#!/bin/sh

set -e

LIFEBOAT_ROOT=${LIFEBOAT_ROOT:-"/srv/backup/lifeboat"}

err() {
	printf "lifeboat: %s\n" "$1" >&2
}

errx() {
	err "$1"
	exit 1
}

usage() {
	printf "usage: lifeboat repo [run|restic-cmd]\n"
	exit 1
}

report_backup() {
	cd "$LIFEBOAT_ROOT/$repo"

	test -r config/recipient || errx "Could not read recipient from config/recipient"
	read -r recipient < config/recipient
	test -n "$recipient" || errx "No recipient given in config/recipient"

	cat <<-EOF | sendmail "$recipient"
		From: Lifeboat <lifeboat@$(hostname -f)>
		Subject: lifeboat: backup for $repo on $(date)
		X-Report: lifeboat

		$(run_backup 2>&1)
	EOF
}

run_backup() {
	cd "$LIFEBOAT_ROOT/$repo"

	for i in run retain clean sync; do
		if test -x $i; then
			./$i
		else
			${i}_default;
		fi
	done
}

run_default() {
	restic-priv backup --files-from config/include --exclude-file config/exclude --exclude-caches
}

retain_default() {
	restic forget --keep-daily 7 --keep-weekly 5 --keep-monthly 12 --keep-yearly 2
}

clean_default() {
	restic check --read-data-subset 10%
	restic prune
}

sync_default() {
	test -r config/sync || return 0

	while read -r target_spec; do
		target=$(echo "$target_spec" | cut -f1)
		limit=$(echo "$target_spec" | cut -sf2)

		test -n "$target" || errx "Empty target in config/sync"

		if test -n "$limit" && test "$(du -s "$RESTIC_REPOSITORY" | cut -f1)" -gt "$limit"; then
			err "Warning: size threshold exceeded, skipping sync to $target/$LIFEBOAT_REPO_NAME"
			continue
		fi

		rclone sync --transfers 20 --fast-list "$RESTIC_REPOSITORY" "$target/$LIFEBOAT_REPO_NAME" || err "skipping upload to $target"
	done < config/sync
}

test $# -lt 2 && usage

repo=$1
shift

test -d "$LIFEBOAT_ROOT/$repo" || errx "$repo: no such repository"

export PATH="$HOME/bin:$PATH"
export LIFEBOAT_REPO_NAME="$repo"
export RESTIC_REPOSITORY="$LIFEBOAT_ROOT/$repo/repo"
export RESTIC_PASSWORD_FILE="$LIFEBOAT_ROOT/$repo/credentials/restic"

case "$1" in
	run) run_backup;;
	run-report) report_backup;;
	*) restic "$@";;
esac