#pragma once

#include <memory>

#include "envoy/buffer/buffer.h"

#include "zlib.h"

namespace Envoy {
namespace Zlib {

/**
 * Shared code between the compressor and the decompressor.
 */
// TODO(junr03): move to extensions tree once the compressor side is moved to extensions.
class Base {
public:
  Base(uint64_t chunk_size, std::function<void(z_stream*)> zstream_deleter);

  /**
   * It returns the checksum of all output produced so far. Compressor's checksum at the end of
   * the stream has to match decompressor's checksum produced at the end of the decompression.
   * Likewise, the decompressor's checksum has to match the compressor's checksum at the end of
   * compression.
   * @return uint64_t CRC-32 if a gzip stream is being read or Adler-32 for other compression
   * types.
   */
  uint64_t checksum();

protected:
  void updateOutput(Buffer::Instance& output_buffer);

  const uint64_t chunk_size_;
  bool initialized_{false};

  const std::unique_ptr<unsigned char[]> chunk_char_ptr_;
  const std::unique_ptr<z_stream, std::function<void(z_stream*)>> zstream_ptr_;
};

} // namespace Zlib
} // namespace Envoy