{ pkgs, ... }: {

  systemd = {
    timers.backup-timer = {
      wantedBy = [ "timers.target" ];
      partOf = [ "backup-timer.service" ];
      timerConfig.OnCalendar = "*-*-* 4:00:00";
    };
    services.backup-timer = {
      serviceConfig.Type = "oneshot";
      script = ''
        BKG_DIR=/var/backup

        EXCLUDE_APPS=("s3/")
        EXCLUDE_VOLUMES=("wireguard_data")
        EXCLUDE_CLEANUP=("s3/")

        DAYS=7              # how many days should daily backups be stored
        DF=daily            # folder name for daily backups
        WF=weekly           # folder name for weekly backups
        MF=monthly          # folder name for monthly backups

        MBD=22              # day of month for monthly backup
        WBD=3               # weekday for weekly backups
        PV=podman-volumes   # folder name for podman volumes

        cd $BKG_DIR
        PODMAN_VOLUMES=$(podman volume ls --format '{{.Name}}')
        # Podman volume backup
        if [ ! -d $PV ]; then
            mkdir $PV
        fi
        for vol in $PODMAN_VOLUMES; do
            if [[ " $\{EXCLUDE_VOLUMES[@]} " =~ " $\{vol} " ]]; then
                continue
            fi
            cd $BKG_DIR/$PV
            podman volume export $vol --output $vol.tar ; gzip $vol.tar
        done

        BACKUP_APPS=$(fd . -td -d 1 $BKG_DIR)
        # App backup
        for bkg in $BACKUP_APPS; do
            if [[ " $\{EXCLUDE_APPS[@]} " =~ " $\{bkg} " ]]; then
                continue
            fi
            cd $bkg
            #monthly
            if [ ! -d $MF ]; then
        	mkdir $MF
            fi
            DOM=$(date +%d)
            if [ $DOM -eq $MBD ]; then
        	 fd . -tf -d 1 -x cp {/} $MF/$(date +"%Y%m")-{/}
            fi

            #weekly
            if [ ! -d $WF ]; then
        	mkdir $WF
            fi
            DOW=$(date +%u)
            if [ $DOW -eq $WBD ]; then
        	 fd . -tf -d 1 -x cp {/} $WF/$(date +"%U%Y")-{/}
            fi

            #dailies
            if [ ! -d $DF ]; then
        	mkdir $DF
            fi
            fd . -tf -d 1 -x mv {/} $DF/$(date +"%Y%m%d")-{/}
        done

        # Delete old backups
        for bkg in $BACKUP_APPS; do
            if [[ " $\{EXCLUDE_CLEANUP[@]} " =~ " $\{bkg} " ]]; then
                continue
            fi
            fd . $bkg"daily" --changed-before "$DAYS days" -x rm
            fd . $bkg"weekly" --changed-before "4 weeks" -x rm
            fd . $bkg"monthly" --changed-before "8 weeks" -x rm
        done
      '';
    };
  };

}