class RDoc::Markup::ToRdoc

def accept_blank_line blank_line
  @res << "\n"
end

def accept_heading heading
  use_prefix or @res << ' ' * @indent
  @res << @headings[heading.level][0]
  @res << attributes(heading.text)
  @res << @headings[heading.level][1]
  @res << "\n"
end

def accept_list_end list
  @list_index.pop
  @list_type.pop
  @list_width.pop
end

def accept_list_item_end list_item
  width = case @list_type.last
          when :BULLET then
            2
          when :NOTE, :LABEL then
            @res << "\n"
            2
          else
            bullet = @list_index.last.to_s
            @list_index[-1] = @list_index.last.succ
            bullet.length + 2
          end
  @indent -= width
end

def accept_list_item_start list_item
  bullet = case @list_type.last
           when :BULLET then
             '*'
           when :NOTE, :LABEL then
             attributes(list_item.label) + ":\n"
           else
             @list_index.last.to_s + '.'
           end
  case @list_type.last
  when :NOTE, :LABEL then
    @indent += 2
    @prefix = bullet + (' ' * @indent)
  else
    @prefix = (' ' * @indent) + bullet.ljust(bullet.length + 1)
    width = bullet.length + 1
    @indent += width
  end
end

def accept_list_start list
  case list.type
  when :BULLET then
    @list_index << nil
    @list_width << 1
  when :LABEL, :NOTE then
    @list_index << nil
    @list_width << 2
  when :LALPHA then
    @list_index << 'a'
    @list_width << list.items.length.to_s.length
  when :NUMBER then
    @list_index << 1
    @list_width << list.items.length.to_s.length
  when :UALPHA then
    @list_index << 'A'
    @list_width << list.items.length.to_s.length
  else
    raise RDoc::Error, "invalid list type #{list.type}"
  end
  @list_type << list.type
end

def accept_paragraph paragraph
  wrap attributes(paragraph.text)
end

def accept_raw raw
  @res << raw.parts.join("\n")
end

def accept_rule rule
  use_prefix or @res << ' ' * @indent
  @res << '-' * (@width - @indent)
  @res << "\n"
end

def accept_verbatim verbatim
  indent = ' ' * (@indent + 2)
  lines = []
  current_line = []
  # split into lines
  verbatim.parts.each do |part|
    current_line << part
    if part == "\n" then
      lines << current_line
      current_line = []
    end
  end
  lines << current_line unless current_line.empty?
  # calculate margin
  indented = lines.select { |line| line != ["\n"] }
  margin = indented.map { |line| line.first.length }.min
  # flush left
  indented.each { |line| line[0][0...margin] = '' }
  # output
  use_prefix or @res << indent # verbatim is unlikely to have prefix
  @res << lines.shift.join
  lines.each do |line|
    @res << indent unless line == ["\n"]
    @res << line.join
  end
  @res << "\n"
end

def attributes text
  flow = @am.flow text.dup
  convert_flow flow
end

def end_accepting
  @res.join
end

def handle_special_SUPPRESSED_CROSSREF special
  special.text.sub(/\\/, '')
end

def init_tags
  add_tag :BOLD, "<b>", "</b>"
  add_tag :TT,   "<tt>", "</tt>"
  add_tag :EM,   "<em>", "</em>"
end

def initialize
  super
  @markup.add_special(/\\[^\s]/, :SUPPRESSED_CROSSREF)
  @width = 78
  @prefix = ''
  init_tags
  @headings = {}
  @headings.default = []
  @headings[1] = ['= ',      '']
  @headings[2] = ['== ',     '']
  @headings[3] = ['=== ',    '']
  @headings[4] = ['==== ',   '']
  @headings[5] = ['===== ',  '']
  @headings[6] = ['====== ', '']
end

def start_accepting
  @res = [""]
  @indent = 0
  @prefix = nil
  @list_index = []
  @list_type  = []
  @list_width = []
end

def use_prefix
  prefix = @prefix
  @prefix = nil
  @res << prefix if prefix
  prefix
end

def wrap text
  return unless text && !text.empty?
  text_len = @width - @indent
  text_len = 20 if text_len < 20
  re = /^(.{0,#{text_len}})[ \n]/
  next_prefix = ' ' * @indent
  prefix = @prefix || next_prefix
  @prefix = nil
  @res << prefix
  while text.length > text_len
    if text =~ re then
      @res << $1
      text.slice!(0, $&.length)
    else
      @res << text.slice!(0, text_len)
    end
    @res << "\n" << next_prefix
  end
  if text.empty? then
    @res.pop
    @res.pop
  else
    @res << text
    @res << "\n"
  end
end