type RGBPair = readonly [number, number];

const encodeRGB = (value: number): RGBPair =>
  [(value >> 7) & 0x01, value & 0x7F] as const;

const setCustomRGB = (output: Output, pad: number, r: number, g: number, b: number): void => {
  const [rMSB, rLSB] = encodeRGB(r);
  const [gMSB, gLSB] = encodeRGB(g);
  const [bMSB, bLSB] = encodeRGB(b);

  output.send('sysex', [
    0xF0, 0x47, 0x7F, 0x4F, 0x24, 0x00, 0x08,
    pad, pad, rMSB, rLSB, gMSB, gLSB, bMSB, bLSB,
    0xF7
  ]);
};