/********************************************************************\
  * BitlBee -- An IRC to other IM-networks gateway                     *
  *                                                                    *
  * Copyright 2002-2012 Wilmer van der Gaast and others                *
  \********************************************************************/

/*
 * Various utility functions. Some are copied from Gaim to support the
 * IM-modules, most are from BitlBee.
 *
 * Copyright (C) 1998-1999, Mark Spencer <markster@marko.net>
 *                          (and possibly other members of the Gaim team)
 * Copyright 2002-2012 Wilmer van der Gaast <wilmer@gaast.net>
 */

/*
  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 with
  the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL;
  if not, write to the Free Software Foundation, Inc., 51 Franklin St.,
  Fifth Floor, Boston, MA  02110-1301  USA
*/

#define BITLBEE_CORE
#include "nogaim.h"
#include "base64.h"
#include "md5.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <glib.h>
#include <time.h>

#ifdef HAVE_RESOLV_A
#include <arpa/nameser.h>
#include <resolv.h>
#endif

#include "md5.h"
#include "ssl_client.h"

void strip_linefeed(gchar *text)
{
	int i, j;
	gchar *text2 = g_malloc(strlen(text) + 1);

	for (i = 0, j = 0; text[i]; i++) {
		if (text[i] != '\r') {
			text2[j++] = text[i];
		}
	}
	text2[j] = '\0';

	strcpy(text, text2);
	g_free(text2);
}

time_t get_time(int year, int month, int day, int hour, int min, int sec)
{
	struct tm tm;

	memset(&tm, 0, sizeof(struct tm));
	tm.tm_year = year - 1900;
	tm.tm_mon = month - 1;
	tm.tm_mday = day;
	tm.tm_hour = hour;
	tm.tm_min = min;
	tm.tm_sec = sec >= 0 ? sec : time(NULL) % 60;

	return mktime(&tm);
}

time_t mktime_utc(struct tm *tp)
{
	struct tm utc;
	time_t res, tres;

	tp->tm_isdst = -1;
	res = mktime(tp);
	/* Problem is, mktime() just gave us the GMT timestamp for the
	   given local time... While the given time WAS NOT local. So
	   we should fix this now.

	   Now I could choose between messing with environment variables
	   (kludgy) or using timegm() (not portable)... Or doing the
	   following, which I actually prefer...

	   tzset() may also work but in other places I actually want to
	   use local time.

	   FFFFFFFFFFFFFFFFFFFFFUUUUUUUUUUUUUUUUUUUU!! */
	gmtime_r(&res, &utc);
	utc.tm_isdst = -1;
	if (utc.tm_hour == tp->tm_hour && utc.tm_min == tp->tm_min) {
		/* Sweet! We're in UTC right now... */
		return res;
	}

	tres = mktime(&utc);
	res += res - tres;

	/* Yes, this is a hack. And it will go wrong around DST changes.
	   BUT this is more likely to be threadsafe than messing with
	   environment variables, and possibly more portable... */

	return res;
}

typedef struct htmlentity {
	char code[7];
	char is[3];
} htmlentity_t;

static const htmlentity_t ent[] =
{
	{ "lt",     "<" },
	{ "gt",     ">" },
	{ "amp",    "&" },
	{ "apos",   "'" },
	{ "quot",   "\"" },
	{ "aacute", "á" },
	{ "eacute", "é" },
	{ "iacute", "é" },
	{ "oacute", "ó" },
	{ "uacute", "ú" },
	{ "agrave", "à" },
	{ "egrave", "è" },
	{ "igrave", "ì" },
	{ "ograve", "ò" },
	{ "ugrave", "ù" },
	{ "acirc",  "â" },
	{ "ecirc",  "ê" },
	{ "icirc",  "î" },
	{ "ocirc",  "ô" },
	{ "ucirc",  "û" },
	{ "auml",   "ä" },
	{ "euml",   "ë" },
	{ "iuml",   "ï" },
	{ "ouml",   "ö" },
	{ "uuml",   "ü" },
	{ "nbsp",   " " },
	{ "",        ""  }
};

void strip_html(char *in)
{
	char *start = in;
	char out[strlen(in) + 1];
	char *s = out, *cs;
	int i, matched;
	int taglen;

