//----------------------------------------------------------------
// Include Dependencies and Libraries
//----------------------------------------------------------------
#include <TinyGPSPlus.h>
#include <SoftwareSerial.h>
//----------------------------------------------------------------

//**************************************************************************

//----------------------------------------------------------------
// Define Connections
//----------------------------------------------------------------
#define buttonPin   14    //D5 = GPIO14 (ESP8266 - NodeMCU)
//#define RXPin     4     //D2 = GPIO4  (ESP8266 - NodeMCU)
//#define TXPin     5     //D1 = GPIO5  (ESP8266 - NodeMCU)
static const int RXPin = 4, TXPin = 5;
//----------------------------------------------------------------

//**************************************************************************

//----------------------------------------------------------------
// Define Global Variables
//----------------------------------------------------------------
String emergencyContactNumber = "+966538060336";
String s = "www.google.com/maps/dir/";
String LAT, LON, sms;
char charBuf[450];
//----------------------------------------------------------------

//**************************************************************************

//----------------------------------------------------------------
// Define Global Objects
//----------------------------------------------------------------
// The TinyGPSPlus object
TinyGPSPlus gps;

// The serial connection to the GPS device
SoftwareSerial mySerial(RXPin, TXPin);
//----------------------------------------------------------------

//**************************************************************************

//----------------------------------------------------------------
// Main Setup Function
//----------------------------------------------------------------
void setup() {
  Serial.begin(9600);
  initialize_panic_button();
  initialize_A9G_GSM_GPS();
}
//----------------------------------------------------------------

//**************************************************************************

//----------------------------------------------------------------
// Main Loop Function
//----------------------------------------------------------------
void loop() {

  readData_from_A9G_Modem_SMS_and_GPS(5000);

}//end of loop
//----------------------------------------------------------------

//**************************************************************************

//----------------------------------------------------------------
// Functions
//----------------------------------------------------------------
//________________________________________________________________

// Function to Send SMS to Emergancy Contact if Button is Pressed

void ICACHE_RAM_ATTR isr() {
  send_gps_data_via_SMS(emergencyContactNumber);
}

//________________________________________________________________

// Function to Setup A9G Modem To Read GPS Data and Receive SMS

void initialize_A9G_GSM_GPS() {
  mySerial.begin(9600);
  delay(1000);
  mySerial.println("\r");
  mySerial.println("AT\r");
  delay(10);
  mySerial.println("\r");
  mySerial.println("AT+GPS=1\r");
  delay(100);
  mySerial.println("AT+CREG=2\r");
  delay(6000);
  mySerial.println("AT+CGATT=1\r");
  delay(6000);
  mySerial.println("AT+CGDCONT=1,\"IP\",\"WWW\"\r");
  delay(6000);
  mySerial.println("AT+CGACT=1,1\r");
  delay(6000);
  //Initialize ends
  //Initialize GPS
  mySerial.println("\r");
  mySerial.println("AT+GPS=1\r");
  delay(1000);
  mySerial.println("AT+GPSRD=10\r");
  delay(100);
  // set SMS mode to text mode
  mySerial.println("AT+CMGF=1\r");
  delay(1000);
}

//________________________________________________________________

// Function to Connect an Interrupt for the Panic Button

void initialize_panic_button() {
  pinMode(buttonPin, INPUT);
  attachInterrupt(D5, isr, RISING);
}

//________________________________________________________________

// Function to Send SMS with Location Data

void send_gps_data_via_SMS(String NUMBER) {

  if (gps.location.lat() == 0 || gps.location.lng() == 0)
  {
    Serial.println("Return Executed - GPS Satellite [No Signal]");
    // LAT,       LON
    // 21.330791, 39.945985
    LAT = "21.330791";
    LON = "39.945985";
    //return;
  }

  Serial.print(LAT);
  Serial.print(" , ");
  Serial.println(LON);
  Serial.println();
  Serial.println();
  Serial.println();
  Serial.println();
  Serial.println();
  s += LAT;
  s += ",";
  s += LON;
  s += "/";

  //s = "new_new_24-08-2023";
  Serial.println(s);

  Serial.println("Sending Message");

  mySerial.println("AT+CMGF=1\r");
  delay(1000);

  mySerial.println("AT+CNMI=2,2,0,0,0\r");
  delay(1000);

  mySerial.print("AT+CMGS=\"");
  mySerial.print(NUMBER);
  mySerial.print("\"\r");
  delay(1000);
  mySerial.print(s);
  mySerial.write(0x1A);
  delay(1000);
  s = "www.google.com/maps/dir/";

}

//________________________________________________________________

// Function to read Incoming SMS messages and Read GPS Data

void readData_from_A9G_Modem_SMS_and_GPS(unsigned long T) {
  unsigned long Start = millis();
  do
  {
    while (mySerial.available())
      sms = mySerial.readString();
    Serial.println(sms);

    readGPS_Data_and_Show_on_Serial_Monitor();
    readSMS_if_SMS_Requested_Send_Location_To_Sender();

  } while (millis() - Start < T);
}

//________________________________________________________________

// Function to Read GPS data and Save values as (Latitude,Longitude)

void readGPS_Data_and_Show_on_Serial_Monitor() {
  sms.toCharArray(charBuf, 450);
  for (int i = 0; i < 450; i++) {
    gps.encode(charBuf[i]);
  }
  LAT = String(gps.location.lat(), 6);
  LON = String(gps.location.lng(), 6);
  Serial.print(LAT);
  Serial.print(" , ");
  Serial.println(LON);
}

//________________________________________________________________

// Function to Respond with Location SMS if A9G modem receives an SMS

void readSMS_if_SMS_Requested_Send_Location_To_Sender() {
  if (sms.indexOf("+CMT:") != -1) {

    // Get the sender's phone number
    String sender = sms.substring(sms.indexOf("+966"), sms.indexOf("\",,\"20"));
    Serial.println("Sender Number: ");
    Serial.println(sender);//e.g. "+966554433221"

    Serial.println("|||||||||||||||||||||||||||||||||||||||||||||||||||");
    Serial.println("GPS SMS Detected");
    Serial.println("|||||||||||||||||||||||||||||||||||||||||||||||||||");
    send_gps_data_via_SMS(sender);
    delay(5000);
  }
}

//________________________________________________________________

//----------------------------------------------------------------