from typing import Type, Union

import numpy as np
import pytest

from pandas._libs import OutOfBoundsDatetime
from pandas.compat.numpy import _np_version_under1p18

import pandas as pd
import pandas._testing as tm
from pandas.core.arrays import DatetimeArray, PeriodArray, TimedeltaArray
from pandas.core.indexes.datetimes import DatetimeIndex
from pandas.core.indexes.period import PeriodIndex
from pandas.core.indexes.timedeltas import TimedeltaIndex


# TODO: more freq variants
@pytest.fixture(params=["D", "B", "W", "M", "Q", "Y"])
def period_index(request):
    """
    A fixture to provide PeriodIndex objects with different frequencies.

    Most PeriodArray behavior is already tested in PeriodIndex tests,
    so here we just test that the PeriodArray behavior matches
    the PeriodIndex behavior.
    """
    freqstr = request.param
    # TODO: non-monotone indexes; NaTs, different start dates
    pi = pd.period_range(start=pd.Timestamp("2000-01-01"), periods=100, freq=freqstr)
    return pi


@pytest.fixture(params=["D", "B", "W", "M", "Q", "Y"])
def datetime_index(request):
    """
    A fixture to provide DatetimeIndex objects with different frequencies.

    Most DatetimeArray behavior is already tested in DatetimeIndex tests,
    so here we just test that the DatetimeArray behavior matches
    the DatetimeIndex behavior.
    """
    freqstr = request.param
    # TODO: non-monotone indexes; NaTs, different start dates, timezones
    dti = pd.date_range(start=pd.Timestamp("2000-01-01"), periods=100, freq=freqstr)
    return dti


@pytest.fixture
def timedelta_index(request):
    """
    A fixture to provide TimedeltaIndex objects with different frequencies.
     Most TimedeltaArray behavior is already tested in TimedeltaIndex tests,
    so here we just test that the TimedeltaArray behavior matches
    the TimedeltaIndex behavior.
    """
    # TODO: flesh this out
    return pd.TimedeltaIndex(["1 Day", "3 Hours", "NaT"])


class SharedTests:
    index_cls: Type[Union[DatetimeIndex, PeriodIndex, TimedeltaIndex]]

    def test_compare_len1_raises(self):
        # make sure we raise when comparing with different lengths, specific
        #  to the case where one has length-1, which numpy would broadcast
        data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9

        idx = self.index_cls._simple_new(data, freq="D")
        arr = self.array_cls(idx)

        with pytest.raises(ValueError, match="Lengths must match"):
            arr == arr[:1]

        # test the index classes while we're at it, GH#23078
        with pytest.raises(ValueError, match="Lengths must match"):
            idx <= idx[[0]]

    def test_take(self):
        data = np.arange(100, dtype="i8") * 24 * 3600 * 10 ** 9
        np.random.shuffle(data)

        idx = self.index_cls._simple_new(data, freq="D")
        arr = self.array_cls(idx)

        takers = [1, 4, 94]
        result = arr.take(takers)
        expected = idx.take(takers)

        tm.assert_index_equal(self.index_cls(result), expected)

        takers = np.array([1, 4, 94])
        result = arr.take(takers)
        expected = idx.take(takers)

        tm.assert_index_equal(self.index_cls(result), expected)

    def test_take_fill(self):
        data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9

        idx = self.index_cls._simple_new(data, freq="D")
        arr = self.array_cls(idx)

        result = arr.take([-1, 1], allow_fill=True, fill_value=None)
        assert result[0] is pd.NaT

        result = arr.take([-1, 1], allow_fill=True, fill_value=np.nan)
        assert result[0] is pd.NaT

        result = arr.take([-1, 1], allow_fill=True, fill_value=pd.NaT)
        assert result[0] is pd.NaT

        with pytest.raises(ValueError):
            arr.take([0, 1], allow_fill=True, fill_value=2)

        with pytest.raises(ValueError):
            arr.take([0, 1], allow_fill=True, fill_value=2.0)

        with pytest.raises(ValueError):
            arr.take([0, 1], allow_fill=True, fill_value=pd.Timestamp.now().time)