	memset(out, 0, sizeof(out));

	while (*in) {
		if (*in == '<' && (g_ascii_isalpha(*(in + 1)) || *(in + 1) == '/')) {
			/* If in points at a < and in+1 points at a letter or a slash, this is probably
			   a HTML-tag. Try to find a closing > and continue there. If the > can't be
			   found, assume that it wasn't a HTML-tag after all. */

			cs = in;

			while (*in && *in != '>') {
				in++;
			}

			taglen = in - cs - 1;   /* not <0 because the above loop runs at least once */
			if (*in) {
				if (g_strncasecmp(cs + 1, "b", taglen) == 0) {
					*(s++) = '\x02';
				} else if (g_strncasecmp(cs + 1, "/b", taglen) == 0) {
					*(s++) = '\x02';
				} else if (g_strncasecmp(cs + 1, "i", taglen) == 0) {
					*(s++) = '\x1f';
				} else if (g_strncasecmp(cs + 1, "/i", taglen) == 0) {
					*(s++) = '\x1f';
				} else if (g_strncasecmp(cs + 1, "br", taglen) == 0) {
					*(s++) = '\n';
				} else if (g_strncasecmp(cs + 1, "br/", taglen) == 0) {
					*(s++) = '\n';
				} else if (g_strncasecmp(cs + 1, "br /", taglen) == 0) {
					*(s++) = '\n';
				}
				in++;
			} else {
				in = cs;
				*(s++) = *(in++);
			}
		} else if (*in == '&') {
			cs = ++in;
			while (*in && g_ascii_isalpha(*in)) {
				in++;
			}

			if (*in == ';') {
				in++;
			}
			matched = 0;

			for (i = 0; *ent[i].code; i++) {
				if (g_strncasecmp(ent[i].code, cs, strlen(ent[i].code)) == 0) {
					int j;

					for (j = 0; ent[i].is[j]; j++) {
						*(s++) = ent[i].is[j];
					}

					matched = 1;
					break;
				}
			}

			/* None of the entities were matched, so return the string */
			if (!matched) {
				in = cs - 1;
				*(s++) = *(in++);
			}
		} else {
			*(s++) = *(in++);
		}
	}

	strcpy(start, out);
}

char *escape_html(const char *html)
{
	const char *c = html;
	GString *ret;
	char *str;

	if (html == NULL) {
		return(NULL);
	}

	ret = g_string_new("");

	while (*c) {
		switch (*c) {
		case '&':
			ret = g_string_append(ret, "&amp;");
			break;
		case '<':
			ret = g_string_append(ret, "&lt;");
			break;
		case '>':
			ret = g_string_append(ret, "&gt;");
			break;
		case '"':
			ret = g_string_append(ret, "&quot;");
			break;
		default:
			ret = g_string_append_c(ret, *c);
		}
		c++;
	}

	str = ret->str;
	g_string_free(ret, FALSE);
	return(str);
}

/* Decode%20a%20file%20name						*/
void http_decode(char *s)
{
	char *t;
	int i, j, k;

	t = g_new(char, strlen(s) + 1);

	for (i = j = 0; s[i]; i++, j++) {
		if (s[i] == '%') {
			if (sscanf(s + i + 1, "%2x", &k)) {
				t[j] = k;
				i += 2;
			} else {
				*t = 0;
				break;
			}
		} else {
			t[j] = s[i];
		}
	}
	t[j] = 0;

	strcpy(s, t);
	g_free(t);
}

/* Warning: This one explodes the string. Worst-cases can make the string 3x its original size! */
/* This function is safe, but make sure you call it safely as well! */
void http_encode(char *s)
{
	char t[strlen(s) + 1];
	int i, j;

	strcpy(t, s);
	for (i = j = 0; t[i]; i++, j++) {
		/* Warning: g_ascii_isalnum() is locale-aware, so don't use it here! */
		if ((t[i] >= 'A' && t[i] <= 'Z') ||
		    (t[i] >= 'a' && t[i] <= 'z') ||
		    (t[i] >= '0' && t[i] <= '9') ||
		    strchr("._-~", t[i])) {
			s[j] = t[i];
		} else {
			sprintf(s + j, "%%%02X", ((unsigned char *) t)[i]);
			j += 2;
		}
	}
	s[j] = 0;
}

