#include "utils.h"

#include <QFileInfo>
#include <QDir>

#ifdef USE_ZLIB
#include <zlib.h> // gzip decompress
#endif

namespace serversdk {


#ifdef USE_ZLIB
/**
 * @brief Decompress gzip data
 * @param compressed gzip data
 * @return decompressed data
 */
QByteArray Utils::decompress(const QByteArray &compressed)
{
    if (compressed.size() <= 4) {
        qWarning("gUncompress: Input data is truncated");
        return QByteArray();
    }

    QByteArray result;

    int ret;
    z_stream strm;
    static const int CHUNK_SIZE = 1024;
    char out[CHUNK_SIZE];

    /* allocate inflate state */
    strm.zalloc = Z_NULL;
    strm.zfree = Z_NULL;
    strm.opaque = Z_NULL;
    strm.avail_in = compressed.size();
    strm.next_in = (Bytef*)(compressed.data());

    ret = inflateInit2(&strm, 15 +  32); // gzip decoding
    if (ret != Z_OK)
        return QByteArray();

    // run inflate()
    do {
        strm.avail_out = CHUNK_SIZE;
        strm.next_out = (Bytef*)(out);

        ret = inflate(&strm, Z_NO_FLUSH);
        Q_ASSERT(ret != Z_STREAM_ERROR);  // state not clobbered

        switch (ret) {
        case Z_NEED_DICT:
            return QByteArray();
        case Z_DATA_ERROR:
        case Z_MEM_ERROR:
            (void)inflateEnd(&strm);
            return QByteArray();
        }

        result.append(out, CHUNK_SIZE - strm.avail_out);
    } while (strm.avail_out == 0);

    // clean up and return
    inflateEnd(&strm);

    // Calculate compression ratio
    // original   :200
    // compressed :100
    // ratio = 0.5
    float ratio = (float)compressed.count() / (float)result.count();
    float compression = ratio * 100.0;

    qCInfo(sdkutils) << "compress data:" << compressed.count()
                      << "uncompressed data:" << result.count()
                      << "compression:" << compression;

    return result;
}
#endif


} // namespace core