#pragma once

#ifndef TCG_PIXEL_OPS_H

#define TCG_PIXEL_OPS_H

// tcg includes

#include "base.h"

namespace tcg {

//**************************************************************************

//    Pixel Categories

//**************************************************************************

struct grayscale_pixel_tag {};

struct rgb_pixel_tag {};

struct rgbm_pixel_tag : public rgb_pixel_tag {};

struct indexed_pixel_tag {};

//**************************************************************************

//    Pixel Traits Types

//**************************************************************************

template <typename Pix, typename pixel_category = typename Pix::pixel_category>

struct pixel_traits_types;

template <typename Pix>

struct pixel_traits_types<Pix, grayscale_pixel_tag> {

  typedef Pix pixel_type;

  typedef grayscale_pixel_tag pixel_category;

  typedef typename Pix::channel_type channel_type;

  enum { channels_count = 1 };

};

template <typename Pix>

struct pixel_traits_types<Pix, rgb_pixel_tag> {

  typedef Pix pixel_type;

  typedef rgb_pixel_tag pixel_category;

  typedef typename Pix::channel_type channel_type;

  enum { channels_count = 3 };

};

template <typename Pix>

struct pixel_traits_types<Pix, rgbm_pixel_tag>

    : public pixel_traits_types<Pix, rgb_pixel_tag> {

  typedef Pix pixel_type;

  typedef rgbm_pixel_tag pixel_category;

  typedef typename Pix::channel_type channel_type;

  enum { channels_count = 4 };

};

template <typename Pix>

struct pixel_traits_types<Pix, indexed_pixel_tag> {

  typedef Pix pixel_type;

  typedef indexed_pixel_tag pixel_category;

  typedef typename Pix::index_type index_type;

};

//**************************************************************************

//    Pixel Traits

//**************************************************************************

template <typename Pix, typename pixel_category = typename Pix::pixel_category>

struct pixel_traits;

template <typename Pix>

struct pixel_traits<Pix, grayscale_pixel_tag>

    : public pixel_traits_types<Pix, grayscale_pixel_tag> {

  typedef pixel_traits_types<Pix, grayscale_pixel_tag> tr;

public:

  static typename tr::channel_type max_channel_value();

  static typename tr::channel_type l(const typename tr::pixel_type &pix);

  static typename tr::channel_type &l(typename tr::pixel_type &pix);

};

template <typename Pix>

struct pixel_traits<Pix, rgb_pixel_tag> {

  typedef pixel_traits_types<Pix, rgb_pixel_tag> tr;

public:

  static typename tr::channel_type max_channel_value();

  static typename tr::channel_type r(const typename tr::pixel_type &pix);

  static typename tr::channel_type &r(typename tr::pixel_type &pix);

  static typename tr::channel_type g(const typename tr::pixel_type &pix);

  static typename tr::channel_type &g(typename tr::pixel_type &pix);

  static typename tr::channel_type b(const typename tr::pixel_type &pix);

  static typename tr::channel_type &b(typename tr::pixel_type &pix);

};

template <typename Pix>

struct pixel_traits<Pix, rgbm_pixel_tag>

    : public pixel_traits<Pix, rgb_pixel_tag> {

  typedef pixel_traits_types<Pix, rgbm_pixel_tag> tr;

public:

  static typename tr::channel_type m(const typename tr::pixel_type &pix);

  static typename tr::channel_type &m(typename tr::pixel_type &pix);

};

template <typename Pix>

struct pixel_traits<Pix, indexed_pixel_tag> {

  typedef pixel_traits_types<Pix, indexed_pixel_tag> tr;

  typedef typename tr::pixel_type pixel_type;

  typedef typename tr::index_type index_type;

public:

  static typename tr::index_type index(const typename tr::pixel_type &pix);

  static typename tr::index_type &index(typename tr::pixel_type &pix);

};

namespace pixel_ops {

//**************************************************************************

//    Pixel Functions

//**************************************************************************

template <typename PixIn, typename PixOut>

inline PixOut _cast(const PixIn &pix, grayscale_pixel_tag) {

  return PixOut(pixel_traits<PixIn>::l(pix));

