/*
	 Copyright (c) 2003, WebThing Ltd
	 Author: Nick Kew <nick@webthing.com>

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 2 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, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

*/


/* Namespace Handler for XHTML	(http://www.w3.org/1999/xhtml)

   This will process XHTML markup to Appendix-C compatible XHTML that
   can be sent to current and older web browsers as text/html

   * All HTML is written in the default namespace
   * Empty elements end with " />"
   * Substitutes any META element that sets content-type

PURPOSE:
   * Distributed with mod_xmlns as a sample namespace processor
   * May be useful operationally to post-process XHTML that is not
     Appendix-C compliant.

BUGS:
   * If there is a default namespace defined for something other
     than XHTML, it'll get confused.
   * Doesn't reliably support charset declaration in a META element

See the website for details: http://apache.webthing.com/mod_xmlns/

*/
#include "mod_xmlns.h"
#include <http_config.h>
#include <ap_provider.h>

#define F ctx->f
#define BB ctx->bb

#define XHTML10 "http://www.w3.org/1999/xhtml"

static int is_empty(const parsedname* name) {
  const char** p ;
  static const char* empty_elts[] = {
    "br" ,
    "link" ,
    "img" ,
    "hr" ,
    "input" ,
    "meta" ,
    "base" ,
    "area" ,
    "param" ,
    "col" ,
    "frame" ,
    "isindex" ,
    "basefont" ,
    NULL
  } ;
  for ( p = empty_elts ; *p ; ++p )
    if ( ( name->eltlen == strlen(*p) )
	&& !strncmp( *p, name->elt, name->eltlen) )
      return 1 ;
  return 0 ;
}
static apr_status_t hstart(xmlns_public* ctx, const parsedname* name3,
	const xml_char_t** atts) {

  if ( ! strncmp(name3->elt, "meta", 4) ) {
    const xml_char_t** a ;
    for ( a = atts ; *a ; a += 2 )
      if ( !strcasecmp(a[0], "http-equiv")
	&& a[1]
	&& !strcasecmp(a[1], "content-type")
      ) {
	ap_fputs(F, BB, "<meta http-equiv=\"Content-Type\" "
		"content=\"text/html; charset=utf-8\" />") ;
	return APR_SUCCESS ;
      }
  }
  ap_fputc(F, BB, '<') ;
  ap_fwrite(F, BB, name3->elt, name3->eltlen) ;

  if ( atts ) {
    const xml_char_t** a ;
    for ( a = atts ; *a ; a += 2 ) {
	/* Parse the attributes to deal correctly with attributes
	   from other namespaces.
	*/
      parsedname a3 ;
      xmlns_parsename(*a, &a3) ;
      ap_fputc(F, BB, ' ') ;
      switch ( a3.nparts ) {
	case 2:
	  ap_fwrite(F, BB, a3.ns, a3.nslen) ;
	  ap_fputc(F, BB, ':') ;
	  break ;
	case 3:
	  ap_fwrite(F, BB, a3.prefix, a3.prefixlen) ;
	  ap_fputc(F, BB, ':') ;
	  break ;
      }
      ap_fwrite(F, BB, a3.elt, a3.eltlen) ;
      ap_fputstrs(F, BB, "=\"", a[1], "\"", NULL) ;
    }
  }

  if ( !strncmp( "html", name3->elt, 4) )
    ap_fputs(F, BB, " xmlns=\"http://www.w3.org/1999/xhtml\">") ;
  else if ( is_empty(name3) )
    ap_fputs(F, BB, " />") ;
  else
    ap_fputc(F, BB, '>') ;
  return APR_SUCCESS ;
}
static apr_status_t hend(xmlns_public* ctx, const parsedname* name) {
  if ( ! is_empty(name) ) {
    ap_fputs(F, BB, "</") ;
    ap_fwrite(F, BB, name->elt, name->eltlen) ;
    ap_fputc(F, BB, '>') ;
  }
  return APR_SUCCESS ;
}

/* we don't yet implement SSI */
#define CommentStr	NULL
#define hcomment	NULL

static xmlns xmlns_xhtml10 = {
	hstart ,		/* StartElement	*/
	hend ,			/* EndElement	*/
	NULL ,			/* StartNSDecl	*/
	NULL ,			/* EndNSDecl	*/
	CommentStr ,		/* Comment Identifier (should be "#") */
	hcomment		/* Comment Handler */
} ;

static void xhtml_hooks(apr_pool_t* pool) {
  ap_register_provider(pool, "xmlns", XHTML10 , "1.0", &xmlns_xhtml10) ;
}
module AP_MODULE_DECLARE_DATA xhtml_module = {
	STANDARD20_MODULE_STUFF,
	NULL,
	NULL,
	NULL,
	NULL,
	NULL,
	xhtml_hooks
} ;