from __future__ import annotations

from typing import Any

import numpy as np
import pandas as pd
import pytest
from packaging.version import Version

import xarray as xr
from xarray import DataArray, Dataset, set_options
from xarray.tests import (
    assert_allclose,
    assert_array_equal,
    assert_equal,
    assert_identical,
    has_dask,
    requires_dask,
    requires_numbagg,
)

pytestmark = [
    pytest.mark.filterwarnings("error:Mean of empty slice"),
    pytest.mark.filterwarnings("error:All-NaN (slice|axis) encountered"),
]


class TestDataArrayRolling:
    @pytest.mark.parametrize("da", (1, 2), indirect=True)
    @pytest.mark.parametrize("center", [True, False])
    @pytest.mark.parametrize("size", [1, 2, 3, 7])
    def test_rolling_iter(self, da: DataArray, center: bool, size: int) -> None:
        rolling_obj = da.rolling(time=size, center=center)
        rolling_obj_mean = rolling_obj.mean()

        assert len(rolling_obj.window_labels) == len(da["time"])
        assert_identical(rolling_obj.window_labels, da["time"])

        for i, (label, window_da) in enumerate(rolling_obj):
            assert label == da["time"].isel(time=i)

            actual = rolling_obj_mean.isel(time=i)
            expected = window_da.mean("time")

            np.testing.assert_allclose(actual.values, expected.values)

    @pytest.mark.parametrize("da", (1,), indirect=True)
    def test_rolling_repr(self, da) -> None:
        rolling_obj = da.rolling(time=7)
        assert repr(rolling_obj) == "DataArrayRolling [time->7]"
        rolling_obj = da.rolling(time=7, center=True)
        assert repr(rolling_obj) == "DataArrayRolling [time->7(center)]"
        rolling_obj = da.rolling(time=7, x=3, center=True)
        assert repr(rolling_obj) == "DataArrayRolling [time->7(center),x->3(center)]"

    @requires_dask
    def test_repeated_rolling_rechunks(self) -> None:
        # regression test for GH3277, GH2514
        dat = DataArray(np.random.rand(7653, 300), dims=("day", "item"))
        dat_chunk = dat.chunk({"item": 20})
        dat_chunk.rolling(day=10).mean().rolling(day=250).std()

    def test_rolling_doc(self, da) -> None:
        rolling_obj = da.rolling(time=7)

        # argument substitution worked
        assert "`mean`" in rolling_obj.mean.__doc__

    def test_rolling_properties(self, da) -> None:
        rolling_obj = da.rolling(time=4)

        assert rolling_obj.obj.get_axis_num("time") == 1

        # catching invalid args
        with pytest.raises(ValueError, match="window must be > 0"):
            da.rolling(time=-2)

        with pytest.raises(ValueError, match="min_periods must be greater than zero"):
            da.rolling(time=2, min_periods=0)

    @pytest.mark.parametrize("name", ("sum", "mean", "std", "min", "max", "median"))
    @pytest.mark.parametrize("center", (True, False, None))
    @pytest.mark.parametrize("min_periods", (1, None))
    @pytest.mark.parametrize("backend", ["numpy"], indirect=True)
    def test_rolling_wrapped_bottleneck(self, da, name, center, min_periods) -> None:
        bn = pytest.importorskip("bottleneck", minversion="1.1")

        # Test all bottleneck functions
        rolling_obj = da.rolling(time=7, min_periods=min_periods)

        func_name = f"move_{name}"
        actual = getattr(rolling_obj, name)()
        expected = getattr(bn, func_name)(
            da.values, window=7, axis=1, min_count=min_periods
        )
        assert_array_equal(actual.values, expected)

        with pytest.warns(DeprecationWarning, match="Reductions are applied"):
            getattr(rolling_obj, name)(dim="time")

        # Test center
        rolling_obj = da.rolling(time=7, center=center)
        actual = getattr(rolling_obj, name)()["time"]
        assert_equal(actual, da["time"])

