=begin
  locale/driver/cgi.rb 

  Copyright (C) 2002-2008  Masao Mutoh

  You may redistribute it and/or modify it under the same
  license terms as Ruby.

  Original: Ruby-GetText-Package-1.92.0.

  $Id: cgi.rb 27 2008-12-03 15:06:50Z mutoh $
=end

module Locale
  # Locale::Driver module for CGI.
  # Detect the user locales and the charset from CGI parameters.
  # This is a low-level class. Application shouldn't use this directly.
  module Driver
    module CGI
      $stderr.puts self.name + " is loaded." if $DEBUG

      module_function
      # Gets required locales from CGI parameters. (Based on RFC2616)
      #
      # Returns: An Array of Locale::Tag's subclasses
      #          (QUERY_STRING "lang" > COOKIE "lang" > HTTP_ACCEPT_LANGUAGE > "en")
      # 
      def locales
        req = Thread.current[:current_request]
        return nil unless req

        locales = []

        # QUERY_STRING "lang"
        if langs = req[:query_langs]
          langs.each do |lang|
            locales << Locale::Tag.parse(lang)
          end
        end

        unless locales.size > 0
          # COOKIE "lang"
          if langs = req[:cookie_langs]
            langs.each do |lang|
              locales << Locale::Tag.parse(lang) if lang.size > 0
            end
          end
        end

        unless locales.size > 0
          # HTTP_ACCEPT_LANGUAGE
          if lang = req[:accept_language] and lang.size > 0
            locales += lang.gsub(/\s/, "").split(/,/).map{|v| v.split(";q=")}.map{|j| [j[0], j[1] ? j[1].to_f : 1.0]}.sort{|a,b| -(a[1] <=> b[1])}.map{|v| Locale::Tag.parse(v[0])}
          end
        end

        locales.size > 0 ? Locale::TagList.new(locales.uniq) : nil
      end

      # Gets the charset from CGI parameters. (Based on RFC2616)
      #  * Returns: the charset (HTTP_ACCEPT_CHARSET or nil).
     def charset
       req = Thread.current[:current_request]
       return nil unless req

       charsets = req[:accept_charset]
       if charsets and charsets.size > 0
         num = charsets.index(',')
         charset = num ? charsets[0, num] : charsets
         charset = nil if charset == "*"
       else
         charset = nil
       end
       charset
     end

     # Set a request.
     # 
     # * query_langs: An Array of QUERY_STRING value "lang".
     # * cookie_langs: An Array of cookie value "lang".
     # * accept_language: The value of HTTP_ACCEPT_LANGUAGE
     # * accept_charset: The value of HTTP_ACCEPT_CHARSET
     def set_request(query_langs, cookie_langs, accept_language, accept_charset)
       Thread.current[:current_request] = {
         :query_langs => query_langs, 
         :cookie_langs => cookie_langs, 
         :accept_language => accept_language,
         :accept_charset => accept_charset
       }
       self
     end

     # Clear the current request.
     def clear_current_request
       Thread.current[:current_request] = nil
     end
    end
  end

  @@locale_driver_module = Driver::CGI
  
  module_function
  # Sets a request values for lang/charset.
  #
  # * query_langs: An Array of QUERY_STRING value "lang".
  # * cookie_langs: An Array of cookie value "lang".
  # * accept_language: The value of HTTP_ACCEPT_LANGUAGE
  # * accept_charset: The value of HTTP_ACCEPT_CHARSET
  def set_request(query_langs, cookie_langs, accept_language, accept_charset)
    @@locale_driver_module.set_request(query_langs, cookie_langs, accept_language, accept_charset)
    self
  end

  # Sets a CGI object. This is the convenient function of set_request().
  #
  # This method is appeared when Locale.init(:driver => :cgi) is called.
  #
  # * cgi: CGI object
  # * Returns: self
  def set_cgi(cgi)
    set_request(cgi.params["lang"], cgi.cookies["lang"],
                cgi.accept_language, cgi.accept_charset)
    self
  end
  
  # Sets a CGI object.This is the convenient function of set_request().
  #
  # This method is appeared when Locale.init(:driver => :cgi) is called.
  #
  # * cgi: CGI object
  # * Returns: cgi 
  def cgi=(cgi)
    set_cgi(cgi)
    cgi
  end
end