    def test_concat_same_type(self):
        data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9

        idx = self.index_cls._simple_new(data, freq="D").insert(0, pd.NaT)
        arr = self.array_cls(idx)

        result = arr._concat_same_type([arr[:-1], arr[1:], arr])
        expected = idx._concat_same_dtype([idx[:-1], idx[1:], idx], None)

        tm.assert_index_equal(self.index_cls(result), expected)

    def test_unbox_scalar(self):
        data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
        arr = self.array_cls(data, freq="D")
        result = arr._unbox_scalar(arr[0])
        assert isinstance(result, int)

        result = arr._unbox_scalar(pd.NaT)
        assert isinstance(result, int)

        with pytest.raises(ValueError):
            arr._unbox_scalar("foo")

    def test_check_compatible_with(self):
        data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
        arr = self.array_cls(data, freq="D")

        arr._check_compatible_with(arr[0])
        arr._check_compatible_with(arr[:1])
        arr._check_compatible_with(pd.NaT)

    def test_scalar_from_string(self):
        data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
        arr = self.array_cls(data, freq="D")
        result = arr._scalar_from_string(str(arr[0]))
        assert result == arr[0]

    def test_reduce_invalid(self):
        data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
        arr = self.array_cls(data, freq="D")

        with pytest.raises(TypeError, match="cannot perform"):
            arr._reduce("not a method")

    @pytest.mark.parametrize("method", ["pad", "backfill"])
    def test_fillna_method_doesnt_change_orig(self, method):
        data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
        arr = self.array_cls(data, freq="D")
        arr[4] = pd.NaT

        fill_value = arr[3] if method == "pad" else arr[5]

        result = arr.fillna(method=method)
        assert result[4] == fill_value

        # check that the original was not changed
        assert arr[4] is pd.NaT

    def test_searchsorted(self):
        data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
        arr = self.array_cls(data, freq="D")

        # scalar
        result = arr.searchsorted(arr[1])
        assert result == 1

        result = arr.searchsorted(arr[2], side="right")
        assert result == 3

        # own-type
        result = arr.searchsorted(arr[1:3])
        expected = np.array([1, 2], dtype=np.intp)
        tm.assert_numpy_array_equal(result, expected)

        result = arr.searchsorted(arr[1:3], side="right")
        expected = np.array([2, 3], dtype=np.intp)
        tm.assert_numpy_array_equal(result, expected)

        # Following numpy convention, NaT goes at the beginning
        #  (unlike NaN which goes at the end)
        result = arr.searchsorted(pd.NaT)
        assert result == 0

    def test_setitem(self):
        data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
        arr = self.array_cls(data, freq="D")

        arr[0] = arr[1]
        expected = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
        expected[0] = expected[1]

        tm.assert_numpy_array_equal(arr.asi8, expected)

        arr[:2] = arr[-2:]
        expected[:2] = expected[-2:]
        tm.assert_numpy_array_equal(arr.asi8, expected)

    def test_setitem_raises(self):
        data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
        arr = self.array_cls(data, freq="D")
        val = arr[0]

        with pytest.raises(IndexError, match="index 12 is out of bounds"):
            arr[12] = val

        with pytest.raises(TypeError, match="'value' should be a.* 'object'"):
            arr[0] = object()

    def test_inplace_arithmetic(self):
        # GH#24115 check that iadd and isub are actually in-place
        data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
        arr = self.array_cls(data, freq="D")

        expected = arr + pd.Timedelta(days=1)
        arr += pd.Timedelta(days=1)
        tm.assert_equal(arr, expected)

        expected = arr - pd.Timedelta(days=1)
        arr -= pd.Timedelta(days=1)
        tm.assert_equal(arr, expected)

    def test_shift_fill_int_deprecated(self):
        # GH#31971
        data = np.arange(10, dtype="i8") * 24 * 3600 * 10 ** 9
        arr = self.array_cls(data, freq="D")

