module HighLine::StringExtensions

def self.define_style_support_methods(base)
  base.class_eval do
    undef :color if method_defined? :color
    undef :foreground if method_defined? :foreground
    def color(*args)
      self.class.new(HighLine.color(self, *args))
    end
    alias_method :foreground, :color
    undef :on if method_defined? :on
    def on(arg)
      color(("on_" + arg.to_s).to_sym)
    end
    undef :uncolor if method_defined? :uncolor
    def uncolor
      self.class.new(HighLine.uncolor(self))
    end
    undef :rgb if method_defined? :rgb
    def rgb(*colors)
      color_code = setup_color_code(*colors)
      color("rgb_#{color_code}".to_sym)
    end
    undef :on_rgb if method_defined? :on_rgb
    def on_rgb(*colors)
      color_code = setup_color_code(*colors)
      color("on_rgb_#{color_code}".to_sym)
    end
    # @todo Chain existing method_missing?
    undef :method_missing if method_defined? :method_missing
    def method_missing(method, *_args)
      if method.to_s =~ STYLE_METHOD_NAME_PATTERN
        color(method)
      else
        super
      end
    end
    undef :respond_to_missing if method_defined? :respond_to_missing
    def respond_to_missing?(method_name, include_private = false)
      method_name.to_s =~ STYLE_METHOD_NAME_PATTERN || super
    end
    private
    def setup_color_code(*colors)
      color_code = colors.map do |color|
        if color.is_a?(Numeric)
          format("%02x", color)
        else
          color.to_s
        end
      end.join
      raise "Bad RGB color #{colors.inspect}" unless
        color_code =~ /^[a-fA-F0-9]{6}/
      color_code
    end
  end
end