// Aseprite Document Library
// Copyright (C) 2018-2023  Igara Studio S.A.
// Copyright (C) 2001-2016  David Capello
//
// This file is released under the terms of the MIT license.
// Read LICENSE.txt for more information.

#ifndef DOC_IMAGE_IMPL_H_INCLUDED
#define DOC_IMAGE_IMPL_H_INCLUDED
#pragma once

#include <algorithm>
#include <cstdlib>
#include <cstring>

#include "doc/blend_funcs.h"
#include "doc/image.h"
#include "doc/image_traits.h"
#include "doc/palette.h"

namespace doc {

template<typename ImageTraits>
class LockImageBits;

template<class Traits>
class ImageImpl final : public Image {
public:
  using traits_t = Traits;
  using address_t = typename traits_t::address_t;
  using const_address_t = typename traits_t::const_address_t;

private:
  ImageBufferPtr m_buffer;
  address_t* m_rows;
  address_t m_bits;

  inline address_t getLineAddress(int y)
  {
    ASSERT(y >= 0 && y < height());
    return m_rows[y];
  }

  inline const_address_t getLineAddress(int y) const
  {
    ASSERT(y >= 0 && y < height());
    return m_rows[y];
  }

public:
  inline address_t address(int x, int y) const
  {
    if constexpr (Traits::pixels_per_byte == 0) {
      return (address_t)(getLineAddress(y) + x);
    }
    else {
      return (address_t)(getLineAddress(y) + x / Traits::pixels_per_byte);
    }
  }

  ImageImpl(const ImageSpec& spec, const ImageBufferPtr& buffer) : Image(spec), m_buffer(buffer)
  {
    ASSERT(Traits::color_mode == spec.colorMode());

    m_rowBytes = Traits::rowstride_bytes(width());

    const std::size_t for_rows = doc_align_size(sizeof(address_t) * height());
    const std::size_t for_pixels = m_rowBytes * height();
    const std::size_t required_size = for_pixels + for_rows;

    if (!m_buffer)
      m_buffer = std::make_shared<ImageBuffer>(required_size);
    else
      m_buffer->resizeIfNecessary(required_size);

    std::fill(m_buffer->buffer(), m_buffer->buffer() + required_size, 0);

    m_rows = (address_t*)m_buffer->buffer();
    m_bits = (address_t)(m_buffer->buffer() + for_rows);

    auto addr = (uint8_t*)m_bits;
    for (int y = 0; y < height(); ++y) {
      m_rows[y] = (address_t)addr;
      addr += m_rowBytes;
    }
  }

  uint8_t* getPixelAddress(int x, int y) const override
  {
    ASSERT(x >= 0 && x < width());
    ASSERT(y >= 0 && y < height());

    return (uint8_t*)address(x, y);
  }

  color_t getPixel(int x, int y) const override
  {
    ASSERT(x >= 0 && x < width());
    ASSERT(y >= 0 && y < height());

    return *address(x, y);
  }

  void putPixel(int x, int y, color_t color) override
  {
    ASSERT(x >= 0 && x < width());
    ASSERT(y >= 0 && y < height());

    *address(x, y) = color;
  }

  void clear(color_t color) override
  {
    const int w = width();
    const int h = height();
    for (int y = 0; y < h; ++y) {
      address_t p = address(0, y);
      std::fill(p, p + w, color);
    }
  }

  void copy(const Image* _src, gfx::Clip area) override
  {
    const ImageImpl<Traits>* src = (const ImageImpl<Traits>*)_src;
    address_t src_address;
    address_t dst_address;

    if (!area.clip(width(), height(), src->width(), src->height()))
      return;

    for (int end_y = area.dst.y + area.size.h; area.dst.y < end_y; ++area.dst.y, ++area.src.y) {
      src_address = src->address(area.src.x, area.src.y);
      dst_address = address(area.dst.x, area.dst.y);

      std::copy(src_address, src_address + area.size.w, dst_address);
    }
  }

  void drawHLine(int x1, int y, int x2, color_t color) override
  {
    LockImageBits<Traits> bits(this, gfx::Rect(x1, y, x2 - x1 + 1, 1));
    typename LockImageBits<Traits>::iterator it(bits.begin());
    typename LockImageBits<Traits>::iterator end(bits.end());

    for (; it != end; ++it)
      *it = color;
  }

  void fillRect(int x1, int y1, int x2, int y2, color_t color) override
  {
    // Fill the first line
    ImageImpl<Traits>::drawHLine(x1, y1, x2, color);