/* Strip newlines from a string. Modifies the string passed to it. */
char *strip_newlines(char *source)
{
	int i;

	for (i = 0; source[i] != '\0'; i++) {
		if (source[i] == '\n' || source[i] == '\r') {
			source[i] = ' ';
		}
	}

	return source;
}

/* Wrap an IPv4 address into IPv6 space. Not thread-safe... */
char *ipv6_wrap(char *src)
{
	static char dst[64];
	int i;

	for (i = 0; src[i]; i++) {
		if ((src[i] < '0' || src[i] > '9') && src[i] != '.') {
			break;
		}
	}

	/* Hmm, it's not even an IP... */
	if (src[i]) {
		return src;
	}

	g_snprintf(dst, sizeof(dst), "::ffff:%s", src);

	return dst;
}

/* Unwrap an IPv4 address into IPv6 space. Thread-safe, because it's very simple. :-) */
char *ipv6_unwrap(char *src)
{
	int i;

	if (g_strncasecmp(src, "::ffff:", 7) != 0) {
		return src;
	}

	for (i = 7; src[i]; i++) {
		if ((src[i] < '0' || src[i] > '9') && src[i] != '.') {
			break;
		}
	}

	/* Hmm, it's not even an IP... */
	if (src[i]) {
		return src;
	}

	return (src + 7);
}

/* Convert from one charset to another.

   from_cs, to_cs: Source and destination charsets
   src, dst: Source and destination strings
   size: Size if src. 0 == use strlen(). strlen() is not reliable for UNICODE/UTF16 strings though.
   maxbuf: Maximum number of bytes to write to dst

   Returns the number of bytes written to maxbuf or -1 on an error.
*/
signed int do_iconv(char *from_cs, char *to_cs, char *src, char *dst, size_t size, size_t maxbuf)
{
	GIConv cd;
	size_t res;
	size_t inbytesleft, outbytesleft;
	char *inbuf = src;
	char *outbuf = dst;

	cd = g_iconv_open(to_cs, from_cs);
	if (cd == (GIConv) - 1) {
		return -1;
	}

	inbytesleft = size ? size : strlen(src);
	outbytesleft = maxbuf - 1;
	res = g_iconv(cd, &inbuf, &inbytesleft, &outbuf, &outbytesleft);
	*outbuf = '\0';
	g_iconv_close(cd);

	if (res != 0) {
		return -1;
	} else {
		return outbuf - dst;
	}
}

/* A wrapper for /dev/urandom.
 * If /dev/urandom is not present or not usable, it calls abort()
 * to prevent bitlbee from working without a decent entropy source */
void random_bytes(unsigned char *buf, int count)
{
	int fd;

	if (((fd = open("/dev/urandom", O_RDONLY)) == -1) ||
	    (read(fd, buf, count) == -1)) {
		log_message(LOGLVL_ERROR, "/dev/urandom not present - aborting");
		abort();
	}

	close(fd);
}

int is_bool(const char *value)
{
	if (*value == 0) {
		return 0;
	}

	if ((g_strcasecmp(value,
	                  "true") == 0) || (g_strcasecmp(value, "yes") == 0) || (g_strcasecmp(value, "on") == 0)) {
		return 1;
	}
	if ((g_strcasecmp(value,
	                  "false") == 0) || (g_strcasecmp(value, "no") == 0) || (g_strcasecmp(value, "off") == 0)) {
		return 1;
	}

	while (*value) {
		if (!g_ascii_isdigit(*value)) {
			return 0;
		} else {
			value++;
		}
	}

	return 1;
}

int bool2int(const char *value)
{
	int i;

	if ((g_strcasecmp(value,
	                  "true") == 0) || (g_strcasecmp(value, "yes") == 0) || (g_strcasecmp(value, "on") == 0)) {
		return 1;
	}
	if ((g_strcasecmp(value,
	                  "false") == 0) || (g_strcasecmp(value, "no") == 0) || (g_strcasecmp(value, "off") == 0)) {
		return 0;
	}

	if (sscanf(value, "%d", &i) == 1) {
		return i;
	}

	return 0;
}

struct ns_srv_reply **srv_lookup(char *service, char *protocol, char *domain)
{
	struct ns_srv_reply **replies = NULL;

