/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2016 - ROLI Ltd.

   Permission is granted to use this software under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license/

   Permission to use, copy, modify, and/or distribute this software for any
   purpose with or without fee is hereby granted, provided that the above
   copyright notice and this permission notice appear in all copies.

   THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD
   TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
   FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT,
   OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
   USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
   TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
   OF THIS SOFTWARE.

   -----------------------------------------------------------------------------

   To release a closed-source product which uses other parts of JUCE not
   licensed under the ISC terms, commercial licenses are available: visit
   www.juce.com for more information.

  ==============================================================================
*/

class GZIPCompressorOutputStream::GZIPCompressorHelper
{
public:
    GZIPCompressorHelper (const int compressionLevel, const int windowBits)
        : compLevel ((compressionLevel < 0 || compressionLevel > 9) ? -1 : compressionLevel),
          isFirstDeflate (true),
          streamIsValid (false),
          finished (false)
    {
        using namespace zlibNamespace;
        zerostruct (stream);

        streamIsValid = (deflateInit2 (&stream, compLevel, Z_DEFLATED,
                                       windowBits != 0 ? windowBits : MAX_WBITS,
                                       8, strategy) == Z_OK);
    }

    ~GZIPCompressorHelper()
    {
        if (streamIsValid)
            zlibNamespace::deflateEnd (&stream);
    }

    bool write (const uint8* data, size_t dataSize, OutputStream& out)
    {
        // When you call flush() on a gzip stream, the stream is closed, and you can
        // no longer continue to write data to it!
        jassert (! finished);

        while (dataSize > 0)
            if (! doNextBlock (data, dataSize, out, Z_NO_FLUSH))
                return false;

        return true;
    }

    void finish (OutputStream& out)
    {
        const uint8* data = nullptr;
        size_t dataSize = 0;

        while (! finished)
            doNextBlock (data, dataSize, out, Z_FINISH);
    }

private:
    enum { strategy = 0 };

    zlibNamespace::z_stream stream;
    const int compLevel;
    bool isFirstDeflate, streamIsValid, finished;
    zlibNamespace::Bytef buffer[32768];

    bool doNextBlock (const uint8*& data, size_t& dataSize, OutputStream& out, const int flushMode)
    {
        using namespace zlibNamespace;

        if (streamIsValid)
        {
            stream.next_in   = const_cast<uint8*> (data);
            stream.next_out  = buffer;
            stream.avail_in  = (z_uInt) dataSize;
            stream.avail_out = (z_uInt) sizeof (buffer);

            const int result = isFirstDeflate ? deflateParams (&stream, compLevel, strategy)
                                              : deflate (&stream, flushMode);
            isFirstDeflate = false;

            switch (result)
            {
                case Z_STREAM_END:
                    finished = true;
                    // Deliberate fall-through..
                case Z_OK:
                {
                    data += dataSize - stream.avail_in;
                    dataSize = stream.avail_in;
                    const ssize_t bytesDone = (ssize_t) sizeof (buffer) - (ssize_t) stream.avail_out;
                    return bytesDone <= 0 || out.write (buffer, (size_t) bytesDone);
                }

                default:
                    break;
            }
        }

        return false;
    }

    JUCE_DECLARE_NON_COPYABLE (GZIPCompressorHelper)
};

//==============================================================================
GZIPCompressorOutputStream::GZIPCompressorOutputStream (OutputStream* const out,
                                                        const int compressionLevel,
                                                        const bool deleteDestStream,
                                                        const int windowBits)
    : destStream (out, deleteDestStream),
      helper (new GZIPCompressorHelper (compressionLevel, windowBits))
{
    jassert (out != nullptr);
}

GZIPCompressorOutputStream::~GZIPCompressorOutputStream()
{
    flush();
}

void GZIPCompressorOutputStream::flush()
{
    helper->finish (*destStream);
    destStream->flush();
}

bool GZIPCompressorOutputStream::write (const void* destBuffer, size_t howMany)
{
    jassert (destBuffer != nullptr && (ssize_t) howMany >= 0);

    return helper->write (static_cast<const uint8*> (destBuffer), howMany, *destStream);
}

int64 GZIPCompressorOutputStream::getPosition()
{
    return destStream->getPosition();
}

bool GZIPCompressorOutputStream::setPosition (int64 /*newPosition*/)
{
    jassertfalse; // can't do it!
    return false;
}

//==============================================================================
#if JUCE_UNIT_TESTS

class GZIPTests  : public UnitTest
{
public:
    GZIPTests()   : UnitTest ("GZIP") {}

    void runTest() override
    {
        beginTest ("GZIP");
        Random rng = getRandom();

        for (int i = 100; --i >= 0;)
        {
            MemoryOutputStream original, compressed, uncompressed;

            {
                GZIPCompressorOutputStream zipper (&compressed, rng.nextInt (10), false);

                for (int j = rng.nextInt (100); --j >= 0;)
                {
                    MemoryBlock data ((unsigned int) (rng.nextInt (2000) + 1));

                    for (int k = (int) data.getSize(); --k >= 0;)
                        data[k] = (char) rng.nextInt (255);

                    original << data;
                    zipper   << data;
                }
            }

            {
                MemoryInputStream compressedInput (compressed.getData(), compressed.getDataSize(), false);
                GZIPDecompressorInputStream unzipper (compressedInput);

                uncompressed << unzipper;
            }

            expectEquals ((int) uncompressed.getDataSize(),
                          (int) original.getDataSize());

            if (original.getDataSize() == uncompressed.getDataSize())
                expect (memcmp (uncompressed.getData(),
                                original.getData(),
                                original.getDataSize()) == 0);
        }
    }
};

static GZIPTests gzipTests;

#endif
