def test_orcfile_empty():
    from pyarrow import orc
    f = orc.ORCFile(path_for_orc_example('TestOrcFile.emptyFile'))
    table = f.read()
    assert table.num_rows == 0
    schema = table.schema
    expected_schema = pa.schema([
        ('boolean1', pa.bool_()),
        ('byte1', pa.int8()),
        ('short1', pa.int16()),
        ('int1', pa.int32()),
        ('long1', pa.int64()),
        ('float1', pa.float32()),
        ('double1', pa.float64()),
        ('bytes1', pa.binary()),
        ('string1', pa.string()),
        ('middle', pa.struct([
            ('list', pa.list_(pa.struct([
                ('int1', pa.int32()),
                ('string1', pa.string()),
                ]))),
            ])),
        ('list', pa.list_(pa.struct([
            ('int1', pa.int32()),
            ('string1', pa.string()),
            ]))),
        ('map', pa.list_(pa.struct([
            ('key', pa.string()),
            ('value', pa.struct([
                ('int1', pa.int32()),
                ('string1', pa.string()),
                ])),
            ]))),
        ])
    assert schema == expected_schema

def test_struct_type():
    fields = [pa.field('a', pa.int64()),
              pa.field('a', pa.int32()),
              pa.field('b', pa.int32())]
    ty = pa.struct(fields)

    assert len(ty) == ty.num_children == 3
    assert list(ty) == fields

    for a, b in zip(ty, fields):
        a == b

    # Construct from list of tuples
    ty = pa.struct([('a', pa.int64()),
                    ('a', pa.int32()),
                    ('b', pa.int32())])
    assert list(ty) == fields
    for a, b in zip(ty, fields):
        a == b

    # Construct from mapping
    fields = [pa.field('a', pa.int64()),
              pa.field('b', pa.int32())]
    ty = pa.struct(OrderedDict([('a', pa.int64()),
                                ('b', pa.int32())]))
    assert list(ty) == fields
    for a, b in zip(ty, fields):
        a == b

def test_struct_type():
    fields = [
        # Duplicate field name on purpose
        pa.field('a', pa.int64()),
        pa.field('a', pa.int32()),
        pa.field('b', pa.int32())
    ]
    ty = pa.struct(fields)

    assert len(ty) == ty.num_children == 3
    assert list(ty) == fields
    assert ty[0].name == 'a'
    assert ty[2].type == pa.int32()
    with pytest.raises(IndexError):
        assert ty[3]

    assert ty['b'] == ty[2]

    # Duplicate
    with pytest.warns(UserWarning):
        with pytest.raises(KeyError):
            ty['a']

    # Not found
    with pytest.raises(KeyError):
        ty['c']

    # Neither integer nor string
    with pytest.raises(TypeError):
        ty[None]

    for a, b in zip(ty, fields):
        a == b

    # Construct from list of tuples
    ty = pa.struct([('a', pa.int64()),
                    ('a', pa.int32()),
                    ('b', pa.int32())])
    assert list(ty) == fields
    for a, b in zip(ty, fields):
        a == b

    # Construct from mapping
    fields = [pa.field('a', pa.int64()),
              pa.field('b', pa.int32())]
    ty = pa.struct(OrderedDict([('a', pa.int64()),
                                ('b', pa.int32())]))
    assert list(ty) == fields
    for a, b in zip(ty, fields):
        a == b

    # Invalid args
    with pytest.raises(TypeError):
        pa.struct([('a', None)])

def test_struct_array_slice():
    # ARROW-2311: slicing nested arrays needs special care
    ty = pa.struct([pa.field('a', pa.int8()),
                    pa.field('b', pa.float32())])
    arr = pa.array([(1, 2.5), (3, 4.5), (5, 6.5)], type=ty)
    assert arr[1:].to_pylist() == [{'a': 3, 'b': 4.5},
                                   {'a': 5, 'b': 6.5}]

