/*Lab Trial Test August 2024
  Name:  LIUYANG
  Class: DEIOT
  Date: 19/8/2024
*/
bool LEDState = LOW;
unsigned long previousMillis = 0; // will store last time LED
unsigned long interval = 750; // interval at which to blink (milliseconds)

unsigned long previousMillisA = 0;
unsigned long intervalA = 1500;

/*
  MQTT Setup code is below
*/
#include <WiFi.h>
#include <WiFiClient.h>
#include <PubSubClient.h>

const char* ssid = "Wokwi-GUEST";
const char* password = "";

const char* hostname = "broker.hivemq.com";

WiFiClient espClient;
PubSubClient client(espClient);
const char* espClientName = "8374693A"; // yourStudentID must be unique
int PORTNUM = 1883;

void setup_wifi()
{
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED )
  {
    delay(1000);
    Serial.print(".");
  }
  Serial.println();
  Serial.print("Connected to ");
  Serial.println(ssid);
  Serial.print("Given IP by the router to ESP32 is ");
  Serial.println(WiFi.localIP());
}

void connectMQTT()
{
  while (!client.connected() )
  {
    Serial.println("Connecting to MQTT ...");
    if (client.connect(espClientName) ) //, mqttUser, mqttPassword) )
    {
      Serial.println("Connected");
      MQTTSubscribe();
    }
    else
    {
      Serial.print("Failed with state ");
      Serial.print(client.state() );
      delay(2000);
    }
  }
}

void callback(String topic, byte* tpayLoad, unsigned int length)
{
  String payload;

  for (int i = 0; i < length; i++)
  {
    payload += (char)tpayLoad[i];
  }

  /// Handle your topics and payload here
  // Example
  if (topic == "DEIOT/8374693A")
  {
    Serial.print("Status: ");
    if (payload == "OK")
    {
      Serial.print("OK");
      digitalWrite(23, HIGH);
    }
    else if (payload == "Alert")
    {
      Serial.print("ALERT!!!");
      digitalWrite(23, LOW);
    }

  }
}

void MQTTSubscribe()
{
  // Subsccribe to your topics here
  // example
  client.subscribe("DEIOT/8374693A");
}

void setup_MQTT()
{
  client.setServer(hostname, PORTNUM);
  client.setCallback(callback);
}




void setup()
{
  pinMode(18, OUTPUT);
  pinMode(23, OUTPUT);
  Serial.begin(9600);

  /*Set up MQTT Wifi*/
  setup_wifi();
  setup_MQTT();
}

void loop()
{
  if ( !client.connected() )
  {
    connectMQTT();
  }
  client.loop();

  unsigned long currentMillis = millis();
  if (currentMillis - previousMillisA >= intervalA)
  {
    previousMillisA = currentMillis;

    int adcRes = analogRead(A5);
    Serial.print("Local: ");
    Serial.println( adcRes );

    if (adcRes > 2500)
    {
      client.publish("DEIOT/8374693A", "Alert");
      Serial.println("Alert");
    }
    else
    {
      client.publish("DEIOT/8374693A", "OK");
      Serial.println("OK");
    }

  }

  if (currentMillis - previousMillis >= interval)
  {
    previousMillis = currentMillis;
    LEDState = !LEDState;
    digitalWrite(18, LEDState);
  }
}