/*
 * gxpm.c  -- Simple XPath Merge Util
 *	
 * Copyright © 2006-2008  Red Hat, Inc. All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions of the
 * GNU General Public License v.2.  This program is distributed in the hope
 * that it will be useful, but WITHOUT ANY WARRANTY expressed or implied,
 * including the implied warranties 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., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. Any Red Hat
 * trademarks that are incorporated in the source code or documentation are not
 * subject to the GNU General Public License and may only be used or replicated
 * with the express permission of Red Hat, Inc.
 *
 * Red Hat Author(s): Nathan Straz <nstraz@redhat.com>
 */

#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <string.h>
#include <ctype.h>

#include <libxml/parser.h>
#include <libxml/tree.h>
#include <libxml/xpath.h>
#include <libxml/xpathInternals.h>
#include <libxml/xinclude.h>

#include "gxp-int.h"

static void usage(const char *pname);
static int gxpm(char *fn, const char *xpath_query, const char *prefix, xmlDocPtr snip);

int 
main(int argc, char **argv) 
{
	xmlDocPtr snip;
	char *xpath_query = NULL;
	char *prefix = NULL;
	int c;

	while ((c = getopt(argc, argv, "+p:h")) != -1) {
		switch (c) {
			case 'p':
				prefix = strdup(optarg);
				break;
			case 'h':
			case '?':
				usage(argv[0]);
				exit(2);
				break;
		}
	}
	xpath_query = argv[optind];
	if (!xpath_query) {
		fprintf(stderr, "Missing XPath Query\n");
		usage(argv[0]);
		exit(2);
	}

	if (!(snip = xmlReadFd(fileno(stdin), NULL, NULL, 0))) {
		fprintf(stderr, "Failed to parse XML snippet on standard input\n");
		exit(1);
	}

	optind++;
	if (!argv[optind]) {
		/* No files given, filter stdin to stdout */
		gxpm("-", xpath_query, prefix, snip);
	} else {
		/* Rest of the args are the files to change */
#if 0
		if (((argc - optind) > 1) 
		    && (!gxpp_opts.omitfileprefix)) gxpp_opts.addfileprefix = 1;
#endif
		for (c = optind; c < argc; c++) {
			/* Make sure we can write to the file */
			gxpm(argv[c], xpath_query, prefix, snip);
		}
	}
	xmlFreeDoc(snip);
	return 0;
}
	
static int
gxpm(char *fn, const char *xpath_query, const char *prefix, xmlDocPtr snip)
{
	xmlDocPtr doc;
	xmlXPathContextPtr ctx;
	xmlXPathObjectPtr obj;
	int i;

	if (!(doc = xmlParseFile(fn))) {
		fprintf(stderr, "Failed to parse XML file\n");
		exit(1);
	}
	/* xmlXIncludeProcess(doc); */
	ctx = generate_context(doc, prefix);
	obj = xmlXPathEvalExpression((xmlChar *)xpath_query, ctx);
	if (!obj) {
		fprintf(stderr, "XPath expression '%s' did not match in '%s'\n",
				xpath_query, fn);
		exit(1);
	}
	if (obj->type != XPATH_NODESET) {
		fprintf(stderr, "XPath expression '%s' did not match a nodeset.\n", xpath_query);
		exit(1);
	}
	for (i = 0; i < obj->nodesetval->nodeNr; i++) {
		xmlAddChild(obj->nodesetval->nodeTab[i], xmlCopyNode(xmlDocGetRootElement(snip), 1));
	}

	xmlXPathFreeObject(obj);
	xmlXPathFreeContext(ctx);
	xmlSaveFile(fn, doc);

	xmlFreeDoc(doc);

	return 0;
}


static void 
usage(const char *pname)
{
	fprintf(stderr,"%s [OPTION]... XPATH [FILE]... < XML\n", pname);
	fprintf(stderr,"Options:\n"
	               "-p prefix   Set prefix for default namespace\n");
	return;
}