class Middleman::Extensions::Gzip

def after_build(builder)
  num_threads = 4
  paths = ::Middleman::Util.all_files_under(app.config[:build_dir])
  total_savings = 0
  # Fill a queue with inputs
  in_queue = Queue.new
  paths.each do |path|
    in_queue << path if should_gzip?(path)
  end
  num_paths = in_queue.size
  # Farm out gzip tasks to threads and put the results in in_queue
  out_queue = Queue.new
  num_threads.times.each do
    Thread.new do
      while path = in_queue.pop
        out_queue << gzip_file(path.to_s)
      end
    end
  end
  # Insert a nil for each thread to stop it
  num_threads.times do
    in_queue << nil
  end
  old_locale = I18n.locale
  I18n.locale = :en # use the english localizations for printing out file sizes to make sure the localizations exist
  num_paths.times do
    output_filename, old_size, new_size = out_queue.pop
    next unless output_filename
    total_savings += (old_size - new_size)
    size_change_word = (old_size - new_size) > 0 ? 'smaller' : 'larger'
    builder.trigger :created, "#{output_filename} (#{NumberHelpers.new.number_to_human_size((old_size - new_size).abs)} #{size_change_word})"
  end
  builder.trigger :gzip, '', "Total gzip savings: #{NumberHelpers.new.number_to_human_size(total_savings)}"
  I18n.locale = old_locale
end

def gzip_file(path)
  input_file = File.open(path, 'rb').read
  output_filename = options.overwrite ? path : path + '.gz'
  input_file_time = File.mtime(path)
  # Check if the right file's already there
  if !options.overwrite && File.exist?(output_filename) && File.mtime(output_filename) == input_file_time
    return [nil, nil, nil]
  end
  File.open(output_filename, 'wb') do |f|
    gz = Zlib::GzipWriter.new(f, Zlib::BEST_COMPRESSION)
    gz.mtime = input_file_time.to_i
    gz.write input_file
    gz.close
  end
  # Make the file times match, both for Nginx's gzip_static extension
  # and so we can ID existing files. Also, so even if the GZ files are
  # wiped out by build --clean and recreated, we won't rsync them over
  # again because they'll end up with the same mtime.
  File.utime(File.atime(output_filename), input_file_time, output_filename)
  old_size = File.size(path)
  new_size = File.size(output_filename)
  [output_filename, old_size, new_size]
end

def initialize(app, options_hash={})
  super
  require 'zlib'
  require 'stringio'
  require 'find'
  require 'thread'
end

def should_gzip?(path)
  path = path.sub app.config[:build_dir] + '/', ''
  options.exts.include?(path.extname) && options.ignore.none? { |ignore| Middleman::Util.path_match(ignore, path.to_s) }
end