// SPDX-FileCopyrightText: 2019-2024 Connor McLaughlin <stenzek@gmail.com>
// SPDX-License-Identifier: CC-BY-NC-ND-4.0

#include "image.h"

#include "common/assert.h"
#include "common/bitutils.h"
#include "common/error.h"
#include "common/fastjmp.h"
#include "common/file_system.h"
#include "common/gsvector.h"
#include "common/heap_array.h"
#include "common/intrin.h"
#include "common/log.h"
#include "common/path.h"
#include "common/scoped_guard.h"
#include "common/string_util.h"

#include "lunasvg_c.h"

#include <jpeglib.h>
#include <png.h>
#include <webp/decode.h>
#include <webp/encode.h>

// clang-format off
#ifdef _MSC_VER
#pragma warning(disable : 4611) // warning C4611: interaction between '_setjmp' and C++ object destruction is non-portable
#endif
// clang-format on

LOG_CHANNEL(Image);

static bool PNGBufferLoader(Image* image, std::span<const u8> data, Error* error);
static bool PNGBufferSaver(const Image& image, DynamicHeapArray<u8>* data, u8 quality, Error* error);
static bool PNGFileLoader(Image* image, std::string_view filename, std::FILE* fp, Error* error);
static bool PNGFileSaver(const Image& image, std::string_view filename, std::FILE* fp, u8 quality, Error* error);

static bool JPEGBufferLoader(Image* image, std::span<const u8> data, Error* error);
static bool JPEGBufferSaver(const Image& image, DynamicHeapArray<u8>* data, u8 quality, Error* error);
static bool JPEGFileLoader(Image* image, std::string_view filename, std::FILE* fp, Error* error);
static bool JPEGFileSaver(const Image& image, std::string_view filename, std::FILE* fp, u8 quality, Error* error);

static bool WebPBufferLoader(Image* image, std::span<const u8> data, Error* error);
static bool WebPBufferSaver(const Image& image, DynamicHeapArray<u8>* data, u8 quality, Error* error);
static bool WebPFileLoader(Image* image, std::string_view filename, std::FILE* fp, Error* error);
static bool WebPFileSaver(const Image& image, std::string_view filename, std::FILE* fp, u8 quality, Error* error);

struct FormatHandler
{
  const char* extension;
  bool (*buffer_loader)(Image*, std::span<const u8>, Error*);
  bool (*buffer_saver)(const Image&, DynamicHeapArray<u8>*, u8, Error*);
  bool (*file_loader)(Image*, std::string_view, std::FILE*, Error*);
  bool (*file_saver)(const Image&, std::string_view, std::FILE*, u8, Error*);
};

static constexpr FormatHandler s_format_handlers[] = {
  {"png", PNGBufferLoader, PNGBufferSaver, PNGFileLoader, PNGFileSaver},
  {"jpg", JPEGBufferLoader, JPEGBufferSaver, JPEGFileLoader, JPEGFileSaver},
  {"jpeg", JPEGBufferLoader, JPEGBufferSaver, JPEGFileLoader, JPEGFileSaver},
  {"webp", WebPBufferLoader, WebPBufferSaver, WebPFileLoader, WebPFileSaver},
};

static const FormatHandler* GetFormatHandler(std::string_view extension)
{
  for (const FormatHandler& handler : s_format_handlers)
  {
    if (StringUtil::Strncasecmp(extension.data(), handler.extension, extension.size()) == 0)
      return &handler;
  }

  return nullptr;
}

static void SwapBGRAToRGBA(void* pixels_out, u32 pixels_out_pitch, const void* pixels_in, u32 pixels_in_pitch,
                           u32 width, u32 height);

Image::Image() = default;

Image::Image(const Image& copy)
{
  SetPixels(copy.m_width, copy.m_height, copy.m_format, copy.m_pixels.get(), copy.m_pitch);
}

Image::Image(u32 width, u32 height, ImageFormat format, const void* pixels, u32 pitch)
{
  SetPixels(width, height, format, pixels, pitch);
}

Image::Image(u32 width, u32 height, ImageFormat format, PixelStorage pixels, u32 pitch)
  : m_width(width), m_height(height), m_pitch(pitch), m_format(format), m_pixels(std::move(pixels))
{
}

Image::Image(u32 width, u32 height, ImageFormat format)
{
  Resize(width, height, format, false);
}

Image::Image(Image&& move)
{
  m_width = std::exchange(move.m_width, 0);
  m_height = std::exchange(move.m_height, 0);
  m_pitch = std::exchange(move.m_pitch, 0);
  m_format = std::exchange(move.m_format, ImageFormat::None);
  m_pixels = std::move(move.m_pixels);
}

void Image::Resize(u32 new_width, u32 new_height, bool preserve)
{
  Resize(new_width, new_height, m_format, preserve);
}

void Image::Resize(u32 new_width, u32 new_height, ImageFormat format, bool preserve)
{
  if (m_width == new_width && m_height == new_height && m_format == format)
    return;

  if (!preserve)
    m_pixels.reset();

  const u32 old_blocks_y = GetBlockYCount();
  const u32 old_pitch = m_pitch;
  PixelStorage old_pixels =
    std::exchange(m_pixels, Common::make_unique_aligned_for_overwrite<u8[]>(
                              VECTOR_ALIGNMENT, CalculateStorageSize(new_width, new_height, format)));

  m_width = new_width;
  m_height = new_height;
  m_format = format;
  m_pitch = CalculatePitch(new_width, new_height, format);
  if (preserve && old_pixels)
  {
    StringUtil::StrideMemCpy(m_pixels.get(), m_pitch, old_pixels.get(), old_pitch, std::min(old_pitch, m_pitch),
                             std::min(old_blocks_y, GetBlockYCount()));
  }
}

