#include <Adafruit_NeoPixel.h>

// Which pin on the Arduino is connected to the NeoPixels?
#define LED_PIN       6     // Connected to first NeoPixel DIN

// How many NeoPixels are attached to the Arduino?
#define NUMPIXELS     19     // 4 NeoPixels chained together

// NeoPixel library setup
Adafruit_NeoPixel pixels(NUMPIXELS, LED_PIN, NEO_GRB + NEO_KHZ800);

#define DELAYVAL 40         // Time (in milliseconds) to pause between updates (40ms ~= 25fps)

// Potentiometer pins
int RedSliderPin     = A0;  // Red channel slider
int GreenSliderPin   = A1;  // Green channel slider  
int BlueSliderPin    = A2;  // Blue channel slider

// Sensor values
int RedSensorValue   = 0;   
int GreenSensorValue = 0;   
int BlueSensorValue  = 0;   

void setup() {
  Serial.begin(9600);       // For debugging
  pixels.begin();           // INITIALIZE NeoPixel strip object (REQUIRED)
  pixels.clear();           // Set all pixels off initially
  pixels.show();            // Apply the changes
  
  Serial.println("RGB NeoPixel Controller Started!");
  Serial.println("LED 0: Red Channel Only");
  Serial.println("LED 1: Green Channel Only"); 
  Serial.println("LED 2: Blue Channel Only");
  Serial.println("LED 3: RGB Combination");
}

void loop() {
  // Read the values from the sliders and convert to 0-255 range
  RedSensorValue     = analogRead(RedSliderPin) / 4;    // 1023/4 = ~255
  GreenSensorValue   = analogRead(GreenSliderPin) / 4;
  BlueSensorValue    = analogRead(BlueSliderPin) / 4;

  // Clear all pixels
  pixels.clear();           

  // Set individual channel LEDs
  pixels.setPixelColor(0, pixels.Color(RedSensorValue, 0, 0));              // LED 0: Red only
  pixels.setPixelColor(1, pixels.Color(0, GreenSensorValue, 0));            // LED 1: Green only
  pixels.setPixelColor(2, pixels.Color(0, 0, BlueSensorValue));             // LED 2: Blue only
  pixels.fill(pixels.Color(RedSensorValue, GreenSensorValue, BlueSensorValue), 3, NUMPIXELS - 3);
  
  // Send the updated pixel colors to the hardware
  pixels.show();           

  // Debug output (optional)
  Serial.print("R:");  Serial.print(RedSensorValue);
  Serial.print(" G:"); Serial.print(GreenSensorValue);
  Serial.print(" B:"); Serial.println(BlueSensorValue);

  delay(DELAYVAL);         // Pause before next pass through loop
}