import { RGB } from "@watsonb8/wiz-lib";

export const colorTempToRgb = (kelvin: number): RGB => {
    var temp = kelvin / 100;
    var red, green, blue;
    if (temp <= 66) {
        red = 255;
        green = temp;
        green = 99.4708025861 * Math.log(green) - 161.1195681661;

        if (temp <= 19) {
            blue = 0;
        } else {
            blue = temp - 10;
            blue = 138.5177312231 * Math.log(blue) - 305.0447927307;
        }
    } else {
        red = temp - 60;
        red = 329.698727446 * Math.pow(red, -0.1332047592);

        green = temp - 60;
        green = 288.1221695283 * Math.pow(green, -0.0755148492);

        blue = 255;
    }
    return {
        r: clamp(red, 0, 255),
        g: clamp(green, 0, 255),
        b: clamp(blue, 0, 255),
    };
};

const clamp = (x: number, min: number, max: number) => {
    if (x < min) {
        return min;
    }
    if (x > max) {
        return max;
    }
    return x;
};