import io

import os

try:

    import unittest2 as unittest

except ImportError:

    import unittest

try:

    import hypothesis

    import hypothesis.strategies as strategies

except ImportError:

    raise unittest.SkipTest('hypothesis not available')

import zstd

from . common import (

    make_cffi,

    random_input_data,

)

@unittest.skipUnless('ZSTD_SLOW_TESTS' in os.environ, 'ZSTD_SLOW_TESTS not set')

@make_cffi

class TestDecompressor_write_to_fuzzing(unittest.TestCase):

    @hypothesis.given(original=strategies.sampled_from(random_input_data()),

                      level=strategies.integers(min_value=1, max_value=5),

                      write_size=strategies.integers(min_value=1, max_value=8192),

                      input_sizes=strategies.streaming(

                          strategies.integers(min_value=1, max_value=4096)))

    def test_write_size_variance(self, original, level, write_size, input_sizes):

        input_sizes = iter(input_sizes)

        cctx = zstd.ZstdCompressor(level=level)

        frame = cctx.compress(original)

        dctx = zstd.ZstdDecompressor()

        source = io.BytesIO(frame)

        dest = io.BytesIO()

        with dctx.write_to(dest, write_size=write_size) as decompressor:

            while True:

                chunk = source.read(next(input_sizes))

                if not chunk:

                    break

                decompressor.write(chunk)

        self.assertEqual(dest.getvalue(), original)

@unittest.skipUnless('ZSTD_SLOW_TESTS' in os.environ, 'ZSTD_SLOW_TESTS not set')

@make_cffi

class TestDecompressor_copy_stream_fuzzing(unittest.TestCase):

    @hypothesis.given(original=strategies.sampled_from(random_input_data()),

                      level=strategies.integers(min_value=1, max_value=5),

                      read_size=strategies.integers(min_value=1, max_value=8192),

                      write_size=strategies.integers(min_value=1, max_value=8192))

    def test_read_write_size_variance(self, original, level, read_size, write_size):

        cctx = zstd.ZstdCompressor(level=level)

        frame = cctx.compress(original)

        source = io.BytesIO(frame)

        dest = io.BytesIO()

        dctx = zstd.ZstdDecompressor()

        dctx.copy_stream(source, dest, read_size=read_size, write_size=write_size)

        self.assertEqual(dest.getvalue(), original)

@unittest.skipUnless('ZSTD_SLOW_TESTS' in os.environ, 'ZSTD_SLOW_TESTS not set')

@make_cffi

class TestDecompressor_decompressobj_fuzzing(unittest.TestCase):

    @hypothesis.given(original=strategies.sampled_from(random_input_data()),

                      level=strategies.integers(min_value=1, max_value=5),

                      chunk_sizes=strategies.streaming(

                          strategies.integers(min_value=1, max_value=4096)))

    def test_random_input_sizes(self, original, level, chunk_sizes):

        chunk_sizes = iter(chunk_sizes)

        cctx = zstd.ZstdCompressor(level=level)

        frame = cctx.compress(original)

        source = io.BytesIO(frame)

        dctx = zstd.ZstdDecompressor()

        dobj = dctx.decompressobj()

        chunks = []

        while True:

            chunk = source.read(next(chunk_sizes))

            if not chunk:

                break

            chunks.append(dobj.decompress(chunk))

        self.assertEqual(b''.join(chunks), original)

@unittest.skipUnless('ZSTD_SLOW_TESTS' in os.environ, 'ZSTD_SLOW_TESTS not set')

@make_cffi

class TestDecompressor_read_from_fuzzing(unittest.TestCase):

    @hypothesis.given(original=strategies.sampled_from(random_input_data()),

                      level=strategies.integers(min_value=1, max_value=5),

                      read_size=strategies.integers(min_value=1, max_value=4096),

                      write_size=strategies.integers(min_value=1, max_value=4096))

    def test_read_write_size_variance(self, original, level, read_size, write_size):

        cctx = zstd.ZstdCompressor(level=level)

        frame = cctx.compress(original)

        source = io.BytesIO(frame)

        dctx = zstd.ZstdDecompressor()

        chunks = list(dctx.read_from(source, read_size=read_size, write_size=write_size))

        self.assertEqual(b''.join(chunks), original)

@unittest.skipUnless('ZSTD_SLOW_TESTS' in os.environ, 'ZSTD_SLOW_TESTS not set')

class TestDecompressor_multi_decompress_to_buffer_fuzzing(unittest.TestCase):

    @hypothesis.given(original=strategies.lists(strategies.sampled_from(random_input_data()),

                                        min_size=1, max_size=1024),

                threads=strategies.integers(min_value=1, max_value=8),

                use_dict=strategies.booleans())

    def test_data_equivalence(self, original, threads, use_dict):

        kwargs = {}

        if use_dict:

            kwargs['dict_data'] = zstd.ZstdCompressionDict(original[0])

        cctx = zstd.ZstdCompressor(level=1,

                                   write_content_size=True,

                                   write_checksum=True,

                                   **kwargs)

        frames_buffer = cctx.multi_compress_to_buffer(original, threads=-1)

        dctx = zstd.ZstdDecompressor(**kwargs)

        result = dctx.multi_decompress_to_buffer(frames_buffer)

        self.assertEqual(len(result), len(original))

        for i, frame in enumerate(result):

            self.assertEqual(frame.tobytes(), original[i])

        frames_list = [f.tobytes() for f in frames_buffer]

        result = dctx.multi_decompress_to_buffer(frames_list)

        self.assertEqual(len(result), len(original))

        for i, frame in enumerate(result):

            self.assertEqual(frame.tobytes(), original[i])