/******************************************************************************************************************************
   Date:        10/03/2023
   Filename:    LabSage_v1.1.8
   Description: merged v1.1.5 and 1.1.7 to make dynamic smoke and collision thresholds
   Update - Collision threshold can be adjusted via the rtdb if necessary. Smoke threshold auto updates. However if smoke has
            been detected for more than approx 20-30 seconds, the alarm must be reset manually via the app/rtdb. False alarms
            can occur, but they will stop ringing within 20-30 seconds if they are false.
 *****************************************************************************************************************************/
//  INCLUDE LIBRARIES
#include <TaskScheduler.h>        // Install TaskScheduler Arduino Library
#include <WiFiManager.h>          // Install WiFiManager Library
#include <FirebaseESP8266.h>      // Install Firebase ESP8266 library (Mobitz?)
#include <MB_NTP.h>
#include <ESP8266WiFi.h>
#include <DHT.h>                  // Install DHT11 Library and Adafruit Unified Sensor Library
#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_ADXL345_U.h>   // Install Adafruit ADXL345 accelerometer library

//  FIREBASE RTDB PATH AND KEY
#define FIREBASE_HOST "https://smartlab-9b83e-default-rtdb.firebaseio.com/"
#define FIREBASE_AUTH "AIzaSyCiO5owTmUgosDyjL0_SqpxRoAwgKtn5-o"

//  SETTING PINS FOR SENSORS
#define LED D1
#define DHTPIN D2                 // Connect Data pin of DHT to D2
#define GASPIN A0                 // Gas sensor analog pin
#define BUZZERPIN D7              // Connect LED to D7
#define SDA D5                    // Accelerometer Serial Data
#define SCL D6                    // Accelerometer Serial Clock

//  DHT VARIABLE SET
#define DHTTYPE DHT11

//  OBJECT DECLARATIONS
Scheduler runner;                                                 // Multi tasking object
WiFiManager wm;                                                   // Wi-Fi Manager Object
DHT dht(DHTPIN, DHTTYPE);                                         // DHT Object
Adafruit_ADXL345_Unified accel = Adafruit_ADXL345_Unified(12345); // Accelerometer Object

//MQ2 parameter for CO Gas sensing
float gasSensor_volt;
float RS;
const float R0 = 2.12;
const float b = 1.5120222;
const float m = -0.33975668;
float RS_R0_ratio;
float ppm_log;
float ppm;

//  VARIABLE DEFINITION
float t, h, g;                                  // Temp, Humidity, gas value (ppm)
bool buzz = false;                              // Smoke alarm
bool coll = false;                              // Collision Alarm
float x, y, z;                                  // Acceleration in x, y, z directions, storage variables for previous state
float sum = 0;                                  // checksum for smoke detection - false alarm avoidance
unsigned int k = 0;                             // smoke alarm duration counter
float sThreshSum = 0;                           // Sum used for threshold updating
unsigned int j = 0;                             // Counter used for threshold updating
String PATH = "Devices/";                       // Base path on RTDB
String UID = "";                                // ESP Unique ID - Device ID necessary for dynamic path allocation

//  THRESHOLD VALUES                            // Not constant because it needs to be updated every min
float COLLISION_THRESHOLD = 10.0;
float SMOKE_THRESHOLD = 2000;

//  DEFINE FIREBASE DATA OBJECTs
FirebaseData firebaseData;
FirebaseData buzzerData;
FirebaseData collData;
FirebaseJson json;

//  FUNCTION DECLARATION
void dhtSetup(void);
void gasSetup(void);
void ambiRead(void);
void accelSetup(void);
void accelRead(void);
void sensorUpdate(void);
void upload(void);
void uploadAlert(void);
void sensorReset(void);
void reconnection(void);

//  TASK SCHEDULE FUNCTIONS
void task1Callback() {                                                  // Sensor update
  // code for task 1
  sensorUpdate();
}

void task2Callback() {                                                  // Sensor value upload
  // code for task 2
  if (WiFi.status() == WL_CONNECTED) {
    upload();
  }
  else {
    Serial.println("Connection Lost!");
    digitalWrite(LED, !digitalRead(LED));
    Serial.println("Please Reconnect to a different WiFi.\nStarting Soft API...");
    reconnection();
  }
}

void task3Callback() {                                                  // Reset receive and execute
  // Check if there is a fire/smoke
  if (WiFi.status() == WL_CONNECTED) {
    if (Firebase.getBool(buzzerData, PATH + "/reset") && buzzerData.boolData() == true) {                             //Read from firebase for application

