/*
 * Copyright 2011 Michael Drake <tlsa@netsurf-browser.org>
 *
 * This file is part of NetSurf, http://www.netsurf-browser.org/
 *
 * NetSurf 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; version 2 of the License.
 *
 * NetSurf 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 <http://www.gnu.org/licenses/>.
 */

/**
 * \file
 * NetSurf URL handling implementation.
 *
 * This is the common implementation of all URL handling within the
 * browser. This implementation is based upon RFC3986 although this has
 * been superceeded by https://url.spec.whatwg.org/ which is based on
 * actual contemporary implementations.
 *
 * Care must be taken with character encodings within this module as
 * the specifications work with specific ascii ranges and must not be
 * affected by locale. Hence the c library character type functions
 * are not used.
 */

#include <assert.h>
#include <libwapcaplet/libwapcaplet.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>

#include "utils/ascii.h"
#include "utils/corestrings.h"
#include "utils/errors.h"
#include "utils/idna.h"
#include "utils/log.h"
#include "utils/nsurl/private.h"
#include "utils/nsurl.h"
#include "utils/utils.h"


/**
 * Compare two component values.
 *
 * Sets match to false if the components are not the same.
 * Does nothing if the components are the same, so ensure match is
 * preset to true.
 */
#define nsurl__component_compare(c1, c2, match)	      		\
	if (c1 && c2 && lwc_error_ok ==				\
			lwc_string_isequal(c1, c2, match)) {	\
		/* do nothing */                                \
	} else if (c1 || c2) {					\
		*match = false;					\
	}



/******************************************************************************
 * NetSurf URL Public API                                                     *
 ******************************************************************************/

/* exported interface, documented in nsurl.h */
nsurl *nsurl_ref(nsurl *url)
{
	assert(url != NULL);

	url->count++;

	return url;
}


/* exported interface, documented in nsurl.h */
void nsurl_unref(nsurl *url)
{
	assert(url != NULL);
	assert(url->count > 0);

	if (--url->count > 0)
		return;

#ifdef NSURL_DEBUG
	nsurl__dump(url);
#endif

	/* Release lwc strings */
	nsurl__components_destroy(&url->components);

	/* Free the NetSurf URL */
	free(url);
}


/* exported interface, documented in nsurl.h */
bool nsurl_compare(const nsurl *url1, const nsurl *url2, nsurl_component parts)
{
	bool match = true;

	assert(url1 != NULL);
	assert(url2 != NULL);

	/* Compare URL components */

	/* Path, host and query first, since they're most likely to differ */

	if (parts & NSURL_PATH) {
		nsurl__component_compare(url1->components.path,
				url2->components.path, &match);

		if (match == false)
			return false;
	}

	if (parts & NSURL_HOST) {
		nsurl__component_compare(url1->components.host,
				url2->components.host, &match);

		if (match == false)
			return false;
	}

	if (parts & NSURL_QUERY) {
		nsurl__component_compare(url1->components.query,
				url2->components.query, &match);

		if (match == false)
			return false;
	}

	if (parts & NSURL_SCHEME) {
		nsurl__component_compare(url1->components.scheme,
				url2->components.scheme, &match);

		if (match == false)
			return false;
	}

	if (parts & NSURL_USERNAME) {
		nsurl__component_compare(url1->components.username,
				url2->components.username, &match);

		if (match == false)
			return false;
	}

	if (parts & NSURL_PASSWORD) {
		nsurl__component_compare(url1->components.password,
				url2->components.password, &match);

		if (match == false)
			return false;
	}

	if (parts & NSURL_PORT) {
		nsurl__component_compare(url1->components.port,
				url2->components.port, &match);

		if (match == false)
			return false;
	}

	if (parts & NSURL_FRAGMENT) {
		nsurl__component_compare(url1->components.fragment,
				url2->components.fragment, &match);

		if (match == false)
			return false;
	}

	return true;
}


/* exported interface, documented in nsurl.h */
nserror nsurl_get(const nsurl *url, nsurl_component parts,
		char **url_s, size_t *url_l)
{
	assert(url != NULL);

	return nsurl__components_to_string(&(url->components), parts, 0,
			url_s, url_l);
}


