require "gettext"
require "gettext/cgi"

module CASServer
  include GetText
  bindtextdomain("rubycas-server", :path => File.join(File.dirname(File.expand_path(__FILE__)), "../../locale"))
  
  def service(*a)
    GetText.locale = determine_locale
    #puts GetText.locale.inspect
    super(*a)
  end
  
  def determine_locale

    source = nil
    lang = case
    when !input['lang'].blank?
      source = "'lang' request variable"
      cookies['lang'] = input['lang']
      input['lang']
    when !cookies['lang'].blank?
      source = "'lang' cookie"
      cookies['lang']
    when !@env['HTTP_ACCEPT_LANGUAGE'].blank?
      source = "'HTTP_ACCEPT_LANGUAGE' header"
      lang = @env['HTTP_ACCEPT_LANGUAGE']
    when !@env['HTTP_USER_AGENT'].blank? && @env['HTTP_USER_AGENT'] =~ /[^a-z]([a-z]{2}(-[a-z]{2})?)[^a-z]/i
      source = "'HTTP_USER_AGENT' header"
      $~[1]
    when !$CONF['default_locale'].blank?
      source = "'default_locale' config option"
      $CONF[:default_locale]
    else
      source = "default"
      "en"
    end

    $LOG.debug "Detected locale is #{lang.inspect} (from #{source})"

    lang.gsub!('_','-')
    
    # TODO: Need to confirm that this method of splitting the accepted
    #       language string is correct.
    if lang =~ /[,;\|]/
      langs = lang.split(/[,;\|]/)
    else
      langs = [lang]
    end
    
    # TODO: This method of selecting the desired language might not be
    #       standards-compliant. For example, http://www.w3.org/TR/ltli/
    #       suggests that de-de and de-*-DE might be acceptable identifiers
    #       for selecting various wildcards. The algorithm below does not
    #       currently support anything like this.
    
    available = available_locales
    
    # Try to pick a locale exactly matching the desired identifier, otherwise
    # fall back to locale without region (i.e. given "en-US; de-DE", we would
    # first look for "en-US", then "en", then "de-DE", then "de").
    
    chosen_lang = nil
    langs.each do |l| 
      a = available.find{|a| a == l || a =~ Regexp.new("#{l}-\w*")}
      if a
        chosen_lang = a
        break
      end
    end
    
    chosen_lang = "en" if chosen_lang.blank?

    $LOG.debug "Chosen locale is #{chosen_lang.inspect}"
    
    return chosen_lang
  end
  
  def available_locales
    (Dir.glob(File.join(File.dirname(File.expand_path(__FILE__)), "../../locale/[a-z]*")).map{|path| File.basename(path)} << "en").uniq.collect{|l| l.gsub('_','-')}
  end
end