import io

import os

import unittest

try:

    import hypothesis

    import hypothesis.strategies as strategies

except ImportError:

    raise unittest.SkipTest("hypothesis not available")

import zstandard as zstd

from .common import (

    make_cffi,

    NonClosingBytesIO,

    random_input_data,

    TestCase,

)

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

@make_cffi

class TestDecompressor_stream_reader_fuzzing(TestCase):

    @hypothesis.settings(

        suppress_health_check=[

            hypothesis.HealthCheck.large_base_example,

            hypothesis.HealthCheck.too_slow,

        ]

    )

    @hypothesis.given(

        original=strategies.sampled_from(random_input_data()),

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

        streaming=strategies.booleans(),

        source_read_size=strategies.integers(1, 1048576),

        read_sizes=strategies.data(),

    )

    def test_stream_source_read_variance(

        self, original, level, streaming, source_read_size, read_sizes

    ):

        cctx = zstd.ZstdCompressor(level=level)

        if streaming:

            source = io.BytesIO()

            writer = cctx.stream_writer(source)

            writer.write(original)

            writer.flush(zstd.FLUSH_FRAME)

            source.seek(0)

        else:

            frame = cctx.compress(original)

            source = io.BytesIO(frame)

        dctx = zstd.ZstdDecompressor()

        chunks = []

        with dctx.stream_reader(source, read_size=source_read_size) as reader:

            while True:

                read_size = read_sizes.draw(strategies.integers(-1, 131072))

                chunk = reader.read(read_size)

                if not chunk and read_size:

                    break

                chunks.append(chunk)

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

    # Similar to above except we have a constant read() size.

    @hypothesis.settings(

        suppress_health_check=[hypothesis.HealthCheck.large_base_example]

    )

    @hypothesis.given(

        original=strategies.sampled_from(random_input_data()),

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

        streaming=strategies.booleans(),

        source_read_size=strategies.integers(1, 1048576),

        read_size=strategies.integers(-1, 131072),

    )

    def test_stream_source_read_size(

        self, original, level, streaming, source_read_size, read_size

    ):

        if read_size == 0:

            read_size = 1

        cctx = zstd.ZstdCompressor(level=level)

        if streaming:

            source = io.BytesIO()

            writer = cctx.stream_writer(source)

            writer.write(original)

            writer.flush(zstd.FLUSH_FRAME)

            source.seek(0)

        else:

            frame = cctx.compress(original)

            source = io.BytesIO(frame)

        dctx = zstd.ZstdDecompressor()

        chunks = []

        reader = dctx.stream_reader(source, read_size=source_read_size)

        while True:

            chunk = reader.read(read_size)

            if not chunk and read_size:

                break

            chunks.append(chunk)

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

    @hypothesis.settings(

        suppress_health_check=[

            hypothesis.HealthCheck.large_base_example,

            hypothesis.HealthCheck.too_slow,

        ]

    )

    @hypothesis.given(

        original=strategies.sampled_from(random_input_data()),

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

        streaming=strategies.booleans(),

        source_read_size=strategies.integers(1, 1048576),

        read_sizes=strategies.data(),

    )

    def test_buffer_source_read_variance(

        self, original, level, streaming, source_read_size, read_sizes

    ):

        cctx = zstd.ZstdCompressor(level=level)

        if streaming:

            source = io.BytesIO()

            writer = cctx.stream_writer(source)

            writer.write(original)

            writer.flush(zstd.FLUSH_FRAME)

            frame = source.getvalue()

        else:

            frame = cctx.compress(original)

        dctx = zstd.ZstdDecompressor()

        chunks = []

        with dctx.stream_reader(frame, read_size=source_read_size) as reader:

            while True:

                read_size = read_sizes.draw(strategies.integers(-1, 131072))

                chunk = reader.read(read_size)

                if not chunk and read_size:

                    break

                chunks.append(chunk)

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

    # Similar to above except we have a constant read() size.

    @hypothesis.settings(

        suppress_health_check=[hypothesis.HealthCheck.large_base_example]

    )

    @hypothesis.given(

        original=strategies.sampled_from(random_input_data()),

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

        streaming=strategies.booleans(),

        source_read_size=strategies.integers(1, 1048576),

        read_size=strategies.integers(-1, 131072),

    )

    def test_buffer_source_constant_read_size(

        self, original, level, streaming, source_read_size, read_size

    ):

        if read_size == 0:

            read_size = -1

        cctx = zstd.ZstdCompressor(level=level)

        if streaming:

            source = io.BytesIO()

            writer = cctx.stream_writer(source)

            writer.write(original)

            writer.flush(zstd.FLUSH_FRAME)

            frame = source.getvalue()

        else:

            frame = cctx.compress(original)

        dctx = zstd.ZstdDecompressor()

        chunks = []

        reader = dctx.stream_reader(frame, read_size=source_read_size)

        while True:

            chunk = reader.read(read_size)

            if not chunk and read_size:

                break

            chunks.append(chunk)

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

    @hypothesis.settings(

        suppress_health_check=[hypothesis.HealthCheck.large_base_example]

    )

