/*********
  Rui Santos
  Complete project details at https://RandomNerdTutorials.com/esp32-hc-sr04-ultrasonic-arduino/
  
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files.
  
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
*********/

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

const int trigPin = 2;
const int echoPin = 4;
const int ldrPin = 36;
const int unlockSwitch = 15;
int adcValue = 0;
const float GAMMA = 0.7;
const float rl10 = 50;

//define sound speed in cm/uS
#define SOUND_SPEED 0.034
#define SERVO_PIN 26 // ESP32 pin GPIO26 connected to servo motor

Servo servoMotor;
long duration;
float distanceCm;
float percentage;

int RLED = 23;
int YLED = 19;
int GLED = 18;
int WLED = 5;

//WiFi
//const char* ssid = "Adar's Galaxy N10+";
//const char* password = "Adarwashere";
const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* hostname = "broker.hivemq.com";

const char *topicPubSmartbin = "iotgprj/town/smartbin/amount";  
const char *topicPubUnlockStatus = "iotgprj/town/smartbin/status";
const char *topicSubUnlock = "iotgprj/town/smartbin/unlock";

WiFiClient espClient;
PubSubClient client(espClient);
unsigned long lastMsg = 0;
#define MSG_BUFFER_SIZE (50)
char msg[MSG_BUFFER_SIZE];
int value = 0;

// Change the espClientName **************
const char* espClientName = "iotg_project";
//**************
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 unlockBin(String &payload) {          // ../smartbin/unlock
  if (payload == "Unlocked") {
    digitalWrite(15, LOW);
    unlock();
    delay(5000);
  }
  else if (payload == "Locked") {
    digitalWrite(15, HIGH);
    char buf[10] = "Locked";
    publishTopic(topicPubUnlockStatus, buf);
  }
}

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];
  }

  if (topic == topicSubUnlock)
    unlockBin(messageTemp);
}

void MQTTSubscribe() 
{
  client.subscribe(topicSubUnlock);
}

bool publishTopic(const char* topic, const char *str) {
  Serial.printf("\nPublishing topic \"%s\" + payload \"%s\"", topic, str);
  if (client.publish(topic, str)) {
    Serial.print(" -- Done ");
    return true;
  }
  else {
    Serial.print("\nPublishing encounter error");
    return false;
  }
}

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

void setup() {
  Serial.begin(115200); // Starts the serial communication
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input
  servoMotor.attach(SERVO_PIN);  // attaches the servo on ESP32 pin
  pinMode(unlockSwitch, INPUT);
  
  setup_wifi();
  setup_MQTT();
  connectMQTT();

  //LEDs
  pinMode(23, OUTPUT);
  pinMode(19, OUTPUT);
  pinMode(18, OUTPUT);
  pinMode(5, OUTPUT);
}

void loop() {

  client.loop();

  LDR();
  UltrasonicSensor();
  
  delay(100);
}

void UltrasonicSensor() {
  // 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);

  digitalWrite(23, HIGH);
  digitalWrite(19, HIGH);
  digitalWrite(18, HIGH);
  
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  
  // Calculate the distance
  distanceCm = duration * SOUND_SPEED/2;

  //distance is converted into percentage for easier data analysis
  //average bin depth is 100cm
  percentage = map(distanceCm, 1, 120, 100, 0);

  if (percentage < 0)   //percentage is considered zero beyond the 100cm mark
    percentage = 0;

  // Prints the distance in the Serial Monitor
  Serial.print("Amount of Trash Filled: ");
  Serial.print(percentage);
  Serial.println("%");

  if (percentage < 100) {

    if (percentage < 50) {
      Serial.println("Rubbish Bin is Available.");
      servoMotor.write(0);
      delay(10); // waits 10ms to reach the position
      digitalWrite(18, LOW);
    }

    else if (percentage >= 50 && percentage < 80) {
      Serial.println("Rubbish Bin is Half Full.");
      // rotates from 0 degrees to 180 degrees
      servoMotor.write(0);
      delay(10); // waits 10ms to reach the position
      digitalWrite(18, LOW);
    }

    else if (percentage >= 80 && percentage < 100) {
      Serial.println("Rubbish Bin is Almost Full.");
      // rotates from 0 degrees to 180 degrees
      servoMotor.write(90);
      delay(10); // waits 10ms to reach the position
      digitalWrite(19, LOW);
    }

    char buf[10] = "Unlocked";
    publishTopic(topicPubUnlockStatus, buf);
  }

  else if (percentage == 100) {
    Serial.println("Rubbish Bin is Full!");
    // rotates from 0 degrees to 180 degrees
    servoMotor.write(180);
    delay(10); // waits 15ms to reach the position
    digitalWrite(23, LOW);

    if (digitalRead(unlockSwitch) == LOW) {
      unlock();
    }
    else if (digitalRead(unlockSwitch) == HIGH) {
      char buf[10] = "Locked";
      //buf[0] = topicPubUnlockStatus ? 'Locked' : 'Unlocked';
      publishTopic(topicPubUnlockStatus, buf);
    }
  }

  char buf[10];
  itoa(percentage, buf, 10);    // integer to string in buf
  Serial.printf("\nPublishing capacity reading");
  publishTopic(topicPubSmartbin, buf);
  delay(500);
}

void LDR() {
  int adcValue = analogRead(ldrPin);
  float voltage = adcValue / 1024.0 * 5;
  float resistance = 2000 * voltage / (1 - voltage / 5);
  float lux = pow(rl10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));

  Serial.println(lux);

  if (lux >= 400.00) {    //during daytime, the White LED is turned off
    Serial.println("Daytime");
    digitalWrite(5, HIGH);
  }

  else {                  //from dusk to dawn, the White LED is turned on
    Serial.println("Nighttime");
    digitalWrite(5, LOW);
  }

  delay(500);
}

void unlock() {
  servoMotor.write(0);
  delay(10);
  char buf[10] = "Unlocked";
  publishTopic(topicPubUnlockStatus, buf);
  delay(50);
}