#include <ESP8266WiFi.h>
#include <PubSubClient.h>

#define pinTrigger  0 // D3
#define pinEcho 5 //D1

// Parametri network //
const char* ssid = " SID RETE WIFI";
const char* password = "PASSWD RETE WIFI";

// Parametri mosquitto //
const char* mqtt_server      = "IP MOSQUITTO";
const char* mqtt_user        = "USER_MOSQUITTO";
const char* mqtt_password = "PASSWORD MOSQUITTO";

long durata, cm;
char cmstr[16];

WiFiClient espClient;
PubSubClient client(espClient);
long lastMsg = 0;
char msg[50];
int value = 0;

void setup_wifi() {

  delay(10);
  // Connessione alla rete
  Serial.println();
  Serial.print("Connettendo a ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  randomSeed(micros());

  Serial.println("");
  Serial.println("WiFi connesso");
  Serial.println("Indirizzo IP : ");
  Serial.println(WiFi.localIP());
}

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

}

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Create a random client ID
    String clientId = "ESP8266Client-";
    clientId += String(random(0xffff), HEX);
    // Attempt to connect
    if (client.connect(clientId.c_str(),mqtt_user,mqtt_password)) {
      Serial.println("connected");
      // Once connected, publish an announcement...
      client.publish("stufaTopic", "Inizio");
      // ... and resubscribe
      client.subscribe("inTopic");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void setup() {

  setup_wifi();

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

  pinMode(pinTrigger, OUTPUT); // Sets the trigPin as an Output
  pinMode(pinEcho, INPUT); // Sets the echoPin as an Input

  Serial.begin(115200);


}

void loop() {

  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  long now = millis();
  if (now - lastMsg > 5000) {
    lastMsg = now;

    // Il ping e' triggerato da un HIGH di 2 o piu' microsec
    // Precediamo con un LOW corto per avere un HIGH pulito

    digitalWrite(pinTrigger, LOW);
    delayMicroseconds(2);

    digitalWrite(pinTrigger, HIGH);
    delayMicroseconds(10);
    digitalWrite(pinTrigger, LOW);

     durata = pulseIn(pinEcho, HIGH);
     cm = microsecToCm(durata);

     Serial.print("Durata : ");
     Serial.println(durata);
     Serial.print("Cm : ");
     Serial.println(cm);


     itoa(cm, cmstr, 10);

    Serial.print("Publish message: ");
    Serial.println(cmstr);
    client.publish("stufaTopic", cmstr);
  }
}

long microsecToCm (long microsec)
{ return microsec / 29 / 2 ;  }