        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False):
            result = arr.shift(1, fill_value=1)

        expected = arr.copy()
        if self.array_cls is PeriodArray:
            fill_val = PeriodArray._scalar_type._from_ordinal(1, freq=arr.freq)
        else:
            fill_val = arr._scalar_type(1)
        expected[0] = fill_val
        expected[1:] = arr[:-1]
        tm.assert_equal(result, expected)


class TestDatetimeArray(SharedTests):
    index_cls = pd.DatetimeIndex
    array_cls = DatetimeArray

    def test_round(self, tz_naive_fixture):
        # GH#24064
        tz = tz_naive_fixture
        dti = pd.date_range("2016-01-01 01:01:00", periods=3, freq="H", tz=tz)

        result = dti.round(freq="2T")
        expected = dti - pd.Timedelta(minutes=1)
        tm.assert_index_equal(result, expected)

    def test_array_interface(self, datetime_index):
        arr = DatetimeArray(datetime_index)

        # default asarray gives the same underlying data (for tz naive)
        result = np.asarray(arr)
        expected = arr._data
        assert result is expected
        tm.assert_numpy_array_equal(result, expected)
        result = np.array(arr, copy=False)
        assert result is expected
        tm.assert_numpy_array_equal(result, expected)

        # specifying M8[ns] gives the same result as default
        result = np.asarray(arr, dtype="datetime64[ns]")
        expected = arr._data
        assert result is expected
        tm.assert_numpy_array_equal(result, expected)
        result = np.array(arr, dtype="datetime64[ns]", copy=False)
        assert result is expected
        tm.assert_numpy_array_equal(result, expected)
        result = np.array(arr, dtype="datetime64[ns]")
        assert result is not expected
        tm.assert_numpy_array_equal(result, expected)

        # to object dtype
        result = np.asarray(arr, dtype=object)
        expected = np.array(list(arr), dtype=object)
        tm.assert_numpy_array_equal(result, expected)

        # to other dtype always copies
        result = np.asarray(arr, dtype="int64")
        assert result is not arr.asi8
        assert not np.may_share_memory(arr, result)
        expected = arr.asi8.copy()
        tm.assert_numpy_array_equal(result, expected)

        # other dtypes handled by numpy
        for dtype in ["float64", str]:
            result = np.asarray(arr, dtype=dtype)
            expected = np.asarray(arr).astype(dtype)
            tm.assert_numpy_array_equal(result, expected)

    def test_array_object_dtype(self, tz_naive_fixture):
        # GH#23524
        tz = tz_naive_fixture
        dti = pd.date_range("2016-01-01", periods=3, tz=tz)
        arr = DatetimeArray(dti)

        expected = np.array(list(dti))

        result = np.array(arr, dtype=object)
        tm.assert_numpy_array_equal(result, expected)

        # also test the DatetimeIndex method while we're at it
        result = np.array(dti, dtype=object)
        tm.assert_numpy_array_equal(result, expected)

    def test_array_tz(self, tz_naive_fixture):
        # GH#23524
        tz = tz_naive_fixture
        dti = pd.date_range("2016-01-01", periods=3, tz=tz)
        arr = DatetimeArray(dti)

        expected = dti.asi8.view("M8[ns]")
        result = np.array(arr, dtype="M8[ns]")
        tm.assert_numpy_array_equal(result, expected)

        result = np.array(arr, dtype="datetime64[ns]")
        tm.assert_numpy_array_equal(result, expected)

        # check that we are not making copies when setting copy=False
        result = np.array(arr, dtype="M8[ns]", copy=False)
        assert result.base is expected.base
        assert result.base is not None
        result = np.array(arr, dtype="datetime64[ns]", copy=False)
        assert result.base is expected.base
        assert result.base is not None

    def test_array_i8_dtype(self, tz_naive_fixture):
        tz = tz_naive_fixture
        dti = pd.date_range("2016-01-01", periods=3, tz=tz)
        arr = DatetimeArray(dti)

        expected = dti.asi8
        result = np.array(arr, dtype="i8")
        tm.assert_numpy_array_equal(result, expected)

        result = np.array(arr, dtype=np.int64)
        tm.assert_numpy_array_equal(result, expected)

