// SPDX-License-Identifier: GPL-2.0-or-later

// included header files

#include "gifimage.hpp"

#include "basicio.hpp"

#include "config.h"

#include "error.hpp"

#include "futils.hpp"

#include <array>

#ifdef EXIV2_DEBUG_MESSAGES

#include <iostream>

#endif

// *****************************************************************************

// class member definitions

namespace Exiv2 {

GifImage::GifImage(BasicIo::UniquePtr io) : Image(ImageType::gif, mdNone, std::move(io)) {

}

std::string GifImage::mimeType() const {

  return "image/gif";

}

void GifImage::setExifData(const ExifData& /*exifData*/) {

  // Todo: implement me!

  throw(Error(ErrorCode::kerInvalidSettingForImage, "Exif metadata", "GIF"));

}

void GifImage::setIptcData(const IptcData& /*iptcData*/) {

  // Todo: implement me!

  throw(Error(ErrorCode::kerInvalidSettingForImage, "IPTC metadata", "GIF"));

}

void GifImage::setComment(const std::string&) {

  // not supported

  throw(Error(ErrorCode::kerInvalidSettingForImage, "Image comment", "GIF"));

}

void GifImage::readMetadata() {

#ifdef EXIV2_DEBUG_MESSAGES

  std::cerr << "Exiv2::GifImage::readMetadata: Reading GIF file " << io_->path() << "\n";

#endif

  if (io_->open() != 0) {

    throw Error(ErrorCode::kerDataSourceOpenFailed, io_->path(), strError());

  }

  IoCloser closer(*io_);

  // Ensure that this is the correct image type

  if (!isGifType(*io_, true)) {

    if (io_->error() || io_->eof())

      throw Error(ErrorCode::kerFailedToReadImageData);

    throw Error(ErrorCode::kerNotAnImage, "GIF");

  }

  clearMetadata();

  byte buf[4];

  if (io_->read(buf, sizeof(buf)) == sizeof(buf)) {

    pixelWidth_ = getShort(buf, littleEndian);

    pixelHeight_ = getShort(buf + 2, littleEndian);

  }

}  // GifImage::readMetadata

void GifImage::writeMetadata() {

  // Todo: implement me!

  throw(Error(ErrorCode::kerWritingImageFormatUnsupported, "GIF"));

}  // GifImage::writeMetadata

// *************************************************************************

// free functions

Image::UniquePtr newGifInstance(BasicIo::UniquePtr io, bool /*create*/) {

  auto image = std::make_unique<GifImage>(std::move(io));

  if (!image->good()) {

    return nullptr;

  }

  return image;

}

bool isGifType(BasicIo& iIo, bool advance) {

  const int32_t len = 6;

  const std::array<byte, len> Gif87aId{'G', 'I', 'F', '8', '7', 'a'};

  const std::array<byte, len> Gif89aId{'G', 'I', 'F', '8', '9', 'a'};

  std::array<byte, len> buf;

  iIo.read(buf.data(), len);

  if (iIo.error() || iIo.eof()) {

    return false;

  }

  bool matched = buf == Gif87aId || buf == Gif89aId;

  if (!advance || !matched) {

    iIo.seek(-len, BasicIo::cur);

  }

  return matched;

}

}  // namespace Exiv2