/*
James Khan Fab Academy networking and communication week week.
Version 2 with node recognition.
https://fabacademy.org/2021/labs/vancouver/students/james-khan/assignments/week13/

Used the code I developed for my input week as a starting point and modified for communication.
https://fabacademy.org/2021/labs/vancouver/students/james-khan/assignments/week11/

This program is for an SEEED RP2040 board 
and communicates with my self made ATtiny board (with a different program).

This program constantly listens for a message on two seperate serial ports
Serial is the regular connection to the computer via USB
SErial1 is the UART connection to my second board

When a message comes in on either of the serial ports it "reads" the first character.
If that character is NOT a "l" or "L" it sends the message on the other serial port.

If that character is and "l" or "L" it means this board is being messaged directly and reads the next 3 characters 
and takes action depending on the characters. each character refers to one of 3 onboard leds RED, BLUE and GREEN
in that order. a 1 turns that LED on, anything else turns that led off.

*/

String newstring ; // to hold incomming serial data.

void setup() {
  pinMode(PIN_LED_R, OUTPUT);     // RED LED
  digitalWrite(PIN_LED_R, HIGH);  // initialize off
  pinMode(PIN_LED_G, OUTPUT);     // GREEN LED
  digitalWrite(PIN_LED_G, HIGH);  // initialize off
  pinMode(PIN_LED_B, OUTPUT);     // BLUE LED
  digitalWrite(PIN_LED_B, HIGH);  // initialize off

  delay(2000);
  Serial.begin(115200);               // set's up the connection speed, needs to match the other program
  delay(200);
  Serial1.begin(115200, SERIAL_8N1);  //defines a unique Serial addresses:default Serial is USB/computer, Serial1 is RX/TX or UART
  Serial.println("\n--- UART communication with XIAO RP2040 ---");
  Serial.println("-------------------------------------------------------");
}

void loop() {
  if (Serial.available()) {         // If I send anything from the computer's serial monitor
    newstring=Serial.readString();  // save incomming string from serial
    if ((newstring[0]=='l') || (newstring[0]=='L'))  {      // is this message for me?
      if (newstring[1]=='1') digitalWrite(PIN_LED_R, LOW);  // sets RED LED ON 
        else digitalWrite(PIN_LED_R, HIGH);                 // sets RED LED OFF 
      if (newstring[2]=='1') digitalWrite(PIN_LED_G, LOW);  // sets GREEN LED ON 
        else digitalWrite(PIN_LED_G, HIGH);                 // sets GREEN LED OFF
      if (newstring[3]=='1') digitalWrite(PIN_LED_B, LOW);  // sets BLUE LED ON 
        else digitalWrite(PIN_LED_B, HIGH);                 // sets BLUE LED OFF
      Serial.print("received [for me] and returned: ");     // send back confirmation to sender
      Serial.println(newstring);
    }
    else Serial1.println(newstring);            // if it's not for me send it over UART to other device   
       // read it and send it out Serial1 (pins 0 & 1)
    digitalWrite(29, HIGH);
    delay(50);
    digitalWrite(29, LOW);          // flashes LED to indicate received sent
  }

  if (Serial1.available()) {        // If anything comes in Serial1 (my connected second board)
    newstring=Serial1.readString();  // save incomming string from serial
    if ((newstring[0]=='l') || (newstring[0]=='L'))   {     // is this message for me?
      if (newstring[1]=='1') digitalWrite(PIN_LED_R, LOW);  // sets RED LED ON 
        else digitalWrite(PIN_LED_R, HIGH);                 // sets RED LED OFF 
      if (newstring[2]=='1') digitalWrite(PIN_LED_G, LOW);  // sets GREEN LED ON 
        else digitalWrite(PIN_LED_G, HIGH);                 // sets GREEN LED OFF
      if (newstring[3]=='1') digitalWrite(PIN_LED_B, LOW);  // sets BLUE LED ON 
        else digitalWrite(PIN_LED_B, HIGH);                 // sets BLUE LED OFF
      Serial1.print("received [for me] and returned: ");     // send back confirmation to sender
      Serial1.println(newstring);
    }
    else Serial.println(newstring);   // then send it to the computer's serial monitor
    digitalWrite(29, HIGH);
    delay(50);
    digitalWrite(29, LOW);          // flashes LED to indicate received message
  }
}