/* log.c
 *
 * Tox DHT bootstrap daemon.
 * Logging utility with support of multipel logging backends.
 *
 *  Copyright (C) 2015-2016 Tox project All Rights Reserved.
 *
 *  This file is part of Tox.
 *
 *  Tox 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 3 of the License, or
 *  (at your option) any later version.
 *
 *  Tox 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 Tox.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "log.h"

#include "global.h"

#include <syslog.h>

#include <stdarg.h>
#include <stdio.h>

#define INVALID_BACKEND (LOG_BACKEND)-1u
static LOG_BACKEND current_backend = INVALID_BACKEND;

bool open_log(LOG_BACKEND backend)
{
    if (current_backend != INVALID_BACKEND) {
        return false;
    }

    if (backend == LOG_BACKEND_SYSLOG) {
        openlog(DAEMON_NAME, LOG_NOWAIT | LOG_PID, LOG_DAEMON);
    }

    current_backend = backend;

    return true;
}

bool close_log(void)
{
    if (current_backend == INVALID_BACKEND) {
        return false;
    }

    if (current_backend == LOG_BACKEND_SYSLOG) {
        closelog();
    }

    current_backend = INVALID_BACKEND;

    return true;
}

static int level_syslog(LOG_LEVEL level)
{
    switch (level) {
        case LOG_LEVEL_INFO:
            return LOG_INFO;

        case LOG_LEVEL_WARNING:
            return LOG_WARNING;

        case LOG_LEVEL_ERROR:
            return LOG_ERR;
    }

    return LOG_INFO;
}

static void log_syslog(LOG_LEVEL level, const char *format, va_list args)
{
    vsyslog(level_syslog(level), format, args);
}

static FILE *level_stdout(LOG_LEVEL level)
{
    switch (level) {
        case LOG_LEVEL_INFO:
            return stdout;

        case LOG_LEVEL_WARNING: // intentional fallthrough
        case LOG_LEVEL_ERROR:
            return stderr;
    }

    return stdout;
}

static void log_stdout(LOG_LEVEL level, const char *format, va_list args)
{
    vfprintf(level_stdout(level), format, args);
    fflush(level_stdout(level));
}

bool write_log(LOG_LEVEL level, const char *format, ...)
{
    va_list args;
    va_start(args, format);

    switch (current_backend) {
        case LOG_BACKEND_SYSLOG:
            log_syslog(level, format, args);
            break;

        case LOG_BACKEND_STDOUT:
            log_stdout(level, format, args);
            break;
    }

    va_end(args);

    return current_backend != INVALID_BACKEND;
}