/* 
** Copyright (C) 2010 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
**
** 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 3 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 <stdio.h>

#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <time.h>
#include <errno.h>
#include <string.h>

#include "mu-log.h"
#include "mu-util.h"

#define MU_LOG_FILE "mu.log"

struct _MuLog {
	int _fd;      /* log file descriptor */

	gboolean _own;     /* close _fd with log_destroy? */
	gboolean _debug;   /* add debug-level stuff? */
	gboolean _quiet;   /* don't write non-error to stdout/stderr */
	
	GLogFunc _old_log_func;
};
typedef struct _MuLog MuLog;

static MuLog* MU_LOG = NULL;

static void _log_write (const char* domain, GLogLevelFlags level, 
			const gchar *msg);

static void
_try_close (int fd)
{
	if (fd < 0)
		return;
	
	if (close (fd) < 0) 
		g_printerr ("%s: close() of fd %d failed: %s\n",
			    __FUNCTION__, fd, strerror(errno));
}


static void
silence (void)
{
	return;
}

gboolean
mu_log_init_silence (void)
{
	g_return_val_if_fail (!MU_LOG, FALSE);
	
        MU_LOG = g_new(MuLog, 1);
        MU_LOG->_fd     = -1;
	MU_LOG->_own    = FALSE; /* nobody owns silence */
	
	MU_LOG->_old_log_func =
		g_log_set_default_handler ((GLogFunc)silence, NULL);

	return TRUE;
}


static void
log_handler (const gchar* log_domain, GLogLevelFlags log_level,
	     const gchar* msg)
{
	if (log_level == G_LOG_LEVEL_DEBUG && !MU_LOG->_debug)
	 	return;

	_log_write (log_domain ? log_domain : "mu", log_level, msg);
}


gboolean
mu_log_init_with_fd (int fd, gboolean doclose,
		     gboolean quiet, gboolean debug)
{
	g_return_val_if_fail (!MU_LOG, FALSE);
	
        MU_LOG = g_new(MuLog, 1);

        MU_LOG->_fd     = fd;
	MU_LOG->_quiet  = quiet;
	MU_LOG->_debug  = debug;
        MU_LOG->_own    = doclose; /* if we now own the fd, close it
				    * in _destroy */
	MU_LOG->_old_log_func =
		g_log_set_default_handler ((GLogFunc)log_handler, NULL);
	
	return TRUE;
}

gboolean
mu_log_init  (const char* muhome, gboolean append,
	      gboolean quiet, gboolean debug)
{
	int fd;
	gchar *logfile;
	
	/* only init once... */
	g_return_val_if_fail (!MU_LOG, FALSE);	
	g_return_val_if_fail (muhome, FALSE);

	if (!mu_util_create_dir_maybe(muhome)) {
		g_warning ("Failed to init log in %s", muhome);
		return FALSE;
	}
	
	logfile = g_strdup_printf ("%s%c%s", muhome,
				   G_DIR_SEPARATOR, MU_LOG_FILE);
	fd = open (logfile,  O_WRONLY|O_CREAT|(append ? O_APPEND : O_TRUNC),
		   00600);
	if (fd < 0) 
		g_warning ("%s: open() of '%s' failed: %s\n",  __FUNCTION__,
			   logfile, strerror(errno));
	g_free (logfile);
	
	if (fd < 0 || !mu_log_init_with_fd (fd, FALSE, quiet, debug)) {
		_try_close (fd);
		return FALSE;
	}
	
	return TRUE;
}



void 
mu_log_uninit (void)
{
	g_return_if_fail (MU_LOG);

	if (MU_LOG->_own)
		_try_close (MU_LOG->_fd);

	g_free (MU_LOG);
	MU_LOG = NULL;
}


static const char*
pfx (GLogLevelFlags level)
{
	switch (level) {
	case G_LOG_LEVEL_WARNING:   return  "WARN";
	case G_LOG_LEVEL_ERROR :    return  "ERR ";
	case G_LOG_LEVEL_DEBUG:     return  "DBG ";
	case G_LOG_LEVEL_CRITICAL : return  "CRIT";
	case G_LOG_LEVEL_MESSAGE:   return  "MSG ";
	case G_LOG_LEVEL_INFO :     return  "INFO";
	default:                    return  "LOG "; 
	}
}

static void
_log_write (const char* domain, GLogLevelFlags level, 
	    const gchar *msg)
{
	time_t now;
	ssize_t len;
	
	/* log lines will be truncated at 255 chars */
	char buf [512], timebuf [32];

	/* get the time/date string */
	now = time(NULL);
	strftime (timebuf, sizeof(timebuf), "%F %T", localtime(&now));
		
	/* now put it all together */
	len = snprintf (buf, sizeof(buf), "%s [%s] %s\n", timebuf, 
			pfx(level), msg);
	/* if the buffer is full, add a newline */ 
	if (len == sizeof(buf))
		buf[sizeof(buf)-2] = '\n';
	
	len = write (MU_LOG->_fd, buf, len);
	if (len < 0)
		fprintf (stderr, "%s: failed to write to log: %s\n",
			 __FUNCTION__,  strerror(errno));

	if (!(MU_LOG->_quiet) && level & G_LOG_LEVEL_MESSAGE)
		g_print ("mu: %s\n", msg);
	
	/* for serious errors, log them to stderr as well */
	if (level & G_LOG_LEVEL_ERROR)
		g_printerr ("mu(e): %s\n", msg);
	else if (level & G_LOG_LEVEL_CRITICAL)
		g_printerr ("mu(c): %s\n", msg);
	else if (level & G_LOG_LEVEL_WARNING)
		g_printerr ("mu(w): %s\n", msg);
}