Simple class to generate ANSI Color output

color.rb

# @example basic usage 
#   Color.blue => "\e[1;34m"
# @example chain bold
#   Color.red.bold => "\e[1;31m"
class Color
  NORMAL = 30
  BRIGHT = 90
  BG_DIFF = 10
  CODES = {
    black: 0,
    red: 1,
    green: 2,
    yellow: 3,
    blue: 4,
    magenta: 5,
    cyan: 6,
    white: 7
  }.freeze

  def initialize(code)
    @code = code
    @modifier = nil
  end

  def bold
    @modifier = 1
    self
  end

  def to_s
    modifier = @modifier ? "#{@modifier};" : '' unless @code.zero?
    "\e[#{modifier}#{@code}m"
  end

  def inspect
    "<#{self.class} code=#{@code} mod=#{@modifier.inspect}>"
  end

  define_singleton_method(:reset) { new 0 }

  CODES.each do |color, code|
    define_singleton_method(color) { new(code + NORMAL) }
    define_singleton_method("bright_#{color}") { new(code + BRIGHT) }
    define_singleton_method("bg_#{color}") { new(code + NORMAL + BG_DIFF) }
    define_singleton_method("bg_bright_#{color}") { new(code + BRIGHT + BG_DIFF) }
  end
end