#!/bin/sh
# Copyright (C) 2026 Mailwake contributors
# SPDX-License-Identifier: AGPL-3.0-only
# License: https://www.gnu.org/licenses/agpl-3.0.html
# Back up a running Compose installation; execute as a user with Docker access.
set -eu

if [ "$#" -ne 2 ]; then
  echo "Usage: backup.sh /absolute/compose-directory /absolute/backup-directory" >&2
  exit 2
fi
case "$1:$2" in
  /*:/*) ;;
  *) echo "Use absolute directory paths." >&2; exit 2 ;;
esac
cd "$1"
umask 077
lock=".mailwake-backup.lock"
if ! mkdir "$lock" 2>/dev/null; then
  echo "Could not create $PWD/$lock. Check directory permissions and active backups." >&2
  exit 1
fi
restart=0
cleanup() {
  result=$?
  trap - EXIT
  if [ "$restart" -eq 1 ]; then
    docker compose start core >&2 || result=1
  fi
  rmdir "$lock" || result=1
  exit "$result"
}
trap cleanup EXIT
trap 'exit 130' INT
trap 'exit 143' TERM
container=$(docker compose ps -q core)
if [ -z "$container" ]; then
  echo "Start the Core service before running this backup." >&2
  exit 1
fi
mkdir -p "$2"
backup="$2/mailwake-$(date +%Y%m%d-%H%M%S)"
test ! -e "$backup"
staging="$backup.incomplete"
mkdir "$staging"
mkdir "$staging/data"
docker compose config > "$staging/compose.yaml"
docker inspect --format '{{.Image}}' "$container" > "$staging/image-id.txt"
docker image save --output "$staging/image.tar" "$(cat "$staging/image-id.txt")"
restart=1
docker compose stop core >&2
docker compose cp core:/data/. "$staging/data/" >&2
docker compose start core >&2
restart=0
mv "$staging" "$backup"
printf 'Backup saved: %s\n' "$backup"