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,

)

s_windowlog = strategies.integers(min_value=zstd.WINDOWLOG_MIN,

                                    max_value=zstd.WINDOWLOG_MAX)

s_chainlog = strategies.integers(min_value=zstd.CHAINLOG_MIN,

                                    max_value=zstd.CHAINLOG_MAX)

s_hashlog = strategies.integers(min_value=zstd.HASHLOG_MIN,

                                max_value=zstd.HASHLOG_MAX)

s_searchlog = strategies.integers(min_value=zstd.SEARCHLOG_MIN,

                                    max_value=zstd.SEARCHLOG_MAX)

s_searchlength = strategies.integers(min_value=zstd.SEARCHLENGTH_MIN,

                                        max_value=zstd.SEARCHLENGTH_MAX)

s_targetlength = strategies.integers(min_value=zstd.TARGETLENGTH_MIN,

                                        max_value=zstd.TARGETLENGTH_MAX)

s_strategy = strategies.sampled_from((zstd.STRATEGY_FAST,

                                        zstd.STRATEGY_DFAST,

                                        zstd.STRATEGY_GREEDY,

                                        zstd.STRATEGY_LAZY,

                                        zstd.STRATEGY_LAZY2,

                                        zstd.STRATEGY_BTLAZY2,

                                        zstd.STRATEGY_BTOPT))

@make_cffi

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

class TestCompressionParametersHypothesis(unittest.TestCase):

    @hypothesis.given(s_windowlog, s_chainlog, s_hashlog, s_searchlog,

                        s_searchlength, s_targetlength, s_strategy)

    def test_valid_init(self, windowlog, chainlog, hashlog, searchlog,

                        searchlength, targetlength, strategy):

        # ZSTD_checkCParams moves the goal posts on us from what's advertised

        # in the constants. So move along with them.

        if searchlength == zstd.SEARCHLENGTH_MIN and strategy in (zstd.STRATEGY_FAST, zstd.STRATEGY_GREEDY):

            searchlength += 1

        elif searchlength == zstd.SEARCHLENGTH_MAX and strategy != zstd.STRATEGY_FAST:

            searchlength -= 1

        p = zstd.CompressionParameters(windowlog, chainlog, hashlog,

                                        searchlog, searchlength,

                                        targetlength, strategy)

        cctx = zstd.ZstdCompressor(compression_params=p)

        with cctx.write_to(io.BytesIO()):

            pass

    @hypothesis.given(s_windowlog, s_chainlog, s_hashlog, s_searchlog,

                        s_searchlength, s_targetlength, s_strategy)

    def test_estimate_compression_context_size(self, windowlog, chainlog,

                                                hashlog, searchlog,

                                                searchlength, targetlength,

                                                strategy):

        if searchlength == zstd.SEARCHLENGTH_MIN and strategy in (zstd.STRATEGY_FAST, zstd.STRATEGY_GREEDY):

            searchlength += 1

        elif searchlength == zstd.SEARCHLENGTH_MAX and strategy != zstd.STRATEGY_FAST:

            searchlength -= 1

        p = zstd.CompressionParameters(windowlog, chainlog, hashlog,

                            searchlog, searchlength,

                            targetlength, strategy)

        size = zstd.estimate_compression_context_size(p)