# coding: utf-8

module ONIX

  # Builds hashes for all code lists in the ONIX spec.
  #
  # Use like so:
  #
  #   ONIX::Lists.list(7)
  #   => { "BB" => "Hardback", ... }
  #
  # There are also some constants for commonly used lists:
  #
  #   ONIX::Lists::PRODUCT_FORM
  #   => { "BB" => "Hardback", ... }
  #
  class Lists
    include Singleton

    # retrieve a hash with the specified code list
    #
    #  ONIX::Lists.list(7)
    #  => { "BB" => "Hardback", ... }
    #
    def self.list(number)
      self.instance.list(number)
    end

    # Shortcut to retrieve a common code list
    #
    def self.audience_code
      self.instance.list(28)
    end

    # Shortcut to retrieve a common code list
    #
    def self.contributor_role
      self.instance.list(17)
    end

    # Shortcut to retrieve a common code list
    #
    def self.country_code
      self.instance.list(91)
    end

    # Shortcut to retrieve a common code list
    #
    def self.language_code
      self.instance.list(74)
    end

    # Shortcut to retrieve a common code list
    #
    def self.language_role
      self.instance.list(22)
    end

    # Shortcut to retrieve a common code list
    #
    def self.notification_type
      self.instance.list(1)
    end

    # Shortcut to retrieve a common code list
    #
    def self.product_availability
      self.instance.list(65)
    end

    # Shortcut to retrieve a common code list
    #
    def self.product_form
      self.instance.list(7)
    end

    # Shortcut to retrieve a common code list
    #
    def self.product_form_detail
      self.instance.list(78)
    end

    # return a hash with the data for a single code list.
    #
    # number should be a fixnum specifying the list to retrieve
    #
    #  ONIX::Lists.instance.list(7)
    #  => { "BB" => "Hardback", ... }
    #
    def list(number)
      cache[number] ||= build_hash(number)
    end

    private

    def build_hash(number)
      val = {}
      data(number).each_line do |line|
        code, desc, ldesc = *line.split("\t")
        code = code.to_i if code.to_s.match(/\d+/)
        val[code] = desc
      end
      val
    end

    def cache
      @cache ||= {}
    end

    def path(number)
      code_dir = File.dirname(__FILE__) + "/../../support/codes"
      filename = number.to_s.rjust(3, "0") + ".tsv"
      File.join(code_dir, filename)
    end

    def data(number)
      File.open(path(number)) { |f| f.read }
    end

    public

    # These are here for backwards compatability with the onix gem <= 0.8.3
    AUDIENCE_CODE        = ONIX::Lists.audience_code
    CONTRIBUTOR_ROLE     = ONIX::Lists.contributor_role
    COUNTRY_CODE         = ONIX::Lists.country_code
    LANGUAGE_CODE        = ONIX::Lists.language_code
    LANGUAGE_ROLE        = ONIX::Lists.language_role
    NOTIFICATION_TYPE    = ONIX::Lists.notification_type
    PRODUCT_AVAILABILITY = ONIX::Lists.product_availability
    PRODUCT_FORM         = ONIX::Lists.product_form
    PRODUCT_FORM_DETAIL  = ONIX::Lists.product_form_detail

  end
end