import io
import xml
import functools
import itertools
import warnings

import numpy as np
import pandas as pd
import matplotlib as mpl
import matplotlib.pyplot as plt
from PIL import Image

import pytest
from pandas.testing import assert_frame_equal, assert_series_equal
from numpy.testing import assert_array_equal, assert_array_almost_equal

from seaborn._core.plot import Plot, Default
from seaborn._core.scales import Continuous, Nominal, Temporal
from seaborn._core.moves import Move, Shift, Dodge
from seaborn._core.rules import categorical_order
from seaborn._core.exceptions import PlotSpecError
from seaborn._marks.base import Mark
from seaborn._stats.base import Stat
from seaborn._marks.dot import Dot
from seaborn._stats.aggregation import Agg
from seaborn.external.version import Version

assert_vector_equal = functools.partial(
    # TODO do we care about int/float dtype consistency?
    # Eventually most variables become floats ... but does it matter when?
    # (Or rather, does it matter if it happens too early?)
    assert_series_equal, check_names=False, check_dtype=False,
)


def assert_gridspec_shape(ax, nrows=1, ncols=1):

    gs = ax.get_gridspec()
    if Version(mpl.__version__) < Version("3.2"):
        assert gs._nrows == nrows
        assert gs._ncols == ncols
    else:
        assert gs.nrows == nrows
        assert gs.ncols == ncols


class MockMark(Mark):

    _grouping_props = ["color"]

    def __init__(self, *args, **kwargs):

        super().__init__(*args, **kwargs)
        self.passed_keys = []
        self.passed_data = []
        self.passed_axes = []
        self.passed_scales = None
        self.passed_orient = None
        self.n_splits = 0

    def _plot(self, split_gen, scales, orient):

        for keys, data, ax in split_gen():
            self.n_splits += 1
            self.passed_keys.append(keys)
            self.passed_data.append(data)
            self.passed_axes.append(ax)

        self.passed_scales = scales
        self.passed_orient = orient

    def _legend_artist(self, variables, value, scales):

        a = mpl.lines.Line2D([], [])
        a.variables = variables
        a.value = value
        return a


class TestInit:

    def test_empty(self):

        p = Plot()
        assert p._data.source_data is None
        assert p._data.source_vars == {}

    def test_data_only(self, long_df):

        p = Plot(long_df)
        assert p._data.source_data is long_df
        assert p._data.source_vars == {}

    def test_df_and_named_variables(self, long_df):

        variables = {"x": "a", "y": "z"}
        p = Plot(long_df, **variables)
        for var, col in variables.items():
            assert_vector_equal(p._data.frame[var], long_df[col])
        assert p._data.source_data is long_df
        assert p._data.source_vars.keys() == variables.keys()

    def test_df_and_mixed_variables(self, long_df):

        variables = {"x": "a", "y": long_df["z"]}
        p = Plot(long_df, **variables)
        for var, col in variables.items():
            if isinstance(col, str):
                assert_vector_equal(p._data.frame[var], long_df[col])
            else:
                assert_vector_equal(p._data.frame[var], col)
        assert p._data.source_data is long_df
        assert p._data.source_vars.keys() == variables.keys()

    def test_vector_variables_only(self, long_df):

        variables = {"x": long_df["a"], "y": long_df["z"]}
        p = Plot(**variables)
        for var, col in variables.items():
            assert_vector_equal(p._data.frame[var], col)
        assert p._data.source_data is None
        assert p._data.source_vars.keys() == variables.keys()

    def test_vector_variables_no_index(self, long_df):

        variables = {"x": long_df["a"].to_numpy(), "y": long_df["z"].to_list()}
        p = Plot(**variables)
        for var, col in variables.items():
            assert_vector_equal(p._data.frame[var], pd.Series(col))
            assert p._data.names[var] is None
        assert p._data.source_data is None
        assert p._data.source_vars.keys() == variables.keys()

    def test_data_only_named(self, long_df):

        p = Plot(data=long_df)
        assert p._data.source_data is long_df
        assert p._data.source_vars == {}

    def test_positional_and_named_data(self, long_df):

        err = "`data` given by both name and position"
        with pytest.raises(TypeError, match=err):
            Plot(long_df, data=long_df)

    @pytest.mark.parametrize("var", ["x", "y"])
    def test_positional_and_named_xy(self, long_df, var):

        err = f"`{var}` given by both name and position"
        with pytest.raises(TypeError, match=err):
            Plot(long_df, "a", "b", **{var: "c"})

    def test_positional_data_x_y(self, long_df):

        p = Plot(long_df, "a", "b")
        assert p._data.source_data is long_df
        assert list(p._data.source_vars) == ["x", "y"]

    def test_positional_x_y(self, long_df):

        p = Plot(long_df["a"], long_df["b"])
        assert p._data.source_data is None
        assert list(p._data.source_vars) == ["x", "y"]

    def test_positional_data_x(self, long_df):

        p = Plot(long_df, "a")
        assert p._data.source_data is long_df
        assert list(p._data.source_vars) == ["x"]

    def test_positional_x(self, long_df):

        p = Plot(long_df["a"])
        assert p._data.source_data is None
        assert list(p._data.source_vars) == ["x"]

    def test_positional_too_many(self, long_df):

        err = r"Plot\(\) accepts no more than 3 positional arguments \(data, x, y\)"
        with pytest.raises(TypeError, match=err):
            Plot(long_df, "x", "y", "z")

    def test_unknown_keywords(self, long_df):

        err = r"Plot\(\) got unexpected keyword argument\(s\): bad"
        with pytest.raises(TypeError, match=err):
            Plot(long_df, bad="x")


class TestLayerAddition:

    def test_without_data(self, long_df):

        p = Plot(long_df, x="x", y="y").add(MockMark()).plot()
        layer, = p._layers
        assert_frame_equal(p._data.frame, layer["data"].frame, check_dtype=False)

    def test_with_new_variable_by_name(self, long_df):

        p = Plot(long_df, x="x").add(MockMark(), y="y").plot()
        layer, = p._layers
        assert layer["data"].frame.columns.to_list() == ["x", "y"]
        for var in "xy":
            assert_vector_equal(layer["data"].frame[var], long_df[var])

    def test_with_new_variable_by_vector(self, long_df):

        p = Plot(long_df, x="x").add(MockMark(), y=long_df["y"]).plot()
        layer, = p._layers
        assert layer["data"].frame.columns.to_list() == ["x", "y"]
        for var in "xy":
            assert_vector_equal(layer["data"].frame[var], long_df[var])

    def test_with_late_data_definition(self, long_df):

        p = Plot().add(MockMark(), data=long_df, x="x", y="y").plot()
        layer, = p._layers
        assert layer["data"].frame.columns.to_list() == ["x", "y"]
        for var in "xy":
            assert_vector_equal(layer["data"].frame[var], long_df[var])

    def test_with_new_data_definition(self, long_df):

        long_df_sub = long_df.sample(frac=.5)

        p = Plot(long_df, x="x", y="y").add(MockMark(), data=long_df_sub).plot()
        layer, = p._layers
        assert layer["data"].frame.columns.to_list() == ["x", "y"]
        for var in "xy":
            assert_vector_equal(
                layer["data"].frame[var], long_df_sub[var].reindex(long_df.index)
            )

    def test_drop_variable(self, long_df):

        p = Plot(long_df, x="x", y="y").add(MockMark(), y=None).plot()
        layer, = p._layers
        assert layer["data"].frame.columns.to_list() == ["x"]
        assert_vector_equal(layer["data"].frame["x"], long_df["x"], check_dtype=False)

    @pytest.mark.xfail(reason="Need decision on default stat")
    def test_stat_default(self):

        class MarkWithDefaultStat(Mark):
            default_stat = Stat

        p = Plot().add(MarkWithDefaultStat())
        layer, = p._layers
        assert layer["stat"].__class__ is Stat

    def test_stat_nondefault(self):

        class MarkWithDefaultStat(Mark):
            default_stat = Stat

        class OtherMockStat(Stat):
            pass

        p = Plot().add(MarkWithDefaultStat(), OtherMockStat())
        layer, = p._layers
        assert layer["stat"].__class__ is OtherMockStat

