class RDoc::Markup::PreProcess

def self.post_process &block
  @post_processors << block
end

def self.post_processors
  @post_processors
end

def self.register directive, &block
  @registered[directive] = block
end

def self.registered
  @registered
end

def self.reset
  @post_processors = []
  @registered = {}
end

def find_include_file(name)
  to_search = [File.dirname(@input_file_name)].concat @include_path
  to_search.each do |dir|
    full_name = File.join(dir, name)
    stat = File.stat(full_name) rescue next
    return full_name if stat.readable?
  end
  nil
end

def handle text, code_object = nil, &block
  first_line = 1
  if RDoc::Comment === text then
    comment = text
    text = text.text
    first_line = comment.line || 1
  end
  # regexp helper (square brackets for optional)
  # $1      $2  $3        $4      $5
  # [prefix][\]:directive:[spaces][param]newline
  text = text.lines.map.with_index(first_line) do |line, num|
    next line unless line =~ /\A([ \t]*(?:#|\/?\*)?[ \t]*)(\\?):([\w-]+):([ \t]*)(.+)?(\r?\n|$)/
    # skip something like ':toto::'
    next $& if $4.empty? and $5 and $5[0, 1] == ':'
    # skip if escaped
    next "#$1:#$3:#$4#$5\n" unless $2.empty?
    # This is not in handle_directive because I didn't want to pass another
    # argument into it
    if comment and $3 == 'markup' then
      next "#{$1.strip}\n" unless $5
      comment.format = $5.downcase
      next "#{$1.strip}\n"
    end
    handle_directive $1, $3, $5, code_object, text.encoding, num, &block
  end.join
  if comment then
    comment.text = text
  else
    comment = text
  end
  self.class.post_processors.each do |handler|
    handler.call comment, code_object
  end
  text
end

def handle_directive prefix, directive, param, code_object = nil,
                     encoding = nil, line = nil
  blankline = "#{prefix.strip}\n"
  directive = directive.downcase
  case directive
  when 'arg', 'args' then
    return "#{prefix}:#{directive}: #{param}\n" unless code_object && code_object.kind_of?(RDoc::AnyMethod)
    code_object.params = param
    blankline
  when 'category' then
    if RDoc::Context === code_object then
      section = code_object.add_section param
      code_object.temporary_section = section
    elsif RDoc::AnyMethod === code_object then
      code_object.section_title = param
    end
    blankline # ignore category if we're not on an RDoc::Context
  when 'doc' then
    return blankline unless code_object
    code_object.document_self = true
    code_object.force_documentation = true
    blankline
  when 'enddoc' then
    return blankline unless code_object
    code_object.done_documenting = true
    blankline
  when 'include' then
    filename = param.split(' ', 2).first
    include_file filename, prefix, encoding
  when 'main' then
    @options.main_page = param if @options.respond_to? :main_page
    warn <<~MSG
      The :main: directive is deprecated and will be removed in RDoc 7.
      You can use these options to specify the initial page displayed instead:
      - `--main=#{param}` via the command line
      - `rdoc.main = "#{param}"` if you use `RDoc::Task`
      - `main_page: #{param}` in your `.rdoc_options` file
    MSG
    blankline
  when 'nodoc' then
    return blankline unless code_object
    code_object.document_self = nil # notify nodoc
    code_object.document_children = param !~ /all/i
    blankline
  when 'notnew', 'not_new', 'not-new' then
    return blankline unless RDoc::AnyMethod === code_object
    code_object.dont_rename_initialize = true
    blankline
  when 'startdoc' then
    return blankline unless code_object
    code_object.start_doc
    code_object.force_documentation = true
    blankline
  when 'stopdoc' then
    return blankline unless code_object
    code_object.stop_doc
    blankline
  when 'title' then
    @options.default_title = param if @options.respond_to? :default_title=
    warn <<~MSG
      The :title: directive is deprecated and will be removed in RDoc 7.
      You can use these options to specify the title displayed instead:
      - `--title=#{param}` via the command line
      - `rdoc.title = "#{param}"` if you use `RDoc::Task`
      - `title: #{param}` in your `.rdoc_options` file
    MSG
    blankline
  when 'yield', 'yields' then
    return blankline unless code_object
    # remove parameter &block
    code_object.params = code_object.params.sub(/,?\s*&\w+/, '') if code_object.params
    code_object.block_params = param || ''
    blankline
  else
    result = yield directive, param, line if block_given?
    case result
    when nil then
      code_object.metadata[directive] = param if code_object
      if RDoc::Markup::PreProcess.registered.include? directive then
        handler = RDoc::Markup::PreProcess.registered[directive]
        result = handler.call directive, param if handler
      else
        result = "#{prefix}:#{directive}: #{param}\n"
      end
    when false then
      result = "#{prefix}:#{directive}: #{param}\n"
    end
    result
  end
end

def include_file name, indent, encoding
  full_name = find_include_file name
  unless full_name then
    warn "Couldn't find file to include '#{name}' from #{@input_file_name}"
    return ''
  end
  content = RDoc::Encoding.read_file full_name, encoding, true
  content = RDoc::Encoding.remove_magic_comment content
  # strip magic comment
  content = content.sub(/\A# .*coding[=:].*$/, '').lstrip
  # strip leading '#'s, but only if all lines start with them
  if content =~ /^[^#]/ then
    content.gsub(/^/, indent)
  else
    content.gsub(/^#?/, indent)
  end
end

def initialize(input_file_name, include_path)
  @input_file_name = input_file_name
  @include_path = include_path
  @options = nil
end