#include <Servo.h>

#define POTPIN A0
#define SERVOPIN 9
#define LED 13

Servo myservo;
String command;
long blinkStartTime;
bool shouldBlink = false;
bool shouldSync = false;

void setup() {
  Serial.begin(9600);
  Serial.println("Hello Arduino\n");
  pinMode(POTPIN, INPUT);
  pinMode(LED, OUTPUT);
  myservo.attach(SERVOPIN);
}

void loop() {
 // process incoming command if there's one
 if( Serial.available() ){
   command = Serial.readString();
   command.trim();
   Serial.println(command);
   if( command == "RIGHT" ) {
     myservo.write(135);
     shouldSync = false;
   }
   if( command == "LEFT" ) {
     myservo.write(45);
     shouldSync = false;
   }
   if( command == "SYNC" ) {
     shouldSync = true;
   }
   if( command == "BLINK" ) {
     blinkStartTime = millis();
     shouldBlink = true;
   }
 }
 
 // if servo is in sync mode, just sync it
 // with the mapped potentiometer value
 if(shouldSync){
   int syncedDegree = map(analogRead(POTPIN), 0, 1023, 45, 135);
   myservo.write(syncedDegree);
 }

 if ( shouldBlink && (blinkStartTime - millis() < 5000) ){
   digitalWrite(LED, HIGH);
   delay(50);
   digitalWrite(LED, LOW);
 }
 else if ( blinkStartTime - millis() > 5000 ){
   shouldBlink = false;
 }
}