def test_buffers_nested():
    a = pa.array([[1, 2], None, [3, None, 4, 5]], type=pa.list_(pa.int64()))
    buffers = a.buffers()
    assert len(buffers) == 4
    # The parent buffers
    null_bitmap = buffers[0].to_pybytes()
    assert bytearray(null_bitmap)[0] == 0b00000101
    offsets = buffers[1].to_pybytes()
    assert struct.unpack('4i', offsets) == (0, 2, 2, 6)
    # The child buffers
    null_bitmap = buffers[2].to_pybytes()
    assert bytearray(null_bitmap)[0] == 0b00110111
    values = buffers[3].to_pybytes()
    assert struct.unpack('qqq8xqq', values) == (1, 2, 3, 4, 5)

    a = pa.array([(42, None), None, (None, 43)],
                 type=pa.struct([pa.field('a', pa.int8()),
                                 pa.field('b', pa.int16())]))
    buffers = a.buffers()
    assert len(buffers) == 5
    # The parent buffer
    null_bitmap = buffers[0].to_pybytes()
    assert bytearray(null_bitmap)[0] == 0b00000101
    # The child buffers: 'a'
    null_bitmap = buffers[1].to_pybytes()
    assert bytearray(null_bitmap)[0] == 0b00000001
    values = buffers[2].to_pybytes()
    assert struct.unpack('bxx', values) == (42,)
    # The child buffers: 'b'
    null_bitmap = buffers[3].to_pybytes()
    assert bytearray(null_bitmap)[0] == 0b00000100
    values = buffers[4].to_pybytes()
    assert struct.unpack('4xh', values) == (43,)

def test_type_schema_pickling():
    cases = [
        pa.int8(),
        pa.string(),
        pa.binary(),
        pa.binary(10),
        pa.list_(pa.string()),
        pa.struct([
            pa.field('a', 'int8'),
            pa.field('b', 'string')
        ]),
        pa.time32('s'),
        pa.time64('us'),
        pa.date32(),
        pa.date64(),
        pa.timestamp('ms'),
        pa.timestamp('ns'),
        pa.decimal(12, 2),
        pa.field('a', 'string', metadata={b'foo': b'bar'})
    ]

    for val in cases:
        roundtripped = pickle.loads(pickle.dumps(val))
        assert val == roundtripped

    fields = []
    for i, f in enumerate(cases):
        if isinstance(f, pa.Field):
            fields.append(f)
        else:
            fields.append(pa.field('_f{}'.format(i), f))

    schema = pa.schema(fields, metadata={b'foo': b'bar'})
    roundtripped = pickle.loads(pickle.dumps(schema))
    assert schema == roundtripped

def test_cast_from_null():
    in_data = [None] * 3
    in_type = pa.null()
    out_types = [
        pa.null(),
        pa.uint8(),
        pa.float16(),
        pa.utf8(),
        pa.binary(),
        pa.binary(10),
        pa.list_(pa.int16()),
        pa.decimal128(19, 4),
        pa.timestamp('us'),
        pa.timestamp('us', tz='UTC'),
        pa.timestamp('us', tz='Europe/Paris'),
        pa.struct([pa.field('a', pa.int32()),
                   pa.field('b', pa.list_(pa.int8())),
                   pa.field('c', pa.string())]),
        ]
    for out_type in out_types:
        _check_cast_case((in_data, in_type, in_data, out_type))

    out_types = [
        pa.dictionary(pa.int32(), pa.string()),
        pa.union([pa.field('a', pa.binary(10)),
                  pa.field('b', pa.string())], mode=pa.lib.UnionMode_DENSE),
        pa.union([pa.field('a', pa.binary(10)),
                  pa.field('b', pa.string())], mode=pa.lib.UnionMode_SPARSE),
        ]
    in_arr = pa.array(in_data, type=pa.null())
    for out_type in out_types:
        with pytest.raises(NotImplementedError):
            in_arr.cast(out_type)

def test_struct_from_tuples():
    ty = pa.struct([pa.field('a', pa.int32()),
                    pa.field('b', pa.string()),
                    pa.field('c', pa.bool_())])

    data = [(5, 'foo', True),
            (6, 'bar', False)]
    expected = [{'a': 5, 'b': 'foo', 'c': True},
                {'a': 6, 'b': 'bar', 'c': False}]
    arr = pa.array(data, type=ty)

    data_as_ndarray = np.empty(len(data), dtype=object)
    data_as_ndarray[:] = data
    arr2 = pa.array(data_as_ndarray, type=ty)
    assert arr.to_pylist() == expected

    assert arr.equals(arr2)

