/*
  Forum: https://forum.arduino.cc/t/replace-delay-with-milllis/1421640
  Wokwi: https://wokwi.com/projects/451598397933631489

  2025/12/28
  ec2021

  Example using arrays and boolean variables to control the function handleLeds()

  SerialCommand library used for this example:
  https://www.arduinolibraries.info/libraries/serial-command-advanced


*/

#include <SerialCommand.h>

SerialCommand SerialCommandHandler;

constexpr int noOfItems = 3;
constexpr unsigned long multiplier[noOfItems] {4, 1, 3};
constexpr byte pin[noOfItems] {2, 3, 4};

boolean startCmdReceived = false;
boolean stopCmdReceived = false;

void setup()
{
  Serial.begin(115200);
  SerialCommandHandler.addCommand("Start", Cmd_Start);
  SerialCommandHandler.addCommand("Stop", Cmd_Stop);
  SerialCommandHandler.setDefaultHandler(unrecognized);
  Serial.println("Begin");
  for (int i = 0; i < noOfItems; i++) {
    pinMode(pin[i], OUTPUT);
  }
}

void loop()
{
  SerialCommandHandler.readSerial();
  handleLeds();
  doSomethingElseAllTheTime(500);
}

// Commands Start and Stop
// set boolean variables to true
// that enable the required functionality

void Cmd_Start()
{
  Serial.println(F("The Start command is handled"));
  startCmdReceived = true;
}

void Cmd_Stop()
{
  Serial.println(F("The Stop command is handled"));
  stopCmdReceived = true;
}

// Invalid commands leave a message
void unrecognized(const char *command) {
  Serial.println("Invalid command ..");
}

// The function handleLeds()
// handles Start and Stop command
// On Stop command
//    * all leds are switched off
//    * the local static variables are set to their start values
//    * the booleans that control handleLeds() are set to false
// On Start command
//   * the items are handled according to the index itemNo
//   * in the first loop the item is switched on and the recent time is stored
//   * in further loops, when the delay time has expired, everything is prepared
//     for the next item
//   * if all items have been handled, itemNo is set to 0 and startCmdReceived
//     is cleared (set to false)


void handleLeds() {
  static byte itemNo = 0;
  static unsigned long switchOnTime = 0;
  static boolean isSwitchedOff = true;
  if (stopCmdReceived) {
    for (int i = 0; i < noOfItems; i++) {
      digitalWrite(pin[i], LOW);
    }
    itemNo = 0;
    startCmdReceived = false;
    isSwitchedOff = true;
    stopCmdReceived = false;
    return;  // Not really necessary in this case as the rest of the function depends on startCmdReceived = true
  }
  if (startCmdReceived) {
    if (isSwitchedOff) {
      digitalWrite(pin[itemNo], HIGH);
      isSwitchedOff = false;
      switchOnTime = millis();
    }
    if (millis() - switchOnTime > multiplier[itemNo] * 1000) {
      digitalWrite(pin[itemNo], LOW);
      isSwitchedOff = true;
      itemNo++;
    }
    if (itemNo >= noOfItems) {
      itemNo = 0;
      startCmdReceived = false;
    }
  }
}

// The following function blinks the blue led
// to verify that handleLeds() is not blocking
// loop()

void doSomethingElseAllTheTime(unsigned long interval) {
  constexpr byte bluePin {5};
  static unsigned long lastChange = 0;
  if (lastChange == 0) pinMode(bluePin, OUTPUT);
  if (millis() - lastChange > interval) {
    lastChange = millis();
    byte state = digitalRead(bluePin);
    digitalWrite(bluePin, !state);
  }
}