module Vobject

  class Property

    MAX_LINE_WIDTH = 75

    attr_accessor :group, :prop_name, :params, :value

    def initialize key, options
      self.group = options[:group]
      self.prop_name = key
      self.params = options[:params]
      self.value = parse_value(options[:value])

      raise_invalid_initialization if key != name
    end

    def to_s
      line = group ? "#{group}." : ""
      line << "#{name}"

      (params || {}).each do |pname, pvalue|
        pvalue.to_s.gsub!(/\n/, '\n')

        line << ";#{pname}=#{pvalue}"
      end

      line << ":#{value}"

      line = fold_line(line) << "\n"

      line
    end

    private

    def name
      prop_name
    end

    def parse_value value
      parse_method = :"parse_#{value_type}_value"
      parse_method = respond_to?(parse_method, true) ? parse_method : :parse_text_value
      send(parse_method, value)
    end

    def parse_text_value value
      value
    end

    def value_type
      (params || {})[:VALUE] || default_value_type
    end

    def default_value_type
      "text"
    end

    def raise_invalid_initialization
      raise "vObject property initialization failed"
    end

    # This implements the line folding as specified in
    # http://tools.ietf.org/html/rfc6350#section-3.2
    #
    # NOTE: the "line" here is not including the trailing \n
    def fold_line(line)
      folded_line    = line[0, MAX_LINE_WIDTH]
      remainder_line = line[MAX_LINE_WIDTH, line.length - MAX_LINE_WIDTH] || ''

      max_width = MAX_LINE_WIDTH - 1

      for i in 0..((remainder_line.length - 1) / max_width)
        folded_line << "\n "
        folded_line << remainder_line[i * max_width, max_width]
      end

      folded_line
    end

  end

end