Image& Image::operator=(const Image& copy)
{
  SetPixels(copy.m_width, copy.m_height, copy.m_format, copy.m_pixels.get(), copy.m_pitch);
  return *this;
}

Image& Image::operator=(Image&& move)
{
  m_width = std::exchange(move.m_width, 0);
  m_height = std::exchange(move.m_height, 0);
  m_pitch = std::exchange(move.m_pitch, 0);
  m_format = std::exchange(move.m_format, ImageFormat::None);
  m_pixels = std::move(move.m_pixels);
  return *this;
}

const char* Image::GetFormatName(ImageFormat format)
{
  static constexpr std::array<const char*, static_cast<size_t>(ImageFormat::MaxCount)> names = {
    "None",    // None
    "RGBA8",   // RGBA8
    "BGRA8",   // BGRA8
    "RGB565",  // RGB565
    "RGB5551", // RGBA5551
    "BC1",     // BC1
    "BC2",     // BC2
    "BC3",     // BC3
    "BC7",     // BC7
  };

  return names[static_cast<size_t>(format)];
}

u32 Image::GetPixelSize(ImageFormat format)
{
  static constexpr std::array<u8, static_cast<size_t>(ImageFormat::MaxCount)> sizes = {{
    0,  // Unknown
    4,  // RGBA8
    4,  // BGRA8
    2,  // RGB565
    2,  // RGBA5551
    8,  // BC1 - 16 pixels in 64 bits
    16, // BC2 - 16 pixels in 128 bits
    16, // BC3 - 16 pixels in 128 bits
    16, // BC4 - 16 pixels in 128 bits
  }};

  return sizes[static_cast<size_t>(format)];
}

bool Image::IsCompressedFormat(ImageFormat format)
{
  return (format >= ImageFormat::BC1);
}

u32 Image::CalculatePitch(u32 width, u32 height, ImageFormat format)
{
  const u32 pixel_size = GetPixelSize(format);
  if (!IsCompressedFormat(format))
    return Common::AlignUpPow2(width * pixel_size, 4);

  // All compressed formats use a block size of 4.
  const u32 blocks_wide = Common::AlignUpPow2(width, 4) / 4;
  return blocks_wide * pixel_size;
}

u32 Image::CalculateStorageSize(u32 width, u32 height, ImageFormat format)
{
  const u32 pixel_size = GetPixelSize(format);
  if (!IsCompressedFormat(format))
    return Common::AlignUpPow2(width * pixel_size, 4) * height;

  const u32 blocks_wide = Common::AlignUpPow2(width, 4) / 4;
  const u32 blocks_high = Common::AlignUpPow2(height, 4) / 4;
  return (blocks_wide * pixel_size) * blocks_high;
}

u32 Image::CalculateStorageSize(u32 width, u32 height, u32 pitch, ImageFormat format)
{
  height = IsCompressedFormat(format) ? (Common::AlignUpPow2(height, 4) / 4) : height;
  return pitch * height;
}

u32 Image::GetBlockXCount() const
{
  return IsCompressedFormat(m_format) ? (Common::AlignUpPow2(m_width, 4) / 4) : m_width;
}

u32 Image::GetBlockYCount() const
{
  return IsCompressedFormat(m_format) ? (Common::AlignUpPow2(m_height, 4) / 4) : m_height;
}

u32 Image::GetStorageSize() const
{
  return GetBlockYCount() * m_pitch;
}

std::span<const u8> Image::GetPixelsSpan() const
{
  return std::span<const u8>(m_pixels.get(), GetStorageSize());
}

std::span<u8> Image::GetPixelsSpan()
{
  return std::span<u8>(m_pixels.get(), GetStorageSize());
}

void Image::Clear()
{
  std::memset(m_pixels.get(), 0, CalculateStorageSize(m_width, m_height, m_pitch, m_format));
}

void Image::Invalidate()
{
  m_width = 0;
  m_height = 0;
  m_pitch = 0;
  m_format = ImageFormat::None;
  m_pixels.reset();
}

void Image::SetPixels(u32 width, u32 height, ImageFormat format, const void* pixels, u32 pitch)
{
  Resize(width, height, format, false);
  if (m_pixels)
    StringUtil::StrideMemCpy(m_pixels.get(), m_pitch, pixels, pitch, m_pitch, GetBlockYCount());
}

void Image::SetPixels(u32 width, u32 height, ImageFormat format, PixelStorage pixels, u32 pitch)
{
  m_width = width;
  m_height = height;
  m_format = format;
  m_pitch = pitch;
  m_pixels = std::move(pixels);
}

bool Image::SetAllPixelsOpaque()
{
  if (m_format == ImageFormat::RGBA8 || m_format == ImageFormat::BGRA8)
  {
    for (u32 y = 0; y < m_height; y++)
    {
      u8* row = GetRowPixels(y);
      for (u32 x = 0; x < m_width; x++, row += sizeof(u32))
        row[3] = 0xFF;
    }

    return true;
  }
  else if (m_format == ImageFormat::RGBA5551)
  {
    for (u32 y = 0; y < m_height; y++)
    {
      u8* row = GetRowPixels(y);
      for (u32 x = 0; x < m_width; x++, row += sizeof(u32))
        row[1] |= 0x80;
    }

    return true;
  }
  else if (m_format == ImageFormat::RGB565)
  {
    // Already opaque
    return true;
  }
  else
  {
    // Unhandled format
    return false;
  }
}

