class RDoc::Markup::Formatter

def self.gen_relative_url path, target
  from        = File.dirname path
  to, to_file = File.split target
  from = from.split "/"
  to   = to.split "/"
  from.delete '.'
  to.delete '.'
  while from.size > 0 and to.size > 0 and from[0] == to[0] do
    from.shift
    to.shift
  end
  from.fill ".."
  from.concat to
  from << to_file
  File.join(*from)
end

def accept_document document
  document.parts.each do |item|
    case item
    when RDoc::Markup::Document then # HACK
      accept_document item
    else
      item.accept self
    end
  end
end

def add_special_RDOCLINK
  @markup.add_special(/rdoc-[a-z]+:[^\s\]]+/, :RDOCLINK)
end

def add_special_TIDYLINK
  @markup.add_special(/(?:
                        \{.*?\} |    # multi-word label
                        \b[^\s{}]+? # single-word label
                       )
                       \[\S+?\]     # link target
                      /x, :TIDYLINK)
end

def add_tag(name, start, stop)
  attr = @attributes.bitmap_for name
  @attr_tags << InlineTag.new(attr, start, stop)
end

def annotate(tag)
  tag
end

def convert content
  @markup.convert content, self
end

def convert_flow(flow)
  res = []
  flow.each do |item|
    case item
    when String then
      res << convert_string(item)
    when RDoc::Markup::AttrChanger then
      off_tags res, item
      on_tags res, item
    when RDoc::Markup::Special then
      res << convert_special(item)
    else
      raise "Unknown flow element: #{item.inspect}"
    end
  end
  res.join
end

def convert_special special
  return special.text if in_tt?
  handled = false
  @attributes.each_name_of special.type do |name|
    method_name = "handle_special_#{name}"
    if respond_to? method_name then
      special.text = send method_name, special
      handled = true
    end
  end
  unless handled then
    special_name = @attributes.as_string special.type
    raise RDoc::Error, "Unhandled special #{special_name}: #{special}"
  end
  special.text
end

def convert_string string
  string
end

def ignore *node
end

def in_tt?
  @in_tt > 0
end

def initialize options, markup = nil
  @options = options
  @markup = markup || RDoc::Markup.new
  @am     = @markup.attribute_manager
  @am.add_special(/<br>/, :HARD_BREAK)
  @attributes = @am.attributes
  @attr_tags = []
  @in_tt = 0
  @tt_bit = @attributes.bitmap_for :TT
  @hard_break = ''
  @from_path = '.'
end

def off_tags res, item
  attr_mask = item.turn_off
  return if attr_mask.zero?
  @attr_tags.reverse_each do |tag|
    if attr_mask & tag.bit != 0 then
      @in_tt -= 1 if tt? tag
      res << annotate(tag.off)
    end
  end
end

def on_tags res, item
  attr_mask = item.turn_on
  return if attr_mask.zero?
  @attr_tags.each do |tag|
    if attr_mask & tag.bit != 0 then
      res << annotate(tag.on)
      @in_tt += 1 if tt? tag
    end
  end
end

def parse_url url
  case url
  when /^rdoc-label:([^:]*)(?::(.*))?/ then
    scheme = 'link'
    path   = "##{$1}"
    id     = " id=\"#{$2}\"" if $2
  when /([A-Za-z]+):(.*)/ then
    scheme = $1.downcase
    path   = $2
  when /^#/ then
  else
    scheme = 'http'
    path   = url
    url    = url
  end
  if scheme == 'link' then
    url = if path[0, 1] == '#' then # is this meaningful?
            path
          else
            self.class.gen_relative_url @from_path, path
          end
  end
  [scheme, url, id]
end

def tt? tag
  tag.bit == @tt_bit
end