/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) version 3.
 *
 * 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with the program; if not, see <http://www.gnu.org/licenses/>
 *
 *
 * Authors:
 *		Jeffrey Stedfast <fejj@ximian.com>
 *
 * Copyright (C) 1999-2008 Novell, Inc. (www.novell.com)
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

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

#include <libedataserver/e-data-server-util.h>
#include "e-util.h"
#include "e-mktemp.h"

#define d(x)

/* define to put temporary files in ~/evolution/cache/tmp */
#define TEMP_HOME (1)

/* how old things need to be to expire */
#define TEMP_EXPIRE (60*60*2)
/* dont scan more often than this */
#define TEMP_SCAN (60)

static gint
expire_dir_rec(const gchar *base, time_t now)
{
	GDir *dir;
	const gchar *d;
	GString *path;
	gsize len;
	struct stat st;
	gint count = 0;

	d(printf("expire dir '%s'\n", base));

	dir = g_dir_open(base, 0, NULL);
	if (dir == NULL)
		return 0;

	path = g_string_new(base);
	len = path->len;

	while ( (d = g_dir_read_name(dir)) ) {
		g_string_truncate(path, len);
		g_string_append_printf(path, "/%s", d);
		d(printf("Checking '%s' for expiry\n", path->str));

		if (g_stat(path->str, &st) == 0
		    && st.st_atime + TEMP_EXPIRE < now) {
			if (S_ISDIR(st.st_mode)) {
				if (expire_dir_rec(path->str, now) == 0) {
					d(printf("Removing dir '%s'\n", path->str));
					g_rmdir(path->str);
				} else {
					count++;
				}
			} else if (g_unlink(path->str) == -1) {
				d(printf("expiry failed: %s\n", g_strerror(errno)));
				count++;
			} else {
				d(printf("expired %s\n", path->str));
			}
		} else {
			count++;
		}
	}
	g_string_free(path, TRUE);
	g_dir_close(dir);

	d(printf("expire dir '%s' %d remaining files\n", base, count));

	return count;
}

static GString *
get_dir (gboolean make)
{
	GString *path;
	time_t now = time(NULL);
	static time_t last = 0;

#ifdef TEMP_HOME
	gchar *tmpdir = NULL;
	tmpdir = g_build_filename(e_get_user_data_dir (),
		"cache", "tmp", NULL);
	path = g_string_new(tmpdir);
	if (make && g_mkdir_with_parents(tmpdir, 0777) == -1) {
		g_string_free(path, TRUE);
		path = NULL;
	}
	g_free(tmpdir);
#else
	path = g_string_new("/tmp/evolution-");
	g_string_append_printf (path, "%d", (gint) getuid ());
	if (make) {
		gint ret;

		/* shoot now, ask questions later */
		ret = g_mkdir (path->str, S_IRWXU);
		if (ret == -1) {
			if (errno == EEXIST) {
				struct stat st;

				if (g_stat (path->str, &st) == -1) {
					/* reset errno */
					errno = EEXIST;
					g_string_free (path, TRUE);
					return NULL;
				}

				/* make sure this is a directory and belongs to us... */
				if (!S_ISDIR (st.st_mode) || st.st_uid != getuid ()) {
					/* eek! this is bad... */
					g_string_free (path, TRUE);
					return NULL;
				}
			} else {
				/* some other error...do not pass go, do not collect $200 */
				g_string_free (path, TRUE);
				return NULL;
			}
		}
	}
#endif

	d(printf("temp dir '%s'\n", path ? path->str : "(null)"));

	/* fire off an expiry attempt no more often than TEMP_SCAN seconds */
	if (path && (last+TEMP_SCAN) < now) {
		last = now;
		expire_dir_rec(path->str, now);
	}

	return path;
}

gchar *
e_mktemp (const gchar *template)
{
	GString *path;
	gint fd;

	path = get_dir (TRUE);
	if (!path)
		return NULL;

	g_string_append_c (path, '/');
	if (template)
		g_string_append (path, template);
	else
		g_string_append (path, "unknown-XXXXXX");

	fd = g_mkstemp (path->str);

	if (fd != -1) {
		close (fd);
		g_unlink (path->str);
	}

	return g_string_free (path, fd == -1);
}

gint
e_mkstemp (const gchar *template)
{
	GString *path;
	gint fd;

	path = get_dir (TRUE);
	if (!path)
		return -1;

	g_string_append_c (path, '/');
	if (template)
		g_string_append (path, template);
	else
		g_string_append (path, "unknown-XXXXXX");

	fd = g_mkstemp (path->str);
	g_string_free(path, TRUE);

	return fd;
}

gchar *
e_mkdtemp (const gchar *template)
{
	GString *path;
	gchar *tmpdir;

	path = get_dir (TRUE);
	if (!path)
		return NULL;

	g_string_append_c (path, '/');
	if (template)
		g_string_append (path, template);
	else
		g_string_append (path, "unknown-XXXXXX");

#ifdef HAVE_MKDTEMP
	tmpdir = mkdtemp (path->str);
#else
	{
		gint fd = g_mkstemp (path->str);
		if (fd == -1) {
			tmpdir = NULL;
		} else {
			close (fd);
			tmpdir = path->str;
			g_unlink (tmpdir);
		}
	}

	if (tmpdir) {
		if (g_mkdir (tmpdir, S_IRWXU) == -1)
			tmpdir = NULL;
	}
#endif
	g_string_free(path, tmpdir == NULL);

	return tmpdir;
}