    @requires_dask
    @pytest.mark.parametrize("name", ("mean", "count"))
    @pytest.mark.parametrize("center", (True, False, None))
    @pytest.mark.parametrize("min_periods", (1, None))
    @pytest.mark.parametrize("window", (7, 8))
    @pytest.mark.parametrize("backend", ["dask"], indirect=True)
    def test_rolling_wrapped_dask(self, da, name, center, min_periods, window) -> None:
        # dask version
        rolling_obj = da.rolling(time=window, min_periods=min_periods, center=center)
        actual = getattr(rolling_obj, name)().load()
        if name != "count":
            with pytest.warns(DeprecationWarning, match="Reductions are applied"):
                getattr(rolling_obj, name)(dim="time")
        # numpy version
        rolling_obj = da.load().rolling(
            time=window, min_periods=min_periods, center=center
        )
        expected = getattr(rolling_obj, name)()

        # using all-close because rolling over ghost cells introduces some
        # precision errors
        assert_allclose(actual, expected)

        # with zero chunked array GH:2113
        rolling_obj = da.chunk().rolling(
            time=window, min_periods=min_periods, center=center
        )
        actual = getattr(rolling_obj, name)().load()
        assert_allclose(actual, expected)

    @pytest.mark.parametrize("center", (True, None))
    def test_rolling_wrapped_dask_nochunk(self, center) -> None:
        # GH:2113
        pytest.importorskip("dask.array")

        da_day_clim = xr.DataArray(
            np.arange(1, 367), coords=[np.arange(1, 367)], dims="dayofyear"
        )
        expected = da_day_clim.rolling(dayofyear=31, center=center).mean()
        actual = da_day_clim.chunk().rolling(dayofyear=31, center=center).mean()
        assert_allclose(actual, expected)

    @pytest.mark.parametrize("center", (True, False))
    @pytest.mark.parametrize("min_periods", (None, 1, 2, 3))
    @pytest.mark.parametrize("window", (1, 2, 3, 4))
    def test_rolling_pandas_compat(self, center, window, min_periods) -> None:
        s = pd.Series(np.arange(10))
        da = DataArray.from_series(s)

        if min_periods is not None and window < min_periods:
            min_periods = window

        s_rolling = s.rolling(window, center=center, min_periods=min_periods).mean()
        da_rolling = da.rolling(
            index=window, center=center, min_periods=min_periods
        ).mean()
        da_rolling_np = da.rolling(
            index=window, center=center, min_periods=min_periods
        ).reduce(np.nanmean)

        np.testing.assert_allclose(s_rolling.values, da_rolling.values)
        np.testing.assert_allclose(s_rolling.index, da_rolling["index"])
        np.testing.assert_allclose(s_rolling.values, da_rolling_np.values)
        np.testing.assert_allclose(s_rolling.index, da_rolling_np["index"])

    @pytest.mark.parametrize("center", (True, False))
    @pytest.mark.parametrize("window", (1, 2, 3, 4))
    def test_rolling_construct(self, center, window) -> None:
        s = pd.Series(np.arange(10))
        da = DataArray.from_series(s)

        s_rolling = s.rolling(window, center=center, min_periods=1).mean()
        da_rolling = da.rolling(index=window, center=center, min_periods=1)

        da_rolling_mean = da_rolling.construct("window").mean("window")
        np.testing.assert_allclose(s_rolling.values, da_rolling_mean.values)
        np.testing.assert_allclose(s_rolling.index, da_rolling_mean["index"])

        # with stride
        da_rolling_mean = da_rolling.construct("window", stride=2).mean("window")
        np.testing.assert_allclose(s_rolling.values[::2], da_rolling_mean.values)
        np.testing.assert_allclose(s_rolling.index[::2], da_rolling_mean["index"])

        # with fill_value
        da_rolling_mean = da_rolling.construct("window", stride=2, fill_value=0.0).mean(
            "window"
        )
        assert da_rolling_mean.isnull().sum() == 0
        assert (da_rolling_mean == 0.0).sum() >= 0