        # check that we are still making copies when setting copy=False
        result = np.array(arr, dtype="i8", copy=False)
        assert result.base is not expected.base
        assert result.base is None

    def test_from_array_keeps_base(self):
        # Ensure that DatetimeArray._data.base isn't lost.
        arr = np.array(["2000-01-01", "2000-01-02"], dtype="M8[ns]")
        dta = DatetimeArray(arr)

        assert dta._data is arr
        dta = DatetimeArray(arr[:0])
        assert dta._data.base is arr

    def test_from_dti(self, tz_naive_fixture):
        tz = tz_naive_fixture
        dti = pd.date_range("2016-01-01", periods=3, tz=tz)
        arr = DatetimeArray(dti)
        assert list(dti) == list(arr)

        # Check that Index.__new__ knows what to do with DatetimeArray
        dti2 = pd.Index(arr)
        assert isinstance(dti2, pd.DatetimeIndex)
        assert list(dti2) == list(arr)

    def test_astype_object(self, tz_naive_fixture):
        tz = tz_naive_fixture
        dti = pd.date_range("2016-01-01", periods=3, tz=tz)
        arr = DatetimeArray(dti)
        asobj = arr.astype("O")
        assert isinstance(asobj, np.ndarray)
        assert asobj.dtype == "O"
        assert list(asobj) == list(dti)

    @pytest.mark.parametrize("freqstr", ["D", "B", "W", "M", "Q", "Y"])
    def test_to_perioddelta(self, datetime_index, freqstr):
        # GH#23113
        dti = datetime_index
        arr = DatetimeArray(dti)

        expected = dti.to_perioddelta(freq=freqstr)
        result = arr.to_perioddelta(freq=freqstr)
        assert isinstance(result, TimedeltaArray)

        # placeholder until these become actual EA subclasses and we can use
        #  an EA-specific tm.assert_ function
        tm.assert_index_equal(pd.Index(result), pd.Index(expected))

    @pytest.mark.parametrize("freqstr", ["D", "B", "W", "M", "Q", "Y"])
    def test_to_period(self, datetime_index, freqstr):
        dti = datetime_index
        arr = DatetimeArray(dti)

        expected = dti.to_period(freq=freqstr)
        result = arr.to_period(freq=freqstr)
        assert isinstance(result, PeriodArray)

        # placeholder until these become actual EA subclasses and we can use
        #  an EA-specific tm.assert_ function
        tm.assert_index_equal(pd.Index(result), pd.Index(expected))

    @pytest.mark.parametrize("propname", pd.DatetimeIndex._bool_ops)
    def test_bool_properties(self, datetime_index, propname):
        # in this case _bool_ops is just `is_leap_year`
        dti = datetime_index
        arr = DatetimeArray(dti)
        assert dti.freq == arr.freq

        result = getattr(arr, propname)
        expected = np.array(getattr(dti, propname), dtype=result.dtype)

        tm.assert_numpy_array_equal(result, expected)

    @pytest.mark.parametrize("propname", pd.DatetimeIndex._field_ops)
    def test_int_properties(self, datetime_index, propname):
        dti = datetime_index
        arr = DatetimeArray(dti)

        result = getattr(arr, propname)
        expected = np.array(getattr(dti, propname), dtype=result.dtype)

        tm.assert_numpy_array_equal(result, expected)

    def test_take_fill_valid(self, datetime_index, tz_naive_fixture):
        dti = datetime_index.tz_localize(tz_naive_fixture)
        arr = DatetimeArray(dti)

        now = pd.Timestamp.now().tz_localize(dti.tz)
        result = arr.take([-1, 1], allow_fill=True, fill_value=now)
        assert result[0] == now

        with pytest.raises(ValueError):
            # fill_value Timedelta invalid
            arr.take([-1, 1], allow_fill=True, fill_value=now - now)

        with pytest.raises(ValueError):
            # fill_value Period invalid
            arr.take([-1, 1], allow_fill=True, fill_value=pd.Period("2014Q1"))