    @pytest.mark.parametrize(
        "arg,expected",
        [("x", "x"), ("y", "y"), ("v", "x"), ("h", "y")],
    )
    def test_orient(self, arg, expected):

        class MockStatTrackOrient(Stat):
            def __call__(self, data, groupby, orient, scales):
                self.orient_at_call = orient
                return data

        class MockMoveTrackOrient(Move):
            def __call__(self, data, groupby, orient, scales):
                self.orient_at_call = orient
                return data

        s = MockStatTrackOrient()
        m = MockMoveTrackOrient()
        Plot(x=[1, 2, 3], y=[1, 2, 3]).add(MockMark(), s, m, orient=arg).plot()

        assert s.orient_at_call == expected
        assert m.orient_at_call == expected

    def test_variable_list(self, long_df):

        p = Plot(long_df, x="x", y="y")
        assert p._variables == ["x", "y"]

        p = Plot(long_df).add(MockMark(), x="x", y="y")
        assert p._variables == ["x", "y"]

        p = Plot(long_df, y="x", color="a").add(MockMark(), x="y")
        assert p._variables == ["y", "color", "x"]

        p = Plot(long_df, x="x", y="y", color="a").add(MockMark(), color=None)
        assert p._variables == ["x", "y", "color"]

        p = (
            Plot(long_df, x="x", y="y")
            .add(MockMark(), color="a")
            .add(MockMark(), alpha="s")
        )
        assert p._variables == ["x", "y", "color", "alpha"]

        p = Plot(long_df, y="x").pair(x=["a", "b"])
        assert p._variables == ["y", "x0", "x1"]

    def test_type_checks(self):

        p = Plot()
        with pytest.raises(TypeError, match="mark must be a Mark instance"):
            p.add(MockMark)

        class MockStat(Stat):
            pass

        class MockMove(Move):
            pass

        err = "Transforms must have at most one Stat type"

        with pytest.raises(TypeError, match=err):
            p.add(MockMark(), MockStat)

        with pytest.raises(TypeError, match=err):
            p.add(MockMark(), MockMove(), MockStat())

        with pytest.raises(TypeError, match=err):
            p.add(MockMark(), MockMark(), MockStat())


class TestScaling:

    def test_inference(self, long_df):

        for col, scale_type in zip("zat", ["Continuous", "Nominal", "Temporal"]):
            p = Plot(long_df, x=col, y=col).add(MockMark()).plot()
            for var in "xy":
                assert p._scales[var].__class__.__name__ == scale_type

    def test_inference_from_layer_data(self):

        p = Plot().add(MockMark(), x=["a", "b", "c"]).plot()
        assert p._scales["x"]("b") == 1

    def test_inference_joins(self):

        p = (
            Plot(y=pd.Series([1, 2, 3, 4]))
            .add(MockMark(), x=pd.Series([1, 2]))
            .add(MockMark(), x=pd.Series(["a", "b"], index=[2, 3]))
            .plot()
        )
        assert p._scales["x"]("a") == 2

    def test_inferred_categorical_converter(self):

        p = Plot(x=["b", "c", "a"]).add(MockMark()).plot()
        ax = p._figure.axes[0]
        assert ax.xaxis.convert_units("c") == 1

    def test_explicit_categorical_converter(self):

        p = Plot(y=[2, 1, 3]).scale(y=Nominal()).add(MockMark()).plot()
        ax = p._figure.axes[0]
        assert ax.yaxis.convert_units("3") == 2

    @pytest.mark.xfail(reason="Temporal auto-conversion not implemented")
    def test_categorical_as_datetime(self):

        dates = ["1970-01-03", "1970-01-02", "1970-01-04"]
        p = Plot(x=dates).scale(...).add(MockMark()).plot()
        p  # TODO
        ...

    def test_faceted_log_scale(self):

        p = Plot(y=[1, 10]).facet(col=["a", "b"]).scale(y="log").plot()
        for ax in p._figure.axes:
            xfm = ax.yaxis.get_transform().transform
            assert_array_equal(xfm([1, 10, 100]), [0, 1, 2])

    def test_paired_single_log_scale(self):

        x0, x1 = [1, 2, 3], [1, 10, 100]
        p = Plot().pair(x=[x0, x1]).scale(x1="log").plot()
        ax_lin, ax_log = p._figure.axes
        xfm_lin = ax_lin.xaxis.get_transform().transform
        assert_array_equal(xfm_lin([1, 10, 100]), [1, 10, 100])
        xfm_log = ax_log.xaxis.get_transform().transform
        assert_array_equal(xfm_log([1, 10, 100]), [0, 1, 2])

    @pytest.mark.xfail(reason="Custom log scale needs log name for consistency")
    def test_log_scale_name(self):

        p = Plot().scale(x="log").plot()
        ax = p._figure.axes[0]
        assert ax.get_xscale() == "log"
        assert ax.get_yscale() == "linear"

    def test_mark_data_log_transform_is_inverted(self, long_df):

        col = "z"
        m = MockMark()
        Plot(long_df, x=col).scale(x="log").add(m).plot()
        assert_vector_equal(m.passed_data[0]["x"], long_df[col])

    def test_mark_data_log_transfrom_with_stat(self, long_df):

        class Mean(Stat):
            group_by_orient = True

            def __call__(self, data, groupby, orient, scales):
                other = {"x": "y", "y": "x"}[orient]
                return groupby.agg(data, {other: "mean"})

        col = "z"
        grouper = "a"
        m = MockMark()
        s = Mean()

        Plot(long_df, x=grouper, y=col).scale(y="log").add(m, s).plot()

        expected = (
            long_df[col]
            .pipe(np.log)
            .groupby(long_df[grouper], sort=False)
            .mean()
            .pipe(np.exp)
            .reset_index(drop=True)
        )
        assert_vector_equal(m.passed_data[0]["y"], expected)

    def test_mark_data_from_categorical(self, long_df):

        col = "a"
        m = MockMark()
        Plot(long_df, x=col).add(m).plot()

        levels = categorical_order(long_df[col])
        level_map = {x: float(i) for i, x in enumerate(levels)}
        assert_vector_equal(m.passed_data[0]["x"], long_df[col].map(level_map))

    def test_mark_data_from_datetime(self, long_df):

        col = "t"
        m = MockMark()
        Plot(long_df, x=col).add(m).plot()

        expected = long_df[col].map(mpl.dates.date2num)
        if Version(mpl.__version__) < Version("3.3"):
            expected = expected + mpl.dates.date2num(np.datetime64('0000-12-31'))

        assert_vector_equal(m.passed_data[0]["x"], expected)

    def test_computed_var_ticks(self, long_df):

        class Identity(Stat):
            def __call__(self, df, groupby, orient, scales):
                other = {"x": "y", "y": "x"}[orient]
                return df.assign(**{other: df[orient]})

        tick_locs = [1, 2, 5]
        scale = Continuous().tick(at=tick_locs)
        p = Plot(long_df, "x").add(MockMark(), Identity()).scale(y=scale).plot()
        ax = p._figure.axes[0]
        assert_array_equal(ax.get_yticks(), tick_locs)

    def test_computed_var_transform(self, long_df):

        class Identity(Stat):
            def __call__(self, df, groupby, orient, scales):
                other = {"x": "y", "y": "x"}[orient]
                return df.assign(**{other: df[orient]})

        p = Plot(long_df, "x").add(MockMark(), Identity()).scale(y="log").plot()
        ax = p._figure.axes[0]
        xfm = ax.yaxis.get_transform().transform
        assert_array_equal(xfm([1, 10, 100]), [0, 1, 2])

    def test_explicit_range_with_axis_scaling(self):

        x = [1, 2, 3]
        ymin = [10, 100, 1000]
        ymax = [20, 200, 2000]
        m = MockMark()
        Plot(x=x, ymin=ymin, ymax=ymax).add(m).scale(y="log").plot()
        assert_vector_equal(m.passed_data[0]["ymax"], pd.Series(ymax, dtype=float))

    def test_derived_range_with_axis_scaling(self):

        class AddOne(Stat):
            def __call__(self, df, *args):
                return df.assign(ymax=df["y"] + 1)

        x = y = [1, 10, 100]

        m = MockMark()
        Plot(x, y).add(m, AddOne()).scale(y="log").plot()
        assert_vector_equal(m.passed_data[0]["ymax"], pd.Series([10., 100., 1000.]))

    def test_facet_categories(self):

        m = MockMark()
        p = Plot(x=["a", "b", "a", "c"]).facet(col=["x", "x", "y", "y"]).add(m).plot()
        ax1, ax2 = p._figure.axes
        assert len(ax1.get_xticks()) == 3
        assert len(ax2.get_xticks()) == 3
        assert_vector_equal(m.passed_data[0]["x"], pd.Series([0., 1.], [0, 1]))
        assert_vector_equal(m.passed_data[1]["x"], pd.Series([0., 2.], [2, 3]))

    def test_facet_categories_unshared(self):

        m = MockMark()
        p = (
            Plot(x=["a", "b", "a", "c"])
            .facet(col=["x", "x", "y", "y"])
            .share(x=False)
            .add(m)
            .plot()
        )
        ax1, ax2 = p._figure.axes
        assert len(ax1.get_xticks()) == 2
        assert len(ax2.get_xticks()) == 2
        assert_vector_equal(m.passed_data[0]["x"], pd.Series([0., 1.], [0, 1]))
        assert_vector_equal(m.passed_data[1]["x"], pd.Series([0., 1.], [2, 3]))

    def test_facet_categories_single_dim_shared(self):

        data = [
            ("a", 1, 1), ("b", 1, 1),
            ("a", 1, 2), ("c", 1, 2),
            ("b", 2, 1), ("d", 2, 1),
            ("e", 2, 2), ("e", 2, 1),
        ]
        df = pd.DataFrame(data, columns=["x", "row", "col"]).assign(y=1)
        m = MockMark()
        p = (
            Plot(df, x="x")
            .facet(row="row", col="col")
            .add(m)
            .share(x="row")
            .plot()
        )

        axs = p._figure.axes
        for ax in axs:
            assert ax.get_xticks() == [0, 1, 2]

        assert_vector_equal(m.passed_data[0]["x"], pd.Series([0., 1.], [0, 1]))
        assert_vector_equal(m.passed_data[1]["x"], pd.Series([0., 2.], [2, 3]))
        assert_vector_equal(m.passed_data[2]["x"], pd.Series([0., 1., 2.], [4, 5, 7]))
        assert_vector_equal(m.passed_data[3]["x"], pd.Series([2.], [6]))

    def test_pair_categories(self):

        data = [("a", "a"), ("b", "c")]
        df = pd.DataFrame(data, columns=["x1", "x2"]).assign(y=1)
        m = MockMark()
        p = Plot(df, y="y").pair(x=["x1", "x2"]).add(m).plot()

        ax1, ax2 = p._figure.axes
        assert ax1.get_xticks() == [0, 1]
        assert ax2.get_xticks() == [0, 1]
        assert_vector_equal(m.passed_data[0]["x"], pd.Series([0., 1.], [0, 1]))
        assert_vector_equal(m.passed_data[1]["x"], pd.Series([0., 1.], [0, 1]))