    @pytest.mark.parametrize("da", (1, 2), indirect=True)
    @pytest.mark.parametrize("center", (True, False))
    @pytest.mark.parametrize("min_periods", (None, 1, 2, 3))
    @pytest.mark.parametrize("window", (1, 2, 3, 4))
    @pytest.mark.parametrize("name", ("sum", "mean", "std", "max"))
    def test_rolling_reduce(self, da, center, min_periods, window, name) -> None:
        if min_periods is not None and window < min_periods:
            min_periods = window

        if da.isnull().sum() > 1 and window == 1:
            # this causes all nan slices
            window = 2

        rolling_obj = da.rolling(time=window, center=center, min_periods=min_periods)

        # add nan prefix to numpy methods to get similar # behavior as bottleneck
        actual = rolling_obj.reduce(getattr(np, "nan%s" % name))
        expected = getattr(rolling_obj, name)()
        assert_allclose(actual, expected)
        assert actual.dims == expected.dims

    @pytest.mark.parametrize("center", (True, False))
    @pytest.mark.parametrize("min_periods", (None, 1, 2, 3))
    @pytest.mark.parametrize("window", (1, 2, 3, 4))
    @pytest.mark.parametrize("name", ("sum", "max"))
    def test_rolling_reduce_nonnumeric(self, center, min_periods, window, name) -> None:
        da = DataArray(
            [0, np.nan, 1, 2, np.nan, 3, 4, 5, np.nan, 6, 7], dims="time"
        ).isnull()

        if min_periods is not None and window < min_periods:
            min_periods = window

        rolling_obj = da.rolling(time=window, center=center, min_periods=min_periods)

        # add nan prefix to numpy methods to get similar behavior as bottleneck
        actual = rolling_obj.reduce(getattr(np, "nan%s" % name))
        expected = getattr(rolling_obj, name)()
        assert_allclose(actual, expected)
        assert actual.dims == expected.dims

    def test_rolling_count_correct(self) -> None:
        da = DataArray([0, np.nan, 1, 2, np.nan, 3, 4, 5, np.nan, 6, 7], dims="time")

        kwargs: list[dict[str, Any]] = [
            {"time": 11, "min_periods": 1},
            {"time": 11, "min_periods": None},
            {"time": 7, "min_periods": 2},
        ]
        expecteds = [
            DataArray([1, 1, 2, 3, 3, 4, 5, 6, 6, 7, 8], dims="time"),
            DataArray(
                [
                    np.nan,
                    np.nan,
                    np.nan,
                    np.nan,
                    np.nan,
                    np.nan,
                    np.nan,
                    np.nan,
                    np.nan,
                    np.nan,
                    np.nan,
                ],
                dims="time",
            ),
            DataArray([np.nan, np.nan, 2, 3, 3, 4, 5, 5, 5, 5, 5], dims="time"),
        ]

        for kwarg, expected in zip(kwargs, expecteds):
            result = da.rolling(**kwarg).count()
            assert_equal(result, expected)

            result = da.to_dataset(name="var1").rolling(**kwarg).count()["var1"]
            assert_equal(result, expected)

    @pytest.mark.parametrize("da", (1,), indirect=True)
    @pytest.mark.parametrize("center", (True, False))
    @pytest.mark.parametrize("min_periods", (None, 1))
    @pytest.mark.parametrize("name", ("sum", "mean", "max"))
    def test_ndrolling_reduce(self, da, center, min_periods, name) -> None:
        rolling_obj = da.rolling(time=3, x=2, center=center, min_periods=min_periods)

        actual = getattr(rolling_obj, name)()
        expected = getattr(
            getattr(
                da.rolling(time=3, center=center, min_periods=min_periods), name
            )().rolling(x=2, center=center, min_periods=min_periods),
            name,
        )()

        assert_allclose(actual, expected)
        assert actual.dims == expected.dims

        if name in ["mean"]:
            # test our reimplementation of nanmean using np.nanmean
            expected = getattr(rolling_obj.construct({"time": "tw", "x": "xw"}), name)(
                ["tw", "xw"]
            )
            count = rolling_obj.count()
            if min_periods is None:
                min_periods = 1
            assert_allclose(actual, expected.where(count >= min_periods))

