#include <WiFi.h>
#include <PubSubClient.h>

const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqtt_server = "broker.hivemq.com";
const char* mqtt_topic = "Moola";

WiFiClient espClient;
PubSubClient client(espClient);

const int pwmPin = 13;
const int frequency = 5000;
const uint8_t resolution = 8;

void connectWiFi() {
  WiFi.begin(ssid, password);
  Serial.print("Connecting");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWiFi Connected!");
  Serial.println(WiFi.localIP());
}

void connectMQTT() {
  while (!client.connected()) {
    Serial.println("Attempting MQTT connection...");
    String clientId = "ESP32Client-" + String(random(0xffff), HEX);
    if (client.connect(clientId.c_str())) {
      Serial.println("Connected to MQTT broker");
      client.subscribe(mqtt_topic);
      Serial.print("Subscribed to: ");
      Serial.println(mqtt_topic);
    } else {
      Serial.print("Failed, state: ");
      Serial.println(client.state());
      delay(5000);
    }
  }
}

void callback(char* topic, byte* payload, unsigned int length) {
  String message = "";
  for (int i = 0; i < length; i++) {
    message += (char)payload[i];
  }
  Serial.print("Received on [");
  Serial.print(topic);
  Serial.print("]: ");
  Serial.println(message);

  // Apply PWM from received value
  uint32_t duty = message.toInt();
  duty = constrain(duty, 0, 255);
  ledcWrite(pwmPin, duty);
  Serial.print("PWM duty set to: ");
  Serial.println(duty);
}

void setup() {
  Serial.begin(115200);
  delay(1000);
  connectWiFi();

  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
  connectMQTT();

  ledcAttach(pwmPin, frequency, resolution);
  ledcWrite(pwmPin, 128); // default 50%
}

void loop() {
  if (!client.connected()) {
    connectMQTT();       // reconnect if dropped
  }
  client.loop();         // ← processes incoming messages
  delay(10);             // small delay, not 1000ms — avoids missing messages
}