/*********************************************
* Description - Convert Farbfeld images to VNM
* Author - Vilyaem
* Date - May 03 2024
* *******************************************/

/*----------PREPROCESSOR----------*/

#include <stdio.h>
#include <stdint.h>

#define MAXRES 512

/*----------DATA STRUCTURES----------*/

/*color*/
typedef struct {
    uint8_t r;
    uint8_t g;
    uint8_t b;
} Color;

/*----------GLOBALS----------*/

Color palette[16] = {
    {0, 0, 0},           /*#000000 (Black)*/
    {0, 0, 170},         /*#0000AA (Blue)*/
    {0, 170, 0},         /*#00AA00 (Green)*/
    {0, 170, 170},       /*#00AAAA (Cyan)*/
    {170, 0, 0},         /*#AA0000 (Red)*/
    {170, 0, 170},       /*#AA00AA (Magenta)*/
    {170, 79, 0},        /*#AA5500 (Brown)*/
    {170, 170, 170},     /*#AAAAAA (Light Gray)*/
    {79, 79, 79},        /*#555555 (Dark Gray)*/
    {79, 79, 255},       /*#5555FF (Light Blue)*/
    {79, 255, 79},       /*#55FF55 (Light Green)*/
    {79, 255, 255},      /*#55FFFF (Light Cyan)*/
    {255, 79, 79},       /*#FF5555 (Light Red)*/
    {255, 79, 255},      /*#FF55FF (Light Magenta)*/
    {255, 255, 79},      /*#FFFF55 (Yellow)*/
    {255, 255, 255}      /*#FFFFFF (White)*/
};

int i;

/*----------FUNCTIONS----------*/

/*********************************************
* Description - Find closest colour in the palette
* Author - Vilyaem
* Date - May 03 2024
* *******************************************/
uint8_t findClosestColor(Color pixel) {
    uint8_t closestColor;
    int minDistance;
    closestColor = 0;
    minDistance = 255 * 255 * 3; /* Initialize with max distance value*/

    for (i = 0; i < 16; i++) {
        int dr;
        int dg;
        int db;
        int distance;

        dr = pixel.r - palette[i].r;
        dg = pixel.g - palette[i].g;
        db = pixel.b - palette[i].b;
        distance = dr * dr + dg * dg + db * db;

        if (distance < minDistance) {
            minDistance = distance;
            closestColor = i;
        }
    }

    return closestColor;
}

/*********************************************
* Description - Main
* Author - Vilyaem
* Date - May 03 2024
* *******************************************/
int main(int argc, char* argv[]) {
    uint32_t width;
    uint32_t height;
    FILE* output;
    FILE* input;
    char magic[8];
    Color prevPixel = {0,0,0};
    uint8_t colorCount;


    if (argc != 3) {
        printf("Usage: %s input_image.farbfeld output_image.rle\n", argv[0]);
        return 1;
    }

    input = fopen(argv[1], "rb");
    if (!input) {
        puts("Error: Unable to open input file.\n");
        return 1;
    }

    /*Reading header*/
    fread(magic, 1, 8, input);

     /*Forced width and height*/
    width = MAXRES;
    height = MAXRES;

    /*Output the RLE header*/
    output = fopen(argv[2], "wb");
    fputc('V', output); /* Magic number*/
    fputc(width / 8, output); /* Actual width*/
    fputc(height / 8, output); /* Actual height*/

    /*Read and convert each pixel*/
    colorCount = 1;

    for (i = 0; i < (int)width * (int)height; i++) {
        uint16_t rgba[4];
        uint8_t currentColor;
        Color pixel;

        fread(rgba, sizeof(uint16_t), 4, input);

        /*pixel = (Color){rgba[0] >> 8, rgba[1] >> 8, rgba[2] >> 8};*/
        pixel.r = rgba[0] >> 8;
        pixel.g = rgba[1] >> 8;
        pixel.b = rgba[2] >> 8;

        currentColor = findClosestColor(pixel);

        if (currentColor == findClosestColor(prevPixel) && colorCount < 64) { /*dont make V and A characters and break files!*/
            colorCount++;
        } else {
            fputc(findClosestColor(prevPixel), output);
            fputc(colorCount, output);
            prevPixel = pixel;
            colorCount = 1;
        }
    }

    /*Output the last color run*/
    if (colorCount > 0) {
        fputc(findClosestColor(prevPixel), output);
        fputc(colorCount, output);
    }

    fclose(input);
    fclose(output);

    puts("Conversion complete.\n");
    return 0;
}