}

template <typename PixIn, typename PixOut>

inline PixOut _cast(const PixIn &pix, rgb_pixel_tag) {

  return PixOut(pixel_traits<PixIn>::r(pix), pixel_traits<PixIn>::g(pix),

                pixel_traits<PixIn>::b(pix));

}

template <typename PixIn, typename PixOut>

inline PixOut _cast(const PixIn &pix, rgbm_pixel_tag) {

  return PixOut(pixel_traits<PixIn>::r(pix), pixel_traits<PixIn>::g(pix),

                pixel_traits<PixIn>::b(pix), pixel_traits<PixIn>::m(pix));

}

template <typename PixIn, typename PixOut>

inline PixOut cast(const PixIn &pix) {

  return _cast<PixIn, PixOut>(pix,

                              typename pixel_traits<PixIn>::pixel_category());

}

//------------------------------------------------------------------

template <typename PixIn, typename PixOut>

inline void _assign(PixOut &pixout, const PixIn &pixin, grayscale_pixel_tag) {

  pixel_traits<PixOut>::l(pixout) = pixel_traits<PixIn>::l(pixin);

}

template <typename PixIn, typename PixOut>

inline void _assign(PixOut &pixout, const PixIn &pixin, rgb_pixel_tag) {

  pixel_traits<PixOut>::r(pixout) = pixel_traits<PixIn>::r(pixin);

  pixel_traits<PixOut>::g(pixout) = pixel_traits<PixIn>::g(pixin);

  pixel_traits<PixOut>::b(pixout) = pixel_traits<PixIn>::b(pixin);

}

template <typename PixIn, typename PixOut>

inline void _assign(PixOut &pixout, const PixIn &pixin, rgbm_pixel_tag) {

  pixel_traits<PixOut>::r(pixout) = pixel_traits<PixIn>::r(pixin);

  pixel_traits<PixOut>::g(pixout) = pixel_traits<PixIn>::g(pixin);

  pixel_traits<PixOut>::b(pixout) = pixel_traits<PixIn>::b(pixin);

  pixel_traits<PixOut>::m(pixout) = pixel_traits<PixIn>::m(pixin);

}

template <typename PixIn, typename PixOut>

inline void assign(PixOut &pixout, const PixIn &pixin) {

  _assign<PixIn, PixOut>(pixout, pixin,

                         typename pixel_traits<PixIn>::pixel_category());

}

//------------------------------------------------------------------

template <typename Pix1, typename Pix2>

inline Pix1 _sum(const Pix1 &a, const Pix2 &b, grayscale_pixel_tag) {

  return Pix1(pixel_traits<Pix1>::l(a) + pixel_traits<Pix2>::l(b));

}

template <typename Pix1, typename Pix2>

inline Pix1 _sum(const Pix1 &a, const Pix2 &b, rgb_pixel_tag) {

  return Pix1(pixel_traits<Pix1>::r(a) + pixel_traits<Pix2>::r(b),

              pixel_traits<Pix1>::g(a) + pixel_traits<Pix2>::g(b),

              pixel_traits<Pix1>::b(a) + pixel_traits<Pix2>::b(b));

}

template <typename Pix1, typename Pix2>

inline Pix1 _sum(const Pix1 &a, const Pix2 &b, rgbm_pixel_tag) {

  return Pix1(pixel_traits<Pix1>::r(a) + pixel_traits<Pix2>::r(b),

              pixel_traits<Pix1>::g(a) + pixel_traits<Pix2>::g(b),

              pixel_traits<Pix1>::b(a) + pixel_traits<Pix2>::b(b),

              pixel_traits<Pix1>::m(a) + pixel_traits<Pix2>::m(b));

}

template <typename Pix1, typename Pix2>

inline Pix1 operator+(const Pix1 &a, const Pix2 &b) {

  return _sum(a, b, typename pixel_traits<Pix2>::pixel_category());

}

//------------------------------------------------------------------

template <typename Pix1, typename Pix2>

inline Pix1 _sub(const Pix1 &a, const Pix2 &b, grayscale_pixel_tag) {

  return Pix1(pixel_traits<Pix1>::l(a) - pixel_traits<Pix2>::l(b));

