# -*- coding: utf-8 -*-
"""
Tests for Timestamp timezone-related methods
"""
from datetime import date, timedelta

from distutils.version import LooseVersion
import pytest
import pytz
from pytz.exceptions import AmbiguousTimeError, NonExistentTimeError
import dateutil
from dateutil.tz import gettz, tzoffset

import pandas.util.testing as tm
import pandas.util._test_decorators as td

from pandas import Timestamp, NaT
from pandas.errors import OutOfBoundsDatetime


class TestTimestampTZOperations(object):
    # --------------------------------------------------------------
    # Timestamp.tz_localize

    def test_tz_localize_pushes_out_of_bounds(self):
        # GH#12677
        # tz_localize that pushes away from the boundary is OK
        pac = Timestamp.min.tz_localize('US/Pacific')
        assert pac.value > Timestamp.min.value
        pac.tz_convert('Asia/Tokyo')  # tz_convert doesn't change value
        with pytest.raises(OutOfBoundsDatetime):
            Timestamp.min.tz_localize('Asia/Tokyo')

        # tz_localize that pushes away from the boundary is OK
        tokyo = Timestamp.max.tz_localize('Asia/Tokyo')
        assert tokyo.value < Timestamp.max.value
        tokyo.tz_convert('US/Pacific')  # tz_convert doesn't change value
        with pytest.raises(OutOfBoundsDatetime):
            Timestamp.max.tz_localize('US/Pacific')

    def test_tz_localize_ambiguous_bool(self):
        # make sure that we are correctly accepting bool values as ambiguous
        # GH#14402
        ts = Timestamp('2015-11-01 01:00:03')
        expected0 = Timestamp('2015-11-01 01:00:03-0500', tz='US/Central')
        expected1 = Timestamp('2015-11-01 01:00:03-0600', tz='US/Central')

        with pytest.raises(pytz.AmbiguousTimeError):
            ts.tz_localize('US/Central')

        result = ts.tz_localize('US/Central', ambiguous=True)
        assert result == expected0

        result = ts.tz_localize('US/Central', ambiguous=False)
        assert result == expected1

    def test_tz_localize_ambiguous(self):
        ts = Timestamp('2014-11-02 01:00')
        ts_dst = ts.tz_localize('US/Eastern', ambiguous=True)
        ts_no_dst = ts.tz_localize('US/Eastern', ambiguous=False)

        assert (ts_no_dst.value - ts_dst.value) / 1e9 == 3600
        with pytest.raises(ValueError):
            ts.tz_localize('US/Eastern', ambiguous='infer')

        # GH#8025
        with tm.assert_raises_regex(TypeError,
                                    'Cannot localize tz-aware Timestamp, '
                                    'use tz_convert for conversions'):
            Timestamp('2011-01-01', tz='US/Eastern').tz_localize('Asia/Tokyo')

        with tm.assert_raises_regex(TypeError,
                                    'Cannot convert tz-naive Timestamp, '
                                    'use tz_localize to localize'):
            Timestamp('2011-01-01').tz_convert('Asia/Tokyo')

    @pytest.mark.parametrize('stamp, tz', [
        ('2015-03-08 02:00', 'US/Eastern'),
        ('2015-03-08 02:30', 'US/Pacific'),
        ('2015-03-29 02:00', 'Europe/Paris'),
        ('2015-03-29 02:30', 'Europe/Belgrade')])
    def test_tz_localize_nonexistent(self, stamp, tz):
        # GH#13057
        ts = Timestamp(stamp)
        with pytest.raises(NonExistentTimeError):
            ts.tz_localize(tz)
        with pytest.raises(NonExistentTimeError):
            ts.tz_localize(tz, errors='raise')
        assert ts.tz_localize(tz, errors='coerce') is NaT

    def test_tz_localize_errors_ambiguous(self):
        # GH#13057
        ts = Timestamp('2015-11-1 01:00')
        with pytest.raises(AmbiguousTimeError):
            ts.tz_localize('US/Pacific', errors='coerce')

