#!/bin/bash

set -e
set -x

path=$1
uuid=$(jq -r .client_uuid < /etc/backup/config.json)
server=$(jq -r .server_hostname < /etc/backup/config.json)
ssh="ssh -o StrictHostKeyChecking=no backup-receiver@$server"

source_dataset=$(zfs list -H -o mountpoint,name | grep -P "^$path\t" | cut -d $'\t' -f 2)
target_dataset="tank/$uuid/$source_dataset"
target_dataset_parent=$(echo $target_dataset | rev | cut -d / -f 2- | rev)
new_bookmark="auto-backup_$(date +"%Y-%m-%d_%H:%M:%S")"

echo "BACKUP ZFS DATASET - PATH: $path, SERVER: $server, UUID: $uuid, SOURCE_DATASET: $source_dataset, TARGET_DATASET: $TARGET_DATASET"

if ! $ssh sudo zfs list -t filesystem -H -o name | grep -q "^$target_dataset_parent$"
then
  echo "CREATING PARENT DATASET..."
  $ssh sudo zfs create -p -o mountpoint=none "$target_dataset_parent"
fi

zfs snap $source_dataset@$new_bookmark

if zfs list -t bookmark -H -o name | grep '#auto-backup' | wc -l | grep -q "^0$"
then
  echo "INITIAL BACKUP"
  zfs send -v "$source_dataset@$new_bookmark" | $ssh sudo zfs recv -F $target_dataset
else
  echo "INCREMENTAL BACKUP"
  last_bookmark=$(zfs list -t bookmark -H -o name | sort | tail -1 | cut -d '#' -f 2)
  zfs send -v -i "#$last_bookmark" "$source_dataset@$new_bookmark" | $ssh sudo zfs recv $target_dataset
fi

if [[ "$?" == "0" ]]
then
  zfs bookmark "$source_dataset@$new_bookmark" "$source_dataset#$new_bookmark"
  zfs destroy "$source_dataset@$new_bookmark"
  echo "SUCCESS"
else
  zfs destroy "$source_dataset@$new_bookmark"
  echo "ERROR"
  exit 99
fi