//----------------------------------------Include the NodeMCU ESP8266 Library
//----------------------------------------see here: https://www.youtube.com/watch?v=8jMr94B8iN0 to add NodeMCU ESP12E ESP8266 library and board (ESP8266 Core SDK)
#include <ArduinoJson.h>
#include <ArduinoUniqueID.h>
#include <WiFi.h>
#include <WiFiClientSecure.h>

#include "globals.h"

// Define the device ID for this device, updated on boot
String device_id = "unkown-default";

//----------------------------------------Host & httpsPort
const char* host = "script.google.com";
const int httpsPort = 443;
//----------------------------------------

WiFiClientSecure client; //--> Create a WiFiClientSecure object.
// String GAS_ID = "AKfycbxv-9an4ZeYfB5YuCQkFDUoSkzYUbkgc7vwnNXZ3AJFnMQArMqPr1QSeOxkavDow8HZ"; //--> spreadsheet script ID

int smoke_pin = 34;/* MQ2 O/P pin */
int flame_pin = 14;/* IR flame sensor D6*/
int buzzer = 19; /*Connected to D2 pin of NodeMCU*/
int smokeThres = 200;
int flameThres = 1;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  delay(500);

  // Generate the unique ID for the board
  device_id = generateUniqueID();
  Serial.print("UniqueID: " + device_id);

  // Connect to the WiFi access point
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD); //--> Connect to your WiFi router
  Serial.println("");

  //----------------------------------------Wait for connection
  Serial.print("Connecting");
  while (WiFi.status() != WL_CONNECTED) {
    Serial.print(".");
    delay(500);
    //----------------------------------------Make the On Board Flashing LED on the process of connecting to the wifi router.
  }
  Serial.println("");
  Serial.print("Successfully connected to : ");
  Serial.println(WIFI_SSID);
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
  Serial.println();
  //----------------------------------------

  // Set the GPIO pin mode for input
  pinMode(smoke_pin, INPUT);
  pinMode(flame_pin, INPUT);

  // To skip the CA cert for SSL (HTTPS) connection
  client.setInsecure();

  // Register the device in the database
  registerDevice();
}

void loop() {
  // Reading smoke or flame takes about 250 milliseconds!
  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)

  /* Read from IR flame */
  float flameRead = digitalRead(flame_pin);
  float flame_val = flameRead;

  /* Read from MQ2 smoke sensor */
  float smokeRead = analogRead(smoke_pin) >> 2;
  float smoke_val = smokeRead;

  // Check if any reads failed and exit early (to try again).
  if (isnan(flame_val) || isnan(smoke_val)) {
    Serial.println("Failed to read from sensor!");
    delay(DATA_INVALID_DELAY);
    return;
  }

  if (smoke_val >= smokeThres && flame_val >= flameThres) {
    digitalWrite(buzzer, HIGH);
    delay(500);
    digitalWrite(buzzer, LOW);
  }

  String Smoke = "smoke : " + String(smoke_val);
  String Flame = "flame : " + String(flame_val);
  Serial.println(Smoke);
  Serial.println(Flame);

  sendData((int)smoke_val, flame_val); //--> Calls the sendData Subroutine
  delay(DATA_TELEMETRY_INTERVAL);
}

//==============================================================================
//============================================================================== void sendData
// Subroutine for sending data to Firebase Firestore
void sendData(float smoke, float flame) {
  Serial.println("==========");
  Serial.println("sending data ...");
  Serial.print("connecting to ");
  Serial.println(host);

  //----------------------------------------Connect to Google host
  if (!client.connect(host, httpsPort)) {
    Serial.println("connection failed");
    delay(CONNECTION_FAIL_DELAY);
    return;
  }
  //----------------------------------------

  //----------------------------------------Processing data and sending data
  StaticJsonDocument<64> jsonData;
  jsonData["smoke"] = smoke;
  jsonData["flame"] = flame;

  // Serialize the JSON object into string
  // to send to the Android app
  String data;
  serializeJson(jsonData, data);

  String url = "/macros/s/" + GAS_ID + "/exec?method=push_data&device_id=" + device_id + "&data=" + data;
  Serial.print("requesting URL: ");
  Serial.println(url);

  client.print(String("GET ") + url + " HTTP/1.1\r\n" +
               "Host: " + host + "\r\n" +
               "User-Agent: FireAlarm/ESP8266Board\r\n" +
               "Connection: keep-alive\r\n\r\n");

  Serial.println("request sent");
  //----------------------------------------

  // //----------------------------------------Checking whether the data was sent successfully or not
  while (client.connected()) {
    String line = client.readStringUntil('\n');
    Serial.println(line);
    if (line == "\r") {
      Serial.println("headers received");
      break;
    }
  }

  // There is a HTTP 302 redirect from Google Apps Script
  // read the redirected HTTP response headers too
  while (client.connected()) {
    String line = client.readStringUntil('\n');
    Serial.println(line);
    if (line == "\r") {
      Serial.println("headers received");
      break;
    }
  }

  String line = client.readStringUntil('\n');
  Serial.print("received: ");
  Serial.println(line);

  Serial.println("closing connection");
  Serial.println("==========");
  Serial.println();
}

//==============================================================================
//============================================================================== void registerDevice
// Subroutine to register the device in the Firebase Firestore database
void registerDevice() {
  Serial.println("==========");
  Serial.println("registering device ...");
  Serial.print("connecting to ");
  Serial.println(host);

  //----------------------------------------Connect to Google host
  if (!client.connect(host, httpsPort)) {
    Serial.println("connection failed");
    delay(CONNECTION_FAIL_DELAY);
    return;
  }
  //----------------------------------------

  String url = "/macros/s/" + GAS_ID + "/exec?method=register_device&device_id=" + device_id;
  Serial.print("requesting URL: ");
  Serial.println(url);

  client.print(String("GET ") + url + " HTTP/1.1\r\n" +
               "Host: " + host + "\r\n" +
               "User-Agent: FireAlarm/ESP8266Board\r\n" +
               "Connection: close\r\n\r\n");

  Serial.println("request sent");
  //----------------------------------------

  // //----------------------------------------Checking whether the data was sent successfully or not
  while (client.connected()) {
    String line = client.readStringUntil('\n');
    Serial.println(line);
    if (line == "\r") {
      Serial.println("headers received");
      break;
    }
  }

  // There is a HTTP 302 redirect from Google Apps Script
  // read the redirected HTTP response headers too
  while (client.connected()) {
    String line = client.readStringUntil('\n');
    Serial.println(line);
    if (line == "\r") {
      Serial.println("headers received");
      break;
    }
  }

  String line = client.readStringUntil('\n');
  Serial.print("received: ");
  Serial.println(line);

  Serial.println("closing connection");
  Serial.println("==========");
  Serial.println();
}

//==============================================================================
//============================================================================== String generateUniqueID
// Subroutine to generate the unique ID for the microcontroller board
String generateUniqueID() {
  Serial.println("==========");
  Serial.println("generating unique ID for board ...");

  String id = "";
  for (int i = 0; i < UniqueIDsize; i++) {
    id += String(UniqueID[i], HEX);
  }

  Serial.println("==========");
  Serial.println();

  return id;
}