module Colours
  refine String do
    def reset
      ansi(0)
    end

    # FORMATTING

    def bold
      style 1
    end

    def faint
      style 2
    end

    def italic
      style 3
    end

    def underline
      style 4
    end

    # FOREGROUND COLOURS

    def black
      style 30
    end

    def blue
      style 34
    end

    def cyan
      style 36
    end

    def green
      style 32
    end

    def magenta
      style 35
    end

    # TODO: wrong number
    def purple
      style 35
    end

    def red
      style 31
    end

    def white
      style 37
    end

    def yellow
      style 33
    end

    def bright_black
      style 90
    end

    def bright_blue
      style 94
    end

    def bright_cyan
      style 96
    end

    def bright_green
      style 92
    end

    def bright_magenta
      style 95
    end

    def bright_red
      style 91
    end

    def bright_white
      style 97
    end

    def bright_yellow
      style 93
    end

    # BACKGROUND COLOURS

    def bg_black
      style 40
    end

    def bg_blue
      style 44
    end

    def bg_cyan
      style 46
    end

    def bg_green
      style 42
    end

    def bg_magenta
      style 45
    end

    def bg_red
      style 41
    end

    def bg_white
      style 47
    end

    def bg_yellow
      style 43
    end

    # ANSI 256 COLOURS

    def bg(code)
      style "48;5;#{code}"
    end

    def fg(code)
      style "38;5;#{code}"
    end

    # MISC

    def backticks
      backtick + self + backtick
    end

    def near_black
      bg(240)
    end

    private

    def ansi(code)
      "\e[#{code}m"
    end

    def backtick
      '`'.yellow
    end

    def style(code)
      ansi(code) + self + reset
    end
  end

  class Demo

    class << self

      using Colours

      def all_ansi_256
        puts
        display_all_ansi_256('bg')
        puts
        puts
        display_all_ansi_256('fg')
        puts
        puts
        display_all(styles)
        puts
        puts
        display_all(fg_colours)
        puts
        puts
        display_all(bright_colours)
        puts
        puts
        display_all(bg_colours)
        puts
        puts
      end

      private

      def display_all(formats)
        codes_displayed = 1

        formats.each do |method, complementary_method|
          print ".#{method}".ljust(col_width).send(method).send(complementary_method)

          codes_displayed += 1

          if codes_displayed * col_width > screen_width
            puts
            codes_displayed = 1
          end
        end
      end

      def styles
        {
          bold:      :white,
          faint:     :white,
          italic:    :white,
          underline: :white
        }
      end

      def fg_colours
        {
          black:   :near_black,
          blue:    :bg_black,
          cyan:    :bg_black,
          green:   :bg_black,
          magenta: :bg_black,
          red:     :bg_black,
          white:   :bg_black,
          yellow:  :bg_black
        }
      end

      def bright_colours
        {
          bright_black:   :bg_black,
          bright_blue:    :bg_black,
          bright_cyan:    :bg_black,
          bright_green:   :bg_black,
          bright_magenta: :bg_black,
          bright_red:     :bg_black,
          bright_white:   :bg_black,
          bright_yellow:  :bg_black
        }
      end

      def bg_colours
        {
          bg_black:   :white,
          bg_blue:    :black,
          bg_cyan:    :black,
          bg_green:   :black,
          bg_magenta: :black,
          bg_red:     :black,
          bg_white:   :black,
          bg_yellow:  :black
        }
      end

      def display_all_ansi_256(method)
        # Use `Colours::Demo.all_ansi_256` to see colours available

        codes_displayed = 1

        256.times do |code|
          print ".#{method}(#{code})".ljust(col_width).send(method, code).fg(89)

          codes_displayed += 1

          if codes_displayed * col_width + 2 > screen_width
            puts
            codes_displayed = 1
          end
        end
      end

      def col_width
        @col_width ||= '.bright_magenta  '.length
      end

      def screen_width
        @screen_width ||= `tput cols`.to_i
      end

    end

  end
end