    @pytest.mark.xfail(
        Version(mpl.__version__) < Version("3.4.0"),
        reason="Sharing paired categorical axes requires matplotlib>3.4.0"
    )
    def test_pair_categories_shared(self):

        data = [("a", "a"), ("b", "c")]
        df = pd.DataFrame(data, columns=["x1", "x2"]).assign(y=1)
        m = MockMark()
        p = Plot(df, y="y").pair(x=["x1", "x2"]).add(m).share(x=True).plot()

        for ax in p._figure.axes:
            assert ax.get_xticks() == [0, 1, 2]
        print(m.passed_data)
        assert_vector_equal(m.passed_data[0]["x"], pd.Series([0., 1.], [0, 1]))
        assert_vector_equal(m.passed_data[1]["x"], pd.Series([0., 2.], [0, 1]))

    def test_identity_mapping_linewidth(self):

        m = MockMark()
        x = y = [1, 2, 3, 4, 5]
        lw = pd.Series([.5, .1, .1, .9, 3])
        Plot(x=x, y=y, linewidth=lw).scale(linewidth=None).add(m).plot()
        assert_vector_equal(m.passed_scales["linewidth"](lw), lw)

    def test_pair_single_coordinate_stat_orient(self, long_df):

        class MockStat(Stat):
            def __call__(self, data, groupby, orient, scales):
                self.orient = orient
                return data

        s = MockStat()
        Plot(long_df).pair(x=["x", "y"]).add(MockMark(), s).plot()
        assert s.orient == "x"

    def test_inferred_nominal_passed_to_stat(self):

        class MockStat(Stat):
            def __call__(self, data, groupby, orient, scales):
                self.scales = scales
                return data

        s = MockStat()
        y = ["a", "a", "b", "c"]
        Plot(y=y).add(MockMark(), s).plot()
        assert s.scales["y"].__class__.__name__ == "Nominal"

    # TODO where should RGB consistency be enforced?
    @pytest.mark.xfail(
        reason="Correct output representation for color with identity scale undefined"
    )
    def test_identity_mapping_color_strings(self):

        m = MockMark()
        x = y = [1, 2, 3]
        c = ["C0", "C2", "C1"]
        Plot(x=x, y=y, color=c).scale(color=None).add(m).plot()
        expected = mpl.colors.to_rgba_array(c)[:, :3]
        assert_array_equal(m.passed_scales["color"](c), expected)

    def test_identity_mapping_color_tuples(self):

        m = MockMark()
        x = y = [1, 2, 3]
        c = [(1, 0, 0), (0, 1, 0), (1, 0, 0)]
        Plot(x=x, y=y, color=c).scale(color=None).add(m).plot()
        expected = mpl.colors.to_rgba_array(c)[:, :3]
        assert_array_equal(m.passed_scales["color"](c), expected)

    @pytest.mark.xfail(
        reason="Need decision on what to do with scale defined for unused variable"
    )
    def test_undefined_variable_raises(self):

        p = Plot(x=[1, 2, 3], color=["a", "b", "c"]).scale(y=Continuous())
        err = r"No data found for variable\(s\) with explicit scale: {'y'}"
        with pytest.raises(RuntimeError, match=err):
            p.plot()

    def test_nominal_x_axis_tweaks(self):

        p = Plot(x=["a", "b", "c"], y=[1, 2, 3])
        ax1 = p.plot()._figure.axes[0]
        assert ax1.get_xlim() == (-.5, 2.5)
        assert not any(x.get_visible() for x in ax1.xaxis.get_gridlines())

        lim = (-1, 2.1)
        ax2 = p.limit(x=lim).plot()._figure.axes[0]
        assert ax2.get_xlim() == lim

    def test_nominal_y_axis_tweaks(self):

        p = Plot(x=[1, 2, 3], y=["a", "b", "c"])
        ax1 = p.plot()._figure.axes[0]
        assert ax1.get_ylim() == (2.5, -.5)
        assert not any(y.get_visible() for y in ax1.yaxis.get_gridlines())

        lim = (-1, 2.1)
        ax2 = p.limit(y=lim).plot()._figure.axes[0]
        assert ax2.get_ylim() == lim


class TestPlotting:

    def test_matplotlib_object_creation(self):

        p = Plot().plot()
        assert isinstance(p._figure, mpl.figure.Figure)
        for sub in p._subplots:
            assert isinstance(sub["ax"], mpl.axes.Axes)

    def test_empty(self):

        m = MockMark()
        Plot().add(m).plot()
        assert m.n_splits == 0
        assert not m.passed_data

    def test_no_orient_variance(self):

        x, y = [0, 0], [1, 2]
        m = MockMark()
        Plot(x, y).add(m).plot()
        assert_array_equal(m.passed_data[0]["x"], x)
        assert_array_equal(m.passed_data[0]["y"], y)

    def test_single_split_single_layer(self, long_df):

        m = MockMark()
        p = Plot(long_df, x="f", y="z").add(m).plot()
        assert m.n_splits == 1

        assert m.passed_keys[0] == {}
        assert m.passed_axes == [sub["ax"] for sub in p._subplots]
        for col in p._data.frame:
            assert_series_equal(m.passed_data[0][col], p._data.frame[col])

    def test_single_split_multi_layer(self, long_df):

        vs = [{"color": "a", "linewidth": "z"}, {"color": "b", "pattern": "c"}]

        class NoGroupingMark(MockMark):
            _grouping_props = []

        ms = [NoGroupingMark(), NoGroupingMark()]
        Plot(long_df).add(ms[0], **vs[0]).add(ms[1], **vs[1]).plot()

        for m, v in zip(ms, vs):
            for var, col in v.items():
                assert_vector_equal(m.passed_data[0][var], long_df[col])

    def check_splits_single_var(
        self, data, mark, data_vars, split_var, split_col, split_keys
    ):

        assert mark.n_splits == len(split_keys)
        assert mark.passed_keys == [{split_var: key} for key in split_keys]

        for i, key in enumerate(split_keys):

            split_data = data[data[split_col] == key]
            for var, col in data_vars.items():
                assert_array_equal(mark.passed_data[i][var], split_data[col])

    def check_splits_multi_vars(
        self, data, mark, data_vars, split_vars, split_cols, split_keys
    ):

        assert mark.n_splits == np.prod([len(ks) for ks in split_keys])

        expected_keys = [
            dict(zip(split_vars, level_keys))
            for level_keys in itertools.product(*split_keys)
        ]
        assert mark.passed_keys == expected_keys

        for i, keys in enumerate(itertools.product(*split_keys)):

            use_rows = pd.Series(True, data.index)
            for var, col, key in zip(split_vars, split_cols, keys):
                use_rows &= data[col] == key
            split_data = data[use_rows]
            for var, col in data_vars.items():
                assert_array_equal(mark.passed_data[i][var], split_data[col])

