rgb2tuya - Convert RGB to the Tuya-compatible color string

rgb2tuya.js

function rgb2hsv(r, g, b) {
  r /= 255, g /= 255, b /= 255;
  var max = Math.max(r, g, b), min = Math.min(r, g, b);
  var h, s, v = max;
  var d = max - min;
  s = max == 0 ? 0 : d / max;
  if (max == min) {
    h = 0; // achromatic
  } else {
    switch (max) {
      case r: h = (g - b) / d + (g < b ? 6 : 0); break;
      case g: h = (b - r) / d + 2; break;
      case b: h = (r - g) / d + 4; break;
    }

    h /= 6;
  }
  return [ h, s, v ];
}

function rgb2tuya(r,g,b) {
  //---   Set Up Initial Values   ---//
  const rgb = [r,g,b];
  const hsv = rgb2hsv(rgb[0] / 255, rgb[1] / 255, rgb[2] / 255);
  
  //---   Set Final Values   ---//
  let hexValue = new String();
  let hexValue_hsv = new String();

  //---   Generate HEX   ---//
  for (const i in rgb) {
    let hex = rgb[i].toString(16)
    if (hex.length == 1) hex = '0'+hex;
    hexValue += hex;
  }

  //---   Generate HSV   ---//
  let hsvarray = [parseInt(hsv[0] * 360), parseInt(hsv[1] * 255), parseInt(hsv[2] * 255)]
  for (const i in hsvarray) {
    let hex = hsvarray[i].toString(16)
    if (hex.length == 1) hex = '0'+hex;
    hexValue_hsv += hex;
  }

  //---   Ensure that HSV is correct length   ---//
  if (hexValue_hsv.length == 7) hexValue_hsv = "0"+hexValue_hsv;
  if (hexValue_hsv.length == 6) hexValue_hsv = "00"+hexValue_hsv;

  //---   Return data to function call   ---//
  return hexValue+hexValue_hsv.slice(0,-2)+"ff"; // replacing last 2 digits to force the bulb to use full brightness
}

module.exports = rgb2tuya;