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

#include "helper_functions.hpp"

#include "basicio.hpp"

#include "convert.hpp"

#include "enforce.hpp"

#include <cstring>

#include <numeric>

std::string string_from_unterminated(const char* data, size_t data_length) {

  if (data_length == 0) {

    return {};

  }

  const size_t StringLength = strnlen(data, data_length);

  return {data, StringLength};

}

namespace Exiv2 {

uint64_t readQWORDTag(const BasicIo::UniquePtr& io) {

  Internal::enforce(QWORD <= io->size() - io->tell(), Exiv2::ErrorCode::kerCorruptedMetadata);

  DataBuf FieldBuf = io->read(QWORD);

  return FieldBuf.read_uint64(0, littleEndian);

}

uint32_t readDWORDTag(const BasicIo::UniquePtr& io) {

  Internal::enforce(DWORD <= io->size() - io->tell(), Exiv2::ErrorCode::kerCorruptedMetadata);

  DataBuf FieldBuf = io->read(DWORD);

  return FieldBuf.read_uint32(0, littleEndian);

}

uint16_t readWORDTag(const BasicIo::UniquePtr& io) {

  Internal::enforce(WORD <= io->size() - io->tell(), Exiv2::ErrorCode::kerCorruptedMetadata);

  DataBuf FieldBuf = io->read(WORD);

  return FieldBuf.read_uint16(0, littleEndian);

}

std::string readStringWcharTag(const BasicIo::UniquePtr& io, size_t length) {

  Internal::enforce(length <= io->size() - io->tell(), Exiv2::ErrorCode::kerCorruptedMetadata);

  DataBuf FieldBuf(length + 1);

  io->readOrThrow(FieldBuf.data(), length, ErrorCode::kerFailedToReadImageData);

  std::string wst(FieldBuf.begin(), FieldBuf.end() - 3);

  if (wst.size() % 2 != 0)

    Exiv2::convertStringCharset(wst, "UCS-2LE", "UTF-8");

  Exiv2::convertStringCharset(wst, "UCS-2LE", "UTF-8");

  return wst;

}

std::string readStringTag(const BasicIo::UniquePtr& io, size_t length) {

  Internal::enforce(length <= io->size() - io->tell(), Exiv2::ErrorCode::kerCorruptedMetadata);

  DataBuf FieldBuf(length + 1);

  io->readOrThrow(FieldBuf.data(), length, ErrorCode::kerFailedToReadImageData);

  return Exiv2::toString(FieldBuf.data()).substr(0, length);

}

std::string getAspectRatio(uint64_t width, uint64_t height) {

  if (height == 0 || width == 0)

    return std::to_string(width) + ":" + std::to_string(height);

  auto ratioWidth = width / std::gcd(width, height);

  auto ratioHeight = height / std::gcd(width, height);

  return std::to_string(ratioWidth) + ":" + std::to_string(ratioHeight);

}

}  // namespace Exiv2