60)
        seconds = seconds % 60
        hours = int(hours or 0) + minutes // 60
        minutes = minutes % 60
        days = int(days or 0) + hours // 24
        hours = hours % 24
        months = int(months or 0) + 12 * int(years or 0)

        if sign is None:
            seconds = seconds + (days * 24 + hours) * 3600 + minutes * 60
        else:
            months = -months
            seconds = -seconds - (days * 24 + hours) * 3600 - minutes * 60

        if cls is DayTimeDuration:
            if months:
                raise ValueError('months must be 0 for %r' % cls.__name__)
            return cls(seconds=seconds)
        elif cls is YearMonthDuration:
            if seconds:
                raise ValueError('seconds must be 0 for %r' % cls.__name__)
            return cls(months=months)
        return cls(months=months, seconds=seconds)

    @property
    def sign(self):
        return '-' if self.months < 0 or self.seconds < 0 else ''

    def _compare_durations(self, other, op):
        """
        Ordering is defined through comparison of four datetime.datetime values.

        Ref: https://www.w3.org/TR/2012/REC-xmlschema11-2-20120405/#duration
        """
        if not isinstance(other, self.__class__):
            raise TypeError("wrong type %r for operand %r" % (type(other), other))

        m1, s1 = self.months, int(self.seconds)
        m2, s2 = other.months, int(other.seconds)
        ms1, ms2 = int((self.seconds - s1) * 1000000), int((other.seconds - s2) * 1000000)
        return all([
            op(datetime.timedelta(months2days(1696, 9, m1), s1, ms1),
               datetime.timedelta(months2days(1696, 9, m2), s2, ms2)),
            op(datetime.timedelta(months2days(1697, 2, m1), s1, ms1),
               datetime.timedelta(months2days(1697, 2, m2), s2, ms2)),
            op(datetime.timedelta(months2days(1903, 3, m1), s1, ms1),
               datetime.timedelta(months2days(1903, 3, m2), s2, ms2)),
            op(datetime.timedelta(months2days(1903, 7, m1), s1, ms1),
               datetime.timedelta(months2days(1903, 7, m2), s2, ms2)),
        ])

    def __hash__(self):
        return hash((self.months, self.seconds))

    def __eq__(self, other):
        if isinstance(other, self.__class__):
            return self.months == other.months and self.seconds == other.seconds
        elif isinstance(other, UntypedAtomic):
            return self.__eq__(self.fromstring(other.value))
        else:
            return other == (self.months, self.seconds)

    def __ne__(self, other):
        if isinstance(other, self.__class__):
            return self.months != other.months or self.seconds != other.seconds
        elif isinstance(other, UntypedAtomic):
            return self.__ne__(self.fromstring(other.value))
        else:
            return other != (self.months, self.seconds)

    def __lt__(self, other):
        return self._compare_durations(other, operator.lt)

    def __le__(self, other):
        return self == other or self._compare_durations(other, operator.le)

    def __gt__(self, other):
        return self._compare_durations(other, operator.gt)

    def __ge__(self, other):
        return self == other or self._compare_durations(other, operator.ge)


class YearMonthDuration(Duration):

    name = 'yearMonthDuration'

    def __init__(self, months: int = 0):
        super(YearMonthDuration, self).__init__(months, 0)

    def __repr__(self):
        return '%s(months=%r)' % (self.__class__.__name__, self.months)

    def __str__(self):
        m = abs(self.months)
        years, months = m // 12, m % 12

        if not years:
            return '-P%dM' % months if self.months < 0 else 'P%dM' % months
        elif not months:
            return '-P%dY' % years if self.months < 0 else 'P%dY' % years
        elif self.months < 0:
            return '-P%dY%dM' % (years, months)
        else:
            return 'P%dY%dM' % (years, months)

    def __add__(self, other):
        if isinstance(other, self.__class__):
            return YearMonthDuration(months=self.months + other.months)
        elif isinstance(other, (DateTime10, Date10)):
            return other + self
        raise TypeError("cannot add %r to %r" % (type(other), type(self)))

    def __sub__(self, other):
        if not isinstance(other, self.__class__):
            raise TypeError("cannot subtract %r from %r" % (type(other), type(self)))
        return YearMonthDuration(months=self.months - other.months)

    def __mul__(self, other):
        if not isinstance(other, (float, int, Decimal)):
            raise TypeError("cannot multiply a %r by %r" % (type(self), type(other)))
        return YearMonthDuration(months=int(round_number(self.months * other)))

    def __truediv__(self, other):
        if isinstance(other, self.__class__):
            return self.months / other.months
        elif isinstance(other, (float, int, Decimal)):
            return YearMonthDuration(months=int(round_number(self.months / other)))
        else:
            raise TypeError("cannot divide a %r by %r" % (type(self), type(other)))


class DayTimeDuration(Duration):

    name = 'dayTimeDuration'

    def __init__(self, seconds: Union[Decimal, int] = 0):
        super(DayTimeDuration, self).__init__(0, seconds)

    @classmethod
    def fromtimedelta(cls, td):
        return cls(seconds=Decimal(
            '{}.{:06}'.format(td.days * 86400 + td.seconds, td.microseconds)
        ))

    def get_timedelta(self):
        return datetime.timedelta(
            seconds=int(self.seconds), microseconds=int(self.seconds % 1 * 1000000)
        )

    def __repr__(self):
        return '%s(seconds=%s)' % (self.__class__.__name__, normalized_seconds(self.seconds))

    def __add__(self, other):
        if isinstance(other, (Time, Date10)):
            return other + self
        elif not isinstance(other, self.__class__):
            raise TypeError("cannot add %r to %r" % (type(other), type(self)))
        return DayTimeDuration(self.seconds + other.seconds)

    def __sub__(self, other):
        if not isinstance(other, self.__class__):
            raise TypeError("cannot subtract %r from %r" % (type(other), type(self)))
        return DayTimeDuration(seconds=self.seconds - other.seconds)

    def __mul__(self, other):
        if not isinstance(other, (float, int, Decimal)):
            raise TypeError("cannot multiply a %r by %r" % (type(self), type(other)))
        elif math.isnan(other):
            raise ValueError("cannot multiply a %r by NaN" % type(self))

        if isinstance(other, (int, Decimal)):
            seconds = self.seconds * other
        else:
            seconds = self.seconds * Decimal.from_float(other)

        return DayTimeDuration(seconds)

    def __truediv__(self, other):
        if isinstance(other, self.__class__):
            return self.seconds / other.seconds
        elif not isinstance(other, (float, int, Decimal)):
            raise TypeError("cannot divide a %r by %r" % (type(self), type(other)))
        elif math.isnan(other):
            raise ValueError("cannot divide a %r by NaN" % type(self))

        if isinstance(other, (int, Decimal)):
            seconds = self.seconds / other
        else:
            seconds = self.seconds / Decimal.from_float(other)

        return DayTimeDuration(seconds)
