deskcontrol/src/main.cpp

#include <Homie.h>
#include <Syslog.h>
#include <WiFiUdp.h>
WiFiUDP udpClient;
Syslog syslog(udpClient, SYSLOG_PROTO_IETF);

const int PIN_RELAY = D1;
#define OUTPUT_SET(x)  digitalWrite(PIN_RELAY, x ? LOW : HIGH);
unsigned int timer = 0;
unsigned int next_timer_update = 0;
HomieNode powerNode("power", "Power", "switch");

bool powerStateHandler(const HomieRange& range, const String& value) {
    if (value != "on" && value != "off") return false;
    powerNode.setProperty("state").send(value);
    powerNode.setProperty("timer").send("0");
    timer = 0;
    if(value == "on") {
      OUTPUT_SET(true);
      Homie.getLogger() << "Power is on" << endl;
    } else {
      OUTPUT_SET(false);
      Homie.getLogger() << "Power is off" << endl;
    }
    
    return true;
}

bool powerTimerHandler(const HomieRange& range, const String& value) {
    int settimer = value.toInt();
    if(settimer == 0 || settimer > 120) 
         return false;

    timer = millis() + (settimer * 1000 * 60);
    next_timer_update = millis() + 60*1000;
    powerNode.setProperty("timer").send(String(settimer));
    powerNode.setProperty("state").send("on");
    Homie.getLogger() << "Power is on for " << settimer << "minutes" << endl;
    OUTPUT_SET(true);
    return true;
}


void setupHandler() {
    pinMode(PIN_RELAY, OUTPUT);
    OUTPUT_SET(false);
    powerNode.setProperty("state").send("off");
    powerNode.setProperty("timer").send("0");
}

void loopHandler() {
  if(timer)
  {
    if(timer < millis()) 
    {
      timer = 0;
      OUTPUT_SET(false);
      powerNode.setProperty("timer").send("0");
    }
    if(millis() > next_timer_update) {
      next_timer_update = millis() + 60*1000;
      unsigned int time_remaining = timer - millis();
      unsigned int min_left = time_remaining / (60*1000);
      powerNode.setProperty("timer").send(String(min_left));

    }
  }
}

void onHomieEvent(const HomieEvent& event) {
  switch(event.type) {
    case HomieEventType::OTA_FAILED:
      syslog.log(LOG_INFO, "OTA failed");
      // Do whatever you want when OTA is failed
      break;
    case HomieEventType::OTA_SUCCESSFUL:
      syslog.log(LOG_INFO, "OTA completed");
      break;
    case HomieEventType::WIFI_CONNECTED:
      // Do whatever you want when Wi-Fi is connected in normal mode
      syslog.deviceHostname(Homie.getConfiguration().name);
      syslog.appName("deskcontrol");
      syslog.defaultPriority(LOG_ERR);
      syslog.log(LOG_INFO, "WiFi Connected, software version: 1.0");
      break;
    case HomieEventType::MQTT_READY:
      syslog.log(LOG_INFO, "MQTT connected");
      break;
    case HomieEventType::MQTT_DISCONNECTED:
      syslog.log(LOG_INFO, "MQTT disconnected");
      break;
    default:
      break;
  }
}

void setup() {
    syslog.server("192.168.1.100", 514);

    Serial.begin(115200);

    Serial << endl << endl;
    Serial << "Firmware 0.0.1" << endl;
    Serial << endl << endl;

    Homie_setFirmware("deskcontrol", "1.0.0");
    Homie_setBrand("FuryFire");

    powerNode.advertise("state").settable(powerStateHandler);
    powerNode.advertise("timer").settable(powerTimerHandler);
    Homie.setSetupFunction(setupHandler);
    Homie.onEvent(onHomieEvent); // before Homie.setup()
    Homie.setLoopFunction(loopHandler);
    Homie.setup();
}

void loop() {
    Homie.loop();
}