#!/bin/bash

set -exu

ssh="ssh -o StrictHostKeyChecking=no -o ConnectTimeout=5 root@${server_ip}"
bookmark_prefix="auto-mirror_"
new_bookmark="$bookmark_prefix$(date +"%Y-%m-%d_%H:%M:%S")"

for dataset in $(zfs list -t filesystem -H -o name)
do
  echo "MIRRORING $dataset"
  
  if ! $ssh sudo zfs list -t filesystem -H -o name | grep -q "^$dataset$"
  then
    echo "CREATING PARENT DATASET..."
    $ssh sudo zfs create -p -o mountpoint=none "$dataset"
  fi

  zfs snap "$dataset@$new_bookmark"
  
  if zfs list -t bookmark -H -o name | grep "^$dataset#$bookmark_prefix" | wc -l | grep -q "^0$"
  then
    echo "INITIAL BACKUP"
    # do in subshell, otherwise ctr+c will lead to 0 exitcode  
    $(zfs send -v "$dataset@$new_bookmark" | $ssh sudo zfs recv -F "$dataset" -o mountpoint=none)
  else
    echo "INCREMENTAL BACKUP"
    last_bookmark=$(zfs list -t bookmark -H -o name | grep "^$dataset#$bookmark_prefix" | sort | tail -1 | cut -d '#' -f 2)
    [[ -z "$last_bookmark" ]] && echo "ERROR - last_bookmark is empty" && exit 98
    $(zfs send -v -i "#$last_bookmark" "$dataset@$new_bookmark" | $ssh sudo zfs recv "$dataset" -o mountpoint=none)
  fi

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