Image::PixelStorage Image::TakePixels()
{
  m_width = 0;
  m_height = 0;
  m_format = ImageFormat::None;
  m_pitch = 0;
  return std::move(m_pixels);
}

bool Image::LoadFromFile(const char* filename, Error* error /* = nullptr */)
{
  auto fp = FileSystem::OpenManagedCFile(filename, "rb", error);
  if (!fp)
    return false;

  return LoadFromFile(filename, fp.get(), error);
}

bool Image::SaveToFile(const char* filename, u8 quality /* = DEFAULT_SAVE_QUALITY */,
                       Error* error /* = nullptr */) const
{
  auto fp = FileSystem::OpenManagedCFile(filename, "wb", error);
  if (!fp)
    return false;

  if (SaveToFile(filename, fp.get(), quality, error))
    return true;

  // save failed
  fp.reset();
  FileSystem::DeleteFile(filename);
  return false;
}

bool Image::LoadFromFile(std::string_view filename, std::FILE* fp, Error* error /* = nullptr */)
{
  const std::string_view extension(Path::GetExtension(filename));
  const FormatHandler* handler = GetFormatHandler(extension);
  if (!handler || !handler->file_loader)
  {
    Error::SetStringFmt(error, "Unknown extension '{}'", extension);
    return false;
  }

  return handler->file_loader(this, filename, fp, error);
}

bool Image::LoadFromBuffer(std::string_view filename, std::span<const u8> data, Error* error /* = nullptr */)
{
  const std::string_view extension(Path::GetExtension(filename));
  const FormatHandler* handler = GetFormatHandler(extension);
  if (!handler || !handler->buffer_loader)
  {
    Error::SetStringFmt(error, "Unknown extension '{}'", extension);
    return false;
  }

  return handler->buffer_loader(this, data, error);
}

bool Image::RasterizeSVG(const std::span<const u8> data, u32 width, u32 height, Error* error)
{
  if (width == 0 || height == 0)
  {
    Error::SetStringFmt(error, "Invalid dimensions: {}x{}", width, height);
    return false;
  }

  std::unique_ptr<lunasvg_document, void (*)(lunasvg_document*)> doc(
    lunasvg_document_load_from_data(data.data(), data.size()), lunasvg_document_destroy);
  if (!doc)
  {
    Error::SetStringView(error, "lunasvg_document_load_from_data() failed");
    return false;
  }

  std::unique_ptr<lunasvg_bitmap, void (*)(lunasvg_bitmap*)> bitmap(
    lunasvg_document_render_to_bitmap(doc.get(), width, height, 0), lunasvg_bitmap_destroy);
  if (!bitmap)
  {
    Error::SetStringView(error, "lunasvg_document_render_to_bitmap() failed");
    return false;
  }

  // lunasvg works in BGRA, swap to RGBA
  Resize(width, height, ImageFormat::RGBA8, false);
  SwapBGRAToRGBA(m_pixels.get(), m_pitch, lunasvg_bitmap_data(bitmap.get()), lunasvg_bitmap_stride(bitmap.get()), width,
                 height);
  return true;
}

bool Image::SaveToFile(std::string_view filename, std::FILE* fp, u8 quality /* = DEFAULT_SAVE_QUALITY */,
                       Error* error /* = nullptr */) const
{
  const std::string_view extension(Path::GetExtension(filename));
  const FormatHandler* handler = GetFormatHandler(extension);
  if (!handler || !handler->file_saver)
  {
    Error::SetStringFmt(error, "Unknown extension '{}'", extension);
    return false;
  }

  if (!handler->file_saver(*this, filename, fp, quality, error))
    return false;

  if (std::fflush(fp) != 0)
  {
    Error::SetErrno(error, "fflush() failed: ", errno);
    return false;
  }

  return true;
}

std::optional<DynamicHeapArray<u8>> Image::SaveToBuffer(std::string_view filename,
                                                        u8 quality /* = DEFAULT_SAVE_QUALITY */,
                                                        Error* error /* = nullptr */) const
{
  std::optional<DynamicHeapArray<u8>> ret;

  const std::string_view extension(Path::GetExtension(filename));
  const FormatHandler* handler = GetFormatHandler(extension);
  if (!handler || !handler->file_saver)
  {
    Error::SetStringFmt(error, "Unknown extension '{}'", extension);
    return ret;
  }

  ret = DynamicHeapArray<u8>();
  if (!handler->buffer_saver(*this, &ret.value(), quality, error))
    ret.reset();

  return ret;
}

void SwapBGRAToRGBA(void* pixels_out, u32 pixels_out_pitch, const void* pixels_in, u32 pixels_in_pitch, u32 width,
                    u32 height)
{
#ifdef GSVECTOR_HAS_FAST_INT_SHUFFLE8
  constexpr u32 pixels_per_vec = sizeof(GSVector4i) / 4;
  const u32 aligned_width = Common::AlignDownPow2(width, pixels_per_vec);
#endif

  const u8* pixels_in_ptr = static_cast<const u8*>(pixels_in);
  u8* pixels_out_ptr = static_cast<u8*>(pixels_out);
  for (u32 y = 0; y < height; y++)
  {
    const u8* row_pixels_in_ptr = pixels_in_ptr;
    u8* row_pixels_out_ptr = pixels_out_ptr;
    u32 x = 0;

