#include <WiFi.h>
#include <ESP32Servo.h>
#include "PubSubClient.h"

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


// MQTT Broker
const char *mqtt_server = "broker.emqx.io";
const char *topic = "testtopic/testHit";
const char *mqtt_username = "haihaihai";
const char *mqtt_password = "Kelvin12345";

int port = 1883;
String stMac;
char mac[50];
char clientId[50];

WiFiClient espClient;
PubSubClient client(espClient);

const int servoPin = 2;
Servo servo;

const int trigPin = 13;
const int echoPin = 12;

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

long duration;
float distanceCm;

void setup() {
  Serial.begin(115200);
  servo.attach(servoPin);

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

  randomSeed(analogRead(0));

  delay(10);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  wifiConnect();

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
  Serial.println(WiFi.macAddress());
  stMac = WiFi.macAddress();
  stMac.replace(":", "_");
  Serial.println(stMac);
  
  client.setServer(mqtt_server, port);
  client.setCallback(callback);
  // pinMode(ledPin, OUTPUT);
}

void wifiConnect() {
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
}

void mqttReconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");

    String client_id = "esp8266-client-";
    client_id += String(WiFi.macAddress());
    Serial.printf("The client %s connects to the public mqtt broker\n", client_id.c_str());
    if (client.connect(client_id.c_str(), mqtt_username, mqtt_password)) {
      Serial.print(clientId);
      Serial.println(" connected");
      client.subscribe(topic);
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

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

  if (String(topic) == topic) {
    Serial.print("Changing output to ");
    if(stMessage == "on"){
      Serial.println("on");
      servo.write(180);
      delay(500);
      servo.write(90);
    }
    else if(stMessage == "off"){
      Serial.println("off");
      servo.write(0);
      delay(500);
      servo.write(90);
    }
  }
}

void ultrasonic(){
  // 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;
  
  // Prints the distance in the Serial Monitor
  Serial.print("Distance (cm): ");
  Serial.println(distanceCm);
  
  delay(1000);
}

void loop() {
  delay(10);
  if (!client.connected()) {
    mqttReconnect();
  }
  ultrasonic();
  client.loop();
}