// Copyright (c) the JPEG XL Project Authors. All rights reserved.

//

// Use of this source code is governed by a BSD-style

// license that can be found in the LICENSE file.

#include "lib/jxl/decode_to_jpeg.h"

#include <jxl/decode.h>

#include <algorithm>

#include <cstddef>

#include <cstdint>

#include <cstring>

#include "lib/jxl/base/span.h"

#include "lib/jxl/base/status.h"

#include "lib/jxl/common.h"  // JPEGXL_ENABLE_TRANSCODE_JPEG

#include "lib/jxl/jpeg/dec_jpeg_data.h"

#include "lib/jxl/jpeg/jpeg_data.h"

namespace jxl {

#if JPEGXL_ENABLE_TRANSCODE_JPEG

JxlDecoderStatus JxlToJpegDecoder::Process(const uint8_t** next_in,

                                           size_t* avail_in) {

  if (!inside_box_) {

    JXL_WARNING(

        "processing of JPEG reconstruction data outside JPEG reconstruction "

        "box");

    return JXL_DEC_ERROR;

  }

  Span<const uint8_t> to_decode;

  if (box_until_eof_) {

    // Until EOF means consume all data.

    to_decode = Bytes(*next_in, *avail_in);

    *next_in += *avail_in;

    *avail_in = 0;

  } else {

    // Defined size means consume min(available, needed).

    size_t avail_recon_in =

        std::min<size_t>(*avail_in, box_size_ - buffer_.size());

    to_decode = Bytes(*next_in, avail_recon_in);

    *next_in += avail_recon_in;

    *avail_in -= avail_recon_in;

  }

  bool old_data_exists = !buffer_.empty();

  if (old_data_exists) {

    // Append incoming data to buffer if we already had data in the buffer.

    buffer_.insert(buffer_.end(), to_decode.data(),

                   to_decode.data() + to_decode.size());

    to_decode = Bytes(buffer_.data(), buffer_.size());

  }

  if (!box_until_eof_ && to_decode.size() > box_size_) {

    JXL_WARNING("JPEG reconstruction data to decode larger than expected");

    return JXL_DEC_ERROR;

  }

  if (box_until_eof_ || to_decode.size() == box_size_) {

    // If undefined size, or the right size, try to decode.

    jpeg_data_ = make_unique<jpeg::JPEGData>();

    const auto status = jpeg::DecodeJPEGData(to_decode, jpeg_data_.get());

    if (status.IsFatalError()) return JXL_DEC_ERROR;

    if (status) {

      // Successful decoding, emit event after updating state to track that we

      // are no longer parsing JPEG reconstruction data.

      inside_box_ = false;

      return JXL_DEC_JPEG_RECONSTRUCTION;

    }

    if (box_until_eof_) {

      // Unsuccessful decoding and undefined size, assume incomplete data. Copy

      // the data if we haven't already.

      if (!old_data_exists) {

        buffer_.insert(buffer_.end(), to_decode.data(),

                       to_decode.data() + to_decode.size());

      }

    } else {

      // Unsuccessful decoding of correct amount of data, assume error.

      return JXL_DEC_ERROR;

    }

  } else {

    // Not enough data, copy the data if we haven't already.

    if (!old_data_exists) {

      buffer_.insert(buffer_.end(), to_decode.data(),

                     to_decode.data() + to_decode.size());

    }

  }

  return JXL_DEC_NEED_MORE_INPUT;

}

size_t JxlToJpegDecoder::NumExifMarkers(const jpeg::JPEGData& jpeg_data) {

  size_t num = 0;

  for (size_t i = 0; i < jpeg_data.app_data.size(); ++i) {

    if (jpeg_data.app_marker_type[i] == jxl::jpeg::AppMarkerType::kExif) {

      num++;

    }

  }

  return num;

}

size_t JxlToJpegDecoder::NumXmpMarkers(const jpeg::JPEGData& jpeg_data) {

  size_t num = 0;

  for (size_t i = 0; i < jpeg_data.app_data.size(); ++i) {

    if (jpeg_data.app_marker_type[i] == jxl::jpeg::AppMarkerType::kXMP) {

      num++;