      Serial.println("Call to reset");
      sensorReset();

      if (Firebase.setBool(firebaseData, PATH + "/reset", false))       // Reset the 'reset' value on the database
      {
        Serial.println("PASSED");
        Serial.println("PATH: " + firebaseData.dataPath());
        Serial.println("TYPE: " + firebaseData.dataType());
        Serial.println("ETag: " + firebaseData.ETag());
        Serial.println("------------------------------------");
        Serial.println();
      }
      else
      {
        Serial.println("FAILED");
        Serial.println("REASON: " + firebaseData.errorReason());
        Serial.println("------------------------------------");
        Serial.println();
      }

      uploadAlert();                                                     // Resetting buzzer and collision values on rtdb
    }
    if (Firebase.getFloat(collData, PATH + "/collThresh") && collData.floatData() != COLLISION_THRESHOLD) {           //Read from firebase for application
      COLLISION_THRESHOLD = collData.floatData();
      Serial.print("New Collision Threshold = ");
      Serial.println(COLLISION_THRESHOLD);
    }

    if (buzz || coll) {
      uploadAlert();                                                    // Setting the buzzer and collision values on rtdb
    }
  }
  else {
    Serial.println("Connection Lost!");
    digitalWrite(LED, !digitalRead(LED));
    Serial.println("Please Reconnect to a different WiFi.\nStarting Soft API...");
    reconnection();
  }
}

void task4Callback() {                                                  // Update Smoke sensor threshold
  // code for task 4
  if (sThreshSum != 0) {                                                // To avoid accidental wrongful updates
    if (j == 0) {                                                       // To avoid divide-by-zero error
      j = 1;
    }
    SMOKE_THRESHOLD = sThreshSum / j + 2000;                            // Taking an average value of gas sensor readings because depending on use, the threshold changes greatly
    Serial.print("Smoke threshold auto updated to ");
    Serial.println(SMOKE_THRESHOLD);
    sThreshSum = 0;                                                     // Reset these values for counting again
    j = 0;
  }
  if (WiFi.status() == WL_CONNECTED) {
    if (Firebase.setFloat(firebaseData, PATH + "/smokeThresh", SMOKE_THRESHOLD))                    // Update Smoke Threshold
    {
      Serial.println("PASSED");
      Serial.println("PATH: " + firebaseData.dataPath());
      Serial.println("TYPE: " + firebaseData.dataType());
      Serial.println("ETag: " + firebaseData.ETag());
      Serial.println("------------------------------------");
      Serial.println();
    }
    else
    {
      Serial.println("FAILED");
      Serial.println("REASON: " + firebaseData.errorReason());
      Serial.println("------------------------------------");
      Serial.println();
    }
  }
}

Task t1(1000, TASK_FOREVER, &task1Callback);                    // Task rate: Once every second
Task t2(60000, TASK_FOREVER, &task2Callback);                   // Task rate: Once every minute
Task t3(3000, TASK_FOREVER, &task3Callback);                    // Task rate: Once every 3 seconds
Task t4(30000, TASK_FOREVER, &task4Callback);                   // Task rate: Once every 30 seconds

//  SETUP
void setup() {
//  Set Pin Modes
  pinMode(LED, OUTPUT);
  digitalWrite(LED, LOW);
  pinMode(BUZZERPIN, OUTPUT);
  Serial.begin(9600);
  
  dhtSetup();
  accelSetup();
  gasSetup();
  
