/*
    logger.c -- logging code
    Copyright (C) 2004-2016 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 "logger.h"

debug_t debug_level = DEBUG_NOTHING;
static logmode_t logmode = LOGMODE_STDERR;
static pid_t logpid;
extern char *logfilename;
static FILE *logfile = NULL;
#ifdef HAVE_MINGW
static HANDLE loghandle = NULL;
#endif
static const char *logident = NULL;

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;
	}
}

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

	fflush(logfile);
	FILE *newfile = fopen(logfilename, "a");

	if(!newfile) {
		logger(LOG_ERR, "Unable to reopen log file %s: %s", logfilename, strerror(errno));
		return;
	}

	fclose(logfile);
	logfile = newfile;
}

void logger(int priority, const char *format, ...) {
	va_list ap;
	char timestr[32] = "";
	time_t now;

	va_start(ap, format);

	switch(logmode) {
	case LOGMODE_STDERR:
		vfprintf(stderr, format, ap);
		fprintf(stderr, "\n");
		fflush(stderr);
		break;

	case LOGMODE_FILE:
		now = time(NULL);
		strftime(timestr, sizeof(timestr), "%Y-%m-%d %H:%M:%S", localtime(&now));
		fprintf(logfile, "%s %s[%ld]: ", timestr, logident, (long)logpid);
		vfprintf(logfile, format, ap);
		fprintf(logfile, "\n");
		fflush(logfile);
		break;

	case LOGMODE_SYSLOG:
#ifdef HAVE_MINGW
		{
			char message[4096];
			const char *messages[] = {message};
			vsnprintf(message, sizeof(message), format, ap);
			message[sizeof(message) - 1] = 0;
			ReportEvent(loghandle, priority, 0, 0, NULL, 1, 0, messages, NULL);
		}

#else
#ifdef HAVE_SYSLOG_H
#ifdef HAVE_VSYSLOG
		vsyslog(priority, format, ap);
#else
		{
			char message[4096];
			vsnprintf(message, sizeof(message), format, ap);
			syslog(priority, "%s", message);
		}
#endif
		break;
#endif
#endif

	case LOGMODE_NULL:
		break;
	}

	va_end(ap);
}

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;
	}
}