    }

  }

  return num;

}

JxlDecoderStatus JxlToJpegDecoder::ExifBoxContentSize(

    const jpeg::JPEGData& jpeg_data, size_t* size) {

  for (size_t i = 0; i < jpeg_data.app_data.size(); ++i) {

    if (jpeg_data.app_marker_type[i] == jxl::jpeg::AppMarkerType::kExif) {

      if (jpeg_data.app_data[i].size() < 3 + sizeof(jpeg::kExifTag)) {

        // too small for app marker header

        return JXL_DEC_ERROR;

      }

      // The first 4 bytes are the TIFF header from the box contents, and are

      // not included in the JPEG

      *size = jpeg_data.app_data[i].size() + 4 - 3 - sizeof(jpeg::kExifTag);

      return JXL_DEC_SUCCESS;

    }

  }

  return JXL_DEC_ERROR;

}

JxlDecoderStatus JxlToJpegDecoder::XmlBoxContentSize(

    const jpeg::JPEGData& jpeg_data, size_t* size) {

  for (size_t i = 0; i < jpeg_data.app_data.size(); ++i) {

    if (jpeg_data.app_marker_type[i] == jxl::jpeg::AppMarkerType::kXMP) {

      if (jpeg_data.app_data[i].size() < 3 + sizeof(jpeg::kXMPTag)) {

        // too small for app marker header

        return JXL_DEC_ERROR;

      }

      *size = jpeg_data.app_data[i].size() - 3 - sizeof(jpeg::kXMPTag);

      return JXL_DEC_SUCCESS;

    }

  }

  return JXL_DEC_ERROR;

}

JxlDecoderStatus JxlToJpegDecoder::SetExif(const uint8_t* data, size_t size,

                                           jpeg::JPEGData* jpeg_data) {

  for (size_t i = 0; i < jpeg_data->app_data.size(); ++i) {

    if (jpeg_data->app_marker_type[i] == jxl::jpeg::AppMarkerType::kExif) {

      if (jpeg_data->app_data[i].size() !=

          size + 3 + sizeof(jpeg::kExifTag) - 4)

        return JXL_DEC_ERROR;

      // The first 9 bytes are used for JPEG marker header.

      jpeg_data->app_data[i][0] = 0xE1;

      // The second and third byte are already filled in correctly

      memcpy(jpeg_data->app_data[i].data() + 3, jpeg::kExifTag,

             sizeof(jpeg::kExifTag));

      // The first 4 bytes are the TIFF header from the box contents, and are

      // not included in the JPEG

      memcpy(jpeg_data->app_data[i].data() + 3 + sizeof(jpeg::kExifTag),

             data + 4, size - 4);

      return JXL_DEC_SUCCESS;

    }

  }

  return JXL_DEC_ERROR;

}

JxlDecoderStatus JxlToJpegDecoder::SetXmp(const uint8_t* data, size_t size,

                                          jpeg::JPEGData* jpeg_data) {

  for (size_t i = 0; i < jpeg_data->app_data.size(); ++i) {

    if (jpeg_data->app_marker_type[i] == jxl::jpeg::AppMarkerType::kXMP) {

      if (jpeg_data->app_data[i].size() != size + 3 + sizeof(jpeg::kXMPTag))

        return JXL_DEC_ERROR;

      // The first 9 bytes are used for JPEG marker header.

      jpeg_data->app_data[i][0] = 0xE1;

      // The second and third byte are already filled in correctly

      memcpy(jpeg_data->app_data[i].data() + 3, jpeg::kXMPTag,

             sizeof(jpeg::kXMPTag));

      memcpy(jpeg_data->app_data[i].data() + 3 + sizeof(jpeg::kXMPTag), data,

             size);

      return JXL_DEC_SUCCESS;

    }

  }

  return JXL_DEC_ERROR;

}

#endif  // JPEGXL_ENABLE_TRANSCODE_JPEG

}  // namespace jxl