  UID = ESP.getChipId();                                        // Extract Unique Chip ID for authentication and identity purposes
  Serial.printf("ESP8266 Unique Chip id = %s\n", UID);          // For hex representation, use %08X
  Serial.println();
  Serial.println("Opening WiFi AP");
//  wm.resetSettings();                                         // Comment out before deployment
  
  bool res;
  wm.setConnectTimeout(60);
  wm.setConfigPortalTimeoutCallback(reconnection);
  wm.setWiFiAutoReconnect(true);
  res = wm.autoConnect("SMI_LBS_ESP");                          // auto generated AP name from chipid
  wm.setShowInfoUpdate(false);
  wm.setShowInfoErase(false);
  if (!res) {
    Serial.println("Failed to connect");
  }
  else {
    //if you get here you have connected to the WiFi
    Serial.println("Connected");
  }
  Firebase.begin(FIREBASE_HOST, FIREBASE_AUTH);                 // Begin Firebase Server
  Firebase.reconnectWiFi(true);

  Serial.println(PATH.concat(UID));                             // Dynamic database path allocation
  if (Firebase.setFloat(firebaseData, PATH + "/smokeThresh", SMOKE_THRESHOLD))                        //Uploading the default smoke threshold for the first time
  {
    Serial.println("PASSED");
    Serial.println("PATH: " + firebaseData.dataPath());
    Serial.println("TYPE: " + firebaseData.dataType());
    Serial.println("ETag: " + firebaseData.ETag());
    Serial.println("------------------------------------");
    Serial.println();
  }
  else
  {
    Serial.println("FAILED");
    Serial.println("REASON: " + firebaseData.errorReason());
    Serial.println("------------------------------------");
    Serial.println();
  }
  if (Firebase.setFloat(firebaseData, PATH + "/collThresh", COLLISION_THRESHOLD))                     // Uploading the default collision threshold for the first time
  {
    Serial.println("PASSED");
    Serial.println("PATH: " + firebaseData.dataPath());
    Serial.println("TYPE: " + firebaseData.dataType());
    Serial.println("ETag: " + firebaseData.ETag());
    Serial.println("------------------------------------");
    Serial.println();
  }
  else
  {
    Serial.println("FAILED");
    Serial.println("REASON: " + firebaseData.errorReason());
    Serial.println("------------------------------------");
    Serial.println();
  }
  digitalWrite(LED, HIGH);
  runner.init();                                                // Initialise Scheduler, add tasks to it, and then enable the tasks for multitasking
  runner.addTask(t1);
  runner.addTask(t2);
  runner.addTask(t3);
  runner.addTask(t4);
  t1.enable();
  t2.enable();
  t3.enable();
  t4.enable();
}

//  MAIN LOOP CODE
void loop() {
  runner.execute();                                             // Run the tasks simultaneously
}

void reconnection(void) {                                       // Re-establishing network with new Wi-Fi using Soft AP
  bool res = wm.autoConnect();
  if (!res) {
    Serial.println("Failed to connect");
  }
  else {
    Serial.println("Connected");
  }
}

void accelSetup(void) {                                         // Setup Accelerometer
  Serial.println("Accelerometer Test"); Serial.println("");

  // Initialise I2C communication as MASTER
  Wire.begin(SDA, SCL);

  if (!accel.begin()) {
    Serial.println("Failed to initialize ADXL345 sensor.");
    while (1);
  }
  accel.setRange(ADXL345_RANGE_16_G);                           // Setting Max Range
  
  // Get accelerometer data
  sensors_event_t event;
  accel.getEvent(&event);
  
  //  Assign current values to states
  x = event.acceleration.x;
  y = event.acceleration.y;
  z = event.acceleration.z;
  Serial.println("Accelerometer Ready!"); Serial.println("");
}

void accelRead(void) {                                          // Read Accelerometer
  // Get accelerometer data
  sensors_event_t event;
  accel.getEvent(&event);

  // Print the accelerometer data to serial monitor
  Serial.print("Acceleration: ");
  Serial.print(event.acceleration.x);
  Serial.print(" m/s^2 ");
  Serial.print(event.acceleration.y);
  Serial.print(" m/s^2 ");
  Serial.print(event.acceleration.z);
  Serial.println(" m/s^2 ");
  if (isnan(event.acceleration.x) || isnan(event.acceleration.y) || isnan(event.acceleration.z)) {
    Serial.println(F("Failed to read from Accelerometer!"));
    return;
  }
  
  // Check if there is a collision
  if ((abs(event.acceleration.x - x)) > COLLISION_THRESHOLD ||
      (abs(event.acceleration.y - y)) > COLLISION_THRESHOLD ||
      (abs(event.acceleration.z - z)) > COLLISION_THRESHOLD) {
    Serial.println("Collision detected!");
    coll = true;
    tone(BUZZERPIN, 100);
  }
  
