// From https://randomnerdtutorials.com/esp32-mqtt-publish-subscribe-arduino-ide

#include <WiFi.h>
#include "PubSubClient.h"
#include <LCD_I2C.h>

LCD_I2C lcd(0x27, 16, 2);

//1-configuration du point d accés
const char* ssid = "Wokwi-GUEST";
const char* password = "";

//2-configuration du broker EMQX PORT 1883
const char* mqttServer = "broker.emqx.io";
int port = 1883;

//3-configuration d un clien mqtt (subscriber)
WiFiClient espClient;
PubSubClient client(espClient);//subscriber
const int  seuiltemp=30;
const int buzzerPin = 4;
char clientId[50];

void setup() {
  Serial.begin(115200);
  Serial.println("Connecting to ");
  Serial.println(ssid);
  pinMode(buzzerPin, OUTPUT);
   lcd.begin();
    lcd.backlight();
     lcd.setCursor(0, 0);
    lcd.print(F("Bonjour"));
  wifiConnect();

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
  //4-associer le broker au client (subscriber)
  client.setServer(mqttServer, port);
  //5-l appel de la fonction callback pour lire la valeur
  client.setCallback(callback);

}

void wifiConnect() {
  WiFi.mode(WIFI_STA); //type du wifi=sta
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
}

void mqttReconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    //attribuer un id aleatoire au client
    long r = random(1000);
    sprintf(clientId, "clientId-%ld", r);
    if (client.connect(clientId)) {
      Serial.print(clientId);
      Serial.println(" connected");
      //connexion au topic 
      client.subscribe("topic_temp");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}
//lire le topic
void callback(char* topic, byte* message, unsigned int length) {
  Serial.print("Message arrived on topic: ");
  Serial.print(topic);
  Serial.print(". Message: ");
  String stMessage;
  //lire bit par bit
  for (int i = 0; i < length; i++) {
    Serial.print((char)message[i]);
    stMessage += (char)message[i];
  }
  Serial.println();

      if (String(topic) == "topic_temp") {
    Serial.print("Changing output to ");
   if(stMessage.toInt() > seuiltemp){
      Serial.println("alerte seuil");
      tone(buzzerPin,700,2000);
       lcd.setCursor(0, 0);
    lcd.print(F("ALERTE"));
    
    }
    else {
      Serial.println("etat ok");
      noTone(buzzerPin);
      lcd.clear();
    }
  }
}

void loop() {
  delay(10);
  if (!client.connected()) {
    mqttReconnect();
  }
  client.loop();
}