#!/bin/bash
# I, Ian Kelling, follow the GNU license recommendations at
# https://www.gnu.org/licenses/license-recommendations.en.html. They
# recommend that small programs, < 300 lines, be licensed under the
# Apache License 2.0. This file contains or is part of one or more small
# programs. If a small program grows beyond 300 lines, I plan to switch
# its license to GPL.

# Copyright 2024 Ian Kelling

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#     http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


if ! test "$BASH_VERSION"; then echo "error: shell is not bash" >&2; exit 1; fi
shopt -s inherit_errexit 2>/dev/null ||: # ignore fail in bash < 4.4
set -eE -o pipefail
trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" exit status: $?, PIPESTATUS: ${PIPESTATUS[*]}" >&2' ERR

## This would delete backups that we already have in snapshots,
## 1 second granularity, so we could have some duplicates. However,
## this doesn't account for files received then accidentally deleted,
## all in between two snapshots, so they aren't in any snapshot.
## So, instead, just keep a bunch of backups based on time.

# cd /mnt/o/btrbk
# tmp=(o*)
# last_snap_date=${tmp[-1]#o.}
# time=$(( $(date -d $(sed -r  's/(.{4})(..)(.{5})(..)(.*)/\1-\2-\3:\4:\5/' <<<$last_snap_date) +%s) -1 ))
# find /bu/md -type f \! -newermt @$time -delete

if [[ ! -d /bu/md ]]; then
  exit 0
fi

find /bu/md -type f -mtime +100 -delete