}

template <typename Pix1, typename Pix2>

inline Pix1 _sub(const Pix1 &a, const Pix2 &b, rgb_pixel_tag) {

  return Pix1(pixel_traits<Pix1>::r(a) - pixel_traits<Pix2>::r(b),

              pixel_traits<Pix1>::g(a) - pixel_traits<Pix2>::g(b),

              pixel_traits<Pix1>::b(a) - pixel_traits<Pix2>::b(b));

}

template <typename Pix1, typename Pix2>

inline Pix1 _sub(const Pix1 &a, const Pix2 &b, rgbm_pixel_tag) {

  return Pix1(pixel_traits<Pix1>::r(a) - pixel_traits<Pix2>::r(b),

              pixel_traits<Pix1>::g(a) - pixel_traits<Pix2>::g(b),

              pixel_traits<Pix1>::b(a) - pixel_traits<Pix2>::b(b),

              pixel_traits<Pix1>::m(a) - pixel_traits<Pix2>::m(b));

}

template <typename Pix1, typename Pix2>

inline Pix1 operator-(const Pix1 &a, const Pix2 &b) {

  return _sub(a, b, typename pixel_traits<Pix2>::pixel_category());

}

//------------------------------------------------------------------

template <typename Pix, typename Scalar>

inline Pix _mult(const Pix &a, Scalar k, grayscale_pixel_tag) {

  return Pix(pixel_traits<Pix>::l(a) * k);

}

template <typename Pix, typename Scalar>

inline Pix _mult(const Pix &a, Scalar k, rgb_pixel_tag) {

  return Pix(pixel_traits<Pix>::r(a) * k, pixel_traits<Pix>::g(a) * k,

             pixel_traits<Pix>::b(a) * k);

}

template <typename Pix, typename Scalar>

inline Pix _mult(const Pix &a, Scalar k, rgbm_pixel_tag) {

  return Pix(pixel_traits<Pix>::r(a) * k, pixel_traits<Pix>::g(a) * k,

             pixel_traits<Pix>::b(a) * k, pixel_traits<Pix>::m(a) * k);

}

template <typename Pix, typename Scalar>

inline Pix operator*(Scalar k, const Pix &pix) {

  return _mult(pix, k, typename pixel_traits<Pix>::pixel_category());

}

//------------------------------------------------------------------

template <typename Pix, typename Scalar>

inline Pix _div(const Pix &a, Scalar k, grayscale_pixel_tag) {

  return Pix(pixel_traits<Pix>::l(a) / k);

}

template <typename Pix, typename Scalar>

inline Pix _div(const Pix &a, Scalar k, rgb_pixel_tag) {

  return Pix(pixel_traits<Pix>::r(a) / k, pixel_traits<Pix>::g(a) / k,

             pixel_traits<Pix>::b(a) / k);

}

template <typename Pix, typename Scalar>

inline Pix _div(const Pix &a, Scalar k, rgbm_pixel_tag) {

  return Pix(pixel_traits<Pix>::r(a) / k, pixel_traits<Pix>::g(a) / k,

             pixel_traits<Pix>::b(a) / k, pixel_traits<Pix>::m(a) / k);

}

template <typename Pix, typename Scalar>

inline Pix operator/(const Pix &pix, Scalar k) {

  return _div(pix, k, typename pixel_traits<Pix>::pixel_category());

}

//------------------------------------------------------------------

template <typename Pix, typename Scalar>

inline void premultiply(Pix &pix, Scalar = 0) {

  Scalar factor =

      pixel_traits<Pix>::m(pix) / Scalar(pixel_traits<Pix>::max_channel_value);

  pixel_traits<Pix>::r(pix) = pixel_traits<Pix>::r(pix) * factor;

  pixel_traits<Pix>::g(pix) = pixel_traits<Pix>::g(pix) * factor;

  pixel_traits<Pix>::b(pix) = pixel_traits<Pix>::b(pix) * factor;