    @pytest.mark.parametrize(
        "split_var", [
            "color",  # explicitly declared on the Mark
            "group",  # implicitly used for all Mark classes
        ])
    def test_one_grouping_variable(self, long_df, split_var):

        split_col = "a"
        data_vars = {"x": "f", "y": "z", split_var: split_col}

        m = MockMark()
        p = Plot(long_df, **data_vars).add(m).plot()

        split_keys = categorical_order(long_df[split_col])
        sub, *_ = p._subplots
        assert m.passed_axes == [sub["ax"] for _ in split_keys]
        self.check_splits_single_var(
            long_df, m, data_vars, split_var, split_col, split_keys
        )

    def test_two_grouping_variables(self, long_df):

        split_vars = ["color", "group"]
        split_cols = ["a", "b"]
        data_vars = {"y": "z", **{var: col for var, col in zip(split_vars, split_cols)}}

        m = MockMark()
        p = Plot(long_df, **data_vars).add(m).plot()

        split_keys = [categorical_order(long_df[col]) for col in split_cols]
        sub, *_ = p._subplots
        assert m.passed_axes == [
            sub["ax"] for _ in itertools.product(*split_keys)
        ]
        self.check_splits_multi_vars(
            long_df, m, data_vars, split_vars, split_cols, split_keys
        )

    def test_specified_width(self, long_df):

        m = MockMark()
        Plot(long_df, x="x", y="y").add(m, width="z").plot()
        assert_array_almost_equal(m.passed_data[0]["width"], long_df["z"])

    def test_facets_no_subgroups(self, long_df):

        split_var = "col"
        split_col = "b"
        data_vars = {"x": "f", "y": "z"}

        m = MockMark()
        p = Plot(long_df, **data_vars).facet(**{split_var: split_col}).add(m).plot()

        split_keys = categorical_order(long_df[split_col])
        assert m.passed_axes == list(p._figure.axes)
        self.check_splits_single_var(
            long_df, m, data_vars, split_var, split_col, split_keys
        )

    def test_facets_one_subgroup(self, long_df):

        facet_var, facet_col = fx = "col", "a"
        group_var, group_col = gx = "group", "b"
        split_vars, split_cols = zip(*[fx, gx])
        data_vars = {"x": "f", "y": "z", group_var: group_col}

        m = MockMark()
        p = (
            Plot(long_df, **data_vars)
            .facet(**{facet_var: facet_col})
            .add(m)
            .plot()
        )

        split_keys = [categorical_order(long_df[col]) for col in [facet_col, group_col]]
        assert m.passed_axes == [
            ax
            for ax in list(p._figure.axes)
            for _ in categorical_order(long_df[group_col])
        ]
        self.check_splits_multi_vars(
            long_df, m, data_vars, split_vars, split_cols, split_keys
        )

    def test_layer_specific_facet_disabling(self, long_df):

        axis_vars = {"x": "y", "y": "z"}
        row_var = "a"

        m = MockMark()
        p = Plot(long_df, **axis_vars).facet(row=row_var).add(m, row=None).plot()

        col_levels = categorical_order(long_df[row_var])
        assert len(p._figure.axes) == len(col_levels)

        for data in m.passed_data:
            for var, col in axis_vars.items():
                assert_vector_equal(data[var], long_df[col])

    def test_paired_variables(self, long_df):

        x = ["x", "y"]
        y = ["f", "z"]

        m = MockMark()
        Plot(long_df).pair(x, y).add(m).plot()

        var_product = itertools.product(x, y)

        for data, (x_i, y_i) in zip(m.passed_data, var_product):
            assert_vector_equal(data["x"], long_df[x_i].astype(float))
            assert_vector_equal(data["y"], long_df[y_i].astype(float))

    def test_paired_one_dimension(self, long_df):

        x = ["y", "z"]

        m = MockMark()
        Plot(long_df).pair(x).add(m).plot()

        for data, x_i in zip(m.passed_data, x):
            assert_vector_equal(data["x"], long_df[x_i].astype(float))

    def test_paired_variables_one_subset(self, long_df):

        x = ["x", "y"]
        y = ["f", "z"]
        group = "a"

        long_df["x"] = long_df["x"].astype(float)  # simplify vector comparison

        m = MockMark()
        Plot(long_df, group=group).pair(x, y).add(m).plot()

        groups = categorical_order(long_df[group])
        var_product = itertools.product(x, y, groups)

        for data, (x_i, y_i, g_i) in zip(m.passed_data, var_product):
            rows = long_df[group] == g_i
            assert_vector_equal(data["x"], long_df.loc[rows, x_i])
            assert_vector_equal(data["y"], long_df.loc[rows, y_i])

    def test_paired_and_faceted(self, long_df):

        x = ["y", "z"]
        y = "f"
        row = "c"

        m = MockMark()
        Plot(long_df, y=y).facet(row=row).pair(x).add(m).plot()

        facets = categorical_order(long_df[row])
        var_product = itertools.product(x, facets)

        for data, (x_i, f_i) in zip(m.passed_data, var_product):
            rows = long_df[row] == f_i
            assert_vector_equal(data["x"], long_df.loc[rows, x_i])
            assert_vector_equal(data["y"], long_df.loc[rows, y])

    def test_theme_default(self):

        p = Plot().plot()
        assert mpl.colors.same_color(p._figure.axes[0].get_facecolor(), "#EAEAF2")

    def test_theme_params(self):

        color = ".888"
        p = Plot().theme({"axes.facecolor": color}).plot()
        assert mpl.colors.same_color(p._figure.axes[0].get_facecolor(), color)

    def test_theme_error(self):

        p = Plot()
        with pytest.raises(TypeError, match=r"theme\(\) takes 1 positional"):
            p.theme("arg1", "arg2")

    def test_stat(self, long_df):

        orig_df = long_df.copy(deep=True)

        m = MockMark()
        Plot(long_df, x="a", y="z").add(m, Agg()).plot()

        expected = long_df.groupby("a", sort=False)["z"].mean().reset_index(drop=True)
        assert_vector_equal(m.passed_data[0]["y"], expected)

        assert_frame_equal(long_df, orig_df)   # Test data was not mutated

    def test_move(self, long_df):

        orig_df = long_df.copy(deep=True)

        m = MockMark()
        Plot(long_df, x="z", y="z").add(m, Shift(x=1)).plot()
        assert_vector_equal(m.passed_data[0]["x"], long_df["z"] + 1)
        assert_vector_equal(m.passed_data[0]["y"], long_df["z"])

        assert_frame_equal(long_df, orig_df)   # Test data was not mutated

    def test_stat_and_move(self, long_df):

        m = MockMark()
        Plot(long_df, x="a", y="z").add(m, Agg(), Shift(y=1)).plot()

        expected = long_df.groupby("a", sort=False)["z"].mean().reset_index(drop=True)
        assert_vector_equal(m.passed_data[0]["y"], expected + 1)

    def test_stat_log_scale(self, long_df):

        orig_df = long_df.copy(deep=True)

        m = MockMark()
        Plot(long_df, x="a", y="z").add(m, Agg()).scale(y="log").plot()

        x = long_df["a"]
        y = np.log10(long_df["z"])
        expected = y.groupby(x, sort=False).mean().reset_index(drop=True)
        assert_vector_equal(m.passed_data[0]["y"], 10 ** expected)

        assert_frame_equal(long_df, orig_df)   # Test data was not mutated

    def test_move_log_scale(self, long_df):

        m = MockMark()
        Plot(
            long_df, x="z", y="z"
        ).scale(x="log").add(m, Shift(x=-1)).plot()
        assert_vector_equal(m.passed_data[0]["x"], long_df["z"] / 10)

    def test_multi_move(self, long_df):

        m = MockMark()
        move_stack = [Shift(1), Shift(2)]
        Plot(long_df, x="x", y="y").add(m, *move_stack).plot()
        assert_vector_equal(m.passed_data[0]["x"], long_df["x"] + 3)

    def test_multi_move_with_pairing(self, long_df):
        m = MockMark()
        move_stack = [Shift(1), Shift(2)]
        Plot(long_df, x="x").pair(y=["y", "z"]).add(m, *move_stack).plot()
        for frame in m.passed_data:
            assert_vector_equal(frame["x"], long_df["x"] + 3)

    def test_move_with_range(self, long_df):

        x = [0, 0, 1, 1, 2, 2]
        group = [0, 1, 0, 1, 0, 1]
        ymin = np.arange(6)
        ymax = np.arange(6) * 2

        m = MockMark()
        Plot(x=x, group=group, ymin=ymin, ymax=ymax).add(m, Dodge()).plot()

        signs = [-1, +1]
        for i, df in m.passed_data[0].groupby("group"):
            assert_array_equal(df["x"], np.arange(3) + signs[i] * 0.2)

    def test_methods_clone(self, long_df):

        p1 = Plot(long_df, "x", "y")
        p2 = p1.add(MockMark()).facet("a")

        assert p1 is not p2
        assert not p1._layers
        assert not p1._facet_spec

    def test_default_is_no_pyplot(self):

        p = Plot().plot()

        assert not plt.get_fignums()
        assert isinstance(p._figure, mpl.figure.Figure)

    def test_with_pyplot(self):

        p = Plot().plot(pyplot=True)

        assert len(plt.get_fignums()) == 1
        fig = plt.gcf()
        assert p._figure is fig

    def test_show(self):

        p = Plot()

        with warnings.catch_warnings(record=True) as msg:
            out = p.show(block=False)
        assert out is None
        assert not hasattr(p, "_figure")

        assert len(plt.get_fignums()) == 1
        fig = plt.gcf()

        gui_backend = (
            # From https://github.com/matplotlib/matplotlib/issues/20281
            fig.canvas.manager.show != mpl.backend_bases.FigureManagerBase.show
        )
        if not gui_backend:
            assert msg

    def test_png_repr(self):

        p = Plot()
        data, metadata = p._repr_png_()
        img = Image.open(io.BytesIO(data))

        assert not hasattr(p, "_figure")
        assert isinstance(data, bytes)
        assert img.format == "PNG"
        assert sorted(metadata) == ["height", "width"]
        # TODO test retina scaling

    def test_save(self):

        buf = io.BytesIO()

        p = Plot().save(buf)
        assert isinstance(p, Plot)
        img = Image.open(buf)
        assert img.format == "PNG"

        buf = io.StringIO()
        Plot().save(buf, format="svg")
        tag = xml.etree.ElementTree.fromstring(buf.getvalue()).tag
        assert tag == "{http://www.w3.org/2000/svg}svg"

    def test_layout_size(self):

        size = (4, 2)
        p = Plot().layout(size=size).plot()
        assert tuple(p._figure.get_size_inches()) == size

    def test_on_axes(self):

        ax = mpl.figure.Figure().subplots()
        m = MockMark()
        p = Plot([1], [2]).on(ax).add(m).plot()
        assert m.passed_axes == [ax]
        assert p._figure is ax.figure