#ifdef GSVECTOR_HAS_FAST_INT_SHUFFLE8
    for (; x < aligned_width; x += pixels_per_vec)
    {
      static constexpr GSVector4i mask = GSVector4i::cxpr8(2, 1, 0, 3, 6, 5, 4, 7, 10, 9, 8, 11, 14, 13, 12, 15);
      GSVector4i::store<false>(row_pixels_out_ptr, GSVector4i::load<false>(row_pixels_in_ptr).shuffle8(mask));
      row_pixels_in_ptr += sizeof(GSVector4i);
      row_pixels_out_ptr += sizeof(GSVector4i);
    }
#endif

    for (; x < width; x++)
    {
      u32 pixel;
      std::memcpy(&pixel, row_pixels_in_ptr, sizeof(pixel));
      pixel = (pixel & 0xFF00FF00) | ((pixel & 0xFF) << 16) | ((pixel >> 16) & 0xFF);
      std::memcpy(row_pixels_out_ptr, &pixel, sizeof(pixel));
      row_pixels_in_ptr += sizeof(pixel);
      row_pixels_out_ptr += sizeof(pixel);
    }

    pixels_in_ptr += pixels_in_pitch;
    pixels_out_ptr += pixels_out_pitch;
  }
}

std::optional<Image> Image::ConvertToRGBA8(Error* error) const
{
  std::optional<Image> ret;

  if (!IsValid())
  {
    Error::SetStringView(error, "Image is not valid.");
    return ret;
  }

  switch (m_format)
  {
    case ImageFormat::BGRA8:
    {
      ret = Image(m_width, m_height, ImageFormat::RGBA8);
      SwapBGRAToRGBA(ret->GetPixels(), ret->GetPitch(), m_pixels.get(), m_pitch, m_width, m_height);
    }
    break;

    case ImageFormat::RGBA8:
    {
      ret = Image(m_width, m_height, m_format, m_pixels.get(), m_pitch);
    }
    break;

    case ImageFormat::RGB565:
    {
      ret = Image(m_width, m_height, ImageFormat::RGBA8);
      for (u32 y = 0; y < m_height; y++)
      {
        const u8* pixels_in = GetRowPixels(y);
        u8* pixels_out = ret->GetRowPixels(y);

        for (u32 x = 0; x < m_width; x++)
        {
          // RGB565 -> RGBA8
          u16 pixel_in;
          std::memcpy(&pixel_in, pixels_in, sizeof(u16));
          pixels_in += sizeof(u16);
          const u8 r5 = Truncate8(pixel_in >> 11);
          const u8 g6 = Truncate8((pixel_in >> 5) & 0x3F);
          const u8 b5 = Truncate8(pixel_in & 0x1F);
          const u32 rgba8 = ZeroExtend32((r5 << 3) | (r5 & 7)) | (ZeroExtend32((g6 << 2) | (g6 & 3)) << 8) |
                            (ZeroExtend32((b5 << 3) | (b5 & 7)) << 16) | (0xFF000000u);
          std::memcpy(pixels_out, &rgba8, sizeof(u32));
          pixels_out += sizeof(u32);
        }
      }
    }
    break;

    case ImageFormat::RGBA5551:
    {
      ret = Image(m_width, m_height, ImageFormat::RGBA8);
      for (u32 y = 0; y < m_height; y++)
      {
        const u8* pixels_in = GetRowPixels(y);
        u8* pixels_out = ret->GetRowPixels(y);

        for (u32 x = 0; x < m_width; x++)
        {
          // RGBA5551 -> RGBA8
          u16 pixel_in;
          std::memcpy(&pixel_in, pixels_in, sizeof(u16));
          pixels_in += sizeof(u16);
          const u8 a1 = Truncate8(pixel_in >> 15);
          const u8 r5 = Truncate8((pixel_in >> 10) & 0x1F);
          const u8 g6 = Truncate8((pixel_in >> 5) & 0x1F);
          const u8 b5 = Truncate8(pixel_in & 0x1F);
          const u32 rgba8 = ZeroExtend32((r5 << 3) | (r5 & 7)) | (ZeroExtend32((g6 << 3) | (g6 & 7)) << 8) |
                            (ZeroExtend32((b5 << 3) | (b5 & 7)) << 16) | (a1 ? 0xFF000000u : 0u);
          std::memcpy(pixels_out, &rgba8, sizeof(u32));
          pixels_out += sizeof(u32);
        }
      }
    }
    break;

      // TODO: Block format decompression

    default:
    {
      Error::SetStringFmt(error, "Unhandled format {}", GetFormatName(m_format));
    }
    break;
  }

  return ret;
}

void Image::FlipY()
{
  if (!IsValid())
    return;

  PixelStorage temp = Common::make_unique_aligned_for_overwrite<u8[]>(VECTOR_ALIGNMENT, m_pitch);
  const u32 half_height = m_height / 2;
  for (u32 flip_row = 0; flip_row < half_height; flip_row++)
  {
    u8* top_ptr = &m_pixels[flip_row * m_pitch];
    u8* bottom_ptr = &m_pixels[((m_height - 1) - flip_row) * m_pitch];
    std::memcpy(temp.get(), top_ptr, m_pitch);
    std::memcpy(top_ptr, bottom_ptr, m_pitch);
    std::memcpy(bottom_ptr, temp.get(), m_pitch);
  }
}

static void PNGSetErrorFunction(png_structp png_ptr, Error* error)
{
  png_set_error_fn(
    png_ptr, error,
    [](png_structp png_ptr, png_const_charp message) {
      Error::SetStringView(static_cast<Error*>(png_get_error_ptr(png_ptr)), message);
      png_longjmp(png_ptr, 1);
    },
    [](png_structp png_ptr, png_const_charp message) { WARNING_LOG("libpng warning: {}", message); });
}

static bool PNGCommonLoader(Image* image, png_structp png_ptr, png_infop info_ptr, std::vector<png_bytep>& row_pointers)
{
  png_read_info(png_ptr, info_ptr);

  const u32 width = png_get_image_width(png_ptr, info_ptr);
  const u32 height = png_get_image_height(png_ptr, info_ptr);
  const png_byte color_type = png_get_color_type(png_ptr, info_ptr);
  const png_byte bit_depth = png_get_bit_depth(png_ptr, info_ptr);

