from __future__ import print_function, division, absolute_import

import sys
from zlib import crc32

import numpy as np
import pytest

from distributed.compatibility import PY2
from distributed.protocol import (serialize, deserialize, decompress, dumps,
                                  loads, to_serialize, msgpack)
from distributed.protocol.utils import BIG_BYTES_SHARD_SIZE
from distributed.utils import tmpfile, nbytes
from distributed.utils_test import slow, gen_cluster
from distributed.protocol.numpy import itemsize
from distributed.protocol.compression import maybe_compress


def test_serialize():
    x = np.ones((5, 5))
    header, frames = serialize(x)
    assert header['type']
    assert len(frames) == 1

    if 'compression' in header:
        frames = decompress(header, frames)
    result = deserialize(header, frames)
    assert (result == x).all()


@pytest.mark.parametrize('x', [
    np.ones(5),
    np.array(5),
    np.random.random((5, 5)),
    np.random.random((5, 5))[::2, :],
    np.random.random((5, 5))[:, ::2],
    np.asfortranarray(np.random.random((5, 5))),
    np.asfortranarray(np.random.random((5, 5)))[::2, :],
    np.asfortranarray(np.random.random((5, 5)))[:, ::2],
    np.random.random(5).astype('f4'),
    np.random.random(5).astype('>i8'),
    np.random.random(5).astype('<i8'),
    np.arange(5).astype('M8[us]'),
    np.arange(5).astype('M8[ms]'),
    np.arange(5).astype('m8'),
    np.arange(5).astype('m8[s]'),
    np.arange(5).astype('c16'),
    np.arange(5).astype('c8'),
    np.array([True, False, True]),
    np.ones(shape=5, dtype=[('a', 'i4'), ('b', 'M8[us]')]),
    np.array(['abc'], dtype='S3'),
    np.array(['abc'], dtype='U3'),
    np.array(['abc'], dtype=object),
    np.ones(shape=(5,), dtype=('f8', 32)),
    np.ones(shape=(5,), dtype=[('x', 'f8', 32)]),
    np.ones(shape=(5,), dtype=np.dtype([('a', 'i1'), ('b', 'f8')], align=False)),
    np.ones(shape=(5,), dtype=np.dtype([('a', 'i1'), ('b', 'f8')], align=True)),
    np.ones(shape=(5,), dtype=np.dtype([('a', 'm8[us]')], align=False)),
    # this dtype fails unpickling
    np.ones(shape=(5,), dtype=np.dtype([('a', 'm8')], align=False)),
    np.array([(1, 'abc')], dtype=[('x', 'i4'), ('s', object)]),
    np.zeros(5000, dtype=[('x%d' % i, '<f8') for i in range(4)]),
    np.zeros(5000, dtype='S32'),
    np.zeros((1, 1000, 1000)),
    np.arange(12)[::2],  # non-contiguous array
    np.ones(shape=(5, 6)).astype(dtype=[('total', '<f8'), ('n', '<f8')]),
])
def test_dumps_serialize_numpy(x):
    header, frames = serialize(x)
    if 'compression' in header:
        frames = decompress(header, frames)
    buffer_interface = buffer if PY2 else memoryview  # noqa: F821
    for frame in frames:
        assert isinstance(frame, (bytes, buffer_interface))
    y = deserialize(header, frames)

    np.testing.assert_equal(x, y)
    if x.flags.c_contiguous or x.flags.f_contiguous:
        assert x.strides == y.strides


@pytest.mark.parametrize('x', [
    np.ma.masked_array([5, 6], mask=[True, False], fill_value=10, dtype='i4'),
    np.ma.masked_array([5., 6.], mask=[True, False], fill_value=10, dtype='f4'),
    np.ma.masked_array([5., 6.], mask=[True, False], fill_value=np.nan, dtype='f8'),
    np.ma.masked_array([5., 6.], mask=np.ma.nomask, fill_value=np.nan, dtype='f8'),
    np.ma.masked_array([True, False], mask=np.ma.nomask, fill_value=True, dtype='bool'),
    np.ma.masked_array(['a', 'b'], mask=[True, False], fill_value='c', dtype='O')
])
def test_masked_array_serialize(x):
    y, = loads(dumps([to_serialize(x)]))
    assert x.data.dtype == y.data.dtype
    np.testing.assert_equal(x.data, y.data)
    np.testing.assert_equal(x.mask, y.mask)
    np.testing.assert_equal(x.fill_value, y.fill_value)


