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

const int trigPin = 5;
const int echoPin = 18;

const char* ssid = "Wokwi-GUEST"; ///  wifi ssid 
const char* password = "";
const char* mqtt_server = "test.mosquitto.org";// mosquitto server url

WiFiClient espClient;
PubSubClient client(espClient);
unsigned long lastMsg = 0;

//define sound speed in cm/uS
#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.393701
#define timeSeconds 10

long duration;
float distanceCm;
float distanceInch;
// Set GPIOs for LED and PIR Motion Sensor
const int led = 26;
const int motionSensor = 27;
// Timer: Auxiliary variables
unsigned long now = millis();
unsigned long lastTrigger = 0;
boolean startTimer = false;
boolean motion = false;

// Checks if motion was detected, sets LED HIGH and starts a timer
void IRAM_ATTR detectsMovement() {
  digitalWrite(led, HIGH);  // Allume la LED
  delay(1000);  // Attend 500 millisecondes (0.5 seconde)
  digitalWrite(led, LOW);  // Éteint la LED
  startTimer = true;
  lastTrigger = millis();
}
void setup_wifi() { 
  delay(10);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.mode(WIFI_STA); 
  WiFi.begin(ssid, password);

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

  randomSeed(micros());

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  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]);
  }}
void reconnect() { 
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    String clientId = "ESP32Client-";
    clientId += String(random(0xffff), HEX);
    if (client.connect(clientId.c_str())) {
      Serial.println("Connected");
      client.publish("/ThinkIOT/Publish", "Welcome");
      client.subscribe("/ThinkIOT/Subscribe"); 
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }}
}

void setup() {
  Serial.begin(115200); // Starts the serial communication
  setup_wifi(); 
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback); 
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input
  // PIR Motion Sensor mode INPUT_PULLUP
  pinMode(motionSensor, INPUT_PULLUP);
  // Set motionSensor pin as interrupt, assign interrupt function and set RISING mode
  attachInterrupt(digitalPinToInterrupt(motionSensor), detectsMovement, RISING);

  // Set LED to LOW
  pinMode(led, OUTPUT);
  digitalWrite(led, LOW);
}


void loop() { 
  if (!client.connected()) {
    reconnect();
  }
  client.loop();
  // Clears the trigPin
  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;
  
  // Convert to inches
  distanceInch = distanceCm * CM_TO_INCH;
  
  // Prints the distance in the Serial Monitor
  Serial.print("Distance (cm): ");
  Serial.println(distanceCm);
  String dist = String(distanceCm, 2);
  client.publish("/ThinkIOT/distance", dist.c_str());

  now = millis();
  if((digitalRead(led) == HIGH) && (motion == false)) {
    Serial.println("Motion Detected!!!");
    motion = true;
  }
  // Turn off the LED after the number of seconds defined in the timeSeconds variable
  if(startTimer && (now - lastTrigger > (timeSeconds*1000))) {
    Serial.println("Motion stopped...");
    digitalWrite(led, LOW);
    startTimer = false;
    motion = false;
  }

  delay(1000);
}