  // Read any color_type into 8bit depth, RGBA format.
  // See http://www.libpng.org/pub/png/libpng-manual.txt

  if (bit_depth == 16)
    png_set_strip_16(png_ptr);

  if (color_type == PNG_COLOR_TYPE_PALETTE)
    png_set_palette_to_rgb(png_ptr);

  // PNG_COLOR_TYPE_GRAY_ALPHA is always 8 or 16bit depth.
  if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
    png_set_expand_gray_1_2_4_to_8(png_ptr);

  if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
    png_set_tRNS_to_alpha(png_ptr);

  // These color_type don't have an alpha channel then fill it with 0xff.
  if (color_type == PNG_COLOR_TYPE_RGB || color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_PALETTE)
    png_set_filler(png_ptr, 0xFF, PNG_FILLER_AFTER);

  if (color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
    png_set_gray_to_rgb(png_ptr);

  png_read_update_info(png_ptr, info_ptr);

  image->Resize(width, height, ImageFormat::RGBA8, false);
  row_pointers.reserve(height);
  for (u32 y = 0; y < height; y++)
    row_pointers.push_back(reinterpret_cast<png_bytep>(image->GetRowPixels(y)));

  png_read_image(png_ptr, row_pointers.data());
  return true;
}

bool PNGFileLoader(Image* image, std::string_view filename, std::FILE* fp, Error* error)
{
  png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
  if (!png_ptr)
  {
    Error::SetStringView(error, "png_create_read_struct() failed.");
    return false;
  }

  png_infop info_ptr = png_create_info_struct(png_ptr);
  if (!info_ptr)
  {
    Error::SetStringView(error, "png_create_info_struct() failed.");
    png_destroy_read_struct(&png_ptr, nullptr, nullptr);
    return false;
  }

  ScopedGuard cleanup([&png_ptr, &info_ptr]() { png_destroy_read_struct(&png_ptr, &info_ptr, nullptr); });

  std::vector<png_bytep> row_pointers;

  PNGSetErrorFunction(png_ptr, error);
  if (setjmp(png_jmpbuf(png_ptr)))
  {
    image->Invalidate();
    return false;
  }

  png_set_read_fn(png_ptr, fp, [](png_structp png_ptr, png_bytep data_ptr, png_size_t size) {
    std::FILE* fp = static_cast<std::FILE*>(png_get_io_ptr(png_ptr));
    if (std::fread(data_ptr, size, 1, fp) != 1)
      png_error(png_ptr, "fread() failed");
  });

  return PNGCommonLoader(image, png_ptr, info_ptr, row_pointers);
}

bool PNGBufferLoader(Image* image, std::span<const u8> data, Error* error)
{
  png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
  if (!png_ptr)
  {
    Error::SetStringView(error, "png_create_read_struct() failed.");
    return false;
  }

  png_infop info_ptr = png_create_info_struct(png_ptr);
  if (!info_ptr)
  {
    Error::SetStringView(error, "png_create_info_struct() failed.");
    png_destroy_read_struct(&png_ptr, nullptr, nullptr);
    return false;
  }

  ScopedGuard cleanup([&png_ptr, &info_ptr]() { png_destroy_read_struct(&png_ptr, &info_ptr, nullptr); });

  std::vector<png_bytep> row_pointers;

  PNGSetErrorFunction(png_ptr, error);
  if (setjmp(png_jmpbuf(png_ptr)))
  {
    image->Invalidate();
    return false;
  }

  struct IOData
  {
    std::span<const u8> buffer;
    size_t buffer_pos;
  };
  IOData iodata = {data, 0};

  png_set_read_fn(png_ptr, &iodata, [](png_structp png_ptr, png_bytep data_ptr, png_size_t size) {
    IOData* data = static_cast<IOData*>(png_get_io_ptr(png_ptr));
    const size_t read_size = std::min<size_t>(data->buffer.size() - data->buffer_pos, size);
    if (read_size > 0)
    {
      std::memcpy(data_ptr, &data->buffer[data->buffer_pos], read_size);
      data->buffer_pos += read_size;
    }
  });

  return PNGCommonLoader(image, png_ptr, info_ptr, row_pointers);
}

static void PNGSaveCommon(const Image& image, png_structp png_ptr, png_infop info_ptr, u8 quality)
{
  png_set_compression_level(png_ptr, std::clamp(quality / 10, 0, 9));
  png_set_IHDR(png_ptr, info_ptr, image.GetWidth(), image.GetHeight(), 8, PNG_COLOR_TYPE_RGBA, PNG_INTERLACE_NONE,
               PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
  png_write_info(png_ptr, info_ptr);

  for (u32 y = 0; y < image.GetHeight(); ++y)
    png_write_row(png_ptr, (png_bytep)image.GetRowPixels(y));

  png_write_end(png_ptr, nullptr);
}

bool PNGFileSaver(const Image& image, std::string_view filename, std::FILE* fp, u8 quality, Error* error)
{
  png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
  png_infop info_ptr = nullptr;
  if (!png_ptr)
  {
    Error::SetStringView(error, "png_create_write_struct() failed.");
    return false;
  }

