module Hbc
  class DSL
    class License
      # a generic category can always be given as a license, so
      # category names should be given as both key and value
      VALID_LICENSES = {
                         # license         category
                         unknown:       :unknown,

                         other:         :other,

                         closed:        :closed,
                         commercial:    :closed,
                         gratis:        :closed,
                         freemium:      :closed,

                         oss:           :oss,
                         affero:        :oss,
                         apache:        :oss,
                         arphic:        :oss,
                         artistic:      :oss,
                         bsd:           :oss,
                         cc:            :oss,
                         eclipse:       :oss,
                         gpl:           :oss,
                         isc:           :oss,
                         lppl:          :oss,
                         ncsa:          :oss,
                         mit:           :oss,
                         mpl:           :oss,
                         ofl:           :oss,
                         public_domain: :oss,
                         ubuntu_font:   :oss,
                         x11:           :oss,
                       }.freeze

      DEFAULT_LICENSE = :unknown
      DEFAULT_CATEGORY = VALID_LICENSES[DEFAULT_LICENSE]

      attr_reader :value

      def self.check_constants
        categories = Set.new(VALID_LICENSES.values)
        categories.each do |cat|
          next if VALID_LICENSES.key?(cat)
          raise "license category is not a value: '#{@cat.inspect}'"
        end
      end

      def self.category(license)
        VALID_LICENSES.fetch(license, DEFAULT_CATEGORY)
      end

      def initialize(arg)
        @value = arg
        @value = DEFAULT_LICENSE if @value.nil?
        return if VALID_LICENSES.key?(@value)
        raise "invalid license value: '#{@value.inspect}'"
      end

      def category
        self.class.category(@value)
      end

      def to_s
        @value.inspect
      end
    end
  end
end