// Forum: https://forum.arduino.cc/t/arduino-should-act-as-a-push-button-when-the-loop-is-done/1180814
// This Wokwi project: https://wokwi.com/projects/379276550865486849

#include <FastLED_NeoPixel.h>
#define MAX_P 122
CRGB leds[MAX_P];

Adafruit_NeoPixel strip = Adafruit_NeoPixel(MAX_P, 3, NEO_BRG + NEO_KHZ800);

int potPin0 = 0;    // select the input pin for the potentiometer
int potPin1 = 1;    // select the input pin for the potentiometer
int val0 = 0;       // variable to store the value coming from the sensor
int val1 = 0;       // variable to store the value coming from the sensor
int li=0;
int direction=+1;
uint32_t Red=strip.Color(255, 0, 0);
uint32_t Blank=strip.Color(0, 0, 0);

void setup() {

  FastLED.addLeds<NEOPIXEL, 3>(leds, MAX_P);
  FastLED.setBrightness(255);
  FastLED.clear ();
  fadeAnimation(0, 255, 0);
  delay(500);

  strip.begin();
  strip.show(); 
}

void loop() {

  val0 = analogRead(potPin0) / 50;    // read the value from the sensor
  val1 = analogRead(potPin1) / 34.1;    // read the value from the sensor

  //decay
  for(uint16_t i=0; i<MAX_P; i++) {
    uint8_t r= (strip.getPixelColor(i)>>16) & 0xff;
    r=(r*(69+val1))/100;
      strip.setPixelColor(i, r, 0, 0);
  }

  strip.setPixelColor(li, Red);
  if(li>(MAX_P-1)){
    li=MAX_P;
    direction=-1;
  }else if(li<0){
    li=-1;
    direction=1;
  }
  li+=direction;
  strip.show();
  delay(val0);
}

void fadeAnimation(int red, int green, int blue){
  float r, g, b;

  // FADE OUT
  for(int i = 255; i >= 0; i--) {
    r = (i/256.0)*red;
    g = (i/256.0)*green;
    b = (i/256.0)*blue;
    fill_solid(leds, MAX_P, CRGB(r, g, b));
    FastLED.show();
    delay(8);
  }
}