Example of a Curses colors registry Singleton for IRC

color_registry.rb

# frozen_string_literal: true

require 'curses'
require 'singleton'

module Isene
  class ColorRegistry
    include Singleton

    attr_reader :colors
    attr_reader :pairs
    attr_reader :modified_colors
    attr_reader :modified_pairs
    
    def initialize
      Curses.start_color
      @colors = Array.new(Curses.colors) { [_1, Curses.color_pair(_1)] }
      @pairs = @colors.each_with_index.to_h
      @modified_colors = {}
      @modified_pairs = {}
    end
    
    def init_pair(index, foreground, background)
      return unless Curses.init_pair(index, foreground, background)
      
      pair = [foreground, background]
      @pairs[pair] = index
      @colors[index] = pair
      @modified_pairs[pair] = index
      @modified_colors[index] = pair
    end
    
    def fetch(...) = @pairs.fetch(...)
    def color(index) = @colors[index]
    
    instance.public_methods(false).each do |method_name|
      define_singleton_method(method_name) do |*args, &block|
        instance.public_send(method_name, *args, &block)
      end
    end
  end
end

example.rb

require_relative 'color_registry'

Isene::ColorRegistry.init_pair 255, Curses::COLOR_BLACK, Curses::COLOR_WHITE
Isene::ColorRegistry.fetch [Curses::COLOR_BLACK, Curses::COLOR_WHITE]
#=> 255

Isene::ColorRegistry.modified_pairs
#=> {[0, 7]=>255}

Isene::ColorRegistry.modified_colors
#=> {255=>[0, 7]}