// Networking and Communications - UART Slave Node
// Board: XIAO ESP32-C3 or custom PCB with XIAO ESP32-C3
// Communication: UART wired network
// TX = D4, RX = D5
// Local output device: LED on D2

#include <HardwareSerial.h>

#define RX_PIN D5
#define TX_PIN D4
#define LED_PIN D2

HardwareSerial NodeSerial(1);
String nodeAddress = "SLAVE01";

void setup() {
  Serial.begin(115200);
  delay(2000);

  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);

  NodeSerial.begin(9600, SERIAL_8N1, RX_PIN, TX_PIN);

  Serial.println("SLAVE NODE READY");
  Serial.println("Node address: SLAVE01");
  Serial.println("Waiting for commands...");
}

void loop() {
  if (NodeSerial.available()) {
    String message = NodeSerial.readStringUntil('\n');
    message.trim();

    Serial.print("Message received: ");
    Serial.println(message);

    if (message == "SLAVE01:ON") {
      digitalWrite(LED_PIN, HIGH);
      Serial.println("LED ON");
      NodeSerial.println("SLAVE01:ACK_LED_ON");
    }
    else if (message == "SLAVE01:OFF") {
      digitalWrite(LED_PIN, LOW);
      Serial.println("LED OFF");
      NodeSerial.println("SLAVE01:ACK_LED_OFF");
    }
    else {
      Serial.println("Command not for this node or unknown command");
      NodeSerial.println("SLAVE01:UNKNOWN_COMMAND");
    }
  }
}