/* exported interface, documented in nsurl.h */
lwc_string *nsurl_get_component(const nsurl *url, nsurl_component part)
{
	assert(url != NULL);

	switch (part) {
	case NSURL_SCHEME:
		return (url->components.scheme != NULL) ?
				lwc_string_ref(url->components.scheme) : NULL;

	case NSURL_USERNAME:
		return (url->components.username != NULL) ?
				lwc_string_ref(url->components.username) : NULL;

	case NSURL_PASSWORD:
		return (url->components.password != NULL) ?
				lwc_string_ref(url->components.password) : NULL;

	case NSURL_HOST:
		return (url->components.host != NULL) ?
				lwc_string_ref(url->components.host) : NULL;

	case NSURL_PORT:
		return (url->components.port != NULL) ?
				lwc_string_ref(url->components.port) : NULL;

	case NSURL_PATH:
		return (url->components.path != NULL) ?
				lwc_string_ref(url->components.path) : NULL;

	case NSURL_QUERY:
		return (url->components.query != NULL) ?
				lwc_string_ref(url->components.query) : NULL;

	case NSURL_FRAGMENT:
		return (url->components.fragment != NULL) ?
				lwc_string_ref(url->components.fragment) : NULL;

	default:
		LOG("Unsupported value passed to part param.");
		assert(0);
	}

	return NULL;
}


/* exported interface, documented in nsurl.h */
bool nsurl_has_component(const nsurl *url, nsurl_component part)
{
	assert(url != NULL);

	switch (part) {
	case NSURL_SCHEME:
		if (url->components.scheme != NULL)
			return true;
		else
			return false;

	case NSURL_CREDENTIALS:
		/* Only username required for credentials section */
		/* Fall through */
	case NSURL_USERNAME:
		if (url->components.username != NULL)
			return true;
		else
			return false;

	case NSURL_PASSWORD:
		if (url->components.password != NULL)
			return true;
		else
			return false;

	case NSURL_HOST:
		if (url->components.host != NULL)
			return true;
		else
			return false;

	case NSURL_PORT:
		if (url->components.port != NULL)
			return true;
		else
			return false;

	case NSURL_PATH:
		if (url->components.path != NULL)
			return true;
		else
			return false;

	case NSURL_QUERY:
		if (url->components.query != NULL)
			return true;
		else
			return false;

	case NSURL_FRAGMENT:
		if (url->components.fragment != NULL)
			return true;
		else
			return false;

	default:
		LOG("Unsupported value passed to part param.");
		assert(0);
	}

	return false;
}


/* exported interface, documented in nsurl.h */
const char *nsurl_access(const nsurl *url)
{
	assert(url != NULL);

	return url->string;
}


/* exported interface, documented in nsurl.h */
nserror nsurl_get_utf8(const nsurl *url, char **url_s, size_t *url_l)
{
	nserror err;
	lwc_string *host;
	char *idna_host = NULL;
	size_t idna_host_len;
	char *scheme = NULL;
	size_t scheme_len;
	char *path = NULL;
	size_t path_len;

	assert(url != NULL);

	if (url->components.host == NULL) {
		return nsurl_get(url, NSURL_WITH_FRAGMENT, url_s, url_l);
	}

	host = url->components.host;
	err = idna_decode(lwc_string_data(host), lwc_string_length(host),
			&idna_host, &idna_host_len);
	if (err != NSERROR_OK) {
		goto cleanup;
	}

	err = nsurl_get(url,
			NSURL_SCHEME | NSURL_CREDENTIALS,
			&scheme, &scheme_len);
	if (err != NSERROR_OK) {
		goto cleanup;
	}

	err = nsurl_get(url,
			NSURL_PORT | NSURL_PATH | NSURL_QUERY | NSURL_FRAGMENT,
			&path, &path_len);
	if (err != NSERROR_OK) {
		goto cleanup;
	}

