import numpy as np
import pytest

import pandas as pd
from pandas import Index
import pandas._testing as tm


class TestGetLoc:
    def test_get_loc_raises_object_nearest(self):
        index = Index(["a", "c"])
        with pytest.raises(TypeError, match="unsupported operand type"):
            index.get_loc("a", method="nearest")

    def test_get_loc_raises_object_tolerance(self):
        index = Index(["a", "c"])
        with pytest.raises(TypeError, match="unsupported operand type"):
            index.get_loc("a", method="pad", tolerance="invalid")


class TestGetIndexer:
    @pytest.mark.parametrize(
        "method,expected",
        [
            ("pad", np.array([-1, 0, 1, 1], dtype=np.intp)),
            ("backfill", np.array([0, 0, 1, -1], dtype=np.intp)),
        ],
    )
    def test_get_indexer_strings(self, method, expected):
        index = Index(["b", "c"])
        actual = index.get_indexer(["a", "b", "c", "d"], method=method)

        tm.assert_numpy_array_equal(actual, expected)

    def test_get_indexer_strings_raises(self):
        index = Index(["b", "c"])

        msg = r"unsupported operand type\(s\) for -: 'str' and 'str'"
        with pytest.raises(TypeError, match=msg):
            index.get_indexer(["a", "b", "c", "d"], method="nearest")

        with pytest.raises(TypeError, match=msg):
            index.get_indexer(["a", "b", "c", "d"], method="pad", tolerance=2)

        with pytest.raises(TypeError, match=msg):
            index.get_indexer(
                ["a", "b", "c", "d"], method="pad", tolerance=[2, 2, 2, 2]
            )

    def test_get_indexer_with_NA_values(
        self, unique_nulls_fixture, unique_nulls_fixture2
    ):
        # GH#22332
        # check pairwise, that no pair of na values
        # is mangled
        if unique_nulls_fixture is unique_nulls_fixture2:
            return  # skip it, values are not unique
        arr = np.array([unique_nulls_fixture, unique_nulls_fixture2], dtype=object)
        index = Index(arr, dtype=object)
        result = index.get_indexer(
            [unique_nulls_fixture, unique_nulls_fixture2, "Unknown"]
        )
        expected = np.array([0, 1, -1], dtype=np.intp)
        tm.assert_numpy_array_equal(result, expected)


class TestSliceLocs:
    @pytest.mark.parametrize(
        "in_slice,expected",
        [
            # error: Slice index must be an integer or None
            (pd.IndexSlice[::-1], "yxdcb"),
            (pd.IndexSlice["b":"y":-1], ""),  # type: ignore[misc]
            (pd.IndexSlice["b"::-1], "b"),  # type: ignore[misc]
            (pd.IndexSlice[:"b":-1], "yxdcb"),  # type: ignore[misc]
            (pd.IndexSlice[:"y":-1], "y"),  # type: ignore[misc]
            (pd.IndexSlice["y"::-1], "yxdcb"),  # type: ignore[misc]
            (pd.IndexSlice["y"::-4], "yb"),  # type: ignore[misc]
            # absent labels
            (pd.IndexSlice[:"a":-1], "yxdcb"),  # type: ignore[misc]
            (pd.IndexSlice[:"a":-2], "ydb"),  # type: ignore[misc]
            (pd.IndexSlice["z"::-1], "yxdcb"),  # type: ignore[misc]
            (pd.IndexSlice["z"::-3], "yc"),  # type: ignore[misc]
            (pd.IndexSlice["m"::-1], "dcb"),  # type: ignore[misc]
            (pd.IndexSlice[:"m":-1], "yx"),  # type: ignore[misc]
            (pd.IndexSlice["a":"a":-1], ""),  # type: ignore[misc]
            (pd.IndexSlice["z":"z":-1], ""),  # type: ignore[misc]
            (pd.IndexSlice["m":"m":-1], ""),  # type: ignore[misc]
        ],
    )
    def test_slice_locs_negative_step(self, in_slice, expected):
        index = Index(list("bcdxy"))

        s_start, s_stop = index.slice_locs(in_slice.start, in_slice.stop, in_slice.step)
        result = index[s_start : s_stop : in_slice.step]
        expected = Index(list(expected))
        tm.assert_index_equal(result, expected)

    def test_slice_locs_dup(self):
        index = Index(["a", "a", "b", "c", "d", "d"])
        assert index.slice_locs("a", "d") == (0, 6)
        assert index.slice_locs(end="d") == (0, 6)
        assert index.slice_locs("a", "c") == (0, 4)
        assert index.slice_locs("b", "d") == (2, 6)

        index2 = index[::-1]
        assert index2.slice_locs("d", "a") == (0, 6)
        assert index2.slice_locs(end="a") == (0, 6)
        assert index2.slice_locs("d", "b") == (0, 4)
        assert index2.slice_locs("c", "a") == (2, 6)