    # With omitted values
    data = [(5, 'foo', None),
            None,
            (6, None, False)]
    expected = [{'a': 5, 'b': 'foo', 'c': None},
                None,
                {'a': 6, 'b': None, 'c': False}]
    arr = pa.array(data, type=ty)
    assert arr.to_pylist() == expected

    # Invalid tuple size
    for tup in [(5, 'foo'), (), ('5', 'foo', True, None)]:
        with pytest.raises(ValueError, match="(?i)tuple size"):
            pa.array([tup], type=ty)

def test_struct_array_field():
    ty = pa.struct([pa.field('x', pa.int16()),
                    pa.field('y', pa.float32())])
    a = pa.array([(1, 2.5), (3, 4.5), (5, 6.5)], type=ty)

    x0 = a.field(0)
    y0 = a.field(1)
    x1 = a.field(-2)
    y1 = a.field(-1)
    x2 = a.field('x')
    y2 = a.field('y')

    assert isinstance(x0, pa.lib.Int16Array)
    assert isinstance(y1, pa.lib.FloatArray)
    assert x0.equals(pa.array([1, 3, 5], type=pa.int16()))
    assert y0.equals(pa.array([2.5, 4.5, 6.5], type=pa.float32()))
    assert x0.equals(x1)
    assert x0.equals(x2)
    assert y0.equals(y1)
    assert y0.equals(y2)

    for invalid_index in [None, pa.int16()]:
        with pytest.raises(TypeError):
            a.field(invalid_index)

    for invalid_index in [3, -3]:
        with pytest.raises(IndexError):
            a.field(invalid_index)

    for invalid_name in ['z', '']:
        with pytest.raises(KeyError):
            a.field(invalid_name)

def test_struct_from_dicts_inference():
    expected_type = pa.struct([pa.field('a', pa.int64()),
                               pa.field('b', pa.string()),
                               pa.field('c', pa.bool_())])
    data = [{'a': 5, 'b': u'foo', 'c': True},
            {'a': 6, 'b': u'bar', 'c': False}]
    arr = pa.array(data)
    check_struct_type(arr.type, expected_type)
    assert arr.to_pylist() == data

    # With omitted values
    data = [{'a': 5, 'c': True},
            None,
            {},
            {'a': None, 'b': u'bar'}]
    expected = [{'a': 5, 'b': None, 'c': True},
                None,
                {'a': None, 'b': None, 'c': None},
                {'a': None, 'b': u'bar', 'c': None}]
    arr = pa.array(data)
    data_as_ndarray = np.empty(len(data), dtype=object)
    data_as_ndarray[:] = data
    arr2 = pa.array(data)

    check_struct_type(arr.type, expected_type)
    assert arr.to_pylist() == expected
    assert arr.equals(arr2)

    # Nested
    expected_type = pa.struct([
        pa.field('a', pa.struct([pa.field('aa', pa.list_(pa.int64())),
                                 pa.field('ab', pa.bool_())])),
        pa.field('b', pa.string())])
    data = [{'a': {'aa': [5, 6], 'ab': True}, 'b': 'foo'},
            {'a': {'aa': None, 'ab': False}, 'b': None},
            {'a': None, 'b': 'bar'}]
    arr = pa.array(data)
    assert arr.to_pylist() == data

    # Edge cases
    arr = pa.array([{}])
    assert arr.type == pa.struct([])
    assert arr.to_pylist() == [{}]

    # Mixing structs and scalars is rejected
    with pytest.raises((pa.ArrowInvalid, pa.ArrowTypeError)):
        pa.array([1, {'a': 2}])

def test_field_flatten():
    f0 = pa.field('foo', pa.int32()).add_metadata({b'foo': b'bar'})
    assert f0.flatten() == [f0]

    f1 = pa.field('bar', pa.float64(), nullable=False)
    ff = pa.field('ff', pa.struct([f0, f1]), nullable=False)
    assert ff.flatten() == [
        pa.field('ff.foo', pa.int32()).add_metadata({b'foo': b'bar'}),
        pa.field('ff.bar', pa.float64(), nullable=False)]  # XXX