    @pytest.mark.parametrize("facet", [True, False])
    def test_on_figure(self, facet):

        f = mpl.figure.Figure()
        m = MockMark()
        p = Plot([1, 2], [3, 4]).on(f).add(m)
        if facet:
            p = p.facet(["a", "b"])
        p = p.plot()
        assert m.passed_axes == f.axes
        assert p._figure is f

    @pytest.mark.skipif(
        Version(mpl.__version__) < Version("3.4"),
        reason="mpl<3.4 does not have SubFigure",
    )
    @pytest.mark.parametrize("facet", [True, False])
    def test_on_subfigure(self, facet):

        sf1, sf2 = mpl.figure.Figure().subfigures(2)
        sf1.subplots()
        m = MockMark()
        p = Plot([1, 2], [3, 4]).on(sf2).add(m)
        if facet:
            p = p.facet(["a", "b"])
        p = p.plot()
        assert m.passed_axes == sf2.figure.axes[1:]
        assert p._figure is sf2.figure

    def test_on_type_check(self):

        p = Plot()
        with pytest.raises(TypeError, match="The `Plot.on`.+<class 'list'>"):
            p.on([])

    def test_on_axes_with_subplots_error(self):

        ax = mpl.figure.Figure().subplots()

        p1 = Plot().facet(["a", "b"]).on(ax)
        with pytest.raises(RuntimeError, match="Cannot create multiple subplots"):
            p1.plot()

        p2 = Plot().pair([["a", "b"], ["x", "y"]]).on(ax)
        with pytest.raises(RuntimeError, match="Cannot create multiple subplots"):
            p2.plot()

    def test_on_disables_layout_algo(self):

        f = mpl.figure.Figure()
        p = Plot().on(f).plot()
        assert not p._figure.get_tight_layout()

    def test_axis_labels_from_constructor(self, long_df):

        ax, = Plot(long_df, x="a", y="b").plot()._figure.axes
        assert ax.get_xlabel() == "a"
        assert ax.get_ylabel() == "b"

        ax, = Plot(x=long_df["a"], y=long_df["b"].to_numpy()).plot()._figure.axes
        assert ax.get_xlabel() == "a"
        assert ax.get_ylabel() == ""

    def test_axis_labels_from_layer(self, long_df):

        m = MockMark()

        ax, = Plot(long_df).add(m, x="a", y="b").plot()._figure.axes
        assert ax.get_xlabel() == "a"
        assert ax.get_ylabel() == "b"

        p = Plot().add(m, x=long_df["a"], y=long_df["b"].to_list())
        ax, = p.plot()._figure.axes
        assert ax.get_xlabel() == "a"
        assert ax.get_ylabel() == ""

    def test_axis_labels_are_first_name(self, long_df):

        m = MockMark()
        p = (
            Plot(long_df, x=long_df["z"].to_list(), y="b")
            .add(m, x="a")
            .add(m, x="x", y="y")
        )
        ax, = p.plot()._figure.axes
        assert ax.get_xlabel() == "a"
        assert ax.get_ylabel() == "b"

    def test_limits(self, long_df):

        limit = (-2, 24)
        p = Plot(long_df, x="x", y="y").limit(x=limit).plot()
        ax = p._figure.axes[0]
        assert ax.get_xlim() == limit

        limit = (np.datetime64("2005-01-01"), np.datetime64("2008-01-01"))
        p = Plot(long_df, x="d", y="y").limit(x=limit).plot()
        ax = p._figure.axes[0]
        assert ax.get_xlim() == tuple(mpl.dates.date2num(limit))

        limit = ("b", "c")
        p = Plot(x=["a", "b", "c", "d"], y=[1, 2, 3, 4]).limit(x=limit).plot()
        ax = p._figure.axes[0]
        assert ax.get_xlim() == (0.5, 2.5)

    def test_labels_axis(self, long_df):

        label = "Y axis"
        p = Plot(long_df, x="x", y="y").label(y=label).plot()
        ax = p._figure.axes[0]
        assert ax.get_ylabel() == label

        label = str.capitalize
        p = Plot(long_df, x="x", y="y").label(y=label).plot()
        ax = p._figure.axes[0]
        assert ax.get_ylabel() == "Y"

    def test_labels_legend(self, long_df):

        m = MockMark()

        label = "A"
        p = Plot(long_df, x="x", y="y", color="a").add(m).label(color=label).plot()
        assert p._figure.legends[0].get_title().get_text() == label

        func = str.capitalize
        p = Plot(long_df, x="x", y="y", color="a").add(m).label(color=func).plot()
        assert p._figure.legends[0].get_title().get_text() == label

    def test_labels_facets(self):

        data = {"a": ["b", "c"], "x": ["y", "z"]}
        p = Plot(data).facet("a", "x").label(col=str.capitalize, row="$x$").plot()
        axs = np.reshape(p._figure.axes, (2, 2))
        for (i, j), ax in np.ndenumerate(axs):
            expected = f"A {data['a'][j]} | $x$ {data['x'][i]}"
            assert ax.get_title() == expected

    def test_title_single(self):

        label = "A"
        p = Plot().label(title=label).plot()
        assert p._figure.axes[0].get_title() == label

    def test_title_facet_function(self):

        titles = ["a", "b"]
        p = Plot().facet(titles).label(title=str.capitalize).plot()
        for i, ax in enumerate(p._figure.axes):
            assert ax.get_title() == titles[i].upper()

        cols, rows = ["a", "b"], ["x", "y"]
        p = Plot().facet(cols, rows).label(title=str.capitalize).plot()
        for i, ax in enumerate(p._figure.axes):
            expected = " | ".join([cols[i % 2].upper(), rows[i // 2].upper()])
            assert ax.get_title() == expected


class TestExceptions:

    def test_scale_setup(self):

        x = y = color = ["a", "b"]
        bad_palette = "not_a_palette"
        p = Plot(x, y, color=color).add(MockMark()).scale(color=bad_palette)

        msg = "Scale setup failed for the `color` variable."
        with pytest.raises(PlotSpecError, match=msg) as err:
            p.plot()
        assert isinstance(err.value.__cause__, ValueError)
        assert bad_palette in str(err.value.__cause__)

    def test_coordinate_scaling(self):

        x = ["a", "b"]
        y = [1, 2]
        p = Plot(x, y).add(MockMark()).scale(x=Temporal())

        msg = "Scaling operation failed for the `x` variable."
        with pytest.raises(PlotSpecError, match=msg) as err:
            p.plot()
        # Don't test the cause contents b/c matplotlib owns them here.
        assert hasattr(err.value, "__cause__")

    def test_semantic_scaling(self):

        class ErrorRaising(Continuous):

            def _setup(self, data, prop, axis=None):

                def f(x):
                    raise ValueError("This is a test")

                new = super()._setup(data, prop, axis)
                new._pipeline = [f]
                return new

        x = y = color = [1, 2]
        p = Plot(x, y, color=color).add(Dot()).scale(color=ErrorRaising())
        msg = "Scaling operation failed for the `color` variable."
        with pytest.raises(PlotSpecError, match=msg) as err:
            p.plot()
        assert isinstance(err.value.__cause__, ValueError)
        assert str(err.value.__cause__) == "This is a test"


class TestFacetInterface:

    @pytest.fixture(scope="class", params=["row", "col"])
    def dim(self, request):
        return request.param

