require 'yaml'

module ReVIEW
  class Catalog
    def initialize(file)
      @yaml = YAML.load(file.read)
      @yaml ||= {}
    end

    def predef
      return "" unless @yaml["PREDEF"]
      @yaml["PREDEF"].join("\n")
    end

    def chaps
      return "" unless @yaml["CHAPS"]

      @yaml["CHAPS"].map {|entry|
        if entry.is_a? String
          entry
        elsif entry.is_a? Hash
          entry.values # chaps in a part
        end
      }.flatten.join("\n")
    end

    def parts
      return "" unless @yaml["CHAPS"]

      @yaml["CHAPS"].map {|entry|
        if entry.is_a? Hash
          entry.keys
        end
      }.flatten.reject{|entry| entry.nil?}.join("\n")
    end

    def parts_with_chaps
      return "" unless @yaml["CHAPS"]
      @yaml["CHAPS"].flatten.reject{|entry| entry.nil?}
    end

    def appendix
      return "" unless @yaml["APPENDIX"]
      @yaml["APPENDIX"].join("\n")
    end

    def postdef
      return "" unless @yaml["POSTDEF"]
      @yaml["POSTDEF"].join("\n")
    end
  end
end