    # Nullable parent makes flattened child nullable
    ff = pa.field('ff', pa.struct([f0, f1]))
    assert ff.flatten() == [
        pa.field('ff.foo', pa.int32()).add_metadata({b'foo': b'bar'}),
        pa.field('ff.bar', pa.float64())]

    fff = pa.field('fff', pa.struct([ff]))
    assert fff.flatten() == [pa.field('fff.ff', pa.struct([f0, f1]))]

def test_struct_from_mixed_sequence():
    # It is forbidden to mix dicts and tuples when initializing a struct array
    ty = pa.struct([pa.field('a', pa.int32()),
                    pa.field('b', pa.string()),
                    pa.field('c', pa.bool_())])
    data = [(5, 'foo', True),
            {'a': 6, 'b': 'bar', 'c': False}]
    with pytest.raises(TypeError):
        pa.array(data, type=ty)

def test_table_flatten():
    ty1 = pa.struct([pa.field('x', pa.int16()),
                     pa.field('y', pa.float32())])
    ty2 = pa.struct([pa.field('nest', ty1)])
    a = pa.array([(1, 2.5), (3, 4.5)], type=ty1)
    b = pa.array([((11, 12.5),), ((13, 14.5),)], type=ty2)
    c = pa.array([False, True], type=pa.bool_())

    table = pa.Table.from_arrays([a, b, c], names=['a', 'b', 'c'])
    t2 = table.flatten()
    t2._validate()
    expected = pa.Table.from_arrays([
        pa.array([1, 3], type=pa.int16()),
        pa.array([2.5, 4.5], type=pa.float32()),
        pa.array([(11, 12.5), (13, 14.5)], type=ty1),
        c],
        names=['a.x', 'a.y', 'b.nest', 'c'])
    assert t2.equals(expected)

def test_is_nested_or_struct():
    struct_ex = pa.struct([pa.field('a', pa.int32()),
                           pa.field('b', pa.int8()),
                           pa.field('c', pa.string())])

    assert types.is_struct(struct_ex)
    assert not types.is_struct(pa.list_(pa.int32()))

    assert types.is_nested(struct_ex)
    assert types.is_nested(pa.list_(pa.int32()))
    assert not types.is_nested(pa.int32())

def bq_to_arrow_struct_data_type(field):
    arrow_fields = []
    for subfield in field.fields:
        arrow_subfield = bq_to_arrow_field(subfield)
        if arrow_subfield:
            arrow_fields.append(arrow_subfield)
        else:
            # Could not determine a subfield type. Fallback to type
            # inference.
            return None
    return pyarrow.struct(arrow_fields)

def test_struct_type():
    fields = [pa.field('a', pa.int64()),
              pa.field('a', pa.int32()),
              pa.field('b', pa.int32())]
    ty = pa.struct(fields)

    assert len(ty) == ty.num_children == 3
    assert list(ty) == fields

    for a, b in zip(ty, fields):
        a == b

def get_many_types():
    # returning them from a function is required because of pa.dictionary
    # type holds a pyarrow array and test_array.py::test_toal_bytes_allocated
    # checks that the default memory pool has zero allocated bytes
    return (
        pa.null(),
        pa.bool_(),
        pa.int32(),
        pa.time32('s'),
        pa.time64('us'),
        pa.date32(),
        pa.timestamp('us'),
        pa.timestamp('us', tz='UTC'),
        pa.timestamp('us', tz='Europe/Paris'),
        pa.float16(),
        pa.float32(),
        pa.float64(),
        pa.decimal128(19, 4),
        pa.string(),
        pa.binary(),
        pa.binary(10),
        pa.list_(pa.int32()),
        pa.struct([pa.field('a', pa.int32()),
                   pa.field('b', pa.int8()),
                   pa.field('c', pa.string())]),
        pa.struct([pa.field('a', pa.int32(), nullable=False),
                   pa.field('b', pa.int8(), nullable=False),
                   pa.field('c', pa.string())]),
        pa.union([pa.field('a', pa.binary(10)),
                  pa.field('b', pa.string())], mode=pa.lib.UnionMode_DENSE),
        pa.union([pa.field('a', pa.binary(10)),
                  pa.field('b', pa.string())], mode=pa.lib.UnionMode_SPARSE),
        pa.union([pa.field('a', pa.binary(10), nullable=False),
                  pa.field('b', pa.string())], mode=pa.lib.UnionMode_SPARSE),
        pa.dictionary(pa.int32(), pa.string())
    )