    // Copy all other lines
    address_t first = address(x1, y1);
    int w = x2 - x1 + 1;
    for (int y = y1; y <= y2; ++y)
      std::copy(first, first + w, address(x1, y));
  }

  void blendRect(int x1, int y1, int x2, int y2, color_t color, int opacity) override
  {
    fillRect(x1, y1, x2, y2, color);
  }

private:
  bool clip_rects(const Image* src, int& dst_x, int& dst_y, int& src_x, int& src_y, int& w, int& h)
    const
  {
    // Clip with destionation image
    if (dst_x < 0) {
      w += dst_x;
      src_x -= dst_x;
      dst_x = 0;
    }
    if (dst_y < 0) {
      h += dst_y;
      src_y -= dst_y;
      dst_y = 0;
    }
    if (dst_x + w > width()) {
      w = width() - dst_x;
    }
    if (dst_y + h > height()) {
      h = height() - dst_y;
    }

    // Clip with source image
    if (src_x < 0) {
      w += src_x;
      dst_x -= src_x;
      src_x = 0;
    }
    if (src_y < 0) {
      h += src_y;
      dst_y -= src_y;
      src_y = 0;
    }
    if (src_x + w > src->width()) {
      w = src->width() - src_x;
    }
    if (src_y + h > src->height()) {
      h = src->height() - src_y;
    }

    // Empty cases
    if (w < 1 || h < 1)
      return false;

    if ((src_x + w <= 0) || (src_x >= src->width()) || (src_y + h <= 0) || (src_y >= src->height()))
      return false;

    if ((dst_x + w <= 0) || (dst_x >= width()) || (dst_y + h <= 0) || (dst_y >= height()))
      return false;

    // Check this function is working correctly
    ASSERT(src->bounds().contains(gfx::Rect(src_x, src_y, w, h)));
    ASSERT(bounds().contains(gfx::Rect(dst_x, dst_y, w, h)));
    return true;
  }
};

//////////////////////////////////////////////////////////////////////
// Specializations

template<>
inline void ImageImpl<IndexedTraits>::clear(color_t color)
{
  uint8_t* p = address(0, 0);
  std::fill(p, p + rowBytes() * height(), color);
}

template<>
inline void ImageImpl<BitmapTraits>::clear(color_t color)
{
  uint8_t* p = address(0, 0);
  std::fill(p, p + rowBytes() * height(), (color ? 0xff : 0x00));
}

template<>
inline color_t ImageImpl<BitmapTraits>::getPixel(int x, int y) const
{
  ASSERT(x >= 0 && x < width());
  ASSERT(y >= 0 && y < height());

  std::div_t d = std::div(x, 8);
  return ((*(getLineAddress(y) + d.quot)) & (1 << d.rem)) ? 1 : 0;
}

template<>
inline void ImageImpl<BitmapTraits>::putPixel(int x, int y, color_t color)
{
  ASSERT(x >= 0 && x < width());
  ASSERT(y >= 0 && y < height());

  std::div_t d = std::div(x, 8);
  if (color)
    (*(getLineAddress(y) + d.quot)) |= (1 << d.rem);
  else
    (*(getLineAddress(y) + d.quot)) &= ~(1 << d.rem);
}

template<>
inline void ImageImpl<BitmapTraits>::fillRect(int x1, int y1, int x2, int y2, color_t color)
{
  for (int y = y1; y <= y2; ++y)
    ImageImpl<BitmapTraits>::drawHLine(x1, y, x2, color);
}

template<>
inline void ImageImpl<RgbTraits>::blendRect(int x1,
                                            int y1,
                                            int x2,
                                            int y2,
                                            color_t color,
                                            int opacity)
{
  address_t addr;
  int x, y;

  for (y = y1; y <= y2; ++y) {
    addr = (address_t)getPixelAddress(x1, y);
    for (x = x1; x <= x2; ++x) {
      *addr = rgba_blender_normal(*addr, color, opacity);
      ++addr;
    }
  }
}

void copy_bitmaps(Image* dst, const Image* src, gfx::Clip area);
template<>
inline void ImageImpl<BitmapTraits>::copy(const Image* src, gfx::Clip area)
{
  copy_bitmaps(this, src, area);
}

} // namespace doc

#endif
