/* sane - Scanner Access Now Easy.

   Copyright (C) 2019 Povilas Kanapickas <povilas@radix.lt>

   This file is part of the SANE package.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   This program 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
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.s
*/

#ifndef BACKEND_GENESYS_IMAGE_PIXEL_H
#define BACKEND_GENESYS_IMAGE_PIXEL_H

#include "enums.h"
#include <algorithm>
#include <cstdint>
#include <cstddef>

namespace genesys {

// 16-bit values are in host endian
enum class PixelFormat
{
    UNKNOWN,
    I1,
    RGB111,
    I8,
    RGB888,
    BGR888,
    I16,
    RGB161616,
    BGR161616,
};

struct Pixel
{
    Pixel() = default;
    Pixel(std::uint16_t red, std::uint16_t green, std::uint16_t blue) :
        r{red}, g{green}, b{blue} {}

    std::uint16_t r = 0;
    std::uint16_t g = 0;
    std::uint16_t b = 0;

    bool operator==(const Pixel& other) const
    {
        return r == other.r && g == other.g && b == other.b;
    }
};

struct RawPixel
{
    RawPixel() = default;
    RawPixel(std::uint8_t d0) : data{d0, 0, 0, 0, 0, 0} {}
    RawPixel(std::uint8_t d0, std::uint8_t d1) : data{d0, d1, 0, 0, 0, 0} {}
    RawPixel(std::uint8_t d0, std::uint8_t d1, std::uint8_t d2) : data{d0, d1, d2, 0, 0, 0} {}
    RawPixel(std::uint8_t d0, std::uint8_t d1, std::uint8_t d2,
             std::uint8_t d3, std::uint8_t d4, std::uint8_t d5) : data{d0, d1, d2, d3, d4, d5} {}
    std::uint8_t data[6] = {};

    bool operator==(const RawPixel& other) const
    {
        return std::equal(std::begin(data), std::end(data),
                          std::begin(other.data));
    }
};

ColorOrder get_pixel_format_color_order(PixelFormat format);
unsigned get_pixel_format_depth(PixelFormat format);
unsigned get_pixel_channels(PixelFormat format);
std::size_t get_pixel_row_bytes(PixelFormat format, std::size_t width);

std::size_t get_pixels_from_row_bytes(PixelFormat format, std::size_t row_bytes);

PixelFormat create_pixel_format(unsigned depth, unsigned channels, ColorOrder order);

// retrieves or sets the logical pixel values in 16-bit range.
Pixel get_pixel_from_row(const std::uint8_t* data, std::size_t x, PixelFormat format);
void set_pixel_to_row(std::uint8_t* data, std::size_t x, Pixel pixel, PixelFormat format);

// retrieves or sets the physical pixel values. The low bytes of the RawPixel are interpreted as
// the retrieved values / values to set
RawPixel get_raw_pixel_from_row(const std::uint8_t* data, std::size_t x, PixelFormat format);
void set_raw_pixel_to_row(std::uint8_t* data, std::size_t x, RawPixel pixel, PixelFormat format);

// retrieves or sets the physical value of specific channel of the pixel. The channels are numbered
// in the same order as the pixel is laid out in memory, that is, whichever channel comes first
// has the index 0. E.g. 0-th channel in RGB888 is the red byte, but in BGR888 is the blue byte.
std::uint16_t get_raw_channel_from_row(const std::uint8_t* data, std::size_t x, unsigned channel,
                                       PixelFormat format);
void set_raw_channel_to_row(std::uint8_t* data, std::size_t x, unsigned channel, std::uint16_t pixel,
                            PixelFormat format);

template<PixelFormat Format>
Pixel get_pixel_from_row(const std::uint8_t* data, std::size_t x);
template<PixelFormat Format>
void set_pixel_to_row(std::uint8_t* data, std::size_t x, RawPixel pixel);

template<PixelFormat Format>
Pixel get_raw_pixel_from_row(const std::uint8_t* data, std::size_t x);
template<PixelFormat Format>
void set_raw_pixel_to_row(std::uint8_t* data, std::size_t x, RawPixel pixel);

template<PixelFormat Format>
std::uint16_t get_raw_channel_from_row(const std::uint8_t* data, std::size_t x, unsigned channel);
template<PixelFormat Format>
void set_raw_channel_to_row(std::uint8_t* data, std::size_t x, unsigned channel,
                            std::uint16_t pixel);

} // namespace genesys

#endif // BACKEND_GENESYS_IMAGE_PIXEL_H
