import numpy as np
import pytest

import pandas as pd
from pandas import DataFrame, PeriodIndex, Series, period_range
from pandas.util import testing as tm


class TestPeriodIndex(object):

    def test_asfreq(self):
        pi1 = period_range(freq='A', start='1/1/2001', end='1/1/2001')
        pi2 = period_range(freq='Q', start='1/1/2001', end='1/1/2001')
        pi3 = period_range(freq='M', start='1/1/2001', end='1/1/2001')
        pi4 = period_range(freq='D', start='1/1/2001', end='1/1/2001')
        pi5 = period_range(freq='H', start='1/1/2001', end='1/1/2001 00:00')
        pi6 = period_range(freq='Min', start='1/1/2001', end='1/1/2001 00:00')
        pi7 = period_range(freq='S', start='1/1/2001', end='1/1/2001 00:00:00')

        assert pi1.asfreq('Q', 'S') == pi2
        assert pi1.asfreq('Q', 's') == pi2
        assert pi1.asfreq('M', 'start') == pi3
        assert pi1.asfreq('D', 'StarT') == pi4
        assert pi1.asfreq('H', 'beGIN') == pi5
        assert pi1.asfreq('Min', 'S') == pi6
        assert pi1.asfreq('S', 'S') == pi7

        assert pi2.asfreq('A', 'S') == pi1
        assert pi2.asfreq('M', 'S') == pi3
        assert pi2.asfreq('D', 'S') == pi4
        assert pi2.asfreq('H', 'S') == pi5
        assert pi2.asfreq('Min', 'S') == pi6
        assert pi2.asfreq('S', 'S') == pi7

        assert pi3.asfreq('A', 'S') == pi1
        assert pi3.asfreq('Q', 'S') == pi2
        assert pi3.asfreq('D', 'S') == pi4
        assert pi3.asfreq('H', 'S') == pi5
        assert pi3.asfreq('Min', 'S') == pi6
        assert pi3.asfreq('S', 'S') == pi7

        assert pi4.asfreq('A', 'S') == pi1
        assert pi4.asfreq('Q', 'S') == pi2
        assert pi4.asfreq('M', 'S') == pi3
        assert pi4.asfreq('H', 'S') == pi5
        assert pi4.asfreq('Min', 'S') == pi6
        assert pi4.asfreq('S', 'S') == pi7

        assert pi5.asfreq('A', 'S') == pi1
        assert pi5.asfreq('Q', 'S') == pi2
        assert pi5.asfreq('M', 'S') == pi3
        assert pi5.asfreq('D', 'S') == pi4
        assert pi5.asfreq('Min', 'S') == pi6
        assert pi5.asfreq('S', 'S') == pi7

        assert pi6.asfreq('A', 'S') == pi1
        assert pi6.asfreq('Q', 'S') == pi2
        assert pi6.asfreq('M', 'S') == pi3
        assert pi6.asfreq('D', 'S') == pi4
        assert pi6.asfreq('H', 'S') == pi5
        assert pi6.asfreq('S', 'S') == pi7

        assert pi7.asfreq('A', 'S') == pi1
        assert pi7.asfreq('Q', 'S') == pi2
        assert pi7.asfreq('M', 'S') == pi3
        assert pi7.asfreq('D', 'S') == pi4
        assert pi7.asfreq('H', 'S') == pi5
        assert pi7.asfreq('Min', 'S') == pi6

        pytest.raises(ValueError, pi7.asfreq, 'T', 'foo')
        result1 = pi1.asfreq('3M')
        result2 = pi1.asfreq('M')
        expected = period_range(freq='M', start='2001-12', end='2001-12')
        tm.assert_numpy_array_equal(result1.asi8, expected.asi8)
        assert result1.freqstr == '3M'
        tm.assert_numpy_array_equal(result2.asi8, expected.asi8)
        assert result2.freqstr == 'M'

    def test_asfreq_nat(self):
        idx = PeriodIndex(['2011-01', '2011-02', 'NaT', '2011-04'], freq='M')
        result = idx.asfreq(freq='Q')
        expected = PeriodIndex(['2011Q1', '2011Q1', 'NaT', '2011Q2'], freq='Q')
        tm.assert_index_equal(result, expected)

    @pytest.mark.parametrize('freq', ['D', '3D'])
    def test_asfreq_mult_pi(self, freq):
        pi = PeriodIndex(['2001-01', '2001-02', 'NaT', '2001-03'], freq='2M')

        result = pi.asfreq(freq)
        exp = PeriodIndex(['2001-02-28', '2001-03-31', 'NaT',
                           '2001-04-30'], freq=freq)
        tm.assert_index_equal(result, exp)
        assert result.freq == exp.freq

        result = pi.asfreq(freq, how='S')
        exp = PeriodIndex(['2001-01-01', '2001-02-01', 'NaT',
                           '2001-03-01'], freq=freq)
        tm.assert_index_equal(result, exp)
        assert result.freq == exp.freq

    def test_asfreq_combined_pi(self):
        pi = pd.PeriodIndex(['2001-01-01 00:00', '2001-01-02 02:00', 'NaT'],
                            freq='H')
        exp = PeriodIndex(['2001-01-01 00:00', '2001-01-02 02:00', 'NaT'],
                          freq='25H')
        for freq, how in zip(['1D1H', '1H1D'], ['S', 'E']):
            result = pi.asfreq(freq, how=how)
            tm.assert_index_equal(result, exp)
            assert result.freq == exp.freq

        for freq in ['1D1H', '1H1D']:
            pi = pd.PeriodIndex(['2001-01-01 00:00', '2001-01-02 02:00',
                                 'NaT'], freq=freq)
            result = pi.asfreq('H')
            exp = PeriodIndex(['2001-01-02 00:00', '2001-01-03 02:00', 'NaT'],
                              freq='H')
            tm.assert_index_equal(result, exp)
            assert result.freq == exp.freq

            pi = pd.PeriodIndex(['2001-01-01 00:00', '2001-01-02 02:00',
                                 'NaT'], freq=freq)
            result = pi.asfreq('H', how='S')
            exp = PeriodIndex(['2001-01-01 00:00', '2001-01-02 02:00', 'NaT'],
                              freq='H')
            tm.assert_index_equal(result, exp)
            assert result.freq == exp.freq

    def test_asfreq_ts(self):
        index = period_range(freq='A', start='1/1/2001', end='12/31/2010')
        ts = Series(np.random.randn(len(index)), index=index)
        df = DataFrame(np.random.randn(len(index), 3), index=index)

        result = ts.asfreq('D', how='end')
        df_result = df.asfreq('D', how='end')
        exp_index = index.asfreq('D', how='end')
        assert len(result) == len(ts)
        tm.assert_index_equal(result.index, exp_index)
        tm.assert_index_equal(df_result.index, exp_index)

        result = ts.asfreq('D', how='start')
        assert len(result) == len(ts)
        tm.assert_index_equal(result.index, index.asfreq('D', how='start'))

    def test_astype_asfreq(self):
        pi1 = PeriodIndex(['2011-01-01', '2011-02-01', '2011-03-01'], freq='D')
        exp = PeriodIndex(['2011-01', '2011-02', '2011-03'], freq='M')
        tm.assert_index_equal(pi1.asfreq('M'), exp)
        tm.assert_index_equal(pi1.astype('period[M]'), exp)

        exp = PeriodIndex(['2011-01', '2011-02', '2011-03'], freq='3M')
        tm.assert_index_equal(pi1.asfreq('3M'), exp)
        tm.assert_index_equal(pi1.astype('period[3M]'), exp)
