#include <painlessMesh.h>

#define   MESH_PREFIX     "TestMesh"
#define   MESH_PASSWORD   "password123"
#define   MESH_PORT       5555

#define LED_PIN 2

painlessMesh mesh;

String myMsg;
unsigned long ledOnTime = 0;
bool ledState = LOW;

void receivedCallback(uint32_t from, String &msg) {
  Serial.printf("[RECEIVED] from %u --> %s\n", from, msg.c_str());
}

void flashLED() {
  digitalWrite(LED_PIN, HIGH);
  ledOnTime = millis();
  ledState = HIGH;
}

void setup() {
  Serial.begin(115200);
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);

  mesh.init(MESH_PREFIX, MESH_PASSWORD, &receivedCallback, MESH_PORT);

  myMsg = "Hello from Node " + String(mesh.getNodeId());
  Serial.println("Starting node: " + myMsg);
}

void loop() {
  mesh.update();

  // Broadcast every 3 seconds
  static unsigned long lastSent = 0;
  if (millis() - lastSent > 3000) {
    lastSent = millis();
    mesh.sendBroadcast(myMsg);
    Serial.println("[SEND] " + myMsg);
    flashLED();
  }

  // turn off LED after 100 ms
  if (ledState == HIGH && (millis() - ledOnTime > 100)) {
    digitalWrite(LED_PIN, LOW);
    ledState = LOW;
  }
}