    @pytest.fixture(scope="class", params=["reverse", "subset", "expand"])
    def reorder(self, request):
        return {
            "reverse": lambda x: x[::-1],
            "subset": lambda x: x[:-1],
            "expand": lambda x: x + ["z"],
        }[request.param]

    def check_facet_results_1d(self, p, df, dim, key, order=None):

        p = p.plot()

        order = categorical_order(df[key], order)
        assert len(p._figure.axes) == len(order)

        other_dim = {"row": "col", "col": "row"}[dim]

        for subplot, level in zip(p._subplots, order):
            assert subplot[dim] == level
            assert subplot[other_dim] is None
            assert subplot["ax"].get_title() == f"{level}"
            assert_gridspec_shape(subplot["ax"], **{f"n{dim}s": len(order)})

    def test_1d(self, long_df, dim):

        key = "a"
        p = Plot(long_df).facet(**{dim: key})
        self.check_facet_results_1d(p, long_df, dim, key)

    def test_1d_as_vector(self, long_df, dim):

        key = "a"
        p = Plot(long_df).facet(**{dim: long_df[key]})
        self.check_facet_results_1d(p, long_df, dim, key)

    def test_1d_with_order(self, long_df, dim, reorder):

        key = "a"
        order = reorder(categorical_order(long_df[key]))
        p = Plot(long_df).facet(**{dim: key, "order": order})
        self.check_facet_results_1d(p, long_df, dim, key, order)

    def check_facet_results_2d(self, p, df, variables, order=None):

        p = p.plot()

        if order is None:
            order = {dim: categorical_order(df[key]) for dim, key in variables.items()}

        levels = itertools.product(*[order[dim] for dim in ["row", "col"]])
        assert len(p._subplots) == len(list(levels))

        for subplot, (row_level, col_level) in zip(p._subplots, levels):
            assert subplot["row"] == row_level
            assert subplot["col"] == col_level
            assert subplot["axes"].get_title() == (
                f"{col_level} | {row_level}"
            )
            assert_gridspec_shape(
                subplot["axes"], len(levels["row"]), len(levels["col"])
            )

    def test_2d(self, long_df):

        variables = {"row": "a", "col": "c"}
        p = Plot(long_df).facet(**variables)
        self.check_facet_results_2d(p, long_df, variables)

    def test_2d_with_order(self, long_df, reorder):

        variables = {"row": "a", "col": "c"}
        order = {
            dim: reorder(categorical_order(long_df[key]))
            for dim, key in variables.items()
        }

        p = Plot(long_df).facet(**variables, order=order)
        self.check_facet_results_2d(p, long_df, variables, order)

    @pytest.mark.parametrize("algo", ["tight", "constrained"])
    def test_layout_algo(self, algo):

        if algo == "constrained" and Version(mpl.__version__) < Version("3.3.0"):
            pytest.skip("constrained_layout requires matplotlib>=3.3")

        p = Plot().facet(["a", "b"]).limit(x=(.1, .9))

        p1 = p.layout(engine=algo).plot()
        p2 = p.layout(engine=None).plot()

        # Force a draw (we probably need a method for this)
        p1.save(io.BytesIO())
        p2.save(io.BytesIO())

        bb11, bb12 = [ax.get_position() for ax in p1._figure.axes]
        bb21, bb22 = [ax.get_position() for ax in p2._figure.axes]

        sep1 = bb12.corners()[0, 0] - bb11.corners()[2, 0]
        sep2 = bb22.corners()[0, 0] - bb21.corners()[2, 0]
        assert sep1 < sep2

    def test_axis_sharing(self, long_df):

        variables = {"row": "a", "col": "c"}

        p = Plot(long_df).facet(**variables)

        p1 = p.plot()
        root, *other = p1._figure.axes
        for axis in "xy":
            shareset = getattr(root, f"get_shared_{axis}_axes")()
            assert all(shareset.joined(root, ax) for ax in other)

        p2 = p.share(x=False, y=False).plot()
        root, *other = p2._figure.axes
        for axis in "xy":
            shareset = getattr(root, f"get_shared_{axis}_axes")()
            assert not any(shareset.joined(root, ax) for ax in other)

        p3 = p.share(x="col", y="row").plot()
        shape = (
            len(categorical_order(long_df[variables["row"]])),
            len(categorical_order(long_df[variables["col"]])),
        )
        axes_matrix = np.reshape(p3._figure.axes, shape)

        for (shared, unshared), vectors in zip(
            ["yx", "xy"], [axes_matrix, axes_matrix.T]
        ):
            for root, *other in vectors:
                shareset = {
                    axis: getattr(root, f"get_shared_{axis}_axes")() for axis in "xy"
                }
                assert all(shareset[shared].joined(root, ax) for ax in other)
                assert not any(shareset[unshared].joined(root, ax) for ax in other)

    def test_unshared_spacing(self):

        x = [1, 2, 10, 20]
        y = [1, 2, 3, 4]
        col = [1, 1, 2, 2]

        m = MockMark()
        Plot(x, y).facet(col).add(m).share(x=False).plot()
        assert_array_almost_equal(m.passed_data[0]["width"], [0.8, 0.8])
        assert_array_equal(m.passed_data[1]["width"], [8, 8])

    def test_col_wrapping(self):

        cols = list("abcd")
        wrap = 3
        p = Plot().facet(col=cols, wrap=wrap).plot()

        assert len(p._figure.axes) == 4
        assert_gridspec_shape(p._figure.axes[0], len(cols) // wrap + 1, wrap)

        # TODO test axis labels and titles

    def test_row_wrapping(self):

        rows = list("abcd")
        wrap = 3
        p = Plot().facet(row=rows, wrap=wrap).plot()

        assert_gridspec_shape(p._figure.axes[0], wrap, len(rows) // wrap + 1)
        assert len(p._figure.axes) == 4

        # TODO test axis labels and titles


class TestPairInterface:

    def check_pair_grid(self, p, x, y):

        xys = itertools.product(y, x)

        for (y_i, x_j), subplot in zip(xys, p._subplots):

            ax = subplot["ax"]
            assert ax.get_xlabel() == "" if x_j is None else x_j
            assert ax.get_ylabel() == "" if y_i is None else y_i
            assert_gridspec_shape(subplot["ax"], len(y), len(x))

    @pytest.mark.parametrize("vector_type", [list, pd.Index])
    def test_all_numeric(self, long_df, vector_type):

        x, y = ["x", "y", "z"], ["s", "f"]
        p = Plot(long_df).pair(vector_type(x), vector_type(y)).plot()
        self.check_pair_grid(p, x, y)

    def test_single_variable_key_raises(self, long_df):

        p = Plot(long_df)
        err = "You must pass a sequence of variable keys to `y`"
        with pytest.raises(TypeError, match=err):
            p.pair(x=["x", "y"], y="z")

    @pytest.mark.parametrize("dim", ["x", "y"])
    def test_single_dimension(self, long_df, dim):

        variables = {"x": None, "y": None}
        variables[dim] = ["x", "y", "z"]
        p = Plot(long_df).pair(**variables).plot()
        variables = {k: [v] if v is None else v for k, v in variables.items()}
        self.check_pair_grid(p, **variables)

    def test_non_cross(self, long_df):

        x = ["x", "y"]
        y = ["f", "z"]

        p = Plot(long_df).pair(x, y, cross=False).plot()

        for i, subplot in enumerate(p._subplots):
            ax = subplot["ax"]
            assert ax.get_xlabel() == x[i]
            assert ax.get_ylabel() == y[i]
            assert_gridspec_shape(ax, 1, len(x))

        root, *other = p._figure.axes
        for axis in "xy":
            shareset = getattr(root, f"get_shared_{axis}_axes")()
            assert not any(shareset.joined(root, ax) for ax in other)

    def test_list_of_vectors(self, long_df):

        x_vars = ["x", "z"]
        p = Plot(long_df, y="y").pair(x=[long_df[x] for x in x_vars]).plot()
        assert len(p._figure.axes) == len(x_vars)
        for ax, x_i in zip(p._figure.axes, x_vars):
            assert ax.get_xlabel() == x_i

    def test_with_no_variables(self, long_df):

        p = Plot(long_df).pair().plot()
        assert len(p._figure.axes) == 1

    def test_with_facets(self, long_df):

        x = "x"
        y = ["y", "z"]
        col = "a"

        p = Plot(long_df, x=x).facet(col).pair(y=y).plot()

        facet_levels = categorical_order(long_df[col])
        dims = itertools.product(y, facet_levels)

        for (y_i, col_i), subplot in zip(dims, p._subplots):

            ax = subplot["ax"]
            assert ax.get_xlabel() == x
            assert ax.get_ylabel() == y_i
            assert ax.get_title() == f"{col_i}"
            assert_gridspec_shape(ax, len(y), len(facet_levels))

    @pytest.mark.parametrize("variables", [("rows", "y"), ("columns", "x")])
    def test_error_on_facet_overlap(self, long_df, variables):

        facet_dim, pair_axis = variables
        p = Plot(long_df).facet(**{facet_dim[:3]: "a"}).pair(**{pair_axis: ["x", "y"]})
        expected = f"Cannot facet the {facet_dim} while pairing on `{pair_axis}`."
        with pytest.raises(RuntimeError, match=expected):
            p.plot()

