bluethermd

#!/usr/bin/env ruby

repo_lib = File.dirname($0) + '/../lib/ruby'
if File.directory?(repo_lib)
  $: << repo_lib
end

require 'bluetherm'

require 'optparse'
require 'pathname'

$0 = 'bluethermd'

@sqlite3_loaded = false
begin
  require 'sqlite3'
  @sqlite3_loaded = true
rescue LoadError
end

STDOUT.sync = true
STDERR.sync = true

@device_path = '/dev/rfcomm0'
@is_print = true
@sqlite_path = nil
@poll_interval = 10

OptionParser.new do |opts|
  opts.on('--device=PATH', 'Bluetooth serial device to connect to') \
    { |v| @device_path = v }
  opts.on('--update-interval=SECONDS',
    "Log rate, default is #{@poll_interval}") \
    { |v| @poll_interval = v.to_i }
  opts.on('--quiet', "Suppress terminal output") \
    { |v| @is_print = false }

  if @sqlite3_loaded
    opts.on('--sqlite-path=PATH', 'Temperatures are in milli-Celsius') \
      { |v| @sqlite_path = Pathname.new(v) }
  else
    opts.separator('(SQLite3 support disabled; sqlite3.rb not found!)')
  end
end.parse!

unless @is_print or @sqlite_path
  opts.abort("choose at least one of print-to-stdout or log-to-sqlite")
end

def log(message)
  if @is_print
    puts "bluethermd: #{message}"
  end
end


#
# Helper for writing sensor values to an SQLite3 database.
#
class BlueTherm::Database # :nodoc:
  def initialize(path, logger=nil)
    @conn = SQLite3::Database.new(path.to_s)
    @logger = logger
    @last = {}
    @handles = {}
  end

  def record!(sensor_n, temperature)
    return if temperature == @last[sensor_n]
    @handles[sensor_n] ||= begin
      table = "sensor_#{sensor_n}"
      @conn.execute "
        CREATE TABLE IF NOT EXISTS #{table} (
          epoch INTEGER,
          mC    INTEGER
        )
      "
      @conn.prepare("INSERT INTO #{table} (epoch, mC) VALUES (?, ?)")
    end

    pass = 1
    begin
      @handles[sensor_n].execute(Time.now.to_i, (temperature * 1000).to_i)
      @last[sensor_n] = temperature
    rescue SQLite3::BusyException => ex
      if pass > 3
        log "database is too busy; skipping update: #{ex.message}"
      else
        log "database is busy; retrying..."
        pass += 1
        sleep 0.1
        retry
      end
    end
  end

  def log(message)
    @logger.call(message) if @logger
  end
end

if @sqlite_path
  unless @sqlite_path.exist?
    @sqlite_path.dirname.mkpath
  end
  @db = BlueTherm::Database.new(@sqlite_path, method(:log))
end

begin
  BlueTherm.poll(@device_path, @poll_interval, method(:log)) do |t1, t2|
    if @is_print
      ansi, reset = nil, nil
      if STDOUT.tty?
        ansi = "\033[01m"
        reset = "\033[0m"
      end
      puts "#{ansi}t1=#{t1.round(2)} t2=#{t2.round(2)}#{reset}"
    end

    if @db
      @db.record!(1, t1)
      @db.record!(2, t2)
    end
  end
rescue SignalException => ex
  STDERR.puts "received #{ex}"
  exit
end