#ifdef HAVE_RESOLV_A
	struct ns_srv_reply *reply = NULL;
	char name[1024];
	unsigned char querybuf[1024];
	const unsigned char *buf;
	ns_msg nsh;
	ns_rr rr;
	int n, len, size;

	g_snprintf(name, sizeof(name), "_%s._%s.%s", service, protocol, domain);

	if ((size = res_query(name, ns_c_in, ns_t_srv, querybuf, sizeof(querybuf))) <= 0) {
		return NULL;
	}

	if (ns_initparse(querybuf, size, &nsh) != 0) {
		return NULL;
	}

	n = 0;
	while (ns_parserr(&nsh, ns_s_an, n, &rr) == 0) {
		char name[NS_MAXDNAME];

		if (ns_rr_rdlen(rr) < 7) {
			break;
		}

		buf = ns_rr_rdata(rr);

		if (dn_expand(querybuf, querybuf + size, &buf[6], name, NS_MAXDNAME) == -1) {
			break;
		}

		len = strlen(name) + 1;

		reply = g_malloc(sizeof(struct ns_srv_reply) + len);
		memcpy(reply->name, name, len);

		reply->prio = (buf[0] << 8) | buf[1];
		reply->weight = (buf[2] << 8) | buf[3];
		reply->port = (buf[4] << 8) | buf[5];

		n++;
		replies = g_renew(struct ns_srv_reply *, replies, n + 1);
		replies[n - 1] = reply;
	}
	if (replies) {
		replies[n] = NULL;
	}
#endif

	return replies;
}

void srv_free(struct ns_srv_reply **srv)
{
	int i;

	if (srv == NULL) {
		return;
	}

	for (i = 0; srv[i]; i++) {
		g_free(srv[i]);
	}
	g_free(srv);
}

/* Word wrapping. Yes, I know this isn't UTF-8 clean. I'm willing to take the risk. */
char *word_wrap(const char *msg, int line_len)
{
	GString *ret = g_string_sized_new(strlen(msg) + 16);

	while (strlen(msg) > line_len) {
		int i;

		/* First try to find out if there's a newline already. Don't
		   want to add more splits than necessary. */
		for (i = line_len; i > 0 && msg[i] != '\n'; i--) {
			;
		}
		if (msg[i] == '\n') {
			g_string_append_len(ret, msg, i + 1);
			msg += i + 1;
			continue;
		}

		for (i = line_len; i > 0; i--) {
			if (msg[i] == '-') {
				g_string_append_len(ret, msg, i + 1);
				g_string_append_c(ret, '\n');
				msg += i + 1;
				break;
			} else if (msg[i] == ' ') {
				g_string_append_len(ret, msg, i);
				g_string_append_c(ret, '\n');
				msg += i + 1;
				break;
			}
		}
		if (i == 0) {
			g_string_append_len(ret, msg, line_len);
			g_string_append_c(ret, '\n');
			msg += line_len;
		}
	}
	g_string_append(ret, msg);

	return g_string_free(ret, FALSE);
}

gboolean ssl_sockerr_again(void *ssl)
{
	if (ssl) {
		return ssl_errno == SSL_AGAIN;
	} else {
		return sockerr_again();
	}
}

/* Returns values: -1 == Failure (base64-decoded to something unexpected)
                    0 == Okay
                    1 == Password doesn't match the hash. */
int md5_verify_password(char *password, char *hash)
{
	md5_byte_t *pass_dec = NULL;
	md5_byte_t pass_md5[16];
	md5_state_t md5_state;
	int ret = -1, i;

	if (base64_decode(hash, &pass_dec) == 21) {
		md5_init(&md5_state);
		md5_append(&md5_state, (md5_byte_t *) password, strlen(password));
		md5_append(&md5_state, (md5_byte_t *) pass_dec + 16, 5);  /* Hmmm, salt! */
		md5_finish(&md5_state, pass_md5);

		for (i = 0; i < 16; i++) {
			if (pass_dec[i] != pass_md5[i]) {
				ret = 1;
				break;
			}
		}

