/*

 * HEIF codec.

 * Copyright (c) 2023 Dirk Farin <dirk.farin@gmail.com>

 *

 * This file is part of libheif.

 *

 * libheif is free software: you can redistribute it and/or modify

 * it under the terms of the GNU Lesser General Public License as

 * published by the Free Software Foundation, either version 3 of

 * the License, or (at your option) any later version.

 *

 * libheif is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with libheif.  If not, see <http://www.gnu.org/licenses/>.

 */

#include "decoder_pixel_interleave.h"

#include "context.h"

#include "error.h"

#include <cassert>

#include <vector>

Error PixelInterleaveDecoder::decode_tile(const DataExtent& dataExtent,

                                          const UncompressedImageCodec::unci_properties& properties,

                                          std::shared_ptr<HeifPixelImage>& img,

                                          uint32_t out_x0, uint32_t out_y0,

                                          uint32_t image_width, uint32_t image_height,

                                          uint32_t tile_x, uint32_t tile_y)

{

  if (m_tile_width == 0) {

    return {heif_error_Decoder_plugin_error, heif_suberror_Unspecified, "Internal error: PixelInterleaveDecoder tile_width=0"};

  }

  // --- compute which file range we need to read for the tile

  uint32_t bits_per_row = 0;

  for (uint32_t x = 0; x < m_tile_width; x++) {

    uint32_t bits_per_pixel = 0;

    for (ChannelListEntry& entry : channelList) {

      uint32_t bits_per_component = entry.bits_per_component_sample;

      if (entry.component_alignment > 0) {

        // start at byte boundary

        bits_per_row = (bits_per_row + 7) & ~7U;

        uint32_t bytes_per_component = (bits_per_component + 7) / 8;

        skip_to_alignment(bytes_per_component, entry.component_alignment);

        bits_per_component = bytes_per_component * 8;

      }

      bits_per_pixel += bits_per_component;

    }

    if (m_uncC->get_pixel_size() != 0) {

      uint32_t bytes_per_pixel = (bits_per_pixel + 7) / 8;

      skip_to_alignment(bytes_per_pixel, m_uncC->get_pixel_size());

      bits_per_pixel = bytes_per_pixel * 8;

    }

    bits_per_row += bits_per_pixel;

  }

  uint32_t bytes_per_row = (bits_per_row + 7) / 8;

  skip_to_alignment(bytes_per_row, m_uncC->get_row_align_size());

  uint64_t total_tile_size = bytes_per_row * static_cast<uint64_t>(m_tile_height);

  if (m_uncC->get_tile_align_size() != 0) {

    skip_to_alignment(total_tile_size, m_uncC->get_tile_align_size());

  }

  assert(m_tile_width > 0);

  uint32_t tileIdx = tile_x + tile_y * (image_width / m_tile_width);

  uint64_t tile_start_offset = total_tile_size * tileIdx;

  // --- read required file range

  std::vector<uint8_t> src_data;

  Error err = get_compressed_image_data_uncompressed(dataExtent, properties, &src_data, tile_start_offset, total_tile_size, tileIdx, nullptr);

  //Error err = context->get_heif_file()->append_data_from_iloc(image_id, src_data, tile_start_offset, total_tile_size);

  if (err) {

    return err;

  }

  UncompressedBitReader srcBits(src_data);

  processTile(srcBits, tile_y, tile_x, out_x0, out_y0);

  return Error::Ok;

}

void PixelInterleaveDecoder::processTile(UncompressedBitReader& srcBits, uint32_t tile_row, uint32_t tile_column, uint32_t out_x0, uint32_t out_y0)

{

  for (uint32_t tile_y = 0; tile_y < m_tile_height; tile_y++) {

    srcBits.markRowStart();

    for (uint32_t tile_x = 0; tile_x < m_tile_width; tile_x++) {

      srcBits.markPixelStart();

      for (ChannelListEntry& entry : channelList) {

        if (entry.use_channel) {

          uint64_t dst_row_offset = entry.getDestinationRowOffset(0, tile_y + out_y0);

          if (entry.component_alignment != 0) {

            srcBits.skip_to_byte_boundary();

            int numPadBits = (entry.component_alignment * 8) - entry.bits_per_component_sample;

            srcBits.skip_bits(numPadBits);

          }

          processComponentSample(srcBits, entry, dst_row_offset, 0, out_x0 + tile_x);

        }

        else {

          srcBits.skip_bytes(entry.bytes_per_component_sample);

        }

      }

      srcBits.handlePixelAlignment(m_uncC->get_pixel_size());

    }

    srcBits.handleRowAlignment(m_uncC->get_row_align_size());

  }

}