#include <FastLED.h>
#define PIN 2   // WS2812 pin
#define LED 4   // Number of WS2812
#define MAX 255 // Maximum brightness
CRGB leds[LED];

int oldred, oldgrn, oldblu, r, g, b, brightness = 1; // brightness divixor 1 - 255

void setup() {
  Serial.begin(115200);
  FastLED.addLeds<WS2812, PIN, GRB>(leds, LED);
  FastLED.clear();
  FastLED.setBrightness(MAX);
  FastLED.show();
}

void loop() {
  trim(); // adjust RGB colors
}

void trim() {
  int r = map(analogRead(A0), 0, 1023, 255, 0);
  int g = map(analogRead(A1), 0, 1023, 255, 0);
  int b = map(analogRead(A2), 0, 1023, 255, 0);

  r /= brightness; g /= brightness; b /= brightness; // adjust brightness
  setColor(r, g, b);

  if (r != oldred || g != oldgrn || b != oldblu) { // print changing values
    printrgb(r, g, b);
  }
  oldred = r; oldgrn = g; oldblu = b; // store old values
}

void setColor(int red, int grn, int blu) { // first four pixels
  leds[3] = CRGB(red, 000, 000); FastLED.show(); // red
  leds[2] = CRGB(000, grn, 000); FastLED.show(); // grn
  leds[1] = CRGB(000, 000, blu); FastLED.show(); // blu
  leds[0] = CRGB(red, grn, blu); FastLED.show(); // rgb
}

void printrgb(int r, int g, int b) { // print analog values
  Serial.print("red "); pad (r); Serial.print(r);
  Serial.print(" grn "); pad (g); Serial.print(g);
  Serial.print(" blu "); pad (b); Serial.print(b);
  Serial.println();
}

void pad (int val) { // space pad analog value
  if (val < 100) Serial.print(" ");
  if (val < 10) Serial.print(" ");
}