#!/bin/sh

# This is a backup script that takes snapshots of your device
# In a Time Machine like fashion. You can add this to root's
# crontab for regular backups

# Config
readonly SSH_HOST=192.168.1.34
readonly SSH_USER=pi
readonly SSH_KEY="/home/yigit/.ssh/id_skeleton"
readonly BACKUP_DESTINATION="~/snapshots/backups"
readonly RSYNC_PROFILE="$SSH_USER@$SSH_HOST:$BACKUP_DESTINATION"

[ $(id -u) != "0" ] && printf "This program must be run as root!\n" && exit

alias ssh_cmd="ssh -i \"$SSH_KEY\" $SSH_USER@$SSH_HOST"
[ -f "$XDG_CACHE_HOME/dbus_settings" ] && "$XDG_CACHE_HOME/dbus_settings" # Load the dbus settings for current session


displays="$(ps -u $(id -u) -o pid= \
| xargs -I PID -r cat /proc/PID/environ 2> /dev/null \
| tr '\0' '\n' \
| grep ^DISPLAY=: \
| sort -u \
| xargs \
| cut -d ":" -f2)"
notify() {
        IFS="\n"
        for x in $displays; do
                export DISPLAY=$x
                notify-send --app-name="$1" "$2"
        done ;
}

notify " Periodic backup" "Backup is starting"

DEVICE=tatooine
OPT="-aPh"
SNAP="$RSYNC_PROFILE/$DEVICE/"
date=$(date "+%d.%m.%Y_%I:%M")
older=$(date --date="4 days ago" "+%d.%m.%Y_%I:%M")
# You should enter absolute paths
DIRS="/home/yigit
/etc
/var/lib
/var/spool
/usr/src/linux"

# Check whether backup server is available on network
timeout 3 ssh -i "$SSH_KEY" $SSH_USER@$SSH_HOST id < /dev/null > /dev/null 2> /dev/null || echo "SSH Failed." || exit
ssh -i "$SSH_KEY" $SSH_USER@$SSH_HOST rm -rf "$BACKUP_DESTINATION/$DEVICE/$older" > /dev/null 2> /dev/null

# Run rsync to create snapshot
while IFS= read -r DIR
do
  LINK="--link-dest=/home/$SSH_USER/snapshots/tatooine/last$DIR/"
  ssh -i "$SSH_KEY" $SSH_USER@$SSH_HOST mkdir -p "$BACKUP_DESTINATION/$DEVICE/$date$DIR" < /dev/null
  rsync --exclude '.cache' "$@" -e "ssh -i $SSH_KEY" $OPT "$LINK" "$DIR/" "${SNAP}$date$DIR/"
done << EOF
$DIRS
EOF

# Remove symlink to previous snapshot
ssh_cmd rm -f "$BACKUP_DESTINATION/$DEVICE/last" < /dev/null

# Create new symlink to latest snapshot for the next backup to hardlink
ssh -i "$SSH_KEY" $SSH_USER@$SSH_HOST ln -s "$BACKUP_DESTINATION/$DEVICE/$date" "$BACKUP_DESTINATION/$DEVICE/last" < /dev/null

# pidof slock > /dev/null && { # Shutdown if screen inhibition is enabled
#   shutdown -h now
# }