  //  Assign current values to states
  x = event.acceleration.x;
  y = event.acceleration.y;
  z = event.acceleration.z;
}

void dhtSetup(void) {                                           // Setup DHT11
  Serial.println(F("DHT11 setting up..."));
  dht.begin();
  Serial.println("DHT11 ready!");
}

void gasSetup(void) {                                           // Setup MQ-2 Smoke Sensor
  Serial.println("Gas Sensor setting up...");
  pinMode(GASPIN, INPUT_PULLUP);
  
  //  Smoke Threshold established by taking average of the first five readings from the sensor
  int cnt = 5;
  float temp = 0;
  for (int i = 0; i < cnt; i++) {
    float gasSensorValue = analogRead(GASPIN);
    gasSensor_volt = gasSensorValue / 1024 * 5.0;
    RS = ((5 - gasSensor_volt) / gasSensor_volt);
    RS_R0_ratio = RS / R0;
    ppm_log = ((log (RS_R0_ratio) - b) / m);
    ppm = pow (10, ppm_log);
    // Check if any reads failed and exit early (to try again).
    if (isnan(ppm)) {
      Serial.println(F("Failed to read from Gas sensor!"));
      return;
    }
    temp = temp + ppm;
    delay(1000);
  }

  SMOKE_THRESHOLD = SMOKE_THRESHOLD + (temp / cnt);               // Taking an average value of gas sensor readings because depending on use, the threshold changes greatly
  Serial.println("Gas Sensor ready!");
  Serial.printf("\nSmoke Threshold: %f ppm\n", SMOKE_THRESHOLD);
  Serial.println("");
}

void ambiRead(void) {                                           // Temp, Humidity, Gas reading
  // Read relative humidity in % (the default)
  h = dht.readHumidity();

  // Read temperature as Celsius (the default)
  t = dht.readTemperature();
  
  // Read gas sensor analog data
  float gasSensorValue = analogRead(GASPIN);
  gasSensor_volt = gasSensorValue / 1024 * 5.0;
  RS = ((5 - gasSensor_volt) / gasSensor_volt);
  RS_R0_ratio = RS / R0;
  ppm_log = ((log (RS_R0_ratio) - b) / m);
  ppm = pow (10, ppm_log);
  g = ppm;
/*
  IF SMOKE THRESHOLD SHOULD BE UPDATED EVEN WITH THE SMOKE VALUES, UNCOMMENT THE FOLLOWING
    sThreshSum += g;
    j++;
  AND COMMENT IT IN LINES 412-413 (SUBJECT TO CHANGE)
  */
  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t)) {
    Serial.println(F("Failed to read from DHT sensor!"));
    return;
  }
  if (isnan(g)) {
    Serial.println(F("Failed to read from Gas sensor!"));
    return;
  }
  // Smoke Detection
  if (g > SMOKE_THRESHOLD) {
    sum += g;
    k++;
    Serial.println("Smoke detected!");
    buzz = true;
    tone(BUZZERPIN, 400);
  }
  else {
    //  because smoke threshold ideally should not be updated for beyond limit values
    sThreshSum += g;
    j++;

    if (k <= 10) {                              // Temporary tolerance count is 10 readings. Could increase it depending on the tolerance desired.
      buzz = false;
      if (coll == false) {
        noTone(BUZZERPIN);
      }
    }
  }
  Serial.print(F("Humidity: "));
  Serial.print(h);
  Serial.print(F("%  Temperature: "));
  Serial.print(t);
  Serial.print(F("C  PPM:"));
  Serial.print(g);
  Serial.println();