        tz = None if dti.tz is not None else "US/Eastern"
        now = pd.Timestamp.now().tz_localize(tz)
        with pytest.raises(TypeError):
            # Timestamp with mismatched tz-awareness
            arr.take([-1, 1], allow_fill=True, fill_value=now)

        with pytest.raises(ValueError):
            # require NaT, not iNaT, as it could be confused with an integer
            arr.take([-1, 1], allow_fill=True, fill_value=pd.NaT.value)

    def test_concat_same_type_invalid(self, datetime_index):
        # different timezones
        dti = datetime_index
        arr = DatetimeArray(dti)

        if arr.tz is None:
            other = arr.tz_localize("UTC")
        else:
            other = arr.tz_localize(None)

        with pytest.raises(AssertionError):
            arr._concat_same_type([arr, other])

    def test_concat_same_type_different_freq(self):
        # we *can* concatenate DTI with different freqs.
        a = DatetimeArray(pd.date_range("2000", periods=2, freq="D", tz="US/Central"))
        b = DatetimeArray(pd.date_range("2000", periods=2, freq="H", tz="US/Central"))
        result = DatetimeArray._concat_same_type([a, b])
        expected = DatetimeArray(
            pd.to_datetime(
                [
                    "2000-01-01 00:00:00",
                    "2000-01-02 00:00:00",
                    "2000-01-01 00:00:00",
                    "2000-01-01 01:00:00",
                ]
            ).tz_localize("US/Central")
        )

        tm.assert_datetime_array_equal(result, expected)

    def test_strftime(self, datetime_index):
        arr = DatetimeArray(datetime_index)

        result = arr.strftime("%Y %b")
        expected = np.array([ts.strftime("%Y %b") for ts in arr], dtype=object)
        tm.assert_numpy_array_equal(result, expected)

    def test_strftime_nat(self):
        # GH 29578
        arr = DatetimeArray(DatetimeIndex(["2019-01-01", pd.NaT]))

        result = arr.strftime("%Y-%m-%d")
        expected = np.array(["2019-01-01", np.nan], dtype=object)
        tm.assert_numpy_array_equal(result, expected)


class TestTimedeltaArray(SharedTests):
    index_cls = pd.TimedeltaIndex
    array_cls = TimedeltaArray

    def test_from_tdi(self):
        tdi = pd.TimedeltaIndex(["1 Day", "3 Hours"])
        arr = TimedeltaArray(tdi)
        assert list(arr) == list(tdi)

        # Check that Index.__new__ knows what to do with TimedeltaArray
        tdi2 = pd.Index(arr)
        assert isinstance(tdi2, pd.TimedeltaIndex)
        assert list(tdi2) == list(arr)

    def test_astype_object(self):
        tdi = pd.TimedeltaIndex(["1 Day", "3 Hours"])
        arr = TimedeltaArray(tdi)
        asobj = arr.astype("O")
        assert isinstance(asobj, np.ndarray)
        assert asobj.dtype == "O"
        assert list(asobj) == list(tdi)

    def test_to_pytimedelta(self, timedelta_index):
        tdi = timedelta_index
        arr = TimedeltaArray(tdi)

        expected = tdi.to_pytimedelta()
        result = arr.to_pytimedelta()

        tm.assert_numpy_array_equal(result, expected)

    def test_total_seconds(self, timedelta_index):
        tdi = timedelta_index
        arr = TimedeltaArray(tdi)

        expected = tdi.total_seconds()
        result = arr.total_seconds()

        tm.assert_numpy_array_equal(result, expected.values)

    @pytest.mark.parametrize("propname", pd.TimedeltaIndex._field_ops)
    def test_int_properties(self, timedelta_index, propname):
        tdi = timedelta_index
        arr = TimedeltaArray(tdi)

        result = getattr(arr, propname)
        expected = np.array(getattr(tdi, propname), dtype=result.dtype)

        tm.assert_numpy_array_equal(result, expected)

    def test_array_interface(self, timedelta_index):
        arr = TimedeltaArray(timedelta_index)