  ScopedGuard cleanup([&png_ptr, &info_ptr]() {
    if (png_ptr)
      png_destroy_write_struct(&png_ptr, info_ptr ? &info_ptr : nullptr);
  });

  info_ptr = png_create_info_struct(png_ptr);
  if (!info_ptr)
  {
    Error::SetStringView(error, "png_create_info_struct() failed.");
    return false;
  }

  PNGSetErrorFunction(png_ptr, error);
  if (setjmp(png_jmpbuf(png_ptr)))
    return false;

  png_set_write_fn(
    png_ptr, fp,
    [](png_structp png_ptr, png_bytep data_ptr, png_size_t size) {
      if (std::fwrite(data_ptr, size, 1, static_cast<std::FILE*>(png_get_io_ptr(png_ptr))) != 1)
        png_error(png_ptr, "fwrite() failed");
    },
    [](png_structp png_ptr) {});

  PNGSaveCommon(image, png_ptr, info_ptr, quality);
  return true;
}

bool PNGBufferSaver(const Image& image, DynamicHeapArray<u8>* data, u8 quality, Error* error)
{
  png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
  png_infop info_ptr = nullptr;
  if (!png_ptr)
  {
    Error::SetStringView(error, "png_create_write_struct() failed.");
    return false;
  }

  ScopedGuard cleanup([&png_ptr, &info_ptr]() {
    if (png_ptr)
      png_destroy_write_struct(&png_ptr, info_ptr ? &info_ptr : nullptr);
  });

  info_ptr = png_create_info_struct(png_ptr);
  if (!info_ptr)
  {
    Error::SetStringView(error, "png_create_info_struct() failed.");
    return false;
  }

  struct IOData
  {
    DynamicHeapArray<u8>* buffer;
    size_t buffer_pos;
  };
  IOData iodata = {data, 0};

  data->resize(image.GetWidth() * image.GetHeight() * 2);

  PNGSetErrorFunction(png_ptr, error);
  if (setjmp(png_jmpbuf(png_ptr)))
    return false;

  png_set_write_fn(
    png_ptr, data,
    [](png_structp png_ptr, png_bytep data_ptr, png_size_t size) {
      IOData* iodata = static_cast<IOData*>(png_get_io_ptr(png_ptr));
      const size_t new_pos = iodata->buffer_pos + size;
      if (new_pos > iodata->buffer->size())
        iodata->buffer->resize(std::max(new_pos, iodata->buffer->size() * 2));
      std::memcpy(iodata->buffer->data() + iodata->buffer_pos, data_ptr, size);
      iodata->buffer_pos += size;
    },
    [](png_structp png_ptr) {});

  PNGSaveCommon(image, png_ptr, info_ptr, quality);
  iodata.buffer->resize(iodata.buffer_pos);
  return true;
}

namespace {
struct JPEGErrorHandler
{
  jpeg_error_mgr err;
  Error* errptr;
  fastjmp_buf jbuf;

  JPEGErrorHandler()
  {
    jpeg_std_error(&err);
    err.error_exit = &ErrorExit;
  }

  static void ErrorExit(j_common_ptr cinfo)
  {
    JPEGErrorHandler* eh = (JPEGErrorHandler*)cinfo->err;
    char msg[JMSG_LENGTH_MAX];
    eh->err.format_message(cinfo, msg);
    Error::SetStringFmt(eh->errptr, "libjpeg fatal error: {}", msg);
    fastjmp_jmp(&eh->jbuf, 1);
  }
};
} // namespace

template<typename T>
static bool WrapJPEGDecompress(Image* image, Error* error, T setup_func)
{
  std::vector<u8> scanline;
  jpeg_decompress_struct info = {};

  // NOTE: Be **very** careful not to allocate memory after calling this function.
  // It won't get freed, because fastjmp does not unwind the stack.
  JPEGErrorHandler errhandler;
  if (fastjmp_set(&errhandler.jbuf) != 0)
  {
    jpeg_destroy_decompress(&info);
    return false;
  }

  info.err = &errhandler.err;
  jpeg_create_decompress(&info);
  setup_func(info);

  const int herr = jpeg_read_header(&info, TRUE);
  if (herr != JPEG_HEADER_OK)
  {
    Error::SetStringFmt(error, "jpeg_read_header() returned {}", herr);
    return false;
  }

  if (info.image_width == 0 || info.image_height == 0 || info.num_components < 3)
  {
    Error::SetStringFmt(error, "Invalid image dimensions: {}x{}x{}", info.image_width, info.image_height,
                        info.num_components);
    return false;
  }

  info.out_color_space = JCS_RGB;
  info.out_color_components = 3;

  if (!jpeg_start_decompress(&info))
  {
    Error::SetStringFmt(error, "jpeg_start_decompress() returned failure");
    return false;
  }

  image->Resize(info.image_width, info.image_height, ImageFormat::RGBA8, false);
  scanline.resize(info.image_width * 3);

  u8* scanline_buffer[1] = {scanline.data()};
  bool result = true;
  for (u32 y = 0; y < info.image_height; y++)
  {
    if (jpeg_read_scanlines(&info, scanline_buffer, 1) != 1)
    {
      Error::SetStringFmt(error, "jpeg_read_scanlines() failed at row {}", y);
      result = false;
      break;
    }