}

void sensorUpdate(void) {
  ambiRead();
  accelRead();
}

void sensorReset(void) {
  coll = false;
  buzz = false;
  noTone(BUZZERPIN);
  sum = 0;
  k = 0;
}

void upload(void) {                                               // Uploading Sensor values
  if (Firebase.setFloat(firebaseData, PATH + "/temperature", t))
  {
    Serial.println("PASSED");
    Serial.println("PATH: " + firebaseData.dataPath());
    Serial.println("TYPE: " + firebaseData.dataType());
    Serial.println("ETag: " + firebaseData.ETag());
    Serial.println("------------------------------------");
    Serial.println();
  }
  else
  {
    Serial.println("FAILED");
    Serial.println("REASON: " + firebaseData.errorReason());
    Serial.println("------------------------------------");
    Serial.println();
  }

  if (Firebase.setFloat(firebaseData, PATH + "/humidity", h))
  {
    Serial.println("PASSED");
    Serial.println("PATH: " + firebaseData.dataPath());
    Serial.println("TYPE: " + firebaseData.dataType());
    Serial.println("ETag: " + firebaseData.ETag());
    Serial.println("------------------------------------");
    Serial.println();
  }
  else
  {
    Serial.println("FAILED");
    Serial.println("REASON: " + firebaseData.errorReason());
    Serial.println("------------------------------------");
    Serial.println();
  }
  if (Firebase.setFloat(firebaseData, PATH + "/ppm", g))
  {
    Serial.println("PASSED");
    Serial.println("PATH: " + firebaseData.dataPath());
    Serial.println("TYPE: " + firebaseData.dataType());
    Serial.println("ETag: " + firebaseData.ETag());
    Serial.println("------------------------------------");
    Serial.println();
  }
  else
  {
    Serial.println("FAILED");
    Serial.println("REASON: " + firebaseData.errorReason());
    Serial.println("------------------------------------");
    Serial.println();
  }

  if (Firebase.setFloat(firebaseData, PATH + "/x", x))
  {
    Serial.println("PASSED");
    Serial.println("PATH: " + firebaseData.dataPath());
    Serial.println("TYPE: " + firebaseData.dataType());
    Serial.println("ETag: " + firebaseData.ETag());
    Serial.println("------------------------------------");
    Serial.println();
  }
  else
  {
    Serial.println("FAILED");
    Serial.println("REASON: " + firebaseData.errorReason());
    Serial.println("------------------------------------");
    Serial.println();
  }
  if (Firebase.setFloat(firebaseData, PATH + "/y", y))
  {
    Serial.println("PASSED");
    Serial.println("PATH: " + firebaseData.dataPath());
    Serial.println("TYPE: " + firebaseData.dataType());
    Serial.println("ETag: " + firebaseData.ETag());
    Serial.println("------------------------------------");
    Serial.println();
  }
  else
  {
    Serial.println("FAILED");
    Serial.println("REASON: " + firebaseData.errorReason());
    Serial.println("------------------------------------");
    Serial.println();
  }
  if (Firebase.setFloat(firebaseData, PATH + "/z", z))
  {
    Serial.println("PASSED");
    Serial.println("PATH: " + firebaseData.dataPath());
    Serial.println("TYPE: " + firebaseData.dataType());
    Serial.println("ETag: " + firebaseData.ETag());
    Serial.println("------------------------------------");
    Serial.println();
  }
  else
  {
    Serial.println("FAILED");
    Serial.println("REASON: " + firebaseData.errorReason());
    Serial.println("------------------------------------");
    Serial.println();
  }
}

void uploadAlert(void) {                                                // Uploading Alarm status
  if (Firebase.setBool(firebaseData, PATH + "/buzzer", buzz))
  {
    Serial.println("PASSED");
    Serial.println("PATH: " + firebaseData.dataPath());
    Serial.println("TYPE: " + firebaseData.dataType());
    Serial.println("ETag: " + firebaseData.ETag());
    Serial.println("------------------------------------");
    Serial.println();
  }
  else
  {
    Serial.println("FAILED");
    Serial.println("REASON: " + firebaseData.errorReason());
    Serial.println("------------------------------------");
    Serial.println();
  }
  if (Firebase.setBool(firebaseData, PATH + "/collision", coll))
  {
    Serial.println("PASSED");
    Serial.println("PATH: " + firebaseData.dataPath());
    Serial.println("TYPE: " + firebaseData.dataType());
    Serial.println("ETag: " + firebaseData.ETag());
    Serial.println("------------------------------------");
    Serial.println();
  }
  else
  {
    Serial.println("FAILED");
    Serial.println("REASON: " + firebaseData.errorReason());
    Serial.println("------------------------------------");
    Serial.println();
  }
}