        # default asarray gives the same underlying data
        result = np.asarray(arr)
        expected = arr._data
        assert result is expected
        tm.assert_numpy_array_equal(result, expected)
        result = np.array(arr, copy=False)
        assert result is expected
        tm.assert_numpy_array_equal(result, expected)

        # specifying m8[ns] gives the same result as default
        result = np.asarray(arr, dtype="timedelta64[ns]")
        expected = arr._data
        assert result is expected
        tm.assert_numpy_array_equal(result, expected)
        result = np.array(arr, dtype="timedelta64[ns]", copy=False)
        assert result is expected
        tm.assert_numpy_array_equal(result, expected)
        result = np.array(arr, dtype="timedelta64[ns]")
        assert result is not expected
        tm.assert_numpy_array_equal(result, expected)

        # to object dtype
        result = np.asarray(arr, dtype=object)
        expected = np.array(list(arr), dtype=object)
        tm.assert_numpy_array_equal(result, expected)

        # to other dtype always copies
        result = np.asarray(arr, dtype="int64")
        assert result is not arr.asi8
        assert not np.may_share_memory(arr, result)
        expected = arr.asi8.copy()
        tm.assert_numpy_array_equal(result, expected)

        # other dtypes handled by numpy
        for dtype in ["float64", str]:
            result = np.asarray(arr, dtype=dtype)
            expected = np.asarray(arr).astype(dtype)
            tm.assert_numpy_array_equal(result, expected)

    def test_take_fill_valid(self, timedelta_index):
        tdi = timedelta_index
        arr = TimedeltaArray(tdi)

        td1 = pd.Timedelta(days=1)
        result = arr.take([-1, 1], allow_fill=True, fill_value=td1)
        assert result[0] == td1

        now = pd.Timestamp.now()
        with pytest.raises(ValueError):
            # fill_value Timestamp invalid
            arr.take([0, 1], allow_fill=True, fill_value=now)

        with pytest.raises(ValueError):
            # fill_value Period invalid
            arr.take([0, 1], allow_fill=True, fill_value=now.to_period("D"))


class TestPeriodArray(SharedTests):
    index_cls = pd.PeriodIndex
    array_cls = PeriodArray

    def test_from_pi(self, period_index):
        pi = period_index
        arr = PeriodArray(pi)
        assert list(arr) == list(pi)

        # Check that Index.__new__ knows what to do with PeriodArray
        pi2 = pd.Index(arr)
        assert isinstance(pi2, pd.PeriodIndex)
        assert list(pi2) == list(arr)

    def test_astype_object(self, period_index):
        pi = period_index
        arr = PeriodArray(pi)
        asobj = arr.astype("O")
        assert isinstance(asobj, np.ndarray)
        assert asobj.dtype == "O"
        assert list(asobj) == list(pi)

    @pytest.mark.parametrize("how", ["S", "E"])
    def test_to_timestamp(self, how, period_index):
        pi = period_index
        arr = PeriodArray(pi)

        expected = DatetimeArray(pi.to_timestamp(how=how))
        result = arr.to_timestamp(how=how)
        assert isinstance(result, DatetimeArray)

        # placeholder until these become actual EA subclasses and we can use
        #  an EA-specific tm.assert_ function
        tm.assert_index_equal(pd.Index(result), pd.Index(expected))

    def test_to_timestamp_out_of_bounds(self):
        # GH#19643 previously overflowed silently
        pi = pd.period_range("1500", freq="Y", periods=3)
        with pytest.raises(OutOfBoundsDatetime):
            pi.to_timestamp()

        with pytest.raises(OutOfBoundsDatetime):
            pi._data.to_timestamp()

    @pytest.mark.parametrize("propname", PeriodArray._bool_ops)
    def test_bool_properties(self, period_index, propname):
        # in this case _bool_ops is just `is_leap_year`
        pi = period_index
        arr = PeriodArray(pi)

        result = getattr(arr, propname)
        expected = np.array(getattr(pi, propname))

        tm.assert_numpy_array_equal(result, expected)

