from datetime import timedelta

import numpy as np
import pytest

import pandas as pd
import pandas.util.testing as tm
from pandas import TimedeltaIndex, timedelta_range, to_timedelta, Timedelta


class TestTimedeltaIndex(object):

    def test_int64_nocopy(self):
        # GH#23539 check that a copy isn't made when we pass int64 data
        #  and copy=False
        arr = np.arange(10, dtype=np.int64)
        tdi = TimedeltaIndex(arr, copy=False)
        assert tdi._data.base is arr

    def test_infer_from_tdi(self):
        # GH#23539
        # fast-path for inferring a frequency if the passed data already
        #  has one
        tdi = pd.timedelta_range('1 second', periods=10**7, freq='1s')

        result = pd.TimedeltaIndex(tdi, freq='infer')
        assert result.freq == tdi.freq

        # check that inferred_freq was not called by checking that the
        #  value has not been cached
        assert "inferred_freq" not in getattr(result, "_cache", {})

    def test_infer_from_tdi_mismatch(self):
        # GH#23539
        # fast-path for invalidating a frequency if the passed data already
        #  has one and it does not match the `freq` input
        tdi = pd.timedelta_range('1 second', periods=100, freq='1s')

        msg = ("Inferred frequency .* from passed values does "
               "not conform to passed frequency")
        with pytest.raises(ValueError, match=msg):
            TimedeltaIndex(tdi, freq='D')

    def test_dt64_data_invalid(self):
        # GH#23539
        # passing tz-aware DatetimeIndex raises, naive or ndarray[datetime64]
        #  does not yet, but will in the future
        dti = pd.date_range('2016-01-01', periods=3)

        msg = "cannot be converted to timedelta64"
        with pytest.raises(TypeError, match=msg):
            TimedeltaIndex(dti.tz_localize('Europe/Brussels'))

        with tm.assert_produces_warning(FutureWarning):
            TimedeltaIndex(dti)

        with tm.assert_produces_warning(FutureWarning):
            TimedeltaIndex(np.asarray(dti))

    def test_float64_ns_rounded(self):
        # GH#23539 without specifying a unit, floats are regarded as nanos,
        #  and fractional portions are truncated
        tdi = TimedeltaIndex([2.3, 9.7])
        expected = TimedeltaIndex([2, 9])
        tm.assert_index_equal(tdi, expected)

        # integral floats are non-lossy
        tdi = TimedeltaIndex([2.0, 9.0])
        expected = TimedeltaIndex([2, 9])
        tm.assert_index_equal(tdi, expected)

        # NaNs get converted to NaT
        tdi = TimedeltaIndex([2.0, np.nan])
        expected = TimedeltaIndex([pd.Timedelta(nanoseconds=2), pd.NaT])
        tm.assert_index_equal(tdi, expected)

    def test_float64_unit_conversion(self):
        # GH#23539
        tdi = TimedeltaIndex([1.5, 2.25], unit='D')
        expected = TimedeltaIndex([Timedelta(days=1.5), Timedelta(days=2.25)])
        tm.assert_index_equal(tdi, expected)

    def test_construction_base_constructor(self):
        arr = [pd.Timedelta('1 days'), pd.NaT, pd.Timedelta('3 days')]
        tm.assert_index_equal(pd.Index(arr), pd.TimedeltaIndex(arr))
        tm.assert_index_equal(pd.Index(np.array(arr)),
                              pd.TimedeltaIndex(np.array(arr)))

        arr = [np.nan, pd.NaT, pd.Timedelta('1 days')]
        tm.assert_index_equal(pd.Index(arr), pd.TimedeltaIndex(arr))
        tm.assert_index_equal(pd.Index(np.array(arr)),
                              pd.TimedeltaIndex(np.array(arr)))

    def test_constructor(self):
        expected = TimedeltaIndex(['1 days', '1 days 00:00:05', '2 days',
                                   '2 days 00:00:02', '0 days 00:00:03'])
        result = TimedeltaIndex(['1 days', '1 days, 00:00:05', np.timedelta64(
            2, 'D'), timedelta(days=2, seconds=2), pd.offsets.Second(3)])
        tm.assert_index_equal(result, expected)

        # unicode
        result = TimedeltaIndex([u'1 days', '1 days, 00:00:05', np.timedelta64(
            2, 'D'), timedelta(days=2, seconds=2), pd.offsets.Second(3)])

        expected = TimedeltaIndex(['0 days 00:00:00', '0 days 00:00:01',
                                   '0 days 00:00:02'])
        tm.assert_index_equal(TimedeltaIndex(range(3), unit='s'), expected)
        expected = TimedeltaIndex(['0 days 00:00:00', '0 days 00:00:05',
                                   '0 days 00:00:09'])
        tm.assert_index_equal(TimedeltaIndex([0, 5, 9], unit='s'), expected)
        expected = TimedeltaIndex(
            ['0 days 00:00:00.400', '0 days 00:00:00.450',
             '0 days 00:00:01.200'])
        tm.assert_index_equal(TimedeltaIndex([400, 450, 1200], unit='ms'),
                              expected)

    def test_constructor_iso(self):
        # GH #21877
        expected = timedelta_range('1s', periods=9, freq='s')
        durations = ['P0DT0H0M{}S'.format(i) for i in range(1, 10)]
        result = to_timedelta(durations)
        tm.assert_index_equal(result, expected)

    def test_constructor_coverage(self):
        rng = timedelta_range('1 days', periods=10.5)
        exp = timedelta_range('1 days', periods=10)
        tm.assert_index_equal(rng, exp)

        msg = 'periods must be a number, got foo'
        with pytest.raises(TypeError, match=msg):
            TimedeltaIndex(start='1 days', periods='foo', freq='D')

        pytest.raises(ValueError, TimedeltaIndex, start='1 days',
                      end='10 days')

        with pytest.raises(TypeError):
            TimedeltaIndex('1 days')

        # generator expression
        gen = (timedelta(i) for i in range(10))
        result = TimedeltaIndex(gen)
        expected = TimedeltaIndex([timedelta(i) for i in range(10)])
        tm.assert_index_equal(result, expected)

        # NumPy string array
        strings = np.array(['1 days', '2 days', '3 days'])
        result = TimedeltaIndex(strings)
        expected = to_timedelta([1, 2, 3], unit='d')
        tm.assert_index_equal(result, expected)

        from_ints = TimedeltaIndex(expected.asi8)
        tm.assert_index_equal(from_ints, expected)

        # non-conforming freq
        pytest.raises(ValueError, TimedeltaIndex,
                      ['1 days', '2 days', '4 days'], freq='D')

        pytest.raises(ValueError, TimedeltaIndex, periods=10, freq='D')

    def test_constructor_name(self):
        idx = TimedeltaIndex(start='1 days', periods=1, freq='D', name='TEST')
        assert idx.name == 'TEST'

        # GH10025
        idx2 = TimedeltaIndex(idx, name='something else')
        assert idx2.name == 'something else'
