#include <WiFi.h>
#include <PubSubClient.h>
#include <LiquidCrystal_I2C.h>
#include <DHT.h>

// --- Configurações de rede e MQTT ---
const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqtt_server = "broker.hivemq.com";
const int mqtt_port = 1883;

const char* mqtt_sub_topic = "esp32/led";
const char* mqtt_pub_topic = "esp32/dados";
const char* mqtt_status_topic = "esp32/status";
const char* mqtt_heartbeat_topic = "esp32/heartbeat";

// --- Pinos ---
#define LED_PIN     19
#define BUZZER_PIN  27
#define DHT_PIN     4
#define DHT_TYPE    DHT22

// --- Objetos ---
WiFiClient espClient;
PubSubClient mqttClient(espClient);
LiquidCrystal_I2C lcd(0x27, 16, 2);
DHT dht(DHT_PIN, DHT_TYPE);

// --- Variáveis de controle ---
bool ledState = false;
unsigned long lastDataSent = 0;
unsigned long lastHeartbeat = 0;
const unsigned long DATA_INTERVAL = 10000;
const unsigned long HEARTBEAT_INTERVAL = 15000;

// --- Funções ---

void showLCD(const String& line1, const String& line2 = "") {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(line1);
  lcd.setCursor(0, 1);
  lcd.print(line2);
}

void mqttCallback(char* topic, byte* payload, unsigned int length) {
  String msg;
  for (int i = 0; i < length; i++) msg += (char)payload[i];
  msg.trim();

  Serial.print("[MQTT] Mensagem recebida: ");
  Serial.println(msg);

  if (msg.equalsIgnoreCase("ligar")) {
    ledState = true;
    digitalWrite(LED_PIN, HIGH);
    showLCD("LED LIGADO");
  } else if (msg.equalsIgnoreCase("desligar")) {
    ledState = false;
    digitalWrite(LED_PIN, LOW);
    showLCD("LED DESLIGADO");
  }
}

bool connectMQTT() {
  if (mqttClient.connected()) return true;

  Serial.print("Conectando ao MQTT... ");
  String clientId = "ESP32-" + String(random(0xffff), HEX);
  if (mqttClient.connect(clientId.c_str(), "", "", mqtt_status_topic, 1, true, "offline")) {
    Serial.println("conectado!");
    mqttClient.publish(mqtt_status_topic, "online", true);
    mqttClient.subscribe(mqtt_sub_topic);
    return true;
  } else {
    Serial.print("Falha, rc=");
    Serial.println(mqttClient.state());
    return false;
  }
}

void setupWiFi() {
  WiFi.begin(ssid, password);
  Serial.print("Conectando Wi-Fi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWi-Fi conectado.");
}

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

  lcd.init();
  lcd.backlight();
  showLCD("Iniciando...");
  
  dht.begin();

  setupWiFi();
  mqttClient.setServer(mqtt_server, mqtt_port);
  mqttClient.setCallback(mqttCallback);
  randomSeed(micros());
}

void beepBuzzer() {
  digitalWrite(BUZZER_PIN, HIGH);
  delay(200);
  digitalWrite(BUZZER_PIN, LOW);
}

void loop() {
  // Reconectar MQTT se necessário
  if (!mqttClient.connected()) {
    connectMQTT();
  } else {
    mqttClient.loop();
  }

  unsigned long now = millis();

  // Enviar dados a cada 10 segundos
  if (now - lastDataSent > DATA_INTERVAL) {
    lastDataSent = now;

    float temp = dht.readTemperature();
    float umid = dht.readHumidity();

    if (isnan(temp) || isnan(umid)) {
      Serial.println("Falha ao ler DHT22");
      return;
    }

    char payload[64];
    sprintf(payload, "{\"temp\": %.2f, \"umid\": %.2f}", temp, umid);
    mqttClient.publish(mqtt_pub_topic, payload);
    Serial.println(String("[MQTT] Dados publicados: ") + payload);

    if (umid < 40.0) {
      showLCD("ALERTA UMIDADE!", "Umi: " + String(umid, 1) + "%");
      beepBuzzer();
    } else {
      String linha1 = ledState ? "LED LIGADO" : "LED DESLIGADO";
      String linha2 = "T:" + String(temp, 1) + " U:" + String(umid, 1);
      showLCD(linha1, linha2);
    }
  }

  // Heartbeat
  if (now - lastHeartbeat > HEARTBEAT_INTERVAL) {
    lastHeartbeat = now;
    char hb[64];
    sprintf(hb, "{\"uptime_ms\": %lu}", now);
    mqttClient.publish(mqtt_heartbeat_topic, hb);
    Serial.println(String("[MQTT] Heartbeat: ") + hb);
  }

  delay(10);  // loop mais leve
}