    @pytest.mark.parametrize('tz', ['UTC', 'Asia/Tokyo',
                                    'US/Eastern', 'dateutil/US/Pacific'])
    @pytest.mark.parametrize('stamp', ['2014-02-01 09:00', '2014-07-08 09:00',
                                       '2014-11-01 17:00', '2014-11-05 00:00'])
    def test_tz_localize_roundtrip(self, stamp, tz):
        ts = Timestamp(stamp)
        localized = ts.tz_localize(tz)
        assert localized == Timestamp(stamp, tz=tz)

        with pytest.raises(TypeError):
            localized.tz_localize(tz)

        reset = localized.tz_localize(None)
        assert reset == ts
        assert reset.tzinfo is None

    def test_tz_localize_ambiguous_compat(self):
        # validate that pytz and dateutil are compat for dst
        # when the transition happens
        naive = Timestamp('2013-10-27 01:00:00')

        pytz_zone = 'Europe/London'
        dateutil_zone = 'dateutil/Europe/London'
        result_pytz = naive.tz_localize(pytz_zone, ambiguous=0)
        result_dateutil = naive.tz_localize(dateutil_zone, ambiguous=0)
        assert result_pytz.value == result_dateutil.value
        assert result_pytz.value == 1382835600000000000

        if LooseVersion(dateutil.__version__) < LooseVersion('2.6.0'):
            # dateutil 2.6 buggy w.r.t. ambiguous=0
            # see gh-14621
            # see https://github.com/dateutil/dateutil/issues/321
            assert (result_pytz.to_pydatetime().tzname() ==
                    result_dateutil.to_pydatetime().tzname())
            assert str(result_pytz) == str(result_dateutil)
        elif LooseVersion(dateutil.__version__) > LooseVersion('2.6.0'):
            # fixed ambiguous behavior
            assert result_pytz.to_pydatetime().tzname() == 'GMT'
            assert result_dateutil.to_pydatetime().tzname() == 'BST'
            assert str(result_pytz) != str(result_dateutil)

        # 1 hour difference
        result_pytz = naive.tz_localize(pytz_zone, ambiguous=1)
        result_dateutil = naive.tz_localize(dateutil_zone, ambiguous=1)
        assert result_pytz.value == result_dateutil.value
        assert result_pytz.value == 1382832000000000000

        # dateutil < 2.6 is buggy w.r.t. ambiguous timezones
        if LooseVersion(dateutil.__version__) > LooseVersion('2.5.3'):
            # see gh-14621
            assert str(result_pytz) == str(result_dateutil)
            assert (result_pytz.to_pydatetime().tzname() ==
                    result_dateutil.to_pydatetime().tzname())

    @pytest.mark.parametrize('tz', [pytz.timezone('US/Eastern'),
                                    gettz('US/Eastern'),
                                    'US/Eastern', 'dateutil/US/Eastern'])
    def test_timestamp_tz_localize(self, tz):
        stamp = Timestamp('3/11/2012 04:00')

        result = stamp.tz_localize(tz)
        expected = Timestamp('3/11/2012 04:00', tz=tz)
        assert result.hour == expected.hour
        assert result == expected

    # ------------------------------------------------------------------
    # Timestamp.tz_convert

    @pytest.mark.parametrize('tz', ['UTC', 'Asia/Tokyo',
                                    'US/Eastern', 'dateutil/US/Pacific'])
    @pytest.mark.parametrize('stamp', ['2014-02-01 09:00', '2014-07-08 09:00',
                                       '2014-11-01 17:00', '2014-11-05 00:00'])
    def test_tz_convert_roundtrip(self, stamp, tz):
        ts = Timestamp(stamp, tz='UTC')
        converted = ts.tz_convert(tz)

        reset = converted.tz_convert(None)
        assert reset == Timestamp(stamp)
        assert reset.tzinfo is None
        assert reset == converted.tz_convert('UTC').tz_localize(None)

    @pytest.mark.parametrize('tzstr', ['US/Eastern', 'dateutil/US/Eastern'])
    def test_astimezone(self, tzstr):
        # astimezone is an alias for tz_convert, so keep it with
        # the tz_convert tests
        utcdate = Timestamp('3/11/2012 22:00', tz='UTC')
        expected = utcdate.tz_convert(tzstr)
        result = utcdate.astimezone(tzstr)
        assert expected == result
        assert isinstance(result, Timestamp)

    @td.skip_if_windows
    def test_tz_convert_utc_with_system_utc(self):
        from pandas._libs.tslibs.timezones import maybe_get_tz

        # from system utc to real utc
        ts = Timestamp('2001-01-05 11:56', tz=maybe_get_tz('dateutil/UTC'))
        # check that the time hasn't changed.
        assert ts == ts.tz_convert(dateutil.tz.tzutc())

