//#define INTERVAL1 1000
//#define INTERVAL2 100
//#define LED_BUILTIN 5
#define LED1 5
#define LED2 2
int period1=100, period2=200;
// ---- for command interpreter ----
String rcvdstring;   // string received from serial
String cmdstring;   // command part of received string
String  parmstring; // parameter part of received string
float parmvalfloat;
int parmvalint;
bool newcmd = 0;     // flag when new command received
int sepIndex;       // index of seperator
int noparm=0;
// -----------------------------------

long previousMillis1 = 0, previousMillis2 = 0;

void setup() {
  pinMode(LED2, OUTPUT); // red
  pinMode(LED1, OUTPUT); // green
  Serial.begin(115200);
}

void loop() {
  long currentMillis = millis();
  
  if(currentMillis - previousMillis1 > period1) {
    previousMillis1 = currentMillis;  
     

    digitalWrite(LED1, !digitalRead(LED1));
  }
  if(currentMillis - previousMillis2 > period2) {
    previousMillis2 = currentMillis;  

    digitalWrite(LED2, !digitalRead(LED2));
  }  
    if (Serial.available() > 0)   {  // detect new input
     rcvdstring = Serial.readString();
     newcmd = 1;
  }
  if (newcmd)   { // execute this part only when new command received
    cmdInt();   // invoke the interpreter
    newcmd = 0;
  }
}

void cmdInt(void)
{
    rcvdstring.trim();  // remove leading&trailing whitespace, if any
    // find index of separator (blank character)
    sepIndex = rcvdstring.indexOf('=');
    if (sepIndex==-1) {
      cmdstring = rcvdstring;
      noparm = 1;
    }
    else  {
    // extract command and parameter
      cmdstring = rcvdstring.substring(0, sepIndex);
      cmdstring.trim();
      parmstring = rcvdstring.substring(sepIndex+1);
      parmstring.trim();
      noparm = 0;
    }
    // check if received command string is a valid command
    if (cmdstring.equalsIgnoreCase("period1"))   {
        // task for command 1
        parmvalint = parmstring.toInt();
        if (parmvalint<50 | parmvalint>2000)   {
          Serial.println("Period1 out of range!");
        }
        else   {
          period1 = parmvalint;
          Serial.print("Period1 changed to ");
          Serial.println(period1);
        }

    }

    else if (cmdstring.equalsIgnoreCase("period2"))   {
        // task for command 1
        parmvalint = parmstring.toInt();
        if (parmvalint<50 | parmvalint>2000)   {
          Serial.println("Period2 out of range!");
        }
        else   {
          period2 = parmvalint;
          Serial.print("Period2 changed to ");
          Serial.println(period2);
        }
    }
}