module MList
  module Util
    
    # Copyright (c) 2004-2008 David Heinemeier Hansson
    #
    # Taken from ActionMailer. Modified to make charset first argument in all
    # signatures, allowing for a consistent pattern of invocation.
    #
    module Quoting #:nodoc:
      # Convert the given text into quoted printable format, with an instruction
      # that the text be eventually interpreted in the given charset.
      def quoted_printable(charset, text)
        text = text.gsub( /[^a-z ]/i ) { quoted_printable_encode($&) }.
                    gsub( / /, "_" )
        "=?#{charset}?Q?#{text}?="
      end

      # Convert the given character to quoted printable format, taking into
      # account multi-byte characters (if executing with $KCODE="u", for instance)
      def quoted_printable_encode(character)
        result = ""
        character.each_byte { |b| result << "=%02x" % b }
        result
      end

      # A quick-and-dirty regexp for determining whether a string contains any
      # characters that need escaping.
      if !defined?(CHARS_NEEDING_QUOTING)
        CHARS_NEEDING_QUOTING = /[\000-\011\013\014\016-\037\177-\377]/
      end

      # Quote the given text if it contains any "illegal" characters
      def quote_if_necessary(charset, text)
        text = text.dup.force_encoding(Encoding::ASCII_8BIT) if text.respond_to?(:force_encoding)

        (text =~ CHARS_NEEDING_QUOTING) ?
          quoted_printable(charset, text) :
          text
      end

      # Quote any of the given strings if they contain any "illegal" characters
      def quote_any_if_necessary(charset, *args)
        args.map { |v| quote_if_necessary(charset, v) }
      end

      # Quote the given address if it needs to be. The address may be a
      # regular email address, or it can be a phrase followed by an address in
      # brackets. The phrase is the only part that will be quoted, and only if
      # it needs to be. This allows extended characters to be used in the
      # "to", "from", "cc", "bcc" and "reply-to" headers.
      def quote_address_if_necessary(charset, address)
        if Array === address
          address.map { |a| quote_address_if_necessary(charset, a) }
        elsif address =~ /^(\S.*)\s+(<.*>)$/
          address = $2
          phrase = quote_if_necessary(charset, $1.gsub(/^['"](.*)['"]$/, '\1'))
          "\"#{phrase}\" #{address}"
        else
          address
        end
      end

      # Quote any of the given addresses, if they need to be.
      def quote_any_address_if_necessary(charset, *args)
        args.map { |v| quote_address_if_necessary(charset, v) }
      end
    end

  end
end