import pytest
import numpy as np
from numpy.testing import assert_allclose

from sklearn.ensemble._hist_gradient_boosting._bitset import (
    set_bitset_memoryview,
    in_bitset_memoryview,
    set_raw_bitset_from_binned_bitset
)
from sklearn.ensemble._hist_gradient_boosting.common import X_DTYPE


@pytest.mark.parametrize("values_to_insert, expected_bitset", [
    ([0, 4, 33], np.array([2**0 + 2**4, 2**1, 0], dtype=np.uint32)),
    ([31, 32, 33, 79], np.array([2**31, 2**0 + 2**1, 2**15], dtype=np.uint32))
])
def test_set_get_bitset(values_to_insert, expected_bitset):
    n_32bits_ints = 3
    bitset = np.zeros(n_32bits_ints, dtype=np.uint32)
    for value in values_to_insert:
        set_bitset_memoryview(bitset, value)
    assert_allclose(expected_bitset, bitset)
    for value in range(32 * n_32bits_ints):
        if value in values_to_insert:
            assert in_bitset_memoryview(bitset, value)
        else:
            assert not in_bitset_memoryview(bitset, value)


@pytest.mark.parametrize(
    "raw_categories, binned_cat_to_insert, expected_raw_bitset", [
        ([3, 4, 5, 10, 31, 32, 43],
         [0, 2, 4, 5, 6],
         [2**3 + 2**5 + 2**31, 2**0 + 2**11]),

        ([3, 33, 50, 52],
         [1, 3],
         [0, 2**1 + 2**20]),
        ]
)
def test_raw_bitset_from_binned_bitset(raw_categories, binned_cat_to_insert,
                                       expected_raw_bitset):
    binned_bitset = np.zeros(2, dtype=np.uint32)
    raw_bitset = np.zeros(2, dtype=np.uint32)
    raw_categories = np.asarray(raw_categories, dtype=X_DTYPE)

    for val in binned_cat_to_insert:
        set_bitset_memoryview(binned_bitset, val)

    set_raw_bitset_from_binned_bitset(raw_bitset, binned_bitset,
                                      raw_categories)

    assert_allclose(expected_raw_bitset, raw_bitset)
    for binned_cat_val, raw_cat_val in enumerate(raw_categories):
        if binned_cat_val in binned_cat_to_insert:
            assert in_bitset_memoryview(raw_bitset, raw_cat_val)
        else:
            assert not in_bitset_memoryview(raw_bitset, raw_cat_val)
