module AASM
  class Localizer
    def human_event_name(klass, event)
      checklist = ancestors_list(klass).inject([]) do |list, ancestor|
        list << :"#{i18n_scope(klass)}.events.#{i18n_klass(ancestor)}.#{event}"
        list
      end
      translate_queue(checklist) || I18n.translate(checklist.shift, :default => event.to_s.humanize)
    end

    def human_state_name(klass, state)
      checklist = ancestors_list(klass).inject([]) do |list, ancestor|
        list << item_for(klass, state, ancestor)
        list << item_for(klass, state, ancestor, :old_style => true)
        list
      end
      translate_queue(checklist) || I18n.translate(checklist.shift, :default => state.to_s.humanize)
    end

  private

    def item_for(klass, state, ancestor, options={})
      separator = options[:old_style] ? '.' : '/'
      :"#{i18n_scope(klass)}.attributes.#{i18n_klass(ancestor)}.#{klass.aasm(state.state_machine.name).attribute_name}#{separator}#{state}"
    end

    def translate_queue(checklist)
      (0...(checklist.size-1)).each do |i|
        begin
          return I18n.translate(checklist.shift, :raise => true)
        rescue I18n::MissingTranslationData
          # that's okay
        end
      end
      nil
    end

    # added for rails 2.x compatibility
    def i18n_scope(klass)
      klass.respond_to?(:i18n_scope) ? klass.i18n_scope : :activerecord
    end

    # added for rails < 3.0.3 compatibility
    def i18n_klass(klass)
      klass.model_name.respond_to?(:i18n_key) ? klass.model_name.i18n_key : klass.name.underscore
    end

    def ancestors_list(klass)
      klass.ancestors.select do |ancestor|
        ancestor.respond_to?(:model_name) unless ancestor.name == 'ActiveRecord::Base'
      end
    end
  end
end # AASM