Modified version of "Rake task to find unused images on a Rails project"

find_unused_images.rake

# Modified version of: https://gist.github.com/rafaelp/4467738
# Uses ACK 2 library and parallalel gem

task :find_unused_images do
  images = Dir.glob(Rails.root.join('app/assets/images/**/*'))
  puts "Images found: #{images.count}"

  images_to_delete = []
  Parallel.each(images, in_threads: 4) do |image|
    unless File.directory?(image)
      puts "Checking #{image}..."
      # print "."

      result = `ack -g -i '(app|public)' | ack -x -w '#{File.basename(image)}'`
      if result.empty?
        images_to_delete << image
      else
      end
    end
  end

  puts "\n\nDelete unused files:"
  images_to_delete.sort.each do |unused_file|
    puts "rm #{unused_file}"
  end
end