#!/usr/bin/env ruby
# encoding: utf-8
# ruby: 2.4.1
require 'serialport'

DEBUG = true # show communication

unless ARGV.length > 0 and File.exist?(ARGV[0]) then
  puts "this script will configure HC-05 bluetooth modules"
  puts "provide path to serial port as argument"
  exit
end

def send(at)
  puts "< "+at if DEBUG # output request
  @serial.write(at) # send request
  @serial.write("\r\n") unless at.end_with?("\r\n")
  @serial.flush
  sleep 0.1
  response = ""
  until response.end_with?("OK") do
    activity = IO.select([@serial],nil,nil,3) # wait for response
    return nil unless activity # no response received
    response += @serial.read(1) # get response
  end
  puts "> "+response if DEBUG # output response
  return false unless response.end_with?("OK")
  return response.chomp.gsub(/OK$/, "").chomp
end  
  
@serial = SerialPort.open(ARGV[0],{ baud: 38400, databits: 8, parity: SerialPort::NONE, stop_bit: 1, flow_control: SerialPort::NONE})
@serial.baud = 38400 # sometimes the baud rate does not get set
@serial.read_timeout = 3000 # don't wait forever for an answer (in ms)

# commands to send
# get some general information
commands = ["AT", "AT+VERSION?", "AT+ADDR?", "AT+ROLE?", "AT+UART?", "AT+PSWD?", "AT+BIND?"]
#commands << "AT+NAME?" # somehow this does not work
commands << "AT+ORGL" # reset of factory settings
commands << 'AT+NAME="dachtuer"' # set name
commands << "AT+PSWD=1234" # set pin (1234 by default)
commands << "AT+UART=115200,0,2" # set usual baud rate (even parity, to be compatible with the bootloader)
commands << "AT+RESET" # reset to take effect (goes into non ART command mode)

# send all commands
commands.each do |command|
  raise "error communicating will HC-05. ensure it is in AT mode by pressing on button while powering up" unless send(command)
end
@serial.close