# encoding: utf-8
require "logstash/filters/base"
require 'securerandom'

# This  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 .
class LogStash::Filters::Mask < LogStash::Filters::Base

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

  # Replace the message with this value.
  config :keys_to_mask, :validate => :string, :default => nil
  config :mask_key, :validate => :string, :default => "*****"
  config :message, :validate => :string, :default => "message"

  public
  def register
    # Add instance variables
  end # def register

  public
  def filter(event)
    data = event.get(@message)

    if @keys_to_mask.nil? || @keys_to_mask.empty?
      raise "keys_to_mask missing"
    end
    keys = keys_to_mask.to_s.split(",")
    logs = data['logs']

    mLogs = logs.map do |log|
      # This if condition is to avoid  any boolean or strng type value in array of logs object
      # as it is not a valid values
      if !log.is_a?(FalseClass) && !log.is_a?(TrueClass) && !log.is_a?(String)
        message = log['message']
        if log["mask"] == "maskAll" && log["type"].match(/input|output/)
          log = maskLog(log)
        elsif log["type"].match(/input/)
          log["message"] = maskTokens(keys, message)
        end
        log["uid"] = "log-#{SecureRandom.uuid}"
        log
      end
    end
    mLogs = mLogs.compact
    mLogs.compact
    event.set("message", mLogs)

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

  def maskLog(data)
    if data["type"] == "input"
      data["message"] = "Input data is masked"
    elsif data["type"] == "output"
      data["message"] = "Output data is masked"
    end
    return data
  end

  def maskTokens(keys, message)
    begin
      message = JSON.parse(message)
    rescue
      return message
    end
    for i in keys do
      if !message[i].nil?
        message[i] = mask_key
      end
    end
    return message.to_json
  end
end # class LogStash::Filters::Mask