    @pytest.mark.parametrize("variables", [("columns", "y"), ("rows", "x")])
    def test_error_on_wrap_overlap(self, long_df, variables):

        facet_dim, pair_axis = variables
        p = (
            Plot(long_df)
            .facet(wrap=2, **{facet_dim[:3]: "a"})
            .pair(**{pair_axis: ["x", "y"]})
        )
        expected = f"Cannot wrap the {facet_dim} while pairing on `{pair_axis}``."
        with pytest.raises(RuntimeError, match=expected):
            p.plot()

    def test_axis_sharing(self, long_df):

        p = Plot(long_df).pair(x=["a", "b"], y=["y", "z"])
        shape = 2, 2

        p1 = p.plot()
        axes_matrix = np.reshape(p1._figure.axes, shape)

        for root, *other in axes_matrix:  # Test row-wise sharing
            x_shareset = getattr(root, "get_shared_x_axes")()
            assert not any(x_shareset.joined(root, ax) for ax in other)
            y_shareset = getattr(root, "get_shared_y_axes")()
            assert all(y_shareset.joined(root, ax) for ax in other)

        for root, *other in axes_matrix.T:  # Test col-wise sharing
            x_shareset = getattr(root, "get_shared_x_axes")()
            assert all(x_shareset.joined(root, ax) for ax in other)
            y_shareset = getattr(root, "get_shared_y_axes")()
            assert not any(y_shareset.joined(root, ax) for ax in other)

        p2 = p.share(x=False, y=False).plot()
        root, *other = p2._figure.axes
        for axis in "xy":
            shareset = getattr(root, f"get_shared_{axis}_axes")()
            assert not any(shareset.joined(root, ax) for ax in other)

    def test_axis_sharing_with_facets(self, long_df):

        p = Plot(long_df, y="y").pair(x=["a", "b"]).facet(row="c").plot()
        shape = 2, 2

        axes_matrix = np.reshape(p._figure.axes, shape)

        for root, *other in axes_matrix:  # Test row-wise sharing
            x_shareset = getattr(root, "get_shared_x_axes")()
            assert not any(x_shareset.joined(root, ax) for ax in other)
            y_shareset = getattr(root, "get_shared_y_axes")()
            assert all(y_shareset.joined(root, ax) for ax in other)

        for root, *other in axes_matrix.T:  # Test col-wise sharing
            x_shareset = getattr(root, "get_shared_x_axes")()
            assert all(x_shareset.joined(root, ax) for ax in other)
            y_shareset = getattr(root, "get_shared_y_axes")()
            assert all(y_shareset.joined(root, ax) for ax in other)

    def test_x_wrapping(self, long_df):

        x_vars = ["f", "x", "y", "z"]
        wrap = 3
        p = Plot(long_df, y="y").pair(x=x_vars, wrap=wrap).plot()

        assert_gridspec_shape(p._figure.axes[0], len(x_vars) // wrap + 1, wrap)
        assert len(p._figure.axes) == len(x_vars)
        for ax, var in zip(p._figure.axes, x_vars):
            label = ax.xaxis.get_label()
            assert label.get_visible()
            assert label.get_text() == var

    def test_y_wrapping(self, long_df):

        y_vars = ["f", "x", "y", "z"]
        wrap = 3
        p = Plot(long_df, x="x").pair(y=y_vars, wrap=wrap).plot()

        n_row, n_col = wrap, len(y_vars) // wrap + 1
        assert_gridspec_shape(p._figure.axes[0], n_row, n_col)
        assert len(p._figure.axes) == len(y_vars)
        label_array = np.empty(n_row * n_col, object)
        label_array[:len(y_vars)] = y_vars
        label_array = label_array.reshape((n_row, n_col), order="F")
        label_array = [y for y in label_array.flat if y is not None]
        for i, ax in enumerate(p._figure.axes):
            label = ax.yaxis.get_label()
            assert label.get_visible()
            assert label.get_text() == label_array[i]

    def test_non_cross_wrapping(self, long_df):

        x_vars = ["a", "b", "c", "t"]
        y_vars = ["f", "x", "y", "z"]
        wrap = 3

        p = (
            Plot(long_df, x="x")
            .pair(x=x_vars, y=y_vars, wrap=wrap, cross=False)
            .plot()
        )

        assert_gridspec_shape(p._figure.axes[0], len(x_vars) // wrap + 1, wrap)
        assert len(p._figure.axes) == len(x_vars)

    def test_cross_mismatched_lengths(self, long_df):

        p = Plot(long_df)
        with pytest.raises(ValueError, match="Lengths of the `x` and `y`"):
            p.pair(x=["a", "b"], y=["x", "y", "z"], cross=False)

    def test_orient_inference(self, long_df):

        orient_list = []

        class CaptureOrientMove(Move):
            def __call__(self, data, groupby, orient, scales):
                orient_list.append(orient)
                return data

        (
            Plot(long_df, x="x")
            .pair(y=["b", "z"])
            .add(MockMark(), CaptureOrientMove())
            .plot()
        )

        assert orient_list == ["y", "x"]

    def test_computed_coordinate_orient_inference(self, long_df):

        class MockComputeStat(Stat):
            def __call__(self, df, groupby, orient, scales):
                other = {"x": "y", "y": "x"}[orient]
                return df.assign(**{other: df[orient] * 2})

        m = MockMark()
        Plot(long_df, y="y").add(m, MockComputeStat()).plot()
        assert m.passed_orient == "y"

    def test_two_variables_single_order_error(self, long_df):

        p = Plot(long_df)
        err = "When faceting on both col= and row=, passing `order`"
        with pytest.raises(RuntimeError, match=err):
            p.facet(col="a", row="b", order=["a", "b", "c"])

    def test_limits(self, long_df):

        limit = (-2, 24)
        p = Plot(long_df, y="y").pair(x=["x", "z"]).limit(x1=limit).plot()
        ax1 = p._figure.axes[1]
        assert ax1.get_xlim() == limit

    def test_labels(self, long_df):

        label = "Z"
        p = Plot(long_df, y="y").pair(x=["x", "z"]).label(x1=label).plot()
        ax1 = p._figure.axes[1]
        assert ax1.get_xlabel() == label


class TestLabelVisibility:

    def test_single_subplot(self, long_df):

        x, y = "a", "z"
        p = Plot(long_df, x=x, y=y).plot()
        subplot, *_ = p._subplots
        ax = subplot["ax"]
        assert ax.xaxis.get_label().get_visible()
        assert ax.yaxis.get_label().get_visible()
        assert all(t.get_visible() for t in ax.get_xticklabels())
        assert all(t.get_visible() for t in ax.get_yticklabels())

    @pytest.mark.parametrize(
        "facet_kws,pair_kws", [({"col": "b"}, {}), ({}, {"x": ["x", "y", "f"]})]
    )
    def test_1d_column(self, long_df, facet_kws, pair_kws):

        x = None if "x" in pair_kws else "a"
        y = "z"
        p = Plot(long_df, x=x, y=y).plot()
        first, *other = p._subplots

        ax = first["ax"]
        assert ax.xaxis.get_label().get_visible()
        assert ax.yaxis.get_label().get_visible()
        assert all(t.get_visible() for t in ax.get_xticklabels())
        assert all(t.get_visible() for t in ax.get_yticklabels())

        for s in other:
            ax = s["ax"]
            assert ax.xaxis.get_label().get_visible()
            assert not ax.yaxis.get_label().get_visible()
            assert all(t.get_visible() for t in ax.get_xticklabels())
            assert not any(t.get_visible() for t in ax.get_yticklabels())

    @pytest.mark.parametrize(
        "facet_kws,pair_kws", [({"row": "b"}, {}), ({}, {"y": ["x", "y", "f"]})]
    )
    def test_1d_row(self, long_df, facet_kws, pair_kws):

        x = "z"
        y = None if "y" in pair_kws else "z"
        p = Plot(long_df, x=x, y=y).plot()
        first, *other = p._subplots

        ax = first["ax"]
        assert ax.xaxis.get_label().get_visible()
        assert all(t.get_visible() for t in ax.get_xticklabels())
        assert ax.yaxis.get_label().get_visible()
        assert all(t.get_visible() for t in ax.get_yticklabels())

        for s in other:
            ax = s["ax"]
            assert not ax.xaxis.get_label().get_visible()
            assert ax.yaxis.get_label().get_visible()
            assert not any(t.get_visible() for t in ax.get_xticklabels())
            assert all(t.get_visible() for t in ax.get_yticklabels())

    def test_1d_column_wrapped(self):

        p = Plot().facet(col=["a", "b", "c", "d"], wrap=3).plot()
        subplots = list(p._subplots)

        for s in [subplots[0], subplots[-1]]:
            ax = s["ax"]
            assert ax.yaxis.get_label().get_visible()
            assert all(t.get_visible() for t in ax.get_yticklabels())

        for s in subplots[1:]:
            ax = s["ax"]
            assert ax.xaxis.get_label().get_visible()
            assert all(t.get_visible() for t in ax.get_xticklabels())

        for s in subplots[1:-1]:
            ax = s["ax"]
            assert not ax.yaxis.get_label().get_visible()
            assert not any(t.get_visible() for t in ax.get_yticklabels())

        ax = subplots[0]["ax"]
        assert not ax.xaxis.get_label().get_visible()
        assert not any(t.get_visible() for t in ax.get_xticklabels())

    def test_1d_row_wrapped(self):

        p = Plot().facet(row=["a", "b", "c", "d"], wrap=3).plot()
        subplots = list(p._subplots)

        for s in subplots[:-1]:
            ax = s["ax"]
            assert ax.yaxis.get_label().get_visible()
            assert all(t.get_visible() for t in ax.get_yticklabels())

        for s in subplots[-2:]:
            ax = s["ax"]
            assert ax.xaxis.get_label().get_visible()
            assert all(t.get_visible() for t in ax.get_xticklabels())

        for s in subplots[:-2]:
            ax = s["ax"]
            assert not ax.xaxis.get_label().get_visible()
            assert not any(t.get_visible() for t in ax.get_xticklabels())

        ax = subplots[-1]["ax"]
        assert not ax.yaxis.get_label().get_visible()
        assert not any(t.get_visible() for t in ax.get_yticklabels())

