class Mail::AttachmentsList

def [](index_value)
  if index_value.is_a?(Fixnum)
    self.fetch(index_value)
  else
    self.select { |a| a.filename == index_value }.first
  end
end

def []=(name, value)
  default_values = { :content_type => "#{set_mime_type(name)}; filename=\"#{name}\"",
                     :content_transfer_encoding => 'Base64',
                     :content_disposition => "attachment; filename=\"#{name}\"" }
  if value.is_a?(Hash)
    default_values[:body] = value.delete(:content) if value[:content]
    default_values[:body] = value.delete(:data) if value[:data]
    # Only force encode base64 if the user has not specified an encoding
    if value[:transfer_encoding]
      default_values[:content_transfer_encoding] = value.delete(:transfer_encoding)
    elsif value[:encoding]
      default_values[:content_transfer_encoding] = value.delete(:encoding)
    else
      default_values[:body] = Mail::Encodings::Base64.encode(default_values[:body])
    end
    if value[:mime_type]
      default_values[:content_type] = value.delete(:mime_type)
    end
    hash = default_values.merge(value)
  else
    default_values[:body] = Mail::Encodings::Base64.encode(value)
    hash = default_values
  end
  @parts_list << Part.new(hash)
end

def initialize(parts_list)
  @parts_list = parts_list
  parts_list.map { |p|
    if p.parts.empty?
      p if p.attachment?
    else
      p.attachments
    end
  }.flatten.compact.each { |a| self << a }
  self
end

def set_mime_type(filename)
  # Have to do this because MIME::Types is not Ruby 1.9 safe yet
  if RUBY_VERSION >= '1.9'
    new_file = String.new(filename).force_encoding(Encoding::BINARY)
    ext = new_file.split('.'.force_encoding(Encoding::BINARY)).last
    filename = "file.#{ext}".force_encoding('US-ASCII')
  end
  @mime_type = MIME::Types.type_for(filename).first
end