require 'vedeu/presentation/presentation'

require 'vedeu/models/view/streams'
require 'vedeu/models/view/stream'

module Vedeu

  # A Line represents a single row of the terminal. It is a container for
  # {Vedeu::Stream} objects. A line's width is determined by the
  # {Vedeu::Interface} it belongs to.
  #
  # @api private
  class Line

    include Vedeu::Model
    include Vedeu::Presentation

    attr_accessor :parent,
      :streams

    alias_method :value, :streams

    class << self

      # @option attributes streams []
      # @option attributes parent []
      # @option attributes colour []
      # @option attributes style []
      # @option attributes client []
      def build(attributes = {}, &block)
        attributes = defaults.merge(attributes)

        model = new(attributes[:streams],
                    attributes[:parent],
                    attributes[:colour],
                    attributes[:style])
        model.deputy(attributes[:client]).instance_eval(&block) if block_given?
        model
      end

      private

      # The default values for a new instance of this class.
      #
      # @return [Hash]
      def defaults
        {
          client:  nil,
          colour:  nil,
          parent:  nil,
          streams: [],
          style:   nil,
        }
      end
    end

    # Returns a new instance of Line.
    #
    # @return [Line]
    def initialize(streams = [], parent = nil, colour = nil, style = nil)
      @colour  = colour
      @parent  = parent
      @streams = streams
      @style   = style
    end

    # @param child []
    # @return []
    def add(child)
      @streams = streams.add(child)
    end

    # Returns an array of all the characters with formatting for this line.
    #
    # @return [Array]
    # @see Vedeu::Stream
    def chars
      return [] if empty?

      streams.map(&:chars).flatten
    end

    # Returns a boolean indicating whether the line has content.
    #
    # @return [Boolean]
    def empty?
      streams.empty?
    end

    # Returns log friendly output.
    #
    # @return [String]
    def inspect
      "<#{self.class.name} (streams:#{streams.size})>"
    end

    # Returns the size of the content in characters without formatting.
    #
    # @return [Fixnum]
    def size
      streams.map(&:size).inject(0, :+) { |sum, x| sum += x }
    end

    # @return [Vedeu::Streams]
    def streams
      children.coerce(@streams, self)
    end

    # Delegate to Vedeu::Interface#width if available.
    #
    # @return [Fixnum]
    def width
      parent.width if parent
    end

    private

    # Return the class name for the children on this model.
    #
    # @return [Class]
    def child
      Vedeu::Stream
    end

    # Return the class name for the children on this model.
    #
    # @return [Class]
    def children
      Vedeu::Streams
    end

  end # Line

end # Vedeu