    @pytest.mark.parametrize("center", (True, False, (True, False)))
    @pytest.mark.parametrize("fill_value", (np.nan, 0.0))
    def test_ndrolling_construct(self, center, fill_value) -> None:
        da = DataArray(
            np.arange(5 * 6 * 7).reshape(5, 6, 7).astype(float),
            dims=["x", "y", "z"],
            coords={"x": ["a", "b", "c", "d", "e"], "y": np.arange(6)},
        )
        actual = da.rolling(x=3, z=2, center=center).construct(
            x="x1", z="z1", fill_value=fill_value
        )
        if not isinstance(center, tuple):
            center = (center, center)
        expected = (
            da.rolling(x=3, center=center[0])
            .construct(x="x1", fill_value=fill_value)
            .rolling(z=2, center=center[1])
            .construct(z="z1", fill_value=fill_value)
        )
        assert_allclose(actual, expected)

    @pytest.mark.parametrize(
        "funcname, argument",
        [
            ("reduce", (np.mean,)),
            ("mean", ()),
            ("construct", ("window_dim",)),
            ("count", ()),
        ],
    )
    def test_rolling_keep_attrs(self, funcname, argument) -> None:
        attrs_da = {"da_attr": "test"}

        data = np.linspace(10, 15, 100)
        coords = np.linspace(1, 10, 100)

        da = DataArray(
            data, dims=("coord"), coords={"coord": coords}, attrs=attrs_da, name="name"
        )

        # attrs are now kept per default
        func = getattr(da.rolling(dim={"coord": 5}), funcname)
        result = func(*argument)
        assert result.attrs == attrs_da
        assert result.name == "name"

        # discard attrs
        func = getattr(da.rolling(dim={"coord": 5}), funcname)
        result = func(*argument, keep_attrs=False)
        assert result.attrs == {}
        assert result.name == "name"

        # test discard attrs using global option
        func = getattr(da.rolling(dim={"coord": 5}), funcname)
        with set_options(keep_attrs=False):
            result = func(*argument)
        assert result.attrs == {}
        assert result.name == "name"

        # keyword takes precedence over global option
        func = getattr(da.rolling(dim={"coord": 5}), funcname)
        with set_options(keep_attrs=False):
            result = func(*argument, keep_attrs=True)
        assert result.attrs == attrs_da
        assert result.name == "name"

        func = getattr(da.rolling(dim={"coord": 5}), funcname)
        with set_options(keep_attrs=True):
            result = func(*argument, keep_attrs=False)
        assert result.attrs == {}
        assert result.name == "name"

    @requires_dask
    @pytest.mark.parametrize("dtype", ["int", "float32", "float64"])
    def test_rolling_dask_dtype(self, dtype) -> None:
        data = DataArray(
            np.array([1, 2, 3], dtype=dtype), dims="x", coords={"x": [1, 2, 3]}
        )
        unchunked_result = data.rolling(x=3, min_periods=1).mean()
        chunked_result = data.chunk({"x": 1}).rolling(x=3, min_periods=1).mean()
        assert chunked_result.dtype == unchunked_result.dtype


@requires_numbagg
class TestDataArrayRollingExp:
    @pytest.mark.parametrize("dim", ["time", "x"])
    @pytest.mark.parametrize(
        "window_type, window",
        [["span", 5], ["alpha", 0.5], ["com", 0.5], ["halflife", 5]],
    )
    @pytest.mark.parametrize("backend", ["numpy"], indirect=True)
    @pytest.mark.parametrize("func", ["mean", "sum"])
    def test_rolling_exp_runs(self, da, dim, window_type, window, func) -> None:
        import numbagg

        if (
            Version(getattr(numbagg, "__version__", "0.1.0")) < Version("0.2.1")
            and func == "sum"
        ):
            pytest.skip("rolling_exp.sum requires numbagg 0.2.1")

        da = da.where(da > 0.2)

        rolling_exp = da.rolling_exp(window_type=window_type, **{dim: window})
        result = getattr(rolling_exp, func)()
        assert isinstance(result, DataArray)

