#
# sub system_tidy_xhtml($infile,$outfile)
#
# Runs tidy on a XHTML file semi-safely (using a secondary file)
# Converts HTML to XHTML if necessary
#
# Arguments:
#  $htmlfile : The filename to tidy
#
# Global variables:
#   $tidycmd : the location of the tidy executable
#   $tidyconfig : the location of the config file to use
#   $tidyxhtmlerrors : the filename to use to output errors
#   $tidysafety: the safety factor to use
#
# Returns the return value from tidy
# Dies horribly if the return value is unexpected
#
# Expected return codes from tidy:
# 0 - no errors
# 1 - warnings only (leave errorfile)
# 2 - errors (leave errorfile and htmlfile)
#
sub system_tidy_xhtml
{
    my $infile;
    my $outfile;
    my @configopt = ();
    my $retval;

    ($infile,$outfile) = @_;
    die("system_tidy_xhtml called with no input file") if(!$infile);
    die("system_tidy_xhtml called with no output file") if(!$outfile);
    
    @configopt = ('-config',"$datapath/$tidyconfig")
	if(-f "$datapath/$tidyconfig");

    $retval = system($tidycmd,@configopt,
		     '-q','-utf8',
		     '-asxhtml',
		     '--doctype','transitional',
		     '-f',$tidyxhtmlerrors,
		     '-o',$outfile,
		     $infile);

    # Some systems may return a two-byte code, so deal with that first
    if($retval >= 256) { $retval = $retval >> 8 };
    if($retval == 0)
    {
	rename($outfile,$infile) if($tidysafety < 4);
	unlink($tidyxhtmlerrors);
    }
    elsif($retval == 1)
    {
	rename($outfile,$infile) if($tidysafety < 3);
	unlink($tidyxhtmlerrors) if($tidysafety < 2);
    }
    elsif($retval == 2)
    {
	print STDERR "WARNING: Tidy errors encountered.  Check ",$tidyxhtmlerrors,"\n"
	    if($tidysafety > 0);
	unlink($tidyxhtmlerrors) if($tidysafety < 1);
    }
    return $retval;
}