//code sourced from [Bytes N Bits]
#include <SoftwareSerial.h>
#define led 3
const byte bt_RX = 2, bt_TX = 3, bt_Vin = 4;
const byte button_Vin = 9, button_Vout = 11;

SoftwareSerial BTSerial(bt_RX, bt_TX);


void setup() {
  // put your setup code here, to run once:

  Serial.begin(9600);
  BTSerial.begin(9600);
  delay(1000);

  pinMode(bt_RX, INPUT);
  pinMode(bt_TX, OUTPUT);
  pinMode(bt_Vin, OUTPUT); //powers bluetooth module
  pinMode(button_Vin, OUTPUT);
  pinMode(button_Vout, INPUT_PULLUP);
  delay(100);
  digitalWrite(bt_Vin, HIGH); //powers bluetooth module

  delay(500);
  
  if(BTSerial.available()) 
  BTSerial.read(); //clears mysterious byte from bluetooth serial buffer
  /*
  BTSerial.write("AT+BAUD4"); //sets bluetooth's baud rate to 9600
  delay(100);
  BTSerial.write("AT+NAMEBackseat Guardian"); //changes display name
  delay(100);
  BTSerial.write("AT+VERSION"); //shows bluetooth version
  delay(100);
  */
  
  for (int i = 0; i < 32; i++ ) {
    if (BTSerial.available()) Serial.write((char)BTSerial.read());
  }
  Serial.println("");
  
}

void loop() {
  
  static String msg_to_bt = "";
  static String msg_from_bt = "";
  static String atm = "";
  static byte dByte = "";
  
  //writes "AT" to bluetooth when button is pressed
  if(digitalRead(button_Vout) == 0) { //press
    Serial.println("AT");
    BTSerial.write(":P\n");
    Serial.println("Noman 12084");
    digitalWrite(led, LOW);
    delay(100);
  }
  else if(digitalRead(button_Vout) == 1){
      digitalWrite(led,HIGH);
    }
  //command line -> bluetooth module
  msg_to_bt = "";
  while(Serial.available()){
    dByte = Serial.read();
    if (dByte >= 97 && dByte <= 122) dByte -= 32; //capitalizes message
    Serial.print((char)dByte);
    if (dByte > 31 && dByte < 127) msg_to_bt += (char)dByte; //only stores printing bytes
  }
  if (msg_to_bt != "") BTSerial.println(msg_to_bt);

  //since HC-06 is always in slave mode when paired, Arduino must emulate AT functions
  if(msg_to_bt == "AT") BTSerial.write(" OK\n");
  if(msg_to_bt == "AT+NAME") BTSerial.write(" Backseat Guardian\n");
  if(msg_to_bt == "AT+VERSION") BTSerial.write(" LINVORV1.8\n");
  if(msg_to_bt == "AT+BAUD") BTSerial.write(" 9600\n");

  //bluetooth module -> serial monitor
  msg_from_bt = "";
  while(BTSerial.available()){
    dByte = BTSerial.read();
    if (dByte >= 97 && dByte <=122) dByte -= 32; //capitalizes message
    Serial.print((char)dByte);
    if (dByte > 31 && dByte < 127) msg_from_bt += (char)dByte; //only stores printing bytes
  }
  
  atm = "";
  delay(100);
  atm += msg_from_bt[0];
  atm += msg_from_bt[1];
  atm += msg_from_bt[2];
  
  if (msg_from_bt != "") {
  //since HC-06 is always in slave mode when paired, Arduino must emulate AT functions
    if (atm == "AT+") {
      if(msg_from_bt == "AT+NAME") BTSerial.write("+NAME:Backseat Guardian\n"); //"AT+NAME"
      if(msg_from_bt == "AT+VERSION") BTSerial.write("LINVORV1.8\n"); //"AT+VERSION"
      if(msg_from_bt == "AT+BAUD") BTSerial.write("9600\n"); //"AT+BAUD"
      Serial.print(".");
    }
    if(msg_from_bt == "AT") BTSerial.write("OK\n"); //"AT"
    if(msg_from_bt == "HELLO") BTSerial.write("Welcome!\n");
    if(msg_from_bt == "LOCATION") BTSerial.write("I'm right here: \n");
    if(msg_from_bt == "BYE") {
      digitalWrite(bt_Vin, LOW); //disconnects bluetooth
      delay(1000);
      BTSerial.read();
      digitalWrite(bt_Vin, HIGH);
      delay(1000);
    }
  }
   
}