        # from system utc to real utc
        ts = Timestamp('2001-01-05 11:56', tz=maybe_get_tz('dateutil/UTC'))
        # check that the time hasn't changed.
        assert ts == ts.tz_convert(dateutil.tz.tzutc())

    # ------------------------------------------------------------------
    # Timestamp.__init__ with tz str or tzinfo

    def test_timestamp_constructor_tz_utc(self):
        utc_stamp = Timestamp('3/11/2012 05:00', tz='utc')
        assert utc_stamp.tzinfo is pytz.utc
        assert utc_stamp.hour == 5

        utc_stamp = Timestamp('3/11/2012 05:00').tz_localize('utc')
        assert utc_stamp.hour == 5

    def test_timestamp_to_datetime_tzoffset(self):
        tzinfo = tzoffset(None, 7200)
        expected = Timestamp('3/11/2012 04:00', tz=tzinfo)
        result = Timestamp(expected.to_pydatetime())
        assert expected == result

    def test_timestamp_constructor_near_dst_boundary(self):
        # GH#11481 & GH#15777
        # Naive string timestamps were being localized incorrectly
        # with tz_convert_single instead of tz_localize_to_utc

        for tz in ['Europe/Brussels', 'Europe/Prague']:
            result = Timestamp('2015-10-25 01:00', tz=tz)
            expected = Timestamp('2015-10-25 01:00').tz_localize(tz)
            assert result == expected

            with pytest.raises(pytz.AmbiguousTimeError):
                Timestamp('2015-10-25 02:00', tz=tz)

        result = Timestamp('2017-03-26 01:00', tz='Europe/Paris')
        expected = Timestamp('2017-03-26 01:00').tz_localize('Europe/Paris')
        assert result == expected

        with pytest.raises(pytz.NonExistentTimeError):
            Timestamp('2017-03-26 02:00', tz='Europe/Paris')

        # GH#11708
        naive = Timestamp('2015-11-18 10:00:00')
        result = naive.tz_localize('UTC').tz_convert('Asia/Kolkata')
        expected = Timestamp('2015-11-18 15:30:00+0530', tz='Asia/Kolkata')
        assert result == expected

        # GH#15823
        result = Timestamp('2017-03-26 00:00', tz='Europe/Paris')
        expected = Timestamp('2017-03-26 00:00:00+0100', tz='Europe/Paris')
        assert result == expected

        result = Timestamp('2017-03-26 01:00', tz='Europe/Paris')
        expected = Timestamp('2017-03-26 01:00:00+0100', tz='Europe/Paris')
        assert result == expected

        with pytest.raises(pytz.NonExistentTimeError):
            Timestamp('2017-03-26 02:00', tz='Europe/Paris')

        result = Timestamp('2017-03-26 02:00:00+0100', tz='Europe/Paris')
        naive = Timestamp(result.value)
        expected = naive.tz_localize('UTC').tz_convert('Europe/Paris')
        assert result == expected

        result = Timestamp('2017-03-26 03:00', tz='Europe/Paris')
        expected = Timestamp('2017-03-26 03:00:00+0200', tz='Europe/Paris')
        assert result == expected

    @pytest.mark.parametrize('tz', [pytz.timezone('US/Eastern'),
                                    gettz('US/Eastern'),
                                    'US/Eastern', 'dateutil/US/Eastern'])
    def test_timestamp_constructed_by_date_and_tz(self, tz):
        # GH#2993, Timestamp cannot be constructed by datetime.date
        # and tz correctly

        result = Timestamp(date(2012, 3, 11), tz=tz)

        expected = Timestamp('3/11/2012', tz=tz)
        assert result.hour == expected.hour
        assert result == expected

    @pytest.mark.parametrize('tz', [pytz.timezone('US/Eastern'),
                                    gettz('US/Eastern'),
                                    'US/Eastern', 'dateutil/US/Eastern'])
    def test_timestamp_add_timedelta_push_over_dst_boundary(self, tz):
        # GH#1389

        # 4 hours before DST transition
        stamp = Timestamp('3/10/2012 22:00', tz=tz)

        result = stamp + timedelta(hours=6)

        # spring forward, + "7" hours
        expected = Timestamp('3/11/2012 05:00', tz=tz)

        assert result == expected