    @hypothesis.given(

        original=strategies.sampled_from(random_input_data()),

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

        streaming=strategies.booleans(),

        source_read_size=strategies.integers(1, 1048576),

    )

    def test_stream_source_readall(

        self, original, level, streaming, source_read_size

    ):

        cctx = zstd.ZstdCompressor(level=level)

        if streaming:

            source = io.BytesIO()

            writer = cctx.stream_writer(source)

            writer.write(original)

            writer.flush(zstd.FLUSH_FRAME)

            source.seek(0)

        else:

            frame = cctx.compress(original)

            source = io.BytesIO(frame)

        dctx = zstd.ZstdDecompressor()

        data = dctx.stream_reader(source, read_size=source_read_size).readall()

        self.assertEqual(data, original)

    @hypothesis.settings(

        suppress_health_check=[

            hypothesis.HealthCheck.large_base_example,

            hypothesis.HealthCheck.too_slow,

        ]

    )

    @hypothesis.given(

        original=strategies.sampled_from(random_input_data()),

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

        streaming=strategies.booleans(),

        source_read_size=strategies.integers(1, 1048576),

        read_sizes=strategies.data(),

    )

    def test_stream_source_read1_variance(

        self, original, level, streaming, source_read_size, read_sizes

    ):

        cctx = zstd.ZstdCompressor(level=level)

        if streaming:

            source = io.BytesIO()

            writer = cctx.stream_writer(source)

            writer.write(original)

            writer.flush(zstd.FLUSH_FRAME)

            source.seek(0)

        else:

            frame = cctx.compress(original)

            source = io.BytesIO(frame)

        dctx = zstd.ZstdDecompressor()

        chunks = []

        with dctx.stream_reader(source, read_size=source_read_size) as reader:

            while True:

                read_size = read_sizes.draw(strategies.integers(-1, 131072))

                chunk = reader.read1(read_size)

                if not chunk and read_size:

                    break

                chunks.append(chunk)

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

    @hypothesis.settings(

        suppress_health_check=[

            hypothesis.HealthCheck.large_base_example,

            hypothesis.HealthCheck.too_slow,

        ]

    )

    @hypothesis.given(

        original=strategies.sampled_from(random_input_data()),

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

        streaming=strategies.booleans(),

        source_read_size=strategies.integers(1, 1048576),

        read_sizes=strategies.data(),

    )

    def test_stream_source_readinto1_variance(

        self, original, level, streaming, source_read_size, read_sizes

    ):

        cctx = zstd.ZstdCompressor(level=level)

        if streaming:

            source = io.BytesIO()

            writer = cctx.stream_writer(source)

            writer.write(original)

            writer.flush(zstd.FLUSH_FRAME)

            source.seek(0)

        else:

            frame = cctx.compress(original)

            source = io.BytesIO(frame)

        dctx = zstd.ZstdDecompressor()

        chunks = []

        with dctx.stream_reader(source, read_size=source_read_size) as reader:

            while True:

                read_size = read_sizes.draw(strategies.integers(1, 131072))

                b = bytearray(read_size)

                count = reader.readinto1(b)

                if not count:

                    break

                chunks.append(bytes(b[0:count]))

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

    @hypothesis.settings(

        suppress_health_check=[

            hypothesis.HealthCheck.large_base_example,

            hypothesis.HealthCheck.too_slow,

        ]

    )

    @hypothesis.given(

        original=strategies.sampled_from(random_input_data()),

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

        source_read_size=strategies.integers(1, 1048576),

        seek_amounts=strategies.data(),

        read_sizes=strategies.data(),

    )

    def test_relative_seeks(

        self, original, level, source_read_size, seek_amounts, read_sizes

    ):

        cctx = zstd.ZstdCompressor(level=level)

        frame = cctx.compress(original)

        dctx = zstd.ZstdDecompressor()

        with dctx.stream_reader(frame, read_size=source_read_size) as reader:

            while True:

                amount = seek_amounts.draw(strategies.integers(0, 16384))

                reader.seek(amount, os.SEEK_CUR)

                offset = reader.tell()

                read_amount = read_sizes.draw(strategies.integers(1, 16384))

                chunk = reader.read(read_amount)

                if not chunk:

                    break

                self.assertEqual(original[offset : offset + len(chunk)], chunk)

    @hypothesis.settings(

        suppress_health_check=[

            hypothesis.HealthCheck.large_base_example,

            hypothesis.HealthCheck.too_slow,

        ]

    )

    @hypothesis.given(

        originals=strategies.data(),

        frame_count=strategies.integers(min_value=2, max_value=10),

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

        source_read_size=strategies.integers(1, 1048576),

        read_sizes=strategies.data(),

    )

    def test_multiple_frames(

        self, originals, frame_count, level, source_read_size, read_sizes

    ):

        cctx = zstd.ZstdCompressor(level=level)

        source = io.BytesIO()

        buffer = io.BytesIO()

        writer = cctx.stream_writer(buffer)

        for i in range(frame_count):

            data = originals.draw(strategies.sampled_from(random_input_data()))

            source.write(data)

            writer.write(data)

            writer.flush(zstd.FLUSH_FRAME)

        dctx = zstd.ZstdDecompressor()

        buffer.seek(0)

        reader = dctx.stream_reader(

            buffer, read_size=source_read_size, read_across_frames=True