#!/usr/bin/env bash
#
# cron: 0 1 * * *  rdiffbak.sh &
#
# SPDX-License-Identifier: MIT

# -------------
# CONFIG
# -------------

MAILTO="me@example.com"
MAILSUB="backup report"
# name of the entry in ~/.mailrc
MAILSRV="example"

SRC="/home/foobar"
DST="/data/foobar"
LOG="/data/bkplog"
MAXAGE="1M"

RDIFF="/usr/bin/rdiff-backup"
OPTIONS="--exclude-fifos --exclude-sockets --print-statistics"

TIMESTAMP=$(date +%Y-%m-%d_%H%M)
LOGFILE="${LOG}/${TIMESTAMP}_backup.log"

mkdir -p "$LOG" || exit 1
function mailme() {
  # ~/.mailrc needs to be configured
  if [[ -f "${LOGFILE}" ]]; then
    echo " -- EOF -- " >> "${LOGFILE}"
    # shellcheck disable=SC2002
    cat "${LOGFILE}" | mail -A "$MAILSRV" -s "${MAILSUB}" ${MAILTO}
  fi
}

# ---------------
# BACKUP
# ---------------

echo " -- $TIMESTAMP -- " >> "${LOGFILE}"

if [[ ! -d "$SRC" ]]; then
  echo "$TIMESTAMP Invalid SRC, aborting... " >> "${LOGFILE}"
  mailme
  exit 1
fi
if [[ ! -d "$DST" ]]; then
  echo "$TIMESTAMP Invalid DST, aborting... " >> "${LOGFILE}"
  mailme
  exit 1
fi

echo "Backup: $RDIFF $OPTIONS $SRC $DST" >> "${LOGFILE}"

$RDIFF "$OPTIONS" "$SRC" "$DST" >> "${LOGFILE}"
RDRES=$?

# It went well, remove stuff older than MAXAGE
if [[ $RDRES -eq 0 ]]; then
  $RDIFF --force --remove-older-than "$MAXAGE" "$DST" >> "${LOGFILE}"
else
  echo "rdiff backup failed, exit: $RDRES" >> "${LOGFILE}"
  mailme
  exit 1
fi

find "${LOG}" -type f -mtime +30 -delete
mailme
exit 0