from datetime import time, timedelta

import numpy as np
import pytest

from pandas._libs.tslib import iNaT

import pandas as pd
from pandas import Series, TimedeltaIndex, isna, to_timedelta
import pandas.util.testing as tm
from pandas.util.testing import assert_series_equal


class TestTimedeltas(object):

    def test_to_timedelta(self):
        def conv(v):
            return v.astype('m8[ns]')

        d1 = np.timedelta64(1, 'D')

        assert (to_timedelta('1 days 06:05:01.00003', box=False) ==
                conv(d1 + np.timedelta64(6 * 3600 + 5 * 60 + 1, 's') +
                     np.timedelta64(30, 'us')))
        assert (to_timedelta('15.5us', box=False) ==
                conv(np.timedelta64(15500, 'ns')))

        # empty string
        result = to_timedelta('', box=False)
        assert result.astype('int64') == iNaT

        result = to_timedelta(['', ''])
        assert isna(result).all()

        # pass thru
        result = to_timedelta(np.array([np.timedelta64(1, 's')]))
        expected = pd.Index(np.array([np.timedelta64(1, 's')]))
        tm.assert_index_equal(result, expected)

        # ints
        result = np.timedelta64(0, 'ns')
        expected = to_timedelta(0, box=False)
        assert result == expected

        # Series
        expected = Series([timedelta(days=1), timedelta(days=1, seconds=1)])
        result = to_timedelta(Series(['1d', '1days 00:00:01']))
        tm.assert_series_equal(result, expected)

        # with units
        result = TimedeltaIndex([np.timedelta64(0, 'ns'), np.timedelta64(
            10, 's').astype('m8[ns]')])
        expected = to_timedelta([0, 10], unit='s')
        tm.assert_index_equal(result, expected)

        # single element conversion
        v = timedelta(seconds=1)
        result = to_timedelta(v, box=False)
        expected = np.timedelta64(timedelta(seconds=1))
        assert result == expected

        v = np.timedelta64(timedelta(seconds=1))
        result = to_timedelta(v, box=False)
        expected = np.timedelta64(timedelta(seconds=1))
        assert result == expected

        # arrays of various dtypes
        arr = np.array([1] * 5, dtype='int64')
        result = to_timedelta(arr, unit='s')
        expected = TimedeltaIndex([np.timedelta64(1, 's')] * 5)
        tm.assert_index_equal(result, expected)

        arr = np.array([1] * 5, dtype='int64')
        result = to_timedelta(arr, unit='m')
        expected = TimedeltaIndex([np.timedelta64(1, 'm')] * 5)
        tm.assert_index_equal(result, expected)

        arr = np.array([1] * 5, dtype='int64')
        result = to_timedelta(arr, unit='h')
        expected = TimedeltaIndex([np.timedelta64(1, 'h')] * 5)
        tm.assert_index_equal(result, expected)

        arr = np.array([1] * 5, dtype='timedelta64[s]')
        result = to_timedelta(arr)
        expected = TimedeltaIndex([np.timedelta64(1, 's')] * 5)
        tm.assert_index_equal(result, expected)

        arr = np.array([1] * 5, dtype='timedelta64[D]')
        result = to_timedelta(arr)
        expected = TimedeltaIndex([np.timedelta64(1, 'D')] * 5)
        tm.assert_index_equal(result, expected)

        # Test with lists as input when box=false
        expected = np.array(np.arange(3) * 1000000000, dtype='timedelta64[ns]')
        result = to_timedelta(range(3), unit='s', box=False)
        tm.assert_numpy_array_equal(expected, result)

        result = to_timedelta(np.arange(3), unit='s', box=False)
        tm.assert_numpy_array_equal(expected, result)

        result = to_timedelta([0, 1, 2], unit='s', box=False)
        tm.assert_numpy_array_equal(expected, result)

        # Tests with fractional seconds as input:
        expected = np.array(
            [0, 500000000, 800000000, 1200000000], dtype='timedelta64[ns]')
        result = to_timedelta([0., 0.5, 0.8, 1.2], unit='s', box=False)
        tm.assert_numpy_array_equal(expected, result)

    def test_to_timedelta_invalid(self):

        # bad value for errors parameter
        msg = "errors must be one of"
        with pytest.raises(ValueError, match=msg):
            to_timedelta(['foo'], errors='never')

        # these will error
        pytest.raises(ValueError, lambda: to_timedelta([1, 2], unit='foo'))
        pytest.raises(ValueError, lambda: to_timedelta(1, unit='foo'))

        # time not supported ATM
        pytest.raises(ValueError, lambda: to_timedelta(time(second=1)))
        assert to_timedelta(time(second=1), errors='coerce') is pd.NaT

        pytest.raises(ValueError, lambda: to_timedelta(['foo', 'bar']))
        tm.assert_index_equal(TimedeltaIndex([pd.NaT, pd.NaT]),
                              to_timedelta(['foo', 'bar'], errors='coerce'))

        tm.assert_index_equal(TimedeltaIndex(['1 day', pd.NaT, '1 min']),
                              to_timedelta(['1 day', 'bar', '1 min'],
                                           errors='coerce'))

        # gh-13613: these should not error because errors='ignore'
        invalid_data = 'apple'
        assert invalid_data == to_timedelta(invalid_data, errors='ignore')

        invalid_data = ['apple', '1 days']
        tm.assert_numpy_array_equal(
            np.array(invalid_data, dtype=object),
            to_timedelta(invalid_data, errors='ignore'))

        invalid_data = pd.Index(['apple', '1 days'])
        tm.assert_index_equal(invalid_data, to_timedelta(
            invalid_data, errors='ignore'))

        invalid_data = Series(['apple', '1 days'])
        tm.assert_series_equal(invalid_data, to_timedelta(
            invalid_data, errors='ignore'))

    def test_to_timedelta_via_apply(self):
        # GH 5458
        expected = Series([np.timedelta64(1, 's')])
        result = Series(['00:00:01']).apply(to_timedelta)
        tm.assert_series_equal(result, expected)

        result = Series([to_timedelta('00:00:01')])
        tm.assert_series_equal(result, expected)

    def test_to_timedelta_on_missing_values(self):
        # GH5438
        timedelta_NaT = np.timedelta64('NaT')

        actual = pd.to_timedelta(Series(['00:00:01', np.nan]))
        expected = Series([np.timedelta64(1000000000, 'ns'),
                           timedelta_NaT], dtype='<m8[ns]')
        assert_series_equal(actual, expected)

        actual = pd.to_timedelta(Series(['00:00:01', pd.NaT]))
        assert_series_equal(actual, expected)

        actual = pd.to_timedelta(np.nan)
        assert actual.value == timedelta_NaT.astype('int64')

        actual = pd.to_timedelta(pd.NaT)
        assert actual.value == timedelta_NaT.astype('int64')
