#include <Arduino.h>

#define LED1 18
#define LED2 19

#define BLINK_INTERVAL_1 500
#define BLINK_INTERVAL_2 700

uint64_t led1_last_millis = 0;
uint64_t led2_last_millis = 0;

void toggle_led(int pin){
  digitalWrite(pin, !digitalRead(pin));
} 

void setup() {
  // put your setup code here, to run once:
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);

  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  uint64_t current_millis = millis();

  if (current_millis - led1_last_millis >= BLINK_INTERVAL_1) {
    Serial.print("LED1: ");
    Serial.println(current_millis - led1_last_millis);
    toggle_led(LED1);
    led1_last_millis = current_millis;
  }

  if (current_millis - led2_last_millis > BLINK_INTERVAL_2) {
    Serial.print("LED2: ");
    Serial.println(current_millis - led2_last_millis);
    toggle_led(LED2);
    led2_last_millis = current_millis;
  }

  // delay(10);  // only for wokwi simulation.
}