/*
   =======================================================
   Serial Input Capability using the Serial Event Function
   =======================================================
*/
#define SERIAL_INPUT_MAX_LENGTH 30
 
void handleInputBuffer( const char* input_buffer );
void serialEvent();

char serial_input_buffer[SERIAL_INPUT_MAX_LENGTH+1]; // holds incoming data
int serial_input_buffer_index = 0;

/*
  SerialEvent occurs whenever a new data comes in the
 hardware serial RX.  This routine is run between each
 time loop() runs, so using delay inside loop can delay
 response.  Multiple bytes of data may be available.
 */
void serialEvent() {
  bool serial_input_buffer_complete = false;

  while (Serial.available()) {
    // get the new byte and add it to the buffer
    serial_input_buffer[serial_input_buffer_index] = (char) Serial.read();
    
    // if the incoming character is a newline, set a flag
    // so we can 
    if ( serial_input_buffer[serial_input_buffer_index] == '\n'
      || serial_input_buffer[serial_input_buffer_index] == '\0'
      || serial_input_buffer_index == SERIAL_INPUT_MAX_LENGTH 
    ) {
      serial_input_buffer_complete = true;
      serial_input_buffer[serial_input_buffer_index] = '\0';
      break;
    }

    // Increase the index
    serial_input_buffer_index++;
  }

  if ( serial_input_buffer_complete ) {
    handleInputBuffer( serial_input_buffer );

    // Reset flag and buffer
    serial_input_buffer_complete = false;
    serial_input_buffer_index = 0;
  }
}

/*
 * Handle a command, make sure this is short as serialEvent() uses this function
 */
void handleInputBuffer( const char* input_buffer ){
    // Handle Incoming Line
    for ( int i = 0; i < STR_MAX_LENGTH ; i++ ) {
      // Stop copying when null character found.
      if ( input_buffer[i] == '\0' || input_buffer[i] == '\n') {
        break;
      }
      
      line_buffer[line_buffer_write][i] = input_buffer[i];
    }
    
    line_buffer_write = ((line_buffer_write + 1 ) % LINE_BUFFER_SIZE );
}