class Avatar < ActiveRecord::Base  
  # Image directories
  URL_STUB = "/images/avatars"
  DIRECTORY = File.join("public", "images", "avatars")
  
  def initialize(user, image = nil)
    @user = user
    @image = image
    Dir.mkdir(DIRECTORY) unless File.directory?(DIRECTORY)
  end
  
  def exists?
    File.exists?(File.join(DIRECTORY, filename))
  end

  def exist?
    exists?
  end
  
  def url
    "#{URL_STUB}/#{filename}"
  end
  
  def thumbnail_url
    "#{URL_STUB}/#{thumbnail_name}"
  end

  private
  
  # Return the filename of the main avatar.
  def filename
    "#{@user.screen_name}.png"
  end  
  
  # Return the filename of the avatar thumbnail.
  def thumbnail_name
    "#{@user.screen_name}_thumbnail.png"
  end
  
  # Return the (system-dependent) ImageMagick convert executable.
  def convert
    if ENV["OS"] =~ /Windows/
      # Set this to point to the right Windows directory for ImageMagick.
      "C:\\Program Files\\ImageMagick-6.3.1-Q16\\convert"
    else
      "/usr/bin/convert"
    end
  end
end