#!/usr/bin/env ruby

require "ulaminate"
require "optparse"
require "chunky_png"

Options = Struct.new(:size)
options = Options.new(7)

OptionParser.new do |parser|
  parser.banner = "Usage: ulaminate [options]"

  parser.on("-h", "--help", "Prints this help") do
    puts parser
    exit
  end

  parser.on("--size SIZE", Integer, "The size of the side of the spiral") do |size|
    options.size = size
  end
end.parse!

png = ChunkyPNG::Image.new(options.size, options.size, ChunkyPNG::Color::WHITE)

begin
  sequence = Ulaminate.ulam_sequence(options.size)

  loop do
    x, y, _, is_prime = sequence.next
    next unless is_prime
    png[x, y] = ChunkyPNG::Color::BLACK
  end
rescue StopIteration
  # swallow sequence end
end

puts png.save("ulam_spiral_#{options.size}.png", :best_compression).path