def test_column_flatten():
    ty = pa.struct([pa.field('x', pa.int16()),
                    pa.field('y', pa.float32())])
    a = pa.array([(1, 2.5), (3, 4.5), (5, 6.5)], type=ty)
    col = pa.Column.from_array('foo', a)
    x, y = col.flatten()
    assert x == pa.column('foo.x', pa.array([1, 3, 5], type=pa.int16()))
    assert y == pa.column('foo.y', pa.array([2.5, 4.5, 6.5],
                                            type=pa.float32()))
    # Empty column
    a = pa.array([], type=ty)
    col = pa.Column.from_array('foo', a)
    x, y = col.flatten()
    assert x == pa.column('foo.x', pa.array([], type=pa.int16()))
    assert y == pa.column('foo.y', pa.array([], type=pa.float32()))

    def test_struct_value_subscripting(self):
        ty = pa.struct([pa.field('x', pa.int16()),
                        pa.field('y', pa.float32())])
        arr = pa.array([(1, 2.5), (3, 4.5), (5, 6.5)], type=ty)

        assert arr[0]['x'] == 1
        assert arr[0]['y'] == 2.5
        assert arr[1]['x'] == 3
        assert arr[1]['y'] == 4.5
        assert arr[2]['x'] == 5
        assert arr[2]['y'] == 6.5

        with pytest.raises(IndexError):
            arr[4]['non-existent']

        with pytest.raises(KeyError):
            arr[0]['non-existent']

def test_bq_to_arrow_data_type_w_struct(module_under_test, bq_type):
    fields = (
        schema.SchemaField("field01", "STRING"),
        schema.SchemaField("field02", "BYTES"),
        schema.SchemaField("field03", "INTEGER"),
        schema.SchemaField("field04", "INT64"),
        schema.SchemaField("field05", "FLOAT"),
        schema.SchemaField("field06", "FLOAT64"),
        schema.SchemaField("field07", "NUMERIC"),
        schema.SchemaField("field08", "BOOLEAN"),
        schema.SchemaField("field09", "BOOL"),
        schema.SchemaField("field10", "TIMESTAMP"),
        schema.SchemaField("field11", "DATE"),
        schema.SchemaField("field12", "TIME"),
        schema.SchemaField("field13", "DATETIME"),
        schema.SchemaField("field14", "GEOGRAPHY"),
    )
    field = schema.SchemaField("ignored_name", bq_type, mode="NULLABLE", fields=fields)
    actual = module_under_test.bq_to_arrow_data_type(field)
    expected = pyarrow.struct(
        (
            pyarrow.field("field01", pyarrow.string()),
            pyarrow.field("field02", pyarrow.binary()),
            pyarrow.field("field03", pyarrow.int64()),
            pyarrow.field("field04", pyarrow.int64()),
            pyarrow.field("field05", pyarrow.float64()),
            pyarrow.field("field06", pyarrow.float64()),
            pyarrow.field("field07", module_under_test.pyarrow_numeric()),
            pyarrow.field("field08", pyarrow.bool_()),
            pyarrow.field("field09", pyarrow.bool_()),
            pyarrow.field("field10", module_under_test.pyarrow_timestamp()),
            pyarrow.field("field11", pyarrow.date32()),
            pyarrow.field("field12", module_under_test.pyarrow_time()),
            pyarrow.field("field13", module_under_test.pyarrow_datetime()),
            pyarrow.field("field14", pyarrow.string()),
        )
    )
    assert pyarrow.types.is_struct(actual)
    assert actual.num_children == len(fields)
    assert actual.equals(expected)