/*Lab Test: 19 July 2024
*Name: Shan Win Khant
*Class: DEE Class A
*Date : 19 July 2024
*/  

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

char green_led = 18;
bool green_led_state = LOW;
unsigned long green_led_previous_millis = 0;
unsigned long adc_previous_millis = 0;
unsigned long green_led_interval = 750;
int adc_interval = 1500;

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

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

WiFiClient espClient;
PubSubClient client(espClient);
const char* espClientName = "esp32Client_2012507V"; 
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* payload, unsigned int length)
{
  String messageTemp;
  Serial.print("Message received in topic: ");
  Serial.print(topic);
  Serial.print(" length is: ");
  Serial.println(length);

  Serial.print("Data received from broker: ");
  for (int i = 0; i<length; i++)
  {
    Serial.print( (char)payload[i] );
    messageTemp += (char)payload[i];
  }



void MQTTSubscribe() 
{

  client.subscribe("DEIOT/2021507V");

}

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


void setup() 
{
  pinMode (green_led, OUTPUT);
  Serial.begin(9600);
  delay(5000);
 
  setup_wifi();
  setup_MQTT();
}


void loop() 
{
   
  long current_millis = millis();

  if (current_millis - green_led_previous_millis >= green_led_interval)

      {
        green_led_previous_millis = current_millis;

        if (green_led_state == LOW)
            green_led_state = HIGH;
        else 
            green_led_state = LOW;

        digitalWrite(green_led, green_led_state);    
      }



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

  int ADC_value; 
  ADC_value = analogRead(A5);


  if (current_millis - adc_previous_millis >= adc_interval)
  {
    adc_previous_millis = current_millis;  

    if (ADC_value < 2500)

    {
      client.publish("DEIOT/2012507V","Alert");
    }

    else

   {
      client.publish("DEIOT/2012507V","OK");
    }
  

 
  }




}