#!/bin/sh
set -eu
cd $HOME
LOG=.cache/duplicity/log
PATH=$PATH:/sbin:/usr/sbin

# do backup every day
if [ -e "$LOG" ] && [ $(( `date +%s` - `stat -c %Y $LOG` )) -lt 86300 ]; then
    exit 0
fi

# figure out $DISPLAY when running from cron
export DISPLAY="${DISPLAY:-:0}"

if ! ip route | grep -q '^default.*wl'; then
    notify-send "Backup skipped, not on WLAN"
    exit 0
fi

# figure out ssh agent when running from cron
if [ -z "${SSH_AUTH_SOCK:-}" ]; then
    ssh_socket=$(ls /run/user/`id -u`/keyring*/ssh 2>/dev/null)
    if [ -S "$ssh_socket" ]; then
        export SSH_AUTH_SOCK="$ssh_socket"
    fi
fi

notify-send "Backup started"
mkdir -p $(dirname $LOG)
env PASSPHRASE="$(cat ~/.backup-passphrase)" duplicity --allow-source-mismatch --full-if-older-than 1M --exclude-filelist .duplicity-ignore . rsync://piware.de/backup/laptop >> $LOG || { notify-send "BACKUP FAILED!"; exit 1; }
notify-send "Backup finished successfully"
duplicity remove-all-but-n-full 6 --force rsync://piware.de/backup/laptop