rails smart_link_to highlights itself when the URL matches it's href

smart_link_to.rb

module ApplicationHelper
  
  # `smart_link_to` is an *exact* copy of `link_to`, with some added functionality.
  # I would rather simply call `link_to` and then add in my bits, but I don't know
  # how to proxy `call_to` with the given arguments.
  def smart_link_to(*args, &block)
    
    if block_given?
      options      = args.first || {}
      html_options = args.second
      concat(link_to(capture(&block), options, html_options).html_safe!)
    else
      name         = args.first
      options      = args.second || {}
      html_options = args.third
      
      # Check if a wrapper element should be rendered around the link
      wrap = options[:wrap]
      # Delete wrap option from options so it doesn't affect the rest of the tag...
      options.delete(:wrap) if !wrap.nil?
      
      url = url_for(options)

      if html_options
        html_options = html_options.stringify_keys
        href = html_options['href']
        convert_options_to_javascript!(html_options, url)
        tag_options = tag_options(html_options)
      else
        tag_options = nil
      end
      
      href_attr = "href=\"#{url}\"" unless href
      tag = "<a #{href_attr}#{tag_options}>#{name || url}</a>".html_safe!
      
      # If a wrap was specified, add it to the tag.
      if !wrap.nil?
        tag = "<#{wrap}>" + tag + "</#{wrap}>"
      end
      
      href_value = tag.match(/href="(.*?)"/)[1]
      
      # Check if current request path starts with the rendered href value
      # Unless the rendered href value is "/"
      # Only show "/" link as on if href is exactly "/"
      if (request.path == "/" && href_value =="/") || (href_value != "/" && request.path.starts_with?(tag.match(/href="(.*?)"/)[1]))
        # href and url are equal, add the "on" class to the tag.
        if tag.include?('class="')
          # inject into class attribute
          tag = tag.sub(/(class=")/, '\0on')
        else
          # add class attribute and name
          tag = tag.sub(/>/, ' class="on">')
        end
      end
      
      tag # return the tag
    end
  end
end