/*

 * Copyright (C) 2014, 2016  J. Ali Harlow <ali@juiblex.co.uk>

 *

 * 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.,

 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */

#include "config.h"

#include <stdlib.h>

#include <string.h>

#include <ctype.h>

#include "razor.h"

#include "razor-internal.h"

#include "uri.h"

static int valid_unicode(unsigned unicode)

{

	/*

	 * Within the U+0000..U+10FFFF range defined by RFC3629

	 * but not in the U+D800..U+DFFF range prohibited in UTF-8.

	 */

	return unicode < 0xD800 || (unicode >= 0xE000 && unicode < 0x110000);

}

char *razor_path_from_parsed_uri(const struct razor_uri *ru,

  struct razor_error **error)

{

	int continuation_bytes = 0;

	char *path, *p, *s, *uri;

	unsigned char c;

	unsigned unicode;

	if (!ru->scheme) {

		uri = razor_uri_recompose(ru);

		razor_set_error(error, RAZOR_GENERAL_ERROR,

				RAZOR_GENERAL_ERROR_BAD_URI, uri,

				"URI does not include a scheme");

		free(uri);

		return NULL;

	}

	if (strcmp(ru->scheme, "file")) {

		uri = razor_uri_recompose(ru);

		razor_set_error(error, RAZOR_GENERAL_ERROR,

				RAZOR_GENERAL_ERROR_UNSUPPORTED_URI, uri,

				"Not a file URI");

		free(uri);

		return NULL;

	}

	if (ru->host && *ru->host && strcmp(ru->host, "localhost") ||

	    ru->userinfo || ru->port) {

		uri = razor_uri_recompose(ru);

		razor_set_error(error, RAZOR_GENERAL_ERROR,

				RAZOR_GENERAL_ERROR_UNSUPPORTED_URI, uri,

				"URI refers to a non-local file");

		free(uri);

		return NULL;

	}

	s = ru->path;

#ifdef MSWIN_API

	/*

	 * Under MS-Windows, a path of /c:/xxx maps to c:/xxx

	 * Note that PathCreateFromUrl converts / to \ as well.

	 */

	if (s[0] == '/' && is_alpha(s[1]) && s[2] == ':' && s[3] == '/')

		s++;

#endif

	p = path = malloc(strlen(s) + 1);

	while (*s) {

		if (*s >= 0x7F || *s < 0x20)

			break;

		else if (*s != '%') {

			if (continuation_bytes)

				break;

			else

				*p++ = *s++;

		} else {

			c = pchar_get_char(s);

#ifdef MSWIN_API

			if (c == '/' || c == '\\')

#else

			if (c == '/')

#endif

				break;

			else if (!continuation_bytes) {

				if (c >= 0xF5 || c == 0xC0 || c == 0xC1)

					break;

				else if (c >= 0xF0) {

					unicode = c & 7;

					continuation_bytes = 3;

				} else if (c >= 0xE0) {

					unicode = c & 3;

					continuation_bytes = 2;

				} else if (c >= 0xC0) {

					unicode = c & 1;

					continuation_bytes = 1;

				}

			} else if ((c & 0xC0) != 0x80)

				break;

			else {

				unicode <<= 6;

				unicode |= (c & 0x3F);

				if (!--continuation_bytes &&

				    !valid_unicode(unicode))

					break;

			}

			*p++ = c;

			s += 3;

		}

	}

	if (*s || continuation_bytes) {

		uri = razor_uri_recompose(ru);

		razor_set_error(error, RAZOR_GENERAL_ERROR,

				RAZOR_GENERAL_ERROR_BAD_URI,

				uri, "Illegal character in file URI path");

		free(uri);

		free(path);

		return NULL;

	}

	*p++ = '\0';

	return realloc(path, p - path);

}

RAZOR_EXPORT char *razor_path_from_uri(const char *uri,

  struct razor_error **error)

{

	struct razor_uri ru;

	char *path;

	if (razor_uri_parse(&ru, uri, error))

		return NULL;

	path = razor_path_from_parsed_uri(&ru, error);

	razor_uri_destroy(&ru);

	return path;

}

RAZOR_EXPORT char *razor_path_to_uri(const char *path)

{

	char *uri, *p;

	uri = malloc(6 + 3 * strlen(path) + 1);

	strcpy(uri, "file:");

	p = uri + 5;

#ifdef MSWIN_API

	/*

	 * Under MS-Windows, c:/xxx maps to a path of /c:/xxx

	 */

	if (is_alpha(path[0]) && path[1] == ':' && path[2] == '/')

		*p++ = '/';

#endif

	while(*path) {

		if (*path == '/' || is_unreserved(*path) ||

		    is_sub_delim(*path) || *path == ':' || *path == '@')

			*p++ = *path;

#ifdef MSWIN_API

		else if (*path == '\\')

			*p++ = '/';

#endif

		else {

			*p++ = '%';

			*p++ = "0123456789ABCDEF"[(*(unsigned char *)path)/16];

			*p++ = "0123456789ABCDEF"[(*(unsigned char *)path)%16];

		}

		path++;

	}

	*p++ = '\0';

	return realloc(uri, p - uri);

}

RAZOR_EXPORT char *

razor_path_relative_to_uri(const char *uri, const char *path,

			   struct razor_error **error)

{

	char *rel_uri, *result;

	/* Strictly wrong if uri isn't a file URI, but probably okay */

	rel_uri = razor_path_to_uri(path);

	result = razor_resolve_uri_root(uri, rel_uri + 5, 1, error);

	free(rel_uri);

	return result;

}