// https://forum.arduino.cc/t/relays-stay-on-clicking-on-and-off/1389456/

byte button[] = {2, 3, 4, 5}; // reel spin buttons
#define SPIN 3 // spin button array element
byte relay[]  = {8, 9, 10};   // relay pins, ON = spin, OFF = stop

bool readyToSpin, waitingForButton; // spin button activity

int pulsewidth = 100; // pulse width tells reels to spin
int reeldelay = 500, reelShort = 500, reelLong = 1500, waitShort = 1000, waitLong = 3000;

unsigned long startTime[3], stopTime[3]; // reel start and stop times

void setup() {
  Serial.begin(115200);
  randomSeed(analogRead(A0)); // increase pseudorandomness

  for (int i = 0; i < 4; i++)
    pinMode(button[i], INPUT_PULLUP);  // configure button pins

  for (int i = 0; i < 3; i++) {
    pinMode(relay[i], OUTPUT);   // configure relay pins
    digitalWrite(relay[i], LOW); // reset relay pins
  }

  readyToSpin = true;
  waitingForButton = true;
}

void loop() {
  if (readyToSpin == true && waitingForButton == true) { // ask for spin button
    waitingForButton = false; // reset flag
    Serial.print("\nPress SPIN");
  }

  digitalRead(button[SPIN]); // read spin button

  if ((readyToSpin == true) && (digitalRead(button[SPIN]) == LOW)) { // spin is ready, button is pressed
    readyToSpin = false; // spin in progress, clear flag

    startReels();
    delay(random(waitShort, waitLong)); // time between spin and stop
    stopReels();
    timeDiff(); // show spin time difference

    readyToSpin = true;     // set flags
    waitingForButton = true;
  }
}

void reelControl(byte reel) { // send pulse to relays to start spin
  digitalWrite(relay[reel], HIGH);
  delay(pulsewidth);
  digitalWrite(relay[reel], LOW);
}

void timeDiff() {
  Serial.print(" TIME DIFF:");
  for (int i = 0; i < 3; i++) {
    padTime(stopTime[i] - startTime[i]);
    Serial.print(stopTime[i] - startTime[i]);
  }
  Serial.println();
}

unsigned long padTime(unsigned long value) {
  for (unsigned long i = 1000000; i > 0; i /= 10) {
    if (value < i) Serial.print(" ");
  }
}

void stopReels() {
  Serial.print("\n STOP SPIN:");
  for (int i = 0; i < 3; i++) {
    delay(random(reelShort, reelLong)); // stagger reel stop
    reelControl(i); // stop the reel
    stopTime[i] = millis(); // store reel stop time
    padTime(stopTime[i]);
    Serial.print(stopTime[i]);
  }
  Serial.println();
}

void startReels() {
  Serial.print("\nSTART SPIN:");
  for (int i = 0; i < 3; i++) {
    delay(reeldelay); // stagger reel start
    reelControl(i); // pulse to start a reel
    startTime[i] = millis(); // store reel start time
    padTime(startTime[i]);
    Serial.print(startTime[i]);
  }
}