require 'yajl'

class RuntimeRecorder
  attr_accessor :records

  def initialize(job_state, runtime_filename)
    @records = {}
    @job_state = job_state
    @job_state.add_observer(self)
    @runtime_filename = runtime_filename || ""
  end

  def update payload
    @records[payload[:filename]] = payload[:runtime] if payload[:action] == "finish"
    self.write_records_to_file if @job_state.is_job_complete?
  end

  def write_records_to_file
    return if @runtime_filename.empty?
    make_directories
    @records = Hash[@records.sort_by{|filename, runtime| -1*runtime}]
    File.open(@runtime_filename, 'w') do |f|
      f.write(Yajl::Encoder.encode(@records, pretty: true))
    end
  end


  private

  def make_directories
    dirname = File.dirname(@runtime_filename)
    FileUtils.mkdir_p(dirname) unless File.directory?(dirname)
  end

end