}

//------------------------------------------------------------------

template <typename Pix, typename Scalar>

inline void depremultiply(Pix &pix, Scalar = 0) {

  if (pixel_traits<Pix>::channel_type m = pixel_traits<Pix>::m(pix)) {

    Scalar factor = pixel_traits<Pix>::max_channel_value / Scalar(m);

    pixel_traits<Pix>::r(pix) = pixel_traits<Pix>::r(pix) * factor;

    pixel_traits<Pix>::g(pix) = pixel_traits<Pix>::g(pix) * factor;

    pixel_traits<Pix>::b(pix) = pixel_traits<Pix>::b(pix) * factor;

  }

}

//------------------------------------------------------------------

template <typename Pix, typename Scalar>

inline Pix _blend(const Pix &p0, const Pix &p1, Scalar t, grayscale_pixel_tag) {

  return Pix((1 - t) * pixel_traits<Pix>::l(p0) + t * pixel_traits<Pix>::l(p1));

}

//------------------------------------------------------------------

template <typename Pix, typename Scalar>

inline Pix _blend(const Pix &p0, const Pix &p1, Scalar t, rgb_pixel_tag) {

  Scalar one_t = 1 - t;

  return Pix(one_t * pixel_traits<Pix>::r(p0) + t * pixel_traits<Pix>::r(p1),

             one_t * pixel_traits<Pix>::g(p0) + t * pixel_traits<Pix>::g(p1),

             one_t * pixel_traits<Pix>::m(p0) + t * pixel_traits<Pix>::b(p1));

}

//------------------------------------------------------------------

template <typename Pix, typename Scalar>

inline Pix _blend(const Pix &p0, const Pix &p1, Scalar t, rgbm_pixel_tag) {

  Scalar one_t = 1 - t;

  return Pix(one_t * pixel_traits<Pix>::r(p0) + t * pixel_traits<Pix>::r(p1),

             one_t * pixel_traits<Pix>::g(p0) + t * pixel_traits<Pix>::g(p1),

             one_t * pixel_traits<Pix>::b(p0) + t * pixel_traits<Pix>::b(p1),

             one_t * pixel_traits<Pix>::m(p0) + t * pixel_traits<Pix>::m(p1));

}

//------------------------------------------------------------------

template <typename Pix, typename Scalar>

inline Pix blend(const Pix &p0, const Pix &p1, Scalar t) {

  return _blend(p0, p1, t, pixel_traits<Pix>::pixel_category());

}

//------------------------------------------------------------------

template <typename Pix, typename Scalar>

inline void over_premult(Pix &down, const Pix &up, Scalar = 0) {

  Scalar t =

      (1 -

       pixel_traits<Pix>::m(up) / Scalar(pixel_traits<Pix>::max_channel_value));

  pixel_traits<Pix>::r(down) =

      pixel_traits<Pix>::r(up) + t * pixel_traits<Pix>::r(down);

  pixel_traits<Pix>::g(down) =

      pixel_traits<Pix>::g(up) + t * pixel_traits<Pix>::g(down);

  pixel_traits<Pix>::b(down) =

      pixel_traits<Pix>::b(up) + t * pixel_traits<Pix>::b(down);

  pixel_traits<Pix>::m(down) =

      pixel_traits<Pix>::m(up) + t * pixel_traits<Pix>::m(down);

}

//------------------------------------------------------------------

template <typename Pix, typename Scalar>

inline void over(Pix &down, const Pix &up, Scalar = 0) {

  Scalar t = (1 -

              pixel_traits<Pix>::m(up) /

                  Scalar(pixel_traits<Pix>::max_channel_value)) *

             pixel_traits<Pix>::m(down);

  Scalar m = pixel_traits<Pix>::m(up) + t;

  Scalar up_fac = pixel_traits<Pix>::m(up) / m;

  Scalar dn_fac = t / m;

  pixel_traits<Pix>::r(down) =

      up_fac * pixel_traits<Pix>::r(up) + dn_fac * pixel_traits<Pix>::r(down);

  pixel_traits<Pix>::g(down) =

      up_fac * pixel_traits<Pix>::g(up) + dn_fac * pixel_traits<Pix>::g(down);

  pixel_traits<Pix>::b(down) =

      up_fac * pixel_traits<Pix>::b(up) + dn_fac * pixel_traits<Pix>::b(down);

  pixel_traits<Pix>::m(down) = m;

}

}

}  // namespace tcg::pixel_ops

#endif  // TCG_PIXEL_OPS_H