///////////////////////////////////////////////////////////////////////////////
// Project: Bluetooth LED
// URL:     
// File:    Bluetooth.ino
//
// Description:
//          This Sketch controls a LED connected to an Arduino via 
//          Bluetooth (supplied by an HM-10 Bluetooth module), from an app.
//
// Copyright (C) 2021-2022:
//          José Caetano Silva / CaetanoSoft
//
// License:
//          This file is part of Bluetooth LED.
//
//          Bluetooth LED is free software: you can redistribute it and/or modify
//          it under the terms of the GNU General Public License as published by
//          the Free Software Foundation, either version 3 of the License, or
//          (at your option) any later version.
//
//          Bluetooth LED is distributed in the hope that it will be useful,
//          but WITHOUT ANY WARRANTY; without even the implied warranty of
//          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//          GNU General Public License for more details.
//
//          You should have received a copy of the GNU General Public License
//          along with Bluetooth LED.  If not, see <https://www.gnu.org/licenses/>.
///////////////////////////////////////////////////////////////////////////////


// Remove comment from next line to use Software Serial
// instead of Hardware Serial
//#define SOFTSERIAL

#ifdef SOFTSERIAL
  #include <SoftwareSerial.h>
  // Bluetooth RX pin on Arduino
  #define BT_RX_PIN = 10
  // Bluetooth TX pin on Arduino
  #define BT_TX_PIN = 11
  SoftwareSerial SerialBT(BT_RX_PIN, BT_TX_PIN);
#else 
  HardwareSerial SerialBT = Serial1;
#endif

// The LED anode (+) pin on Arduino
#define LED_PIN 14
int ledPin = LED_PIN;   // The LED anode (+) pin on Arduino
bool ledState = false;  // State: false => Off; true => On

// Incomming Bluetooth message from the external controler device
String incomingMessage = "";

/** 
 *  Change the LED on or off.
 */
void ChangeLED(int ledPin, bool ledState)
{
  if (ledState == false)
  {
    // Turn LED OFF
    digitalWrite(ledPin, LOW);
  
    // Send back, to the Bluetooth device, the message "LED: OFF"
    SerialBT.println("LED: OFF");
    
#ifndef SOFTSERIAL
    // Send debug OK message to the console, the string "OK: LED (pin *) OFF"
    Serial.print("OK: LED (pin ");
    Serial.print(ledPin);
    Serial.println(") OFF");
#endif
  }
  else
  {
    // Turn LED ON
    digitalWrite(ledPin, HIGH);
  
    // Send back, to the Bluetooth device, the message "LED: ON"
  SerialBT.println("LED: ON");
  
#ifndef SOFTSERIALON
    // Send debug OK message to the console, the string "OK: LED (pin *) ON"
    Serial.print("OK: LED (pin ");
    Serial.print(ledPin);
    Serial.println(") ON");
#endif
  }
}

/** 
 *  Processes the Bluetooth command message recived
 */
bool ProcessBluetoothCommand(String incomingMessage)
{
  bool retVal = false;
 
  if(incomingMessage == "0")
  {
    ledPin = LED_PIN;
    ledState = false;
    retVal = true;
  }
  else if(incomingMessage == "1")  
  {
    ledPin = LED_PIN;
    ledState = true;
    retVal = true;
  }
  else
  {
    retVal = false;
  }
  
  return retVal;
}

/** 
 *  The setup function runs once when you press reset or power the board.
 */
void setup()
{
  // Serial communications initialization
#ifdef SOFTSERIAL
  SerialBT.begin(9600); // Default software communication baud rate of the Bluetooth module
  Serial.begin(9600); // Default communication baud rate to the console
#else
  SerialBT.begin(38400); // Default hardware communication baud rate of the Bluetooth module
  Serial.begin(9600); // Default communication baud rate to the console
#endif

  // LED initialization (off)
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);
}

/**
 *  The loop function runs over and over again forever.
 */
void loop()
{
  // Checks whether data is comming from the BlueToorh Serial Port
  if(SerialBT.available() > 0)
  {
    // Read the incoming data string message
    incomingMessage = SerialBT.readString();
  
    // Process the BlueToorh command recived
    if(ProcessBluetoothCommand(incomingMessage))
    {
      ChangeLED(ledPin, ledState);
    }
    else
    {
      // Send back, to the Bluetooth device, the message "ERROR BAD COMMAND"
      Serial.println("ERROR BAD COMMAND");
      
#ifndef SOFTSERIAL
      // Send debug error message to the console
      Serial.print("ERROR: Unknown command '");
      Serial.print(incomingMessage);
      Serial.println("' recived");
#endif
    }
  }
}