BBC-News/wraith

require "wraith"
require "parallel"
require "fileutils"
require "shellwords"

class Wraith::Thumbnails
  attr_reader :wraith

  def initialize(config)
    @wraith = Wraith::Wraith.new(config)
  end

  def generate_thumbnails
    files = Dir.glob("#{wraith.directory}/*/*.png")

    Parallel.each(files, :in_processes => Parallel.processor_count) do |filename|
      new_name = filename.gsub(/^#{wraith.directory}/, "#{wraith.directory}/thumbnails")
      thumbnail_image(filename, new_name)
    end
  end

  def thumbnail_image(png_path, output_path)
    unless File.directory?(File.dirname(output_path))
      FileUtils.mkdir_p(File.dirname(output_path))
    end

    `convert #{png_path.shellescape} -thumbnail 200 -crop #{wraith.thumb_width.to_s}x#{wraith.thumb_height.to_s}+0+0 #{output_path.shellescape}`
  end
end