	*url_l = scheme_len + idna_host_len + path_len + 1; /* +1 for \0 */
	*url_s = malloc(*url_l); 

	if (*url_s == NULL) {
		err = NSERROR_NOMEM;
		goto cleanup;
	}

	snprintf(*url_s, *url_l, "%s%s%s", scheme, idna_host, path);

	err = NSERROR_OK;

cleanup:
	free(idna_host);
	free(scheme);
	free(path);

	return err;
}


/* exported interface, documented in nsurl.h */
const char *nsurl_access_leaf(const nsurl *url)
{
	size_t path_len;
	const char *path;
	const char *leaf;

	assert(url != NULL);

	if (url->components.path == NULL)
		return "";

	path = lwc_string_data(url->components.path);
	path_len = lwc_string_length(url->components.path);

	if (path_len == 0)
		return "";

	if (path_len == 1 && *path == '/')
		return "/";

	leaf = path + path_len;

	do {
		leaf--;
	} while ((leaf != path) && (*leaf != '/'));

	if (*leaf == '/')
		leaf++;

	return leaf;
}


/* exported interface, documented in nsurl.h */
size_t nsurl_length(const nsurl *url)
{
	assert(url != NULL);

	return url->length;
}


/* exported interface, documented in nsurl.h */
uint32_t nsurl_hash(const nsurl *url)
{
	assert(url != NULL);

	return url->hash;
}


/* exported interface, documented in nsurl.h */
nserror nsurl_defragment(const nsurl *url, nsurl **no_frag)
{
	size_t length;
	char *pos;

	assert(url != NULL);

	/* check for source url having no fragment already */
	if (url->components.fragment == NULL) {
		*no_frag = (nsurl *)url;

		(*no_frag)->count++;

		return NSERROR_OK;
	}

	/* Find the change in length from url to new_url */
	length = url->length;
	if (url->components.fragment != NULL) {
		length -= 1 + lwc_string_length(url->components.fragment);
	}

	/* Create NetSurf URL object */
	*no_frag = malloc(sizeof(nsurl) + length + 1); /* Add 1 for \0 */
	if (*no_frag == NULL) {
		return NSERROR_NOMEM;
	}

	/* Copy components */
	(*no_frag)->components.scheme =
			nsurl__component_copy(url->components.scheme);
	(*no_frag)->components.username =
			nsurl__component_copy(url->components.username);
	(*no_frag)->components.password =
			nsurl__component_copy(url->components.password);
	(*no_frag)->components.host =
			nsurl__component_copy(url->components.host);
	(*no_frag)->components.port =
			nsurl__component_copy(url->components.port);
	(*no_frag)->components.path =
			nsurl__component_copy(url->components.path);
	(*no_frag)->components.query =
			nsurl__component_copy(url->components.query);
	(*no_frag)->components.fragment = NULL;

	(*no_frag)->components.scheme_type = url->components.scheme_type;

	(*no_frag)->length = length;

	/* Fill out the url string */
	pos = (*no_frag)->string;
	memcpy(pos, url->string, length);
	pos += length;
	*pos = '\0';

	/* Get the nsurl's hash */
	nsurl__calc_hash(*no_frag);

	/* Give the URL a reference */
	(*no_frag)->count = 1;

	return NSERROR_OK;
}


/* exported interface, documented in nsurl.h */
nserror nsurl_refragment(const nsurl *url, lwc_string *frag, nsurl **new_url)
{
	int frag_len;
	int base_len;
	char *pos;
	size_t len;

	assert(url != NULL);
	assert(frag != NULL);

	/* Find the change in length from url to new_url */
	base_len = url->length;
	if (url->components.fragment != NULL) {
		base_len -= 1 + lwc_string_length(url->components.fragment);
	}
	frag_len = lwc_string_length(frag);

	/* Set new_url's length */
	len = base_len + 1 /* # */ + frag_len;

	/* Create NetSurf URL object */
	*new_url = malloc(sizeof(nsurl) + len + 1); /* Add 1 for \0 */
	if (*new_url == NULL) {
		return NSERROR_NOMEM;
	}

	(*new_url)->length = len;

	/* Set string */
	pos = (*new_url)->string;
	memcpy(pos, url->string, base_len);
	pos += base_len;
	*pos = '#';
	memcpy(++pos, lwc_string_data(frag), frag_len);
	pos += frag_len;
	*pos = '\0';

