#include <stdio.h>
#include "wx/colour.h"

// next code is borrowed from https://stackoverflow.com/questions/3018313/algorithm-to-convert-rgb-to-hsv-and-hsv-to-rgb-in-range-0-255-for-both

typedef struct {
    double r;       // a fraction between 0 and 1
    double g;       // a fraction between 0 and 1
    double b;       // a fraction between 0 and 1
} rgb;

typedef struct {
    double h;       // angle in degrees
    double s;       // a fraction between 0 and 1
    double v;       // a fraction between 0 and 1
} hsv;

static hsv   rgb2hsv(rgb in);
static rgb   hsv2rgb(hsv in);

hsv rgb2hsv(rgb in)
{
    hsv         out;
    double      min, max, delta;

    min = in.r < in.g ? in.r : in.g;
    min = min  < in.b ? min  : in.b;

    max = in.r > in.g ? in.r : in.g;
    max = max  > in.b ? max  : in.b;

    out.v = max;                                // v
    delta = max - min;
    if (delta < 0.00001)
    {
        out.s = 0;
        out.h = 0; // undefined, maybe nan?
        return out;
    }
    if( max > 0.0 ) { // NOTE: if Max is == 0, this divide would cause a crash
        out.s = (delta / max);                  // s
    } else {
        // if max is 0, then r = g = b = 0              
        // s = 0, h is undefined
        out.s = 0.0;
        out.h = NAN;                            // its now undefined
        return out;
    }
    if( in.r >= max )                           // > is bogus, just keeps compilor happy
        out.h = ( in.g - in.b ) / delta;        // between yellow & magenta
    else
    if( in.g >= max )
        out.h = 2.0 + ( in.b - in.r ) / delta;  // between cyan & yellow
    else
        out.h = 4.0 + ( in.r - in.g ) / delta;  // between magenta & cyan

    out.h *= 60.0;                              // degrees

    if( out.h < 0.0 )
        out.h += 360.0;

    return out;
}

hsv rgb2hsv(const std::string& str_clr_in)
{
    wxColour clr(str_clr_in);
    rgb in = { clr.Red() / 255.0, clr.Green() / 255.0, clr.Blue() / 255.0 };
    return rgb2hsv(in);
}


rgb hsv2rgb(hsv in)
{
    double      hh, p, q, t, ff;
    long        i;
    rgb         out;

    if(in.s <= 0.0) {       // < is bogus, just shuts up warnings
        out.r = in.v;
        out.g = in.v;
        out.b = in.v;
        return out;
    }
    hh = in.h;
    if (hh >= 360.0) hh -= 360.0;//hh = 0.0;
    hh /= 60.0;
    i = (long)hh;
    ff = hh - i;
    p = in.v * (1.0 - in.s);
    q = in.v * (1.0 - (in.s * ff));
    t = in.v * (1.0 - (in.s * (1.0 - ff)));

    switch(i) {
    case 0:
        out.r = in.v;
        out.g = t;
        out.b = p;
        break;
    case 1:
        out.r = q;
        out.g = in.v;
        out.b = p;
        break;
    case 2:
        out.r = p;
        out.g = in.v;
        out.b = t;
        break;

    case 3:
        out.r = p;
        out.g = q;
        out.b = in.v;
        break;
    case 4:
        out.r = t;
        out.g = p;
        out.b = in.v;
        break;
    case 5:
    default:
        out.r = in.v;
        out.g = p;
        out.b = q;
        break;
    }
    return out;     
}

double rand_val()
{
    return 0.1 * (10 - rand() % 8);
}

std::string get_opposite_color(const std::string& color)
{
    std::string opp_color = "";

    hsv hsv_clr = rgb2hsv(color);
    hsv_clr.h += 65; // 65 instead 60 to avoid circle values
    hsv_clr.s = rand_val();
    hsv_clr.v = rand_val();

    rgb rgb_opp_color = hsv2rgb(hsv_clr);

    wxString clr_str = wxString::Format(wxT("#%02X%02X%02X"), (unsigned char)(rgb_opp_color.r * 255), (unsigned char)(rgb_opp_color.g * 255), (unsigned char)(rgb_opp_color.b * 255));
    opp_color = clr_str.ToStdString();

    return opp_color;
}

std::string get_opposite_color(const std::string& color_frst, const std::string& color_scnd)
{
    std::string opp_color = "";

    hsv hsv_frst = rgb2hsv(color_frst);
    hsv hsv_scnd = rgb2hsv(color_scnd);

    double delta_h = fabs(hsv_frst.h - hsv_scnd.h);
    double start_h = delta_h > 180 ? std::min<double>(hsv_scnd.h, hsv_frst.h) : std::max<double>(hsv_scnd.h, hsv_frst.h);
    start_h += 5; // to avoid circle change of colors for 120 deg
    if (delta_h < 180)
        delta_h = 360 - delta_h;

    hsv hsv_opp = hsv{ start_h + 0.5 * delta_h, rand_val(), rand_val() };
    rgb rgb_opp_color = hsv2rgb(hsv_opp);

    wxString clr_str = wxString::Format(wxT("#%02X%02X%02X"), (unsigned char)(rgb_opp_color.r * 255), (unsigned char)(rgb_opp_color.g * 255), (unsigned char)(rgb_opp_color.b * 255));
    opp_color = clr_str.ToStdString();

    return opp_color;
}