require 'rdoc/markup/to_html'

##
# Subclass of the RDoc::Markup::ToHtml class that supports looking up words in
# the AllReferences list. Those that are found (like AllReferences in this
# comment) will be hyperlinked

class RDoc::Markup::ToHtmlHyperlink < RDoc::Markup::ToHtml

  attr_accessor :context

  ##
  # We need to record the html path of our caller so we can generate
  # correct relative paths for any hyperlinks that we find

  def initialize(from_path, context, show_hash)
    super()

    # class names, variable names, or instance variables
    @markup.add_special(/(
                           # A::B.meth(**) (for operator in Fortran95)
                           \w+(::\w+)*[.\#]\w+(\([\.\w+\*\/\+\-\=\<\>]+\))?
                           # meth(**) (for operator in Fortran95)
                         | \#\w+(\([.\w\*\/\+\-\=\<\>]+\))?
                         | \b([A-Z]\w*(::\w+)*[.\#]\w+)  #    A::B.meth
                         | \b([A-Z]\w+(::\w+)*)          #    A::B
                         | \#\w+[!?=]?                   #    #meth_name
                         | \\?\b\w+([_\/\.]+\w+)*[!?=]?  #    meth_name
                         )/x,
                        :CROSSREF)

    # external hyperlinks
    @markup.add_special(/((link:|https?:|mailto:|ftp:|www\.)\S+\w)/, :HYPERLINK)

    # and links of the form  <text>[<url>]
    @markup.add_special(/(((\{.*?\})|\b\S+?)\[\S+?\.\S+?\])/, :TIDYLINK)

    @from_path = from_path
    @context = context
    @show_hash = show_hash

    @seen = {}
  end

  ##
  # We're invoked when any text matches the CROSSREF pattern
  # (defined in MarkUp). If we fine the corresponding reference,
  # generate a hyperlink. If the name we're looking for contains
  # no punctuation, we look for it up the module/class chain. For
  # example, HyperlinkHtml is found, even without the Generator::
  # prefix, because we look for it in module Generator first.

  def handle_special_CROSSREF(special)
    name = special.text

    return @seen[name] if @seen.include? name

    if name[0,1] == '#' then
      lookup = name[1..-1]
      name = lookup unless @show_hash
    else
      lookup = name
    end

    # Find class, module, or method in class or module.
    if /([A-Z]\w*)[.\#](\w+[!?=]?)/ =~ lookup then
      container = $1
      method = $2
      ref = @context.find_symbol container, method
    elsif /([A-Za-z]\w*)[.\#](\w+(\([\.\w+\*\/\+\-\=\<\>]+\))?)/ =~ lookup then
      container = $1
      method = $2
      ref = @context.find_symbol container, method
    else
      ref = @context.find_symbol lookup
    end

    out = if lookup =~ /^\\/ then
            $'
          elsif ref and ref.document_self then
            "<a href=\"#{ref.as_href(@from_path)}\">#{name}</a>"
          else
            name
          end

    @seen[name] = out

    out
  end

  ##
  # Generate a hyperlink for url, labeled with text. Handle the
  # special cases for img: and link: described under handle_special_HYPEDLINK

  def gen_url(url, text)
    if url =~ /([A-Za-z]+):(.*)/ then
      type = $1
      path = $2
    else
      type = "http"
      path = url
      url  = "http://#{url}"
    end

    if type == "link" then
      url = if path[0, 1] == '#' then # is this meaningful?
              path
            else
              HTML.gen_url @from_path, path
            end
    end

    if (type == "http" or type == "link") and
       url =~ /\.(gif|png|jpg|jpeg|bmp)$/ then
      "<img src=\"#{url}\" />"
    else
      "<a href=\"#{url}\">#{text.sub(%r{^#{type}:/*}, '')}</a>"
    end
  end

  ##
  # And we're invoked with a potential external hyperlink mailto:
  # just gets inserted. http: links are checked to see if they
  # reference an image. If so, that image gets inserted using an
  # <img> tag. Otherwise a conventional <a href> is used.  We also
  # support a special type of hyperlink, link:, which is a reference
  # to a local file whose path is relative to the --op directory.

  def handle_special_HYPERLINK(special)
    url = special.text
    gen_url url, url
  end

  ##
  # Here's a hypedlink where the label is different to the URL
  #  <label>[url]

  def handle_special_TIDYLINK(special)
    text = special.text

    return text unless text =~ /\{(.*?)\}\[(.*?)\]/ or text =~ /(\S+)\[(.*?)\]/

    label = $1
    url   = $2
    gen_url url, label
  end

end