#!/bin/bash

#set -o xtrace
set -u
set -o pipefail

UMASK="$(umask)"

cprompt () {
  if [[ $UNATTENDED == "true" ]]; then
    return;
  fi
  read -r -s -N 1 -p "Press 'Enter' to backup, 'Escape' to skip..."
  if [[ $REPLY != $'\n' ]]; then
    printf "backup skipped!\n"
    return 1
  else
    printf "backup starting.\n"
  fi
}

usage () {
  printf "v2b.sh <option> [ <prefix> ]\n"
  printf "  <prefix> only backup volumes with this prefix\n"
  printf "  option: k (keep existing backups)\n"
  printf "  option: p (remove prefix from tar archive file name\n"
  printf "  option: u (unattended backup)\n"
  printf "  option: s <address> (send backup directly to remote address via ssh)\n"
}

SEND="false"
ADDR=""
REMOVE="false"
KEEP="false"
UNATTENDED="false"

OUTPUT=""
while getopts ':s:pku' OPT; do
  case $OPT in
    s) SEND="true"; ADDR="${OPTARG}"; OUTPUT="${OUTPUT}  Option: SEND BACKUPS\n";;
    p) REMOVE="true"; OUTPUT="${OUTPUT}  Option: PREFIXES REMOVED\n";;
    k) KEEP="true"; OUTPUT="${OUTPUT}  Option: KEEP EXISTING BACKUPS\n";;
    u) UNATTENDED="true"; OUTPUT="${OUTPUT}  Option: UNATTENDED BACKUP\n";;
    \?) usage; exit;;
  esac
done
shift $((OPTIND -1))

FOLDER="_vols_"

if [[ $# > 0 ]]; then
  VOLUMES="$(sudo docker volume ls -q |grep "${1}_")"
else
  VOLUMES="$(sudo docker volume ls -q)"
fi

if [[ -z $VOLUMES ]]; then
  printf "Cannot find volumes spec: ${1}_\n"
  exit 1
fi

if [[ -d ${FOLDER} ]]; then
  LASTF="$(ls -d --format=single-column ${FOLDER}* |tail -n1)"
else
  LASTF="${FOLDER}"
fi

INDEX="$((( ${LASTF#${FOLDER}} + 0 )))"
NEWFL="${FOLDER}$(printf "%05d" $((( ${INDEX} + 1 ))))"
TEMPF="$(mktemp -dt -p $PWD _XXXXXXXXXXXXXXX_)"

for VOL in ${VOLUMES}; do
  if [[ $REMOVE == "true" ]]; then
    if [[ $# > 0 ]]; then
      TAR="${VOL#${1}_}.tar.bz2"
    else
      TAR="${VOL#*_}.tar.bz2"
    fi
  else
    TAR="${VOL}.tar.bz2"
  fi
  printf "\n${VOL} --> ${TEMPF}/${TAR}\n"
  cprompt || continue
  sudo docker run --rm --log-driver none \
    -v "${VOL}:/volume" \
    -v "${TEMPF}:/backup" \
    loomchild/volume-backup backup -v "${TAR}"
  if [[ -f "${TEMPF}/${TAR}" ]]; then
    sudo chmod 600 "${TEMPF}/${TAR}"
  fi
done

if [[ -z "$(ls -A ${TEMPF})" ]]; then
  rmdir "${TEMPF}"
else
  if [[ $KEEP == "true" ]]; then
    mv "${FOLDER}" "${NEWFL}"
  else
    rm -rf "${FOLDER}"
  fi
  if mv "${TEMPF}" "${FOLDER}"; then
    if [[ $SEND == "true" ]]; then
      if [[ $ADDR =~ ":" ]]; then
        if sudo ssh "${ADDR%:*}" "mkdir -p ${ADDR#*:}"; then
          sudo scp "${FOLDER}"/* "${ADDR}"
        fi
      else
        if sudo ssh "${ADDR}" "mkdir -p ${PWD}/_$(hostname -f)_"; then
          sudo scp "${FOLDER}"/* "${ADDR}:${PWD}/_$(hostname -f)_"
        fi
      fi
    fi
  fi
fi

set +o xtrace