module Middleman::Extensions::SitemapTree::Helpers

def html_sitemap
  sitemap_tree(/\.html$/)
end

def sitemap_tree(regex=nil)
  @sitemap_tree_cache = {}

  key = regex.nil? ? "all" : regex

  if !@sitemap_tree_cache.has_key?(key)
    auto_hash = Hash.new{ |h,k| h[k] = Hash.new &h.default_proc }
    app.sitemap.all_paths.each do |path|
      next if !regex.nil? && !path.match(regex)
      sub = auto_hash
      path.split( "/" ).each{ |dir| sub[dir]; sub = sub[dir] }
    end

    @sitemap_tree_cache[key] = auto_hash
  end

  @sitemap_tree_cache[key]
end