/*
Connecting Arduino to Processing
https://learn.sparkfun.com/tutorials/connecting-arduino-to-processing/to-processing

3. Shaking Hands - when both A and P are both sending and receiving data

*/

#include <SoftwareSerial.h>

#define RX    0
#define TX    1   

SoftwareSerial mySerial(RX, TX);

char val; // Data received from the serial port
int ledPin = 8; // 
boolean ledState = LOW; //to toggle our LED


void setup() {
  pinMode(ledPin, OUTPUT); // Set pin as OUTPUT
  mySerial.begin(9600); //initialize serial communications at 9600 baud rate
  establishContact(); // send a byte to establish contact until receiver responds
}

void loop() {
  if (mySerial.available() > 0) { // If data is available to read,
    val = mySerial.read(); // read it and store it in val
    if(val == '1') //if we get a 1
    {
      ledState = !ledState; //flip the ledState
      digitalWrite(ledPin, ledState);
    }
    delay(100);
  }
    else {
    mySerial.println("Hello, world!"); //send back a hello world
    delay(100);
    }
    //Serial.println("dO S");
    //delay(100);
 }

/*
This function just sends out a string  to see if it hears anything back - 
indicating that Processing is ready to receive data.
*/
void establishContact() {
  while (mySerial.available() <= 0) {
  mySerial.println("A"); // send a capital A
  delay(300);
  }
}