    // RGB -> RGBA
    const u8* src_ptr = scanline.data();
    u8* dst_ptr = image->GetRowPixels(y);
    for (u32 x = 0; x < info.image_width; x++)
    {
      const u32 pixel32 =
        (ZeroExtend32(src_ptr[0]) | (ZeroExtend32(src_ptr[1]) << 8) | (ZeroExtend32(src_ptr[2]) << 16) | 0xFF000000u);
      std::memcpy(dst_ptr, &pixel32, sizeof(pixel32));
      dst_ptr += sizeof(pixel32);
      src_ptr += 3;
    }
  }

  jpeg_finish_decompress(&info);
  jpeg_destroy_decompress(&info);
  return result;
}

bool JPEGBufferLoader(Image* image, std::span<const u8> data, Error* error)
{
  return WrapJPEGDecompress(image, error, [data](jpeg_decompress_struct& info) {
    jpeg_mem_src(&info, static_cast<const unsigned char*>(data.data()), static_cast<unsigned long>(data.size()));
  });
}

bool JPEGFileLoader(Image* image, std::string_view filename, std::FILE* fp, Error* error)
{
  static constexpr u32 BUFFER_SIZE = 16384;

  struct FileCallback
  {
    jpeg_source_mgr mgr;

    std::FILE* fp;
    std::unique_ptr<u8[]> buffer;
    Error* errptr;
    bool end_of_file;
  };

  FileCallback cb = {
    .mgr = {
      .next_input_byte = nullptr,
      .bytes_in_buffer = 0,
      .init_source = [](j_decompress_ptr cinfo) {},
      .fill_input_buffer = [](j_decompress_ptr cinfo) -> boolean {
        FileCallback* cb = BASE_FROM_RECORD_FIELD(cinfo->src, FileCallback, mgr);
        cb->mgr.next_input_byte = cb->buffer.get();
        if (cb->end_of_file)
        {
          cb->buffer[0] = 0xFF;
          cb->buffer[1] = JPEG_EOI;
          cb->mgr.bytes_in_buffer = 2;
          return TRUE;
        }

        const size_t r = std::fread(cb->buffer.get(), 1, BUFFER_SIZE, cb->fp);
        cb->end_of_file |= (std::feof(cb->fp) != 0);
        cb->mgr.bytes_in_buffer = r;
        return TRUE;
      },
      .skip_input_data =
        [](j_decompress_ptr cinfo, long num_bytes) {
          FileCallback* cb = BASE_FROM_RECORD_FIELD(cinfo->src, FileCallback, mgr);
          const size_t skip_in_buffer = std::min<size_t>(cb->mgr.bytes_in_buffer, static_cast<size_t>(num_bytes));
          cb->mgr.next_input_byte += skip_in_buffer;
          cb->mgr.bytes_in_buffer -= skip_in_buffer;

          const size_t seek_cur = static_cast<size_t>(num_bytes) - skip_in_buffer;
          if (seek_cur > 0)
          {
            if (!FileSystem::FSeek64(cb->fp, static_cast<size_t>(seek_cur), SEEK_CUR, cb->errptr))
            {
              cb->end_of_file = true;
              return;
            }
          }
        },
      .resync_to_restart = jpeg_resync_to_restart,
      .term_source = [](j_decompress_ptr cinfo) {},
    },
    .fp = fp,
    .buffer = std::make_unique<u8[]>(BUFFER_SIZE),
    .errptr = error,
    .end_of_file = false,
  };

  return WrapJPEGDecompress(image, error, [&cb](jpeg_decompress_struct& info) { info.src = &cb.mgr; });
}

template<typename T>
static bool WrapJPEGCompress(const Image& image, u8 quality, Error* error, T setup_func)
{
  std::vector<u8> scanline;
  jpeg_compress_struct info = {};

  // NOTE: Be **very** careful not to allocate memory after calling this function.
  // It won't get freed, because fastjmp does not unwind the stack.
  JPEGErrorHandler errhandler;
  if (fastjmp_set(&errhandler.jbuf) != 0)
  {
    jpeg_destroy_compress(&info);
    return false;
  }

  info.err = &errhandler.err;
  jpeg_create_compress(&info);
  setup_func(info);

  info.image_width = image.GetWidth();
  info.image_height = image.GetHeight();
  info.in_color_space = JCS_RGB;
  info.input_components = 3;

  jpeg_set_defaults(&info);
  jpeg_set_quality(&info, quality, TRUE);
  jpeg_start_compress(&info, TRUE);

  scanline.resize(image.GetWidth() * 3);
  u8* scanline_buffer[1] = {scanline.data()};
  bool result = true;
  for (u32 y = 0; y < info.image_height; y++)
  {
    // RGBA -> RGB
    u8* dst_ptr = scanline.data();
    const u8* src_ptr = image.GetRowPixels(y);
    for (u32 x = 0; x < info.image_width; x++)
    {
      u32 rgba;
      std::memcpy(&rgba, src_ptr, sizeof(rgba));
      src_ptr += sizeof(rgba);
      *(dst_ptr++) = Truncate8(rgba);
      *(dst_ptr++) = Truncate8(rgba >> 8);
      *(dst_ptr++) = Truncate8(rgba >> 16);
    }

    if (jpeg_write_scanlines(&info, scanline_buffer, 1) != 1)
    {
      Error::SetStringFmt(error, "jpeg_write_scanlines() failed at row {}", y);
      result = false;
      break;
    }
  }

  jpeg_finish_compress(&info);
  jpeg_destroy_compress(&info);
  return result;
}

bool JPEGBufferSaver(const Image& image, DynamicHeapArray<u8>* buffer, u8 quality, Error* error)
{
  // give enough space to avoid reallocs
  buffer->resize(image.GetWidth() * image.GetHeight() * 2);

  struct MemCallback
  {
    jpeg_destination_mgr mgr;
    DynamicHeapArray<u8>* buffer;
    size_t buffer_used;
  };

