import numpy as np
import pytest

from pandas.core.dtypes.dtypes import DatetimeTZDtype

import pandas as pd
from pandas.core.arrays import DatetimeArray
from pandas.tests.extension import base


@pytest.fixture(params=["US/Central"])
def dtype(request):
    return DatetimeTZDtype(unit="ns", tz=request.param)


@pytest.fixture
def data(dtype):
    data = DatetimeArray(pd.date_range("2000", periods=100, tz=dtype.tz), dtype=dtype)
    return data


@pytest.fixture
def data_missing(dtype):
    return DatetimeArray(
        np.array(["NaT", "2000-01-01"], dtype="datetime64[ns]"), dtype=dtype
    )


@pytest.fixture
def data_for_sorting(dtype):
    a = pd.Timestamp("2000-01-01")
    b = pd.Timestamp("2000-01-02")
    c = pd.Timestamp("2000-01-03")
    return DatetimeArray(np.array([b, c, a], dtype="datetime64[ns]"), dtype=dtype)


@pytest.fixture
def data_missing_for_sorting(dtype):
    a = pd.Timestamp("2000-01-01")
    b = pd.Timestamp("2000-01-02")
    return DatetimeArray(np.array([b, "NaT", a], dtype="datetime64[ns]"), dtype=dtype)


@pytest.fixture
def data_for_grouping(dtype):
    """
    Expected to be like [B, B, NA, NA, A, A, B, C]

    Where A < B < C and NA is missing
    """
    a = pd.Timestamp("2000-01-01")
    b = pd.Timestamp("2000-01-02")
    c = pd.Timestamp("2000-01-03")
    na = "NaT"
    return DatetimeArray(
        np.array([b, b, na, na, a, a, b, c], dtype="datetime64[ns]"), dtype=dtype
    )


@pytest.fixture
def na_cmp():
    def cmp(a, b):
        return a is pd.NaT and a is b

    return cmp


@pytest.fixture
def na_value():
    return pd.NaT


# ----------------------------------------------------------------------------
class BaseDatetimeTests:
    pass


# ----------------------------------------------------------------------------
# Tests
class TestDatetimeDtype(BaseDatetimeTests, base.BaseDtypeTests):
    pass


class TestConstructors(BaseDatetimeTests, base.BaseConstructorsTests):
    pass


class TestGetitem(BaseDatetimeTests, base.BaseGetitemTests):
    pass


class TestMethods(BaseDatetimeTests, base.BaseMethodsTests):
    @pytest.mark.skip(reason="Incorrect expected")
    def test_value_counts(self, all_data, dropna):
        pass

    def test_combine_add(self, data_repeated):
        # Timestamp.__add__(Timestamp) not defined
        pass


class TestInterface(BaseDatetimeTests, base.BaseInterfaceTests):
    def test_array_interface(self, data):
        if data.tz:
            # np.asarray(DTA) is currently always tz-naive.
            pytest.skip("GH-23569")
        else:
            super().test_array_interface(data)


class TestArithmeticOps(BaseDatetimeTests, base.BaseArithmeticOpsTests):
    implements = {"__sub__", "__rsub__"}

    def test_arith_frame_with_scalar(self, data, all_arithmetic_operators):
        # frame & scalar
        if all_arithmetic_operators in self.implements:
            df = pd.DataFrame({"A": data})
            self.check_opname(df, all_arithmetic_operators, data[0], exc=None)
        else:
            # ... but not the rest.
            super().test_arith_frame_with_scalar(data, all_arithmetic_operators)

    def test_arith_series_with_scalar(self, data, all_arithmetic_operators):
        if all_arithmetic_operators in self.implements:
            s = pd.Series(data)
            self.check_opname(s, all_arithmetic_operators, s.iloc[0], exc=None)
        else:
            # ... but not the rest.
            super().test_arith_series_with_scalar(data, all_arithmetic_operators)

    def test_add_series_with_extension_array(self, data):
        # Datetime + Datetime not implemented
        s = pd.Series(data)
        msg = "cannot add DatetimeArray and DatetimeArray"
        with pytest.raises(TypeError, match=msg):
            s + data

    def test_arith_series_with_array(self, data, all_arithmetic_operators):
        if all_arithmetic_operators in self.implements:
            s = pd.Series(data)
            self.check_opname(s, all_arithmetic_operators, s.iloc[0], exc=None)
        else:
            # ... but not the rest.
            super().test_arith_series_with_scalar(data, all_arithmetic_operators)

    def test_error(self, data, all_arithmetic_operators):
        pass

    def test_divmod_series_array(self):
        # GH 23287
        # skipping because it is not implemented
        pass


class TestCasting(BaseDatetimeTests, base.BaseCastingTests):
    pass


class TestComparisonOps(BaseDatetimeTests, base.BaseComparisonOpsTests):
    def _compare_other(self, s, data, op_name, other):
        # the base test is not appropriate for us. We raise on comparison
        # with (some) integers, depending on the value.
        pass


class TestMissing(BaseDatetimeTests, base.BaseMissingTests):
    pass


class TestReshaping(BaseDatetimeTests, base.BaseReshapingTests):
    @pytest.mark.skip(reason="We have DatetimeTZBlock")
    def test_concat(self, data, in_frame):
        pass

    def test_concat_mixed_dtypes(self, data):
        # concat(Series[datetimetz], Series[category]) uses a
        # plain np.array(values) on the DatetimeArray, which
        # drops the tz.
        super().test_concat_mixed_dtypes(data)

    @pytest.mark.parametrize("obj", ["series", "frame"])
    def test_unstack(self, obj):
        # GH-13287: can't use base test, since building the expected fails.
        dtype = DatetimeTZDtype(tz="US/Central")
        data = DatetimeArray._from_sequence(
            ["2000", "2001", "2002", "2003"],
            dtype=dtype,
        )
        index = pd.MultiIndex.from_product(([["A", "B"], ["a", "b"]]), names=["a", "b"])

        if obj == "series":
            ser = pd.Series(data, index=index)
            expected = pd.DataFrame(
                {"A": data.take([0, 1]), "B": data.take([2, 3])},
                index=pd.Index(["a", "b"], name="b"),
            )
            expected.columns.name = "a"

        else:
            ser = pd.DataFrame({"A": data, "B": data}, index=index)
            expected = pd.DataFrame(
                {
                    ("A", "A"): data.take([0, 1]),
                    ("A", "B"): data.take([2, 3]),
                    ("B", "A"): data.take([0, 1]),
                    ("B", "B"): data.take([2, 3]),
                },
                index=pd.Index(["a", "b"], name="b"),
            )
            expected.columns.names = [None, "a"]

        result = ser.unstack(0)
        self.assert_equal(result, expected)


class TestSetitem(BaseDatetimeTests, base.BaseSetitemTests):
    pass


class TestGroupby(BaseDatetimeTests, base.BaseGroupbyTests):
    pass


class TestPrinting(BaseDatetimeTests, base.BasePrintingTests):
    pass