		/* If we reached the end of the loop, it was a match! */
		if (i == 16) {
			ret = 0;
		}
	}

	g_free(pass_dec);

	return ret;
}

/* Split commands (root-style, *not* IRC-style). Handles "quoting of"
   white\ space in 'various ways'. Returns a NULL-terminated static
   char** so watch out with nested use! Definitely not thread-safe. */
char **split_command_parts(char *command, int limit)
{
	static char *cmd[IRC_MAX_ARGS + 1];
	char *s, q = 0;
	int k;

	memset(cmd, 0, sizeof(cmd));
	cmd[0] = command;
	k = 1;
	for (s = command; *s && k < IRC_MAX_ARGS; s++) {
		if (*s == ' ' && !q) {
			*s = 0;
			while (*++s == ' ') {
				;
			}
			if (k != limit && (*s == '"' || *s == '\'')) {
				q = *s;
				s++;
			}
			if (*s) {
				cmd[k++] = s;
				if (limit && k > limit) {
					break;
				}
				s--;
			} else {
				break;
			}
		} else if (*s == '\\' && ((!q && s[1]) || (q && q == s[1]))) {
			char *cpy;

			for (cpy = s; *cpy; cpy++) {
				cpy[0] = cpy[1];
			}
		} else if (*s == q) {
			q = *s = 0;
		}
	}

	/* Full zero-padding for easier argc checking. */
	while (k <= IRC_MAX_ARGS) {
		cmd[k++] = NULL;
	}

	return cmd;
}

char *get_rfc822_header(const char *text, const char *header, int len)
{
	int hlen = strlen(header), i;
	const char *ret;

	if (text == NULL) {
		return NULL;
	}

	if (len == 0) {
		len = strlen(text);
	}

	i = 0;
	while ((i + hlen) < len) {
		/* Maybe this is a bit over-commented, but I just hate this part... */
		if (g_strncasecmp(text + i, header, hlen) == 0) {
			/* Skip to the (probable) end of the header */
			i += hlen;

			/* Find the first non-[: \t] character */
			while (i < len && (text[i] == ':' || text[i] == ' ' || text[i] == '\t')) {
				i++;
			}

			/* Make sure we're still inside the string */
			if (i >= len) {
				return(NULL);
			}

			/* Save the position */
			ret = text + i;

			/* Search for the end of this line */
			while (i < len && text[i] != '\r' && text[i] != '\n') {
				i++;
			}

			/* Copy the found data */
			return(g_strndup(ret, text + i - ret));
		}

		/* This wasn't the header we were looking for, skip to the next line. */
		while (i < len && (text[i] != '\r' && text[i] != '\n')) {
			i++;
		}
		while (i < len && (text[i] == '\r' || text[i] == '\n')) {
			i++;
		}

		/* End of headers? */
		if ((i >= 4 && strncmp(text + i - 4, "\r\n\r\n", 4) == 0) ||
		    (i >= 2 && (strncmp(text + i - 2, "\n\n", 2) == 0 ||
		                strncmp(text + i - 2, "\r\r", 2) == 0))) {
			break;
		}
	}

	return NULL;
}

/* Takes a string, truncates it where it's safe, returns the new length */
int truncate_utf8(char *string, int maxlen)
{
	char *end;

	g_utf8_validate((const gchar *) string, maxlen, (const gchar **) &end);
	*end = '\0';
	return end - string;
}

/* Parses a guint64 from string, returns TRUE on success */
gboolean parse_int64(char *string, int base, guint64 *number)
{
	guint64 parsed;
	char *endptr;

	errno = 0;
	parsed = g_ascii_strtoull(string, &endptr, base);
	if (errno || endptr == string || *endptr != '\0') {
		return FALSE;
	}
	*number = parsed;
	return TRUE;
}

/* Filters all the characters in 'blacklist' replacing them with 'replacement'.
 * Modifies the string in-place and returns the string itself.
 * For the opposite, use g_strcanon() */
char *str_reject_chars(char *string, const char *reject, char replacement)
{
	char *c = string;

	while (*c) {
		c += strcspn(c, reject);
		if (*c) {
			*c = replacement;
		}
	}

	return string;
}