module Hexx

  # A message to be returned by services.
  class Message
    include Comparable

    # @!attribute [r] type
    # The type of the message
    #
    # @example
    #   message = Message.new type: :error, text: "message"
    #   message.type = "error"
    #
    # @return [String] The type of the message.
    attr_reader :type

    # @!attribute [r] text
    # The text of the message
    #
    # @example
    #   message = Message.new type: :error, text: "message"
    #   message.text = "message"
    #
    # @return [String] The text of the message.
    attr_reader :text

    # @!scope class
    # @!method new(options)
    # Constructs the message with type and text.
    #
    # @example
    #   Message.new type: "success", text: "Object created."
    #
    # @param  [Hash] options The list of the message attributes.
    # @option options [String, Symbol] :type The type of the message.
    # @option options [String, Symbol] :text The text of the message.
    # @return [Hexx::Message] The message.

    # @api hide
    def initialize(type:, text:)
      @type, @text = type.to_s, text.to_s
    end

    # Distinguishes two messages by type and text.
    #
    # @example
    #   a = Message.new(type: "a", text: "a")
    #   b = Message.new(type: "a", text: "a")
    #   c = Message.new(type: "b", text: "a")
    #   d = Message.new(type: "a", text: "b")
    #
    #   a == b # => true
    #   a == c # => false
    #   a == d # => false
    #
    # @param [Object] other The object for the comparison.
    # @return [Boolean] The result of the comparison.
    def ==(other)
      return false unless other.is_a? self.class
      [type, text] == [other.type, other.text]
    end

    # Compares messages by type and text.
    #
    # @example
    #   ab = Message.new(type: "a", text: "b")
    #   ba = Message.new(type: "b", text: "a")
    #   ab < ba # => true
    #
    # @param [Object] other The object for the comparison.
    # @return [-1, 0, 1] The result of the comparison if the argument is
    #   comparable with the message.
    # @return [nil] if the result is incomparable with the message.
    def <=>(other)
      fail ArgumentError unless other.is_a? self.class
      [type, text] <=> [other.type, other.text]
    end
  end
end