<?php
/**
 * Rotational Backup for ALL-INKL.COM
 * 
 * Copyright (c) 2018 Helmut Kaczmarek <email@helmutkaczmarek.de>
 * 
 * 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, see <http://www.gnu.org/licenses/>.
 * 
 * Features:
 * Creates the following folder structure and rotates it:
 * current -> /path/to/backup/daily.0
 * daily.0
 * daily.1
 * daily.2
 * daily.3
 * daily.4
 * daily.5
 * daily.6
 * daily.7
 * 
 * Usage:
 * If the script is to be executed automatically via KAS cron job, it must 
 * be accessible on the web. Alternatively, it can be run manually via 
 * shell with the following command: "php /path/to/script.php"
 * 
 * Pitfall wrong PHP CLI version, then e.g.
 * "/usr/bin/php81 /path/to/script.php" for PHP 8.1
 * 
 * Restore folder(s):
 * rsync -avz --progress /backup/folder/ /folder/to/be/restored
 * 
 * @author Helmut Kaczmarek <email@helmutkaczmarek.de>
 * @link https://www.helmutkaczmarek.de
 * @todo You could also back up the directories to a remote server via 
 * SSH. However, at this point one would probably no longer be dependent on 
 * the "trimmed" KAS cron jobs from ALL-INKL.COM. A bash script and crontab 
 * would of course be the first choice in this case. 
 */
 
// Configuration variables
$SRC = "/www/htdocs/v0xxxxx/public_websites/";
$DEST = "/www/htdocs/v0xxxxx/backup/public_websites";
$NUM_BACKUPS = 7;
 
// Creating the directories
for ($i = 0; $i <= $NUM_BACKUPS; $i++) {
    mkdir($DEST . '/daily.' . $i, 0777, true);
}
 
// Delete the oldest backup
system('rm -rf ' . $DEST . '/daily.' . $NUM_BACKUPS);
 
// Rotation of backups
for ($i = $NUM_BACKUPS - 1; $i >= 0; $i--) {
    $prev = $i + 1;
    system('mv ' . $DEST . '/daily.' . $i . ' ' . $DEST . '/daily.' . $prev);
}
 
// Creating the new backup
system('rsync -arl --delete --stats --link-dest=' . $DEST . '/daily.1 ' . $SRC . ' ' . $DEST . '/daily.0');
 
// Symlink to the latest backup
unlink($DEST . '/current');
symlink($DEST . '/daily.0', $DEST . '/current');
 
?>