# encoding: utf-8
require "logstash/filters/base"
require "logstash/namespace"
require "base62-rb"

# This example filter will replace the contents of the default
# message field with whatever you specify in the configuration.
#
# It is only intended to be used as an example.
class LogStash::Filters::Kannel < LogStash::Filters::Base

  # Setting the config_name here is required. This is how you
  # configure this filter from your Logstash config.
  #
  # filter {
  #   kannel {
  #     message => "My message..."
  #   }
  # }
  #
  config_name "kannel"

  # Replace the message with this value.
  config :message, :validate => :string, :default => "Hello World!"

  public
  def register
    # Add instance variables
  end # def register

  public
  def filter(event)

    if @message
      dec = self.get_campaign_id("RTDM aaaSd2.P.f1", "Receive SMS")

      # using the event.set API
      event.set("message", dec)

      # correct debugging log statement for reference
      # using the event.get API
      @logger.debug? && @logger.debug("Message is now: #{event.get("message")}")
    end

    # filter_matched should go in the last line of our successful code
    filter_matched(event)
  end # def filter

  public
  def is_printable(str)
    return str.match(/^[\x20-\x7E]*$/)
  end

  public
  def get_campaign_id(text, action)
    if action == "Receive SMS"
        if is_printable(text)
            if text != "ACTIM3GP"
                if match = text.match(/^(?<keyword>[a-zA-Z0-9]+ )?(?<base62>[a-zA-Z0-9]+).*$/)
                  keyword, base62 = match.captures
                  return Base62.decode(base62)
                end
            end
        end
    end
    return 0
  end

end