#include <ESP32Servo.h>
#include <WiFi.h>
#include <WiFiClient.h>
#include <PubSubClient.h>
#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.393701
#define max_distance 400

int LEDState = 1;
long previousMillis = 0;
int interval = 5000;
char red_led = 2;

const int trigPin = 27;
const int echoPin = 32;
const int pirPin = 25;
const int servoPin = 21;

const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* hostname = "broker.hivemq.com";

WiFiClient espClient;
PubSubClient client(espClient);
const char* espClientName = "esp32Client_5775257W";
int PORTNUM = 1883;

long duration;
float distanceCm;
Servo myServo;

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

/// Handle your topics and payload here
// Example

  if (topic == "IOTGP/letterbox/5775257W")
  {
    Serial.print("Mail deliver");
    if (messageTemp == "Off")
    {
      digitalWrite(2, HIGH);
      Serial.println("Off");
    }
    else if (messageTemp == "On")
    {
      digitalWrite(2, LOW);
      Serial.println("On");
    }
  }
}

void MQTTSubscribe()
{
  client.subscribe("IOTGP/letterbox/5775257W");
} 

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

void setup() 
{
  Serial.begin(115200);
  
  // Initialize GPIO pins
  pinMode(2, OUTPUT);
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input
  pinMode(pirPin, INPUT);
  setup_wifi();
	setup_MQTT();
  
  // Initialize servo motor
  myServo.attach(servoPin);
  myServo.write(0);  // Initial position of the servo
  
  Serial.println("System initialized");
}

void loop() 
{

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

  // Read PIR Motion Sensor
  int pirState = digitalRead(pirPin);
  
  // Debugging statement for PIR sensor state
  Serial.print("PIR State: ");
  Serial.println(pirState);

  if (pirState == HIGH) 
  {
    digitalWrite(2, HIGH);  // Turn off LED
    Serial.println("Motion detected, LED Off");
    
  } 
  else 
  {
    digitalWrite(2, LOW);  // Turn on LED
    Serial.println("Motion detected, LED On");
    
  }

  // Clears the trigPin Measure distance using Ultrasonic Sensor
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  
  // Calculate the distance
  distanceCm = duration * SOUND_SPEED/2;
  Serial.print("duration");
  Serial.println(duration);
  
  
  // Prints the distance in the Serial Monitor
  Serial.print("Distance (cm): ");
  Serial.println(distanceCm);
  // Serial.print("Distance (inch): ");
  // Serial.println(distanceInch);

  // Activate servo if an object is detected within 10 cm
  if (distanceCm <= 10) 
  {
    myServo.write(0);  // Move servo to 0 degrees
    Serial.println("Postman Arrived");
  } 
  else 
  {
    myServo.write(90);  // Move servo to 90 degrees
    Serial.println("Postman left");
  }
  
  delay(1000);


  long currentMillis = millis();

	if ( currentMillis - previousMillis >= interval)
  
	
		 previousMillis = currentMillis;
		 if (LEDState == LOW)
     {
			 LEDState = HIGH;
       Serial.println("REDled On");
       client.publish("IOTGP/letterbox/5775257W","On");
       
     }
		 else
     {
			 LEDState = LOW;
		 digitalWrite(red_led, LEDState);
     
     
     
     }
    
}