	/* Copy components */
	(*new_url)->components.scheme =
			nsurl__component_copy(url->components.scheme);
	(*new_url)->components.username =
			nsurl__component_copy(url->components.username);
	(*new_url)->components.password =
			nsurl__component_copy(url->components.password);
	(*new_url)->components.host =
			nsurl__component_copy(url->components.host);
	(*new_url)->components.port =
			nsurl__component_copy(url->components.port);
	(*new_url)->components.path =
			nsurl__component_copy(url->components.path);
	(*new_url)->components.query =
			nsurl__component_copy(url->components.query);
	(*new_url)->components.fragment =
			lwc_string_ref(frag);

	(*new_url)->components.scheme_type = url->components.scheme_type;

	/* Get the nsurl's hash */
	nsurl__calc_hash(*new_url);

	/* Give the URL a reference */
	(*new_url)->count = 1;

	return NSERROR_OK;
}


/* exported interface, documented in nsurl.h */
nserror nsurl_replace_query(const nsurl *url, const char *query,
		nsurl **new_url)
{
	int query_len;		/* Length of new query string, including '?' */
	int frag_len = 0;	/* Length of fragment, including '#' */
	int base_len;		/* Length of URL up to start of query */
	char *pos;
	size_t len;
	lwc_string *lwc_query;

	assert(url != NULL);
	assert(query != NULL);
	assert(query[0] == '?');

	/* Get the length of the new query */
	query_len = strlen(query);

	/* Find the change in length from url to new_url */
	base_len = url->length;
	if (url->components.query != NULL) {
		base_len -= lwc_string_length(url->components.query);
	}
	if (url->components.fragment != NULL) {
		frag_len = 1 + lwc_string_length(url->components.fragment);
		base_len -= frag_len;
	}

	/* Set new_url's length */
	len = base_len + query_len + frag_len;

	/* Create NetSurf URL object */
	*new_url = malloc(sizeof(nsurl) + len + 1); /* Add 1 for \0 */
	if (*new_url == NULL) {
		return NSERROR_NOMEM;
	}

	if (lwc_intern_string(query, query_len, &lwc_query) != lwc_error_ok) {
		free(*new_url);
		return NSERROR_NOMEM;
	}

	(*new_url)->length = len;

	/* Set string */
	pos = (*new_url)->string;
	memcpy(pos, url->string, base_len);
	pos += base_len;
	memcpy(pos, query, query_len);
	pos += query_len;
	if (url->components.fragment != NULL) {
		const char *frag = lwc_string_data(url->components.fragment);
		*pos = '#';
		memcpy(++pos, frag, frag_len - 1);
		pos += frag_len - 1;
	}
	*pos = '\0';

	/* Copy components */
	(*new_url)->components.scheme =
			nsurl__component_copy(url->components.scheme);
	(*new_url)->components.username =
			nsurl__component_copy(url->components.username);
	(*new_url)->components.password =
			nsurl__component_copy(url->components.password);
	(*new_url)->components.host =
			nsurl__component_copy(url->components.host);
	(*new_url)->components.port =
			nsurl__component_copy(url->components.port);
	(*new_url)->components.path =
			nsurl__component_copy(url->components.path);
	(*new_url)->components.query = lwc_query;
	(*new_url)->components.fragment =
			nsurl__component_copy(url->components.fragment);

	(*new_url)->components.scheme_type = url->components.scheme_type;

	/* Get the nsurl's hash */
	nsurl__calc_hash(*new_url);

	/* Give the URL a reference */
	(*new_url)->count = 1;

	return NSERROR_OK;
}


/* exported interface documented in utils/nsurl.h */
nserror nsurl_nice(const nsurl *url, char **result, bool remove_extensions)
{
	const char *data;
	size_t len;
	size_t pos;
	bool match;
	char *name;

	assert(url != NULL);

	*result = 0;

	/* extract the last component of the path, if possible */
	if ((url->components.path != NULL) &&
	    (lwc_string_length(url->components.path) != 0) &&
	    (lwc_string_isequal(url->components.path,
			corestring_lwc_slash_, &match) == lwc_error_ok) &&
	    (match == false)) {
		bool first = true;
		bool keep_looking;

		/* Get hold of the string data we're examining */
		data = lwc_string_data(url->components.path);
		len = lwc_string_length(url->components.path);
		pos = len;

		do {
			keep_looking = false;
			pos--;

