// https://forum.arduino.cc/t/two-slide-switches-to-sequence-leds/1012696

# include "ezButton.h"

ezButton test(3);
ezButton add(5), stop(4);

void setup() {
  Serial.begin(112500);
  Serial.println("test NPUMPS world!\n");

  test.setDebounceTime(12);
  add.setDebounceTime(12);
  stop.setDebounceTime(12);

  setupPumps();
}

void loop() {

  test.loop();
  add.loop();
  stop.loop();

  if (test.isPressed()) {
    Serial.println("I saw that!");
  }

  if (add.isPressed()) {
    Serial.print("I see that add... ");
    if (addAPump()) Serial.println("and cannot");
    else Serial.println("and did.");
  }

  if (stop.isPressed()) {
    Serial.println("I saw that stop!");
    stopAll();
  }
}

# define NPUMPS 4
const unsigned char pumpPin[] = {A0, A1, A2, A3};

unsigned char nOn;

void setupPumps()
{
  for (unsigned char tt = 0; tt < NPUMPS; tt++)
    pinMode(pumpPin[tt], OUTPUT);

  nOn = 0;
  stopAll();
}

void stopAll()
{
  nOn = 0;

  for (unsigned char tt = 0; tt < NPUMPS; tt++)
    digitalWrite(pumpPin[tt], LOW);
}

unsigned char addAPump()
{
/* load sharing */
  static unsigned char nFirst;
  static unsigned char myNext;

  if (nOn == 0) {
    myNext = nFirst;
    nFirst++; if (nFirst >= NPUMPS) nFirst = 0;
  }

  if (nOn == NPUMPS) return 1;    // FAIL no more pumps

  nOn++;

/* here is where a pump might really be turned on, or the process for doing initiated
  Serial.print("pump ");
  Serial.print(nOn);    // number in the work force 1, 2 &c.
  Serial.print(" is ");
  Serial.print(myNext); // pump ID number
  Serial.println("");
*/
  digitalWrite(pumpPin[myNext], HIGH);

  myNext++; if (myNext >= NPUMPS) myNext = 0;

  return 0;   // SUCCEED

/* non load sharing first
  if (nOn < NPUMPS) nOn++;
  else return 1;

  return 0;
*/
}