  MemCallback cb;
  cb.buffer = buffer;
  cb.buffer_used = 0;
  cb.mgr.next_output_byte = buffer->data();
  cb.mgr.free_in_buffer = buffer->size();
  cb.mgr.init_destination = [](j_compress_ptr cinfo) {};
  cb.mgr.empty_output_buffer = [](j_compress_ptr cinfo) -> boolean {
    MemCallback* cb = (MemCallback*)cinfo->dest;

    // double size
    cb->buffer_used = cb->buffer->size();
    cb->buffer->resize(cb->buffer->size() * 2);
    cb->mgr.next_output_byte = cb->buffer->data() + cb->buffer_used;
    cb->mgr.free_in_buffer = cb->buffer->size() - cb->buffer_used;
    return TRUE;
  };
  cb.mgr.term_destination = [](j_compress_ptr cinfo) {
    MemCallback* cb = (MemCallback*)cinfo->dest;

    // get final size
    cb->buffer->resize(cb->buffer->size() - cb->mgr.free_in_buffer);
  };

  return WrapJPEGCompress(image, quality, error, [&cb](jpeg_compress_struct& info) { info.dest = &cb.mgr; });
}

bool JPEGFileSaver(const Image& image, std::string_view filename, std::FILE* fp, u8 quality, Error* error)
{
  static constexpr u32 BUFFER_SIZE = 16384;

  struct FileCallback
  {
    jpeg_destination_mgr mgr;

    std::FILE* fp;
    std::unique_ptr<u8[]> buffer;
    Error* errptr;
    bool write_error;
  };

  FileCallback cb = {
    .mgr = {
      .next_output_byte = nullptr,
      .free_in_buffer = 0,
      .init_destination =
        [](j_compress_ptr cinfo) {
          FileCallback* cb = BASE_FROM_RECORD_FIELD(cinfo->dest, FileCallback, mgr);
          cb->mgr.next_output_byte = cb->buffer.get();
          cb->mgr.free_in_buffer = BUFFER_SIZE;
        },
      .empty_output_buffer = [](j_compress_ptr cinfo) -> boolean {
        FileCallback* cb = BASE_FROM_RECORD_FIELD(cinfo->dest, FileCallback, mgr);
        if (!cb->write_error)
        {
          if ((cb->write_error = (std::fwrite(cb->buffer.get(), 1, BUFFER_SIZE, cb->fp) != BUFFER_SIZE)))
            Error::SetErrno(cb->errptr, "fwrite() failed: ", errno);
        }

        cb->mgr.next_output_byte = cb->buffer.get();
        cb->mgr.free_in_buffer = BUFFER_SIZE;
        return TRUE;
      },
      .term_destination =
        [](j_compress_ptr cinfo) {
          FileCallback* cb = BASE_FROM_RECORD_FIELD(cinfo->dest, FileCallback, mgr);
          const size_t left = BUFFER_SIZE - cb->mgr.free_in_buffer;
          if (left > 0 && !cb->write_error)
          {
            if ((cb->write_error = (std::fwrite(cb->buffer.get(), 1, left, cb->fp) != left)))
              Error::SetErrno(cb->errptr, "fwrite() failed: ", errno);
          }
        },
    },
    .fp = fp,
    .buffer = std::make_unique<u8[]>(BUFFER_SIZE),
    .errptr = error,
    .write_error = false,
  };

  return (WrapJPEGCompress(image, quality, error, [&cb](jpeg_compress_struct& info) { info.dest = &cb.mgr; }) &&
          !cb.write_error);
}

bool WebPBufferLoader(Image* image, std::span<const u8> data, Error* error)
{
  int width, height;
  if (!WebPGetInfo(data.data(), data.size(), &width, &height) || width <= 0 || height <= 0)
  {
    Error::SetStringView(error, "WebPGetInfo() failed");
    return false;
  }

  image->Resize(static_cast<u32>(width), static_cast<u32>(height), ImageFormat::RGBA8, false);
  if (!WebPDecodeRGBAInto(data.data(), data.size(), image->GetPixels(), image->GetStorageSize(), image->GetPitch()))
  {
    Error::SetStringView(error, "WebPDecodeRGBAInto() failed");
    image->Invalidate();
    return false;
  }

  return true;
}

bool WebPBufferSaver(const Image& image, DynamicHeapArray<u8>* data, u8 quality, Error* error)
{
  u8* encoded_data;
  const size_t encoded_size =
    WebPEncodeRGBA(reinterpret_cast<const u8*>(image.GetPixels()), image.GetWidth(), image.GetHeight(),
                   image.GetPitch(), static_cast<float>(quality), &encoded_data);
  if (encoded_size == 0)
  {
    Error::SetStringFmt(error, "WebPEncodeRGBA() for {}x{} failed.", image.GetWidth(), image.GetHeight());
    return false;
  }

  data->resize(encoded_size);
  std::memcpy(data->data(), encoded_data, encoded_size);
  WebPFree(encoded_data);
  return true;
}

bool WebPFileLoader(Image* image, std::string_view filename, std::FILE* fp, Error* error)
{
  std::optional<DynamicHeapArray<u8>> data = FileSystem::ReadBinaryFile(fp, error);
  if (!data.has_value())
    return false;

  return WebPBufferLoader(image, data->cspan(), error);
}

bool WebPFileSaver(const Image& image, std::string_view filename, std::FILE* fp, u8 quality, Error* error)
{
  DynamicHeapArray<u8> buffer;
  if (!WebPBufferSaver(image, &buffer, quality, error))
    return false;

  if (std::fwrite(buffer.data(), buffer.size(), 1, fp) != 1)
  {
    Error::SetErrno(error, "fwrite() failed: ", errno);
    return false;
  }

  return true;
}