    @pytest.mark.parametrize("dim", ["time", "x"])
    @pytest.mark.parametrize(
        "window_type, window",
        [["span", 5], ["alpha", 0.5], ["com", 0.5], ["halflife", 5]],
    )
    @pytest.mark.parametrize("backend", ["numpy"], indirect=True)
    def test_rolling_exp_mean_pandas(self, da, dim, window_type, window) -> None:
        da = da.isel(a=0).where(lambda x: x > 0.2)

        result = da.rolling_exp(window_type=window_type, **{dim: window}).mean()
        assert isinstance(result, DataArray)

        pandas_array = da.to_pandas()
        assert pandas_array.index.name == "time"
        if dim == "x":
            pandas_array = pandas_array.T
        expected = xr.DataArray(
            pandas_array.ewm(**{window_type: window}).mean()
        ).transpose(*da.dims)

        assert_allclose(expected.variable, result.variable)

    @pytest.mark.parametrize("backend", ["numpy"], indirect=True)
    @pytest.mark.parametrize("func", ["mean", "sum"])
    def test_rolling_exp_keep_attrs(self, da, func) -> None:
        import numbagg

        if (
            Version(getattr(numbagg, "__version__", "0.1.0")) < Version("0.2.1")
            and func == "sum"
        ):
            pytest.skip("rolling_exp.sum requires numbagg 0.2.1")

        attrs = {"attrs": "da"}
        da.attrs = attrs

        # Equivalent of `da.rolling_exp(time=10).mean`
        rolling_exp_func = getattr(da.rolling_exp(time=10), func)

        # attrs are kept per default
        result = rolling_exp_func()
        assert result.attrs == attrs

        # discard attrs
        result = rolling_exp_func(keep_attrs=False)
        assert result.attrs == {}

        # test discard attrs using global option
        with set_options(keep_attrs=False):
            result = rolling_exp_func()
        assert result.attrs == {}

        # keyword takes precedence over global option
        with set_options(keep_attrs=False):
            result = rolling_exp_func(keep_attrs=True)
        assert result.attrs == attrs

        with set_options(keep_attrs=True):
            result = rolling_exp_func(keep_attrs=False)
        assert result.attrs == {}

        with pytest.warns(
            UserWarning,
            match="Passing ``keep_attrs`` to ``rolling_exp`` has no effect.",
        ):
            da.rolling_exp(time=10, keep_attrs=True)


class TestDatasetRolling:
    @pytest.mark.parametrize(
        "funcname, argument",
        [
            ("reduce", (np.mean,)),
            ("mean", ()),
            ("construct", ("window_dim",)),
            ("count", ()),
        ],
    )
    def test_rolling_keep_attrs(self, funcname, argument) -> None:
        global_attrs = {"units": "test", "long_name": "testing"}
        da_attrs = {"da_attr": "test"}
        da_not_rolled_attrs = {"da_not_rolled_attr": "test"}

        data = np.linspace(10, 15, 100)
        coords = np.linspace(1, 10, 100)

        ds = Dataset(
            data_vars={"da": ("coord", data), "da_not_rolled": ("no_coord", data)},
            coords={"coord": coords},
            attrs=global_attrs,
        )
        ds.da.attrs = da_attrs
        ds.da_not_rolled.attrs = da_not_rolled_attrs

        # attrs are now kept per default
        func = getattr(ds.rolling(dim={"coord": 5}), funcname)
        result = func(*argument)
        assert result.attrs == global_attrs
        assert result.da.attrs == da_attrs
        assert result.da_not_rolled.attrs == da_not_rolled_attrs
        assert result.da.name == "da"
        assert result.da_not_rolled.name == "da_not_rolled"

