#!/usr/bin/env ruby

# FIXME
$LOAD_PATH << "/home/pks/.local/lib/ruby/gems/json-2.3.1/lib/"
$LOAD_PATH << "/home/pks/.local/lib/ruby/gems/mqtt-0.5.0/lib/"
$LOAD_PATH << "/home/pks/.local/lib/ruby/gems/optimist-3.0.1/lib/"
$LOAD_PATH << "/home/pks/.local/lib/ruby/gems/sqlite3-1.4.2/lib/"
$LOAD_PATH << "/home/pks/.local/lib/ruby/gems/zipf-1.2.6/lib/"

require 'json'
require 'mqtt'
require 'optimist'
require 'sqlite3'
require 'time'
require 'zipf'

def shutdown
  STDERR.write "Shutting down ...\n"
  $db.close
  $logfile.close
  STDERR.write "Done!\n"
  exit
end

Signal.trap("INT") { shutdown }
Signal.trap("TERM") { shutdown }

def db_open_or_new filename
  if File.exists? filename
    $db = SQLite3::Database.open filename
  else
    $db = SQLite3::Database.new filename
    $db.execute <<-SQL
            create table power_log(
             id INTEGER PRIMARY KEY,
             timestamp DATETIME,
             device_name TEXT,
 	 				   device_location TEXT,
             total FLOAT,
 	 				   total_start_time DATETIME
           );
          SQL
    $db.execute <<-SQL
            create table power_meter(
             id INTEGER PRIMARY KEY,
             timestamp DATETIME,
             total FLOAT
           );
          SQL
  end
end

def db_execute sql, data
  3.times {
    begin
      $db.execute sql, data
      break
    rescue SQLite3::BusyException
      STDERR.write "DB busy, skipping data point '#{d.to_s}'\n"
      sleep 1
    end
  }
end

def parse_topic topic
  parts = topic.split "/"
  else
    _, device_name, _, device_location_1, device_location_2, _ = parts
  end
  device_location = [device_location_1, device_location_2]
  return device_name, device_location
end

def parse_message message
  return  JSON.parse message
end

def insert_power device_name, device_location, data
  if data.has_key? "ENERGY"
    timestamp = Time.parse(data["Time"]).utc.to_i
    total_start_time = Time.parse(data["ENERGY"]["TotalStartTime"]).utc.to_i
    db_execute \
      "INSERT INTO power(timestamp, device_name, device_location_primary, device_location_secondary, total, total_start_time) VALUES(?,?,?,?,?,?)", \
      [timestamp, device_name, device_location[0], device_location[1], data["ENERGY"]["Total"], total_start_time]
  end
end

def main
  options = Optimist::options do
    opt :host, "MQTT hostname",         :type => :string, :default => 'localhost', :short => '-h'
    opt :port, "MQTT port",             :type => :int,    :default => 1883,        :short => '-p'
    opt :db,   "SQLite3 database file", :type => :string, :required => true,       :short => '-d'
    opt :log,  "Logfile",               :type => :string, :required => true,       :short => '-l'
  end

  db_open_or_new options[:db]

  $logfile = WriteFile.new options[:log]

  $mqtt_client = MQTT::Client.connect(
    :host => options[:host],
    :port => options[:port],
    :ssl => false)
  $mqtt_client.subscribe '#'

  $mqtt_client.get do |topic,message|
    begin
      puts "#{topic}\t#{message}
      #device_name, device_location = parse_topic topic
      #data = parse_message message
      #insert_power device_name, device_location, data
      #$logfile.write "#{topic}\t#{message}\n"
    rescue => exception
      $logfile.write "[Ignoring]\t#{topic}\t#{message}\n"
    end
  end

  shutdown
end


main