import pytest
import numpy as np
import pandas as pd

from .base import BaseExtensionTests


class BaseDtypeTests(BaseExtensionTests):
    """Base class for ExtensionDtype classes"""

    def test_name(self, dtype):
        assert isinstance(dtype.name, str)

    def test_kind(self, dtype):
        valid = set('biufcmMOSUV')
        if dtype.kind is not None:
            assert dtype.kind in valid

    def test_construct_from_string_own_name(self, dtype):
        result = dtype.construct_from_string(dtype.name)
        assert type(result) is type(dtype)

        # check OK as classmethod
        result = type(dtype).construct_from_string(dtype.name)
        assert type(result) is type(dtype)

    def test_is_dtype_from_name(self, dtype):
        result = type(dtype).is_dtype(dtype.name)
        assert result is True

    def test_is_dtype_unboxes_dtype(self, data, dtype):
        assert dtype.is_dtype(data) is True

    def test_is_dtype_from_self(self, dtype):
        result = type(dtype).is_dtype(dtype)
        assert result is True

    def test_is_not_string_type(self, dtype):
        return not pd.api.types.is_string_dtype(dtype)

    def test_is_not_object_type(self, dtype):
        return not pd.api.types.is_object_dtype(dtype)

    def test_eq_with_str(self, dtype):
        assert dtype == dtype.name
        assert dtype != dtype.name + '-suffix'

    def test_eq_with_numpy_object(self, dtype):
        assert dtype != np.dtype('object')

    def test_array_type(self, data, dtype):
        assert dtype.construct_array_type() is type(data)

    def test_array_type_with_arg(self, data, dtype):
        with pytest.raises(NotImplementedError):
            dtype.construct_array_type('foo')

    def test_check_dtype(self, data):
        dtype = data.dtype

        # check equivalency for using .dtypes
        df = pd.DataFrame({'A': pd.Series(data, dtype=dtype),
                           'B': data,
                           'C': 'foo', 'D': 1})

        # np.dtype('int64') == 'Int64' == 'int64'
        # so can't distinguish
        if dtype.name == 'Int64':
            expected = pd.Series([True, True, False, True],
                                 index=list('ABCD'))
        else:
            expected = pd.Series([True, True, False, False],
                                 index=list('ABCD'))

        result = df.dtypes == str(dtype)
        self.assert_series_equal(result, expected)

        expected = pd.Series([True, True, False, False],
                             index=list('ABCD'))
        result = df.dtypes.apply(str) == str(dtype)
        self.assert_series_equal(result, expected)