        # discard attrs
        func = getattr(ds.rolling(dim={"coord": 5}), funcname)
        result = func(*argument, keep_attrs=False)
        assert result.attrs == {}
        assert result.da.attrs == {}
        assert result.da_not_rolled.attrs == {}
        assert result.da.name == "da"
        assert result.da_not_rolled.name == "da_not_rolled"

        # test discard attrs using global option
        func = getattr(ds.rolling(dim={"coord": 5}), funcname)
        with set_options(keep_attrs=False):
            result = func(*argument)

        assert result.attrs == {}
        assert result.da.attrs == {}
        assert result.da_not_rolled.attrs == {}
        assert result.da.name == "da"
        assert result.da_not_rolled.name == "da_not_rolled"

        # keyword takes precedence over global option
        func = getattr(ds.rolling(dim={"coord": 5}), funcname)
        with set_options(keep_attrs=False):
            result = func(*argument, keep_attrs=True)

        assert result.attrs == global_attrs
        assert result.da.attrs == da_attrs
        assert result.da_not_rolled.attrs == da_not_rolled_attrs
        assert result.da.name == "da"
        assert result.da_not_rolled.name == "da_not_rolled"

        func = getattr(ds.rolling(dim={"coord": 5}), funcname)
        with set_options(keep_attrs=True):
            result = func(*argument, keep_attrs=False)

        assert result.attrs == {}
        assert result.da.attrs == {}
        assert result.da_not_rolled.attrs == {}
        assert result.da.name == "da"
        assert result.da_not_rolled.name == "da_not_rolled"

    def test_rolling_properties(self, ds) -> None:
        # catching invalid args
        with pytest.raises(ValueError, match="window must be > 0"):
            ds.rolling(time=-2)
        with pytest.raises(ValueError, match="min_periods must be greater than zero"):
            ds.rolling(time=2, min_periods=0)
        with pytest.raises(KeyError, match="time2"):
            ds.rolling(time2=2)

    @pytest.mark.parametrize(
        "name", ("sum", "mean", "std", "var", "min", "max", "median")
    )
    @pytest.mark.parametrize("center", (True, False, None))
    @pytest.mark.parametrize("min_periods", (1, None))
    @pytest.mark.parametrize("key", ("z1", "z2"))
    @pytest.mark.parametrize("backend", ["numpy"], indirect=True)
    def test_rolling_wrapped_bottleneck(
        self, ds, name, center, min_periods, key
    ) -> None:
        bn = pytest.importorskip("bottleneck", minversion="1.1")

        # Test all bottleneck functions
        rolling_obj = ds.rolling(time=7, min_periods=min_periods)

        func_name = f"move_{name}"
        actual = getattr(rolling_obj, name)()
        if key == "z1":  # z1 does not depend on 'Time' axis. Stored as it is.
            expected = ds[key]
        elif key == "z2":
            expected = getattr(bn, func_name)(
                ds[key].values, window=7, axis=0, min_count=min_periods
            )
        else:
            raise ValueError
        assert_array_equal(actual[key].values, expected)

        # Test center
        rolling_obj = ds.rolling(time=7, center=center)
        actual = getattr(rolling_obj, name)()["time"]
        assert_equal(actual, ds["time"])

    @pytest.mark.parametrize("center", (True, False))
    @pytest.mark.parametrize("min_periods", (None, 1, 2, 3))
    @pytest.mark.parametrize("window", (1, 2, 3, 4))
    def test_rolling_pandas_compat(self, center, window, min_periods) -> None:
        df = pd.DataFrame(
            {
                "x": np.random.randn(20),
                "y": np.random.randn(20),
                "time": np.linspace(0, 1, 20),
            }
        )
        ds = Dataset.from_dataframe(df)

        if min_periods is not None and window < min_periods:
            min_periods = window

        df_rolling = df.rolling(window, center=center, min_periods=min_periods).mean()
        ds_rolling = ds.rolling(
            index=window, center=center, min_periods=min_periods
        ).mean()

        np.testing.assert_allclose(df_rolling["x"].values, ds_rolling["x"].values)
        np.testing.assert_allclose(df_rolling.index, ds_rolling["index"])

