/*
    logger.c -- logging code
    Copyright (C) 2004-2015 Guus Sliepen <guus@tinc-vpn.org>
                  2004-2005 Ivo Timmermans

    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 "system.h"

#include "conf.h"
#include "meta.h"
#include "names.h"
#include "logger.h"
#include "connection.h"
#include "control_common.h"
#include "process.h"
#include "sptps.h"

debug_t debug_level = DEBUG_NOTHING;
static logmode_t logmode = LOGMODE_STDERR;
static pid_t logpid;
static FILE *logfile = NULL;
#ifdef HAVE_MINGW
static HANDLE loghandle = NULL;
#endif
static const char *logident = NULL;
bool logcontrol = false;
int umbilical = 0;

static void real_logger(int level, int priority, const char *message) {
	char timestr[32] = "";
	static bool suppress = false;

	// Bail out early if there is nothing to do.
	if(suppress)
		return;

	if(!logcontrol && (level > debug_level || logmode == LOGMODE_NULL))
		return;

	if(level <= debug_level) {
		switch(logmode) {
			case LOGMODE_STDERR:
				fprintf(stderr, "%s\n", message);
				fflush(stderr);
				break;
			case LOGMODE_FILE:
				if(!now.tv_sec)
					gettimeofday(&now, NULL);
				time_t now_sec = now.tv_sec;
				strftime(timestr, sizeof timestr, "%Y-%m-%d %H:%M:%S", localtime(&now_sec));
				fprintf(logfile, "%s %s[%ld]: %s\n", timestr, logident, (long)logpid, message);
				fflush(logfile);
				break;
			case LOGMODE_SYSLOG:
#ifdef HAVE_MINGW
				{
					const char *messages[] = {message};
					ReportEvent(loghandle, priority, 0, 0, NULL, 1, 0, messages, NULL);
				}
#else
#ifdef HAVE_SYSLOG_H
				syslog(priority, "%s", message);
#endif
#endif
				break;
			case LOGMODE_NULL:
				break;
		}

		if(umbilical && do_detach) {
			write(umbilical, message, strlen(message));
			write(umbilical, "\n", 1);
		}
	}

	if(logcontrol) {
		suppress = true;
		logcontrol = false;
		for list_each(connection_t, c, connection_list) {
			if(!c->status.log)
				continue;
			logcontrol = true;
			if(level > (c->outcompression >= 0 ? c->outcompression : debug_level))
				continue;
			int len = strlen(message);
			if(send_request(c, "%d %d %d", CONTROL, REQ_LOG, len))
				send_meta(c, message, len);
		}
		suppress = false;
	}
}

void logger(int level, int priority, const char *format, ...) {
	va_list ap;
	char message[1024] = "";

	va_start(ap, format);
	int len = vsnprintf(message, sizeof message, format, ap);
	va_end(ap);

	if(len > 0 && len < sizeof message && message[len - 1] == '\n')
		message[len - 1] = 0;

	real_logger(level, priority, message);
}

static void sptps_logger(sptps_t *s, int s_errno, const char *format, va_list ap) {
	char message[1024] = "";
	size_t msglen = sizeof message;

	int len = vsnprintf(message, msglen, format, ap);
	if(len > 0 && len < sizeof message) {
		if(message[len - 1] == '\n')
			message[--len] = 0;

		// WARNING: s->handle can point to a connection_t or a node_t,
		// but both types have the name and hostname fields at the same offsets.
		connection_t *c = s->handle;
		if(c)
			snprintf(message + len, sizeof message - len, " from %s (%s)", c->name, c->hostname);
	}

	real_logger(DEBUG_ALWAYS, LOG_ERR, message);
}

void openlogger(const char *ident, logmode_t mode) {
	logident = ident;
	logmode = mode;

	switch(mode) {
		case LOGMODE_STDERR:
			logpid = getpid();
			break;
		case LOGMODE_FILE:
			logpid = getpid();
			logfile = fopen(logfilename, "a");
			if(!logfile) {
				fprintf(stderr, "Could not open log file %s: %s\n", logfilename, strerror(errno));
				logmode = LOGMODE_NULL;
			}
			break;
		case LOGMODE_SYSLOG:
#ifdef HAVE_MINGW
			loghandle = RegisterEventSource(NULL, logident);
			if(!loghandle) {
				fprintf(stderr, "Could not open log handle!");
				logmode = LOGMODE_NULL;
			}
			break;
#else
#ifdef HAVE_SYSLOG_H
			openlog(logident, LOG_CONS | LOG_PID, LOG_DAEMON);
			break;
#endif
#endif
		case LOGMODE_NULL:
			break;
	}

	if(logmode != LOGMODE_NULL)
		sptps_log = sptps_logger;
	else
		sptps_log = sptps_log_quiet;
}

void reopenlogger() {
	if(logmode != LOGMODE_FILE)
		return;

	fflush(logfile);
	FILE *newfile = fopen(logfilename, "a");
	if(!newfile) {
		logger(DEBUG_ALWAYS, LOG_ERR, "Unable to reopen log file %s: %s", logfilename, strerror(errno));
		return;
	}
	fclose(logfile);
	logfile = newfile;
}


void closelogger(void) {
	switch(logmode) {
		case LOGMODE_FILE:
			fclose(logfile);
			break;
		case LOGMODE_SYSLOG:
#ifdef HAVE_MINGW
			DeregisterEventSource(loghandle);
			break;
#else
#ifdef HAVE_SYSLOG_H
			closelog();
			break;
#endif
#endif
		case LOGMODE_NULL:
		case LOGMODE_STDERR:
			break;
	}
}