			/* Find last '/' with stuff after it */
			while (pos != 0) {
				if (data[pos] == '/' && pos < len - 1) {
					break;
				}
				pos--;
			}

			if (pos == 0) {
				break;
			}

			if (first) {
				if (strncasecmp("/default.", data + pos,
						SLEN("/default.")) == 0) {
					keep_looking = true;

				} else if (strncasecmp("/index.",
							data + pos,
							6) == 0) {
					keep_looking = true;

				}
				first = false;
			}

		} while (keep_looking);

		if (data[pos] == '/')
			pos++;

		if (strncasecmp("default.", data + pos, 8) != 0 &&
				strncasecmp("index.", data + pos, 6) != 0) {
			size_t end = pos;
			while (data[end] != '\0' && data[end] != '/') {
				end++;
			}
			if (end - pos != 0) {
				name = malloc(end - pos + 1);
				if (name == NULL) {
					return NSERROR_NOMEM;
				}
				memcpy(name, data + pos, end - pos);
				name[end - pos] = '\0';
				if (remove_extensions) {
					/* strip any extenstion */
					char *dot = strchr(name, '.');
					if (dot && dot != name) {
						*dot = '\0';
					}
				}
				*result = name;
				return NSERROR_OK;
			}
		}
	}

	if (url->components.host != NULL) {
		name = strdup(lwc_string_data(url->components.host));

		for (pos = 0; name[pos] != '\0'; pos++) {
			if (name[pos] == '.') {
				name[pos] = '_';
			}
		}

		*result = name;
		return NSERROR_OK;
	}

	return NSERROR_NOT_FOUND;
}


/* exported interface, documented in nsurl.h */
nserror nsurl_parent(const nsurl *url, nsurl **new_url)
{
	lwc_string *lwc_path;
	size_t old_path_len, new_path_len;
	size_t len;
	const char* path = NULL;
	char *pos;

	assert(url != NULL);

	old_path_len = (url->components.path == NULL) ? 0 :
			lwc_string_length(url->components.path);

	/* Find new path length */
	if (old_path_len == 0) {
		new_path_len = old_path_len;
	} else {
		path = lwc_string_data(url->components.path);

		new_path_len = old_path_len;
		if (old_path_len > 1) {
			/* Skip over any trailing / */
			if (path[new_path_len - 1] == '/')
				new_path_len--;

			/* Work back to next / */
			while (new_path_len > 0 &&
					path[new_path_len - 1] != '/')
				new_path_len--;
		}
	}

	/* Find the length of new_url */
	len = url->length;
	if (url->components.query != NULL) {
		len -= lwc_string_length(url->components.query);
	}
	if (url->components.fragment != NULL) {
		len -= 1; /* # */
		len -= lwc_string_length(url->components.fragment);
	}
	len -= old_path_len - new_path_len;

	/* Create NetSurf URL object */
	*new_url = malloc(sizeof(nsurl) + len + 1); /* Add 1 for \0 */
	if (*new_url == NULL) {
		return NSERROR_NOMEM;
	}

	/* Make new path */
	if (old_path_len == 0) {
		lwc_path = NULL;
	} else if (old_path_len == new_path_len) {
		lwc_path = lwc_string_ref(url->components.path);
	} else {
		if (lwc_intern_string(path, old_path_len - new_path_len,
				&lwc_path) != lwc_error_ok) {
			free(*new_url);
			return NSERROR_NOMEM;
		}
	}

	(*new_url)->length = len;

	/* Set string */
	pos = (*new_url)->string;
	memcpy(pos, url->string, len);
	pos += len;
	*pos = '\0';

	/* Copy components */
	(*new_url)->components.scheme =
			nsurl__component_copy(url->components.scheme);
	(*new_url)->components.username =
			nsurl__component_copy(url->components.username);
	(*new_url)->components.password =
			nsurl__component_copy(url->components.password);
	(*new_url)->components.host =
			nsurl__component_copy(url->components.host);
	(*new_url)->components.port =
			nsurl__component_copy(url->components.port);
	(*new_url)->components.path = lwc_path;
	(*new_url)->components.query = NULL;
	(*new_url)->components.fragment = NULL;

	(*new_url)->components.scheme_type = url->components.scheme_type;

	/* Get the nsurl's hash */
	nsurl__calc_hash(*new_url);

	/* Give the URL a reference */
	(*new_url)->count = 1;

	return NSERROR_OK;
}