/*
  ============================
   Selfmade For-Loop IV
  ============================

   This is an example of a "selfmade" for-loop
   which is usually required where a a non-blocking
   loop is required e.g. to blink an LED

   This is an example of a non-blocking millis() function replacing delay() 
   to blink a LED and counting a variable in given time intervals 

   It is more or less identical to Selfmade For-Loop III but
   the handling of the LED and the counting are taken out of loop()
   into separate functions to "reduce complexity"; it is easier to understand 
   and test functions which are short and at least do not require scrolling
   of the screen 

   First Edition 2023-04-02
   ec2021

   Simulation: https://wokwi.com/projects/360905879808368641
   Discussion: https://forum.arduino.cc/t/millis-instead-of-delay-and-loop-instead-of-for-loop/1110044

   Changed 2023-07-26

*/

constexpr byte LEDPin = 13;
constexpr int MaxCount = 9;

void setup() {
   Serial.begin(115200);
   pinMode(LEDPin, OUTPUT);
}


void loop() {
  handleLED();
  doCountingUpTo(MaxCount);
}   

void handleLED(){
  static unsigned long lastChange = 0;    // Variable to store the time in ms when ledState was changed 
  static unsigned long delayTime  = 300;  // Delay in [ms] when then next change shall take place 
  static boolean firstChange      = true; // To make sure that the if-clause is entered in the first call
                                          // of this function
  if (millis()-lastChange >= delayTime || firstChange){ 
     lastChange = millis();               
     firstChange = false;
     boolean ledState = digitalRead(LEDPin);
     digitalWrite(LEDPin, !ledState); 
   }
}

void doCountingUpTo(int iMax){
   static unsigned long lastCount  = 0;
   static unsigned long delayCount = 500;
   static boolean firstCount = true;
   static int i = 0;
  if (millis()-lastCount >= delayCount||firstCount){ 
     lastCount = millis();
     firstCount = false;
     if (i <= iMax) {                                                            
         Serial.print(i);
         Serial.print("\t"); // prints tabs
         i++;
      } else { 
         Serial.println();
         i = 0;
      }
   }
}