# Nick's web site: xhtml_compat filter.  Perform fixups to improve
# XHTML compatibility with various user agents.
#
# Copyright © 2019-2021 Nick Bowler
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

class XhtmlCompatFilter < Nanoc::Filter
    identifier :xhtml_compat

    def run(content, params = {})
        # Old versions of Netscape get confused by <hr/> but have no problem
        # with <hr />, so avoid that by adding spaces to such elements.
        text = content.gsub(/([^[:space:]])\/>/m, '\1 />');

        # Even older versions of Netscape interpret any script as Javascript,
        # which causes major problems with the CDATA hack; solve that by making
        # the whole thing look like a Javascript comment.
        text.gsub!("<![CDATA[]]x><!--]]>", '/*\&')
        text.gsub!("<![CDATA[-->]]>", '\&*/')

        # Delete any zero-width word joiners added for XSLT processing.
        return text.delete "\u2060"
    end
end