    @pytest.mark.parametrize("propname", PeriodArray._field_ops)
    def test_int_properties(self, period_index, propname):
        pi = period_index
        arr = PeriodArray(pi)

        result = getattr(arr, propname)
        expected = np.array(getattr(pi, propname))

        tm.assert_numpy_array_equal(result, expected)

    def test_array_interface(self, period_index):
        arr = PeriodArray(period_index)

        # default asarray gives objects
        result = np.asarray(arr)
        expected = np.array(list(arr), dtype=object)
        tm.assert_numpy_array_equal(result, expected)

        # to object dtype (same as default)
        result = np.asarray(arr, dtype=object)
        tm.assert_numpy_array_equal(result, expected)

        # to other dtypes
        with pytest.raises(TypeError):
            np.asarray(arr, dtype="int64")

        with pytest.raises(TypeError):
            np.asarray(arr, dtype="float64")

        result = np.asarray(arr, dtype="S20")
        expected = np.asarray(arr).astype("S20")
        tm.assert_numpy_array_equal(result, expected)

    def test_strftime(self, period_index):
        arr = PeriodArray(period_index)

        result = arr.strftime("%Y")
        expected = np.array([per.strftime("%Y") for per in arr], dtype=object)
        tm.assert_numpy_array_equal(result, expected)

    def test_strftime_nat(self):
        # GH 29578
        arr = PeriodArray(PeriodIndex(["2019-01-01", pd.NaT], dtype="period[D]"))

        result = arr.strftime("%Y-%m-%d")
        expected = np.array(["2019-01-01", np.nan], dtype=object)
        tm.assert_numpy_array_equal(result, expected)


@pytest.mark.parametrize(
    "array,casting_nats",
    [
        (
            pd.TimedeltaIndex(["1 Day", "3 Hours", "NaT"])._data,
            (pd.NaT, np.timedelta64("NaT", "ns")),
        ),
        (
            pd.date_range("2000-01-01", periods=3, freq="D")._data,
            (pd.NaT, np.datetime64("NaT", "ns")),
        ),
        (pd.period_range("2000-01-01", periods=3, freq="D")._data, (pd.NaT,)),
    ],
    ids=lambda x: type(x).__name__,
)
def test_casting_nat_setitem_array(array, casting_nats):
    expected = type(array)._from_sequence([pd.NaT, array[1], array[2]])

    for nat in casting_nats:
        arr = array.copy()
        arr[0] = nat
        tm.assert_equal(arr, expected)


@pytest.mark.parametrize(
    "array,non_casting_nats",
    [
        (
            pd.TimedeltaIndex(["1 Day", "3 Hours", "NaT"])._data,
            (np.datetime64("NaT", "ns"), pd.NaT.value),
        ),
        (
            pd.date_range("2000-01-01", periods=3, freq="D")._data,
            (np.timedelta64("NaT", "ns"), pd.NaT.value),
        ),
        (
            pd.period_range("2000-01-01", periods=3, freq="D")._data,
            (np.datetime64("NaT", "ns"), np.timedelta64("NaT", "ns"), pd.NaT.value),
        ),
    ],
    ids=lambda x: type(x).__name__,
)
def test_invalid_nat_setitem_array(array, non_casting_nats):
    for nat in non_casting_nats:
        with pytest.raises(TypeError):
            array[0] = nat


@pytest.mark.parametrize(
    "array",
    [
        pd.date_range("2000", periods=4).array,
        pd.timedelta_range("2000", periods=4).array,
    ],
)
def test_to_numpy_extra(array):
    if _np_version_under1p18:
        # np.isnan(NaT) raises, so use pandas'
        isnan = pd.isna
    else:
        isnan = np.isnan

    array[0] = pd.NaT
    original = array.copy()

    result = array.to_numpy()
    assert isnan(result[0])

    result = array.to_numpy(dtype="int64")
    assert result[0] == -9223372036854775808

    result = array.to_numpy(dtype="int64", na_value=0)
    assert result[0] == 0

    result = array.to_numpy(na_value=array[1].to_numpy())
    assert result[0] == result[1]

    result = array.to_numpy(na_value=array[1].to_numpy(copy=False))
    assert result[0] == result[1]

    tm.assert_equal(array, original)