def test_dumps_serialize_numpy_custom_dtype():
    from six.moves import builtins
    test_rational = pytest.importorskip('numpy.core.test_rational')
    rational = test_rational.rational
    try:
        builtins.rational = rational  # Work around https://github.com/numpy/numpy/issues/9160
        x = np.array([1], dtype=rational)
        header, frames = serialize(x)
        y = deserialize(header, frames)

        np.testing.assert_equal(x, y)
    finally:
        del builtins.rational


def test_memmap():
    with tmpfile('npy') as fn:
        with open(fn, 'wb') as f:  # touch file
            pass
        x = np.memmap(fn, shape=(5, 5), dtype='i4', mode='readwrite')
        x[:] = 5

        header, frames = serialize(x)
        if 'compression' in header:
            frames = decompress(header, frames)
        y = deserialize(header, frames)

        np.testing.assert_equal(x, y)


@slow
def test_dumps_serialize_numpy_large():
    psutil = pytest.importorskip('psutil')
    if psutil.virtual_memory().total < 2e9:
        return
    x = np.random.random(size=int(BIG_BYTES_SHARD_SIZE * 2 // 8)).view('u1')
    assert x.nbytes == BIG_BYTES_SHARD_SIZE * 2
    frames = dumps([to_serialize(x)])
    dtype, shape = x.dtype, x.shape
    checksum = crc32(x)
    del x
    [y] = loads(frames)

    assert (y.dtype, y.shape) == (dtype, shape)
    assert crc32(y) == checksum, "Arrays are unequal"


@pytest.mark.parametrize('dt,size', [('f8', 8),
                                     ('i4', 4),
                                     ('c16', 16),
                                     ('b', 1),
                                     ('S3', 3),
                                     ('M8[us]', 8),
                                     ('M8[s]', 8),
                                     ('U3', 12),
                                     ([('a', 'i4'), ('b', 'f8')], 12),
                                     (('i4', 100), 4),
                                     ([('a', 'i4', 100)], 8),
                                     ([('a', 'i4', 20), ('b', 'f8')], 20 * 4 + 8),
                                     ([('a', 'i4', 200), ('b', 'f8')], 8)])
def test_itemsize(dt, size):
    assert itemsize(np.dtype(dt)) == size


@pytest.mark.skipif(sys.version_info[0] < 3,
                    reason='numpy doesnt use memoryviews')
def test_compress_numpy():
    pytest.importorskip('lz4')
    x = np.ones(10000000, dtype='i4')
    frames = dumps({'x': to_serialize(x)})
    assert sum(map(nbytes, frames)) < x.nbytes

    header = msgpack.loads(frames[2], raw=False, use_list=False)
    try:
        import blosc  # noqa: F401
    except ImportError:
        pass
    else:
        assert all(c == 'blosc' for c in
                   header['headers'][('x',)]['compression'])


def test_compress_memoryview():
    mv = memoryview(b'0' * 1000000)
    compression, compressed = maybe_compress(mv)
    if compression:
        assert len(compressed) < len(mv)


@pytest.mark.skip
def test_dont_compress_uncompressable_data():
    blosc = pytest.importorskip('blosc')
    x = np.random.randint(0, 255, size=100000).astype('uint8')
    header, [data] = serialize(x)
    assert 'compression' not in header
    assert data == x.data

    x = np.ones(1000000)
    header, [data] = serialize(x)
    assert header['compression'] == ['blosc']
    assert data != x.data

    x = np.ones(100)
    header, [data] = serialize(x)
    assert 'compression' not in header
    if isinstance(data, memoryview):
        assert data.obj.ctypes.data == x.ctypes.data


@gen_cluster(client=True, timeout=60)
def test_dumps_large_blosc(c, s, a, b):
    x = c.submit(np.ones, BIG_BYTES_SHARD_SIZE * 2, dtype='u1')
    result = yield x


@pytest.mark.skipif(sys.version_info[0] < 3,
                    reason='numpy doesnt use memoryviews')
def test_compression_takes_advantage_of_itemsize():
    pytest.importorskip('lz4')
    blosc = pytest.importorskip('blosc')
    x = np.arange(1000000, dtype='i8')

    assert (len(blosc.compress(x.data, typesize=8))
            < len(blosc.compress(x.data, typesize=1)))

    _, a = serialize(x)
    aa = [maybe_compress(frame)[1] for frame in a]
    _, b = serialize(x.view('u1'))
    bb = [maybe_compress(frame)[1] for frame in b]

    assert sum(map(nbytes, aa)) < sum(map(nbytes, bb))


def test_large_numpy_array():
    x = np.ones((100000000,), dtype='u4')
    header, frames = serialize(x)
    assert sum(header['lengths']) == sum(map(nbytes, frames))
