EGI-FCTF/oneacct_export

require 'erb'
require 'tempfile'
require 'fileutils'
require 'settings'
require 'logger'
require 'output_types'

# Class responsible for writing data into files in specific format
#
# @attr_reader [Hash] data vm data
# @attr_reader [String] output path to the output file
# @attr_reader [any logger] logger
class OneWriter
  include OutputTypes
  APEL_FILENAME_FORMAT = '%014d'

  attr_reader :data, :output, :log

  def initialize(data, file_number, log = Logger.new(STDOUT))
    fail ArgumentError, 'Data and file number cannot be nil' if data.nil? || file_number.nil?

    output_type = Settings.output['output_type']
    @template = OneWriter.template_filename(output_type) if Settings['output']
    fail ArgumentError, "No such file: #{@template}." unless File.exist?(@template)

    @data = data
    @log = log

    filename = file_number.to_s
    filename = APEL_FILENAME_FORMAT % file_number if APEL_OT.include?(output_type)
    @output = "#{Settings.output['output_dir']}/#{filename}"
  end

  # Write data to file in output directory
  def write
    @log.debug('Creating temporary file...')
    tmp = Tempfile.new('oneacct_export')
    @log.debug("Temporary file: '#{tmp.path}' created.")
    @log.debug('Writing to temporary file...')
    write_to_tmp(tmp, fill_template)
    copy_to_output(tmp.path, @output)
  ensure
    tmp.close(true)
  end

  def write_to_tmp(tmp, data)
    tmp.write(data)
    tmp.flush
  end

  def copy_to_output(from, to)
    @log.debug("Copying temporary file into '#{@output}'")
    FileUtils.cp(from, to)
  end

  # Prepare file content according to ERB template
  #
  # @return [String] transformed content
  def fill_template
    @log.debug("Reading erb template from file: '#{@template}'.")
    erb = ERB.new(File.read(@template), nil, '-')
    erb.filename = @template
    erb.result(binding)
  end

  # Load template for data conversion
  #
  # @param [String] template_name name of the template to look for
  def self.template_filename(template_name)
    "#{File.dirname(__FILE__)}/templates/#{template_name}.erb"
  end
end