    @pytest.mark.parametrize("center", (True, False))
    @pytest.mark.parametrize("window", (1, 2, 3, 4))
    def test_rolling_construct(self, center, window) -> None:
        df = pd.DataFrame(
            {
                "x": np.random.randn(20),
                "y": np.random.randn(20),
                "time": np.linspace(0, 1, 20),
            }
        )

        ds = Dataset.from_dataframe(df)
        df_rolling = df.rolling(window, center=center, min_periods=1).mean()
        ds_rolling = ds.rolling(index=window, center=center)

        ds_rolling_mean = ds_rolling.construct("window").mean("window")
        np.testing.assert_allclose(df_rolling["x"].values, ds_rolling_mean["x"].values)
        np.testing.assert_allclose(df_rolling.index, ds_rolling_mean["index"])

        # with stride
        ds_rolling_mean = ds_rolling.construct("window", stride=2).mean("window")
        np.testing.assert_allclose(
            df_rolling["x"][::2].values, ds_rolling_mean["x"].values
        )
        np.testing.assert_allclose(df_rolling.index[::2], ds_rolling_mean["index"])
        # with fill_value
        ds_rolling_mean = ds_rolling.construct("window", stride=2, fill_value=0.0).mean(
            "window"
        )
        assert (ds_rolling_mean.isnull().sum() == 0).to_array(dim="vars").all()
        assert (ds_rolling_mean["x"] == 0.0).sum() >= 0

    @pytest.mark.slow
    @pytest.mark.parametrize("ds", (1, 2), indirect=True)
    @pytest.mark.parametrize("center", (True, False))
    @pytest.mark.parametrize("min_periods", (None, 1, 2, 3))
    @pytest.mark.parametrize("window", (1, 2, 3, 4))
    @pytest.mark.parametrize(
        "name", ("sum", "mean", "std", "var", "min", "max", "median")
    )
    def test_rolling_reduce(self, ds, center, min_periods, window, name) -> None:
        if min_periods is not None and window < min_periods:
            min_periods = window

        if name == "std" and window == 1:
            pytest.skip("std with window == 1 is unstable in bottleneck")

        rolling_obj = ds.rolling(time=window, center=center, min_periods=min_periods)

        # add nan prefix to numpy methods to get similar behavior as bottleneck
        actual = rolling_obj.reduce(getattr(np, "nan%s" % name))
        expected = getattr(rolling_obj, name)()
        assert_allclose(actual, expected)
        assert ds.dims == actual.dims
        # make sure the order of data_var are not changed.
        assert list(ds.data_vars.keys()) == list(actual.data_vars.keys())

        # Make sure the dimension order is restored
        for key, src_var in ds.data_vars.items():
            assert src_var.dims == actual[key].dims

    @pytest.mark.parametrize("ds", (2,), indirect=True)
    @pytest.mark.parametrize("center", (True, False))
    @pytest.mark.parametrize("min_periods", (None, 1))
    @pytest.mark.parametrize("name", ("sum", "max"))
    @pytest.mark.parametrize("dask", (True, False))
    def test_ndrolling_reduce(self, ds, center, min_periods, name, dask) -> None:
        if dask and has_dask:
            ds = ds.chunk({"x": 4})

        rolling_obj = ds.rolling(time=4, x=3, center=center, min_periods=min_periods)

        actual = getattr(rolling_obj, name)()
        expected = getattr(
            getattr(
                ds.rolling(time=4, center=center, min_periods=min_periods), name
            )().rolling(x=3, center=center, min_periods=min_periods),
            name,
        )()
        assert_allclose(actual, expected)
        assert actual.dims == expected.dims

