#!/bin/bash

# usage: $0
# this script is idempotent

# warning: changes here may affect the close version of this script


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

m() { printf "%s\n" "$*";  "$@"; }


fs_file=/root/crypt-luks-keys-loopback
mapper_name=crypt-luks-keys-loopback

l=$(losetup -j $fs_file | sed -rn 's/^([^ ]+): .*/\1/p' | head -n1 ||:)
if [[ $l ]]; then
  echo "$0: skipping losetup due to existing loopback: $l"
else
  l=$(losetup -f)
  m losetup $l $fs_file
fi
if cryptsetup status /dev/mapper/$mapper_name &>/dev/null; then
  echo "$0: skipping cryptsetup due to existing /dev/mapper/$mapper_name"
else
  if ! cryptsetup luksOpen $l $mapper_name; then
    echo "$0: error luksOpen failed. detaching loopback" >&2
    m losetup -d $l
    exit 1
  fi
fi
if mountpoint -q /dev/mapper/$mapper_name; then
  echo "$0: skipping mount /dev/mapper/$mapper_name /mnt2 due to existing mount"
else
  m mount /dev/mapper/$mapper_name /mnt2
fi