    def test_1d_column_wrapped_non_cross(self, long_df):

        p = (
            Plot(long_df)
            .pair(x=["a", "b", "c"], y=["x", "y", "z"], wrap=2, cross=False)
            .plot()
        )
        for s in p._subplots:
            ax = s["ax"]
            assert ax.xaxis.get_label().get_visible()
            assert all(t.get_visible() for t in ax.get_xticklabels())
            assert ax.yaxis.get_label().get_visible()
            assert all(t.get_visible() for t in ax.get_yticklabels())

    def test_2d(self):

        p = Plot().facet(col=["a", "b"], row=["x", "y"]).plot()
        subplots = list(p._subplots)

        for s in subplots[:2]:
            ax = s["ax"]
            assert not ax.xaxis.get_label().get_visible()
            assert not any(t.get_visible() for t in ax.get_xticklabels())

        for s in subplots[2:]:
            ax = s["ax"]
            assert ax.xaxis.get_label().get_visible()
            assert all(t.get_visible() for t in ax.get_xticklabels())

        for s in [subplots[0], subplots[2]]:
            ax = s["ax"]
            assert ax.yaxis.get_label().get_visible()
            assert all(t.get_visible() for t in ax.get_yticklabels())

        for s in [subplots[1], subplots[3]]:
            ax = s["ax"]
            assert not ax.yaxis.get_label().get_visible()
            assert not any(t.get_visible() for t in ax.get_yticklabels())

    def test_2d_unshared(self):

        p = (
            Plot()
            .facet(col=["a", "b"], row=["x", "y"])
            .share(x=False, y=False)
            .plot()
        )
        subplots = list(p._subplots)

        for s in subplots[:2]:
            ax = s["ax"]
            assert not ax.xaxis.get_label().get_visible()
            assert all(t.get_visible() for t in ax.get_xticklabels())

        for s in subplots[2:]:
            ax = s["ax"]
            assert ax.xaxis.get_label().get_visible()
            assert all(t.get_visible() for t in ax.get_xticklabels())

        for s in [subplots[0], subplots[2]]:
            ax = s["ax"]
            assert ax.yaxis.get_label().get_visible()
            assert all(t.get_visible() for t in ax.get_yticklabels())

        for s in [subplots[1], subplots[3]]:
            ax = s["ax"]
            assert not ax.yaxis.get_label().get_visible()
            assert all(t.get_visible() for t in ax.get_yticklabels())


class TestLegend:

    @pytest.fixture
    def xy(self):
        return dict(x=[1, 2, 3, 4], y=[1, 2, 3, 4])

    def test_single_layer_single_variable(self, xy):

        s = pd.Series(["a", "b", "a", "c"], name="s")
        p = Plot(**xy).add(MockMark(), color=s).plot()
        e, = p._legend_contents

        labels = categorical_order(s)

        assert e[0] == (s.name, s.name)
        assert e[-1] == labels

        artists = e[1]
        assert len(artists) == len(labels)
        for a, label in zip(artists, labels):
            assert isinstance(a, mpl.artist.Artist)
            assert a.value == label
            assert a.variables == ["color"]

    def test_single_layer_common_variable(self, xy):

        s = pd.Series(["a", "b", "a", "c"], name="s")
        sem = dict(color=s, marker=s)
        p = Plot(**xy).add(MockMark(), **sem).plot()
        e, = p._legend_contents

        labels = categorical_order(s)

        assert e[0] == (s.name, s.name)
        assert e[-1] == labels

        artists = e[1]
        assert len(artists) == len(labels)
        for a, label in zip(artists, labels):
            assert isinstance(a, mpl.artist.Artist)
            assert a.value == label
            assert a.variables == list(sem)

    def test_single_layer_common_unnamed_variable(self, xy):

        s = np.array(["a", "b", "a", "c"])
        sem = dict(color=s, marker=s)
        p = Plot(**xy).add(MockMark(), **sem).plot()

        e, = p._legend_contents

        labels = list(np.unique(s))  # assumes sorted order

        assert e[0] == ("", id(s))
        assert e[-1] == labels

        artists = e[1]
        assert len(artists) == len(labels)
        for a, label in zip(artists, labels):
            assert isinstance(a, mpl.artist.Artist)
            assert a.value == label
            assert a.variables == list(sem)

    def test_single_layer_multi_variable(self, xy):

        s1 = pd.Series(["a", "b", "a", "c"], name="s1")
        s2 = pd.Series(["m", "m", "p", "m"], name="s2")
        sem = dict(color=s1, marker=s2)
        p = Plot(**xy).add(MockMark(), **sem).plot()
        e1, e2 = p._legend_contents

        variables = {v.name: k for k, v in sem.items()}

        for e, s in zip([e1, e2], [s1, s2]):
            assert e[0] == (s.name, s.name)

            labels = categorical_order(s)
            assert e[-1] == labels

            artists = e[1]
            assert len(artists) == len(labels)
            for a, label in zip(artists, labels):
                assert isinstance(a, mpl.artist.Artist)
                assert a.value == label
                assert a.variables == [variables[s.name]]

    def test_multi_layer_single_variable(self, xy):

        s = pd.Series(["a", "b", "a", "c"], name="s")
        p = Plot(**xy, color=s).add(MockMark()).add(MockMark()).plot()
        e1, e2 = p._legend_contents

        labels = categorical_order(s)

        for e in [e1, e2]:
            assert e[0] == (s.name, s.name)

            labels = categorical_order(s)
            assert e[-1] == labels

            artists = e[1]
            assert len(artists) == len(labels)
            for a, label in zip(artists, labels):
                assert isinstance(a, mpl.artist.Artist)
                assert a.value == label
                assert a.variables == ["color"]

    def test_multi_layer_multi_variable(self, xy):

        s1 = pd.Series(["a", "b", "a", "c"], name="s1")
        s2 = pd.Series(["m", "m", "p", "m"], name="s2")
        sem = dict(color=s1), dict(marker=s2)
        variables = {"s1": "color", "s2": "marker"}
        p = Plot(**xy).add(MockMark(), **sem[0]).add(MockMark(), **sem[1]).plot()
        e1, e2 = p._legend_contents

        for e, s in zip([e1, e2], [s1, s2]):
            assert e[0] == (s.name, s.name)

            labels = categorical_order(s)
            assert e[-1] == labels

            artists = e[1]
            assert len(artists) == len(labels)
            for a, label in zip(artists, labels):
                assert isinstance(a, mpl.artist.Artist)
                assert a.value == label
                assert a.variables == [variables[s.name]]

    def test_multi_layer_different_artists(self, xy):

        class MockMark1(MockMark):
            def _legend_artist(self, variables, value, scales):
                return mpl.lines.Line2D([], [])

        class MockMark2(MockMark):
            def _legend_artist(self, variables, value, scales):
                return mpl.patches.Patch()

        s = pd.Series(["a", "b", "a", "c"], name="s")
        p = Plot(**xy, color=s).add(MockMark1()).add(MockMark2()).plot()

        legend, = p._figure.legends

        names = categorical_order(s)
        labels = [t.get_text() for t in legend.get_texts()]
        assert labels == names

        if Version(mpl.__version__) >= Version("3.2"):
            contents = legend.get_children()[0]
            assert len(contents.findobj(mpl.lines.Line2D)) == len(names)
            assert len(contents.findobj(mpl.patches.Patch)) == len(names)

    def test_three_layers(self, xy):

        class MockMarkLine(MockMark):
            def _legend_artist(self, variables, value, scales):
                return mpl.lines.Line2D([], [])

        s = pd.Series(["a", "b", "a", "c"], name="s")
        p = Plot(**xy, color=s)
        for _ in range(3):
            p = p.add(MockMarkLine())
        p = p.plot()
        texts = p._figure.legends[0].get_texts()
        assert len(texts) == len(s.unique())

    def test_identity_scale_ignored(self, xy):

        s = pd.Series(["r", "g", "b", "g"])
        p = Plot(**xy).add(MockMark(), color=s).scale(color=None).plot()
        assert not p._legend_contents

    def test_suppression_in_add_method(self, xy):

        s = pd.Series(["a", "b", "a", "c"], name="s")
        p = Plot(**xy).add(MockMark(), color=s, legend=False).plot()
        assert not p._legend_contents

    def test_anonymous_title(self, xy):

        p = Plot(**xy, color=["a", "b", "c", "d"]).add(MockMark()).plot()
        legend, = p._figure.legends
        assert legend.get_title().get_text() == ""

    def test_legendless_mark(self, xy):

        class NoLegendMark(MockMark):
            def _legend_artist(self, variables, value, scales):
                return None

        p = Plot(**xy, color=["a", "b", "c", "d"]).add(NoLegendMark()).plot()
        assert not p._figure.legends

    def test_legend_has_no_offset(self, xy):

        color = np.add(xy["x"], 1e8)
        p = Plot(**xy, color=color).add(MockMark()).plot()
        legend = p._figure.legends[0]
        assert legend.texts
        for text in legend.texts:
            assert float(text.get_text()) > 1e7


class TestDefaultObject:

    def test_default_repr(self):

        assert repr(Default()) == "<default>"