        # Do it in the opposite order
        expected = getattr(
            getattr(
                ds.rolling(x=3, center=center, min_periods=min_periods), name
            )().rolling(time=4, center=center, min_periods=min_periods),
            name,
        )()

        assert_allclose(actual, expected)
        assert actual.dims == expected.dims

    @pytest.mark.parametrize("center", (True, False, (True, False)))
    @pytest.mark.parametrize("fill_value", (np.nan, 0.0))
    @pytest.mark.parametrize("dask", (True, False))
    def test_ndrolling_construct(self, center, fill_value, dask) -> None:
        da = DataArray(
            np.arange(5 * 6 * 7).reshape(5, 6, 7).astype(float),
            dims=["x", "y", "z"],
            coords={"x": ["a", "b", "c", "d", "e"], "y": np.arange(6)},
        )
        ds = xr.Dataset({"da": da})
        if dask and has_dask:
            ds = ds.chunk({"x": 4})

        actual = ds.rolling(x=3, z=2, center=center).construct(
            x="x1", z="z1", fill_value=fill_value
        )
        if not isinstance(center, tuple):
            center = (center, center)
        expected = (
            ds.rolling(x=3, center=center[0])
            .construct(x="x1", fill_value=fill_value)
            .rolling(z=2, center=center[1])
            .construct(z="z1", fill_value=fill_value)
        )
        assert_allclose(actual, expected)

    @pytest.mark.xfail(
        reason="See https://github.com/pydata/xarray/pull/4369 or docstring"
    )
    @pytest.mark.filterwarnings("error")
    @pytest.mark.parametrize("ds", (2,), indirect=True)
    @pytest.mark.parametrize("name", ("mean", "max"))
    def test_raise_no_warning_dask_rolling_assert_close(self, ds, name) -> None:
        """
        This is a puzzle — I can't easily find the source of the warning. It
        requires `assert_allclose` to be run, for the `ds` param to be 2, and is
        different for `mean` and `max`. `sum` raises no warning.
        """

        ds = ds.chunk({"x": 4})

        rolling_obj = ds.rolling(time=4, x=3)

        actual = getattr(rolling_obj, name)()
        expected = getattr(getattr(ds.rolling(time=4), name)().rolling(x=3), name)()
        assert_allclose(actual, expected)


@requires_numbagg
class TestDatasetRollingExp:
    @pytest.mark.parametrize("backend", ["numpy"], indirect=True)
    def test_rolling_exp(self, ds) -> None:
        result = ds.rolling_exp(time=10, window_type="span").mean()
        assert isinstance(result, Dataset)

    @pytest.mark.parametrize("backend", ["numpy"], indirect=True)
    def test_rolling_exp_keep_attrs(self, ds) -> None:
        attrs_global = {"attrs": "global"}
        attrs_z1 = {"attr": "z1"}

        ds.attrs = attrs_global
        ds.z1.attrs = attrs_z1

        # attrs are kept per default
        result = ds.rolling_exp(time=10).mean()
        assert result.attrs == attrs_global
        assert result.z1.attrs == attrs_z1

        # discard attrs
        result = ds.rolling_exp(time=10).mean(keep_attrs=False)
        assert result.attrs == {}
        assert result.z1.attrs == {}

        # test discard attrs using global option
        with set_options(keep_attrs=False):
            result = ds.rolling_exp(time=10).mean()
        assert result.attrs == {}
        assert result.z1.attrs == {}

        # keyword takes precedence over global option
        with set_options(keep_attrs=False):
            result = ds.rolling_exp(time=10).mean(keep_attrs=True)
        assert result.attrs == attrs_global
        assert result.z1.attrs == attrs_z1

        with set_options(keep_attrs=True):
            result = ds.rolling_exp(time=10).mean(keep_attrs=False)
        assert result.attrs == {}
        assert result.z1.attrs == {}

        with pytest.warns(
            UserWarning,
            match="Passing ``keep_attrs`` to ``rolling_exp`` has no effect.",
        ):
            ds.rolling_exp(time=10, keep_attrs=True)
