#!/bin/bash
# Prepare and Handle USB-Disk for encrypted Backup
# Must be run as root to allow correct permissions and file access
# (and also permission change for fuse!)
#
#  (c) by Robert Lange <sd2k9@sethdepot.org>
#  GNU General Public Licence applies
#
#  Project URL: https://github.com/sd2k9/documentation


# *** Settings ***
# Treat uninitialised variable as error and exit script
set -u

# Source device
# UPDATE: Disk partition name
readonly MNT_SRC=/dev/sda1
readonly MNT_CRYPT=backup_offline_crypt
readonly MNT_DEST=/media/backup_offline
# readonly GPG_PWDFILE=~USERNAME/.gnupg/backup_passwd.txt.gpg
# readonly GPG_HOME=~USERNAME/.gnupg/
readonly PROGNAME=${0##*/}

# When set derive password from existing volume,
# otherwise prompt for encryption password
# Query gnupg with string "gnupg"
# readonly MNT_DERIVE=gnupg
# readonly MNT_DERIVE=main_crypt
readonly MNT_DERIVE=

# Virtualbox paths
# UPDATE: Adapt path accordingly
readonly VBOX_IN_DIR=/opt/virtualbox/
readonly VBOX_OUT_DIR=${MNT_DEST}/virtualbox-backup

# Logfile
readonly RS_LOG=/tmp/do-backup.log
# local Hostname
readonly HOSTNAME=$(hostname)


# From command line
# Test mode: True when defined (only echo commands)
TESTMODE=
# Selected Command (see help)
COMMAND_MODE=
# Option to Command (2nd parameter)
COMMAND_1P=
# Option to Command (3nd parameter)
COMMAND_2P=


# *** Functions ***
# Abort on tool error (errorcode <> 0)
function abort_on_error() {
    local err
    err=$1
    shift
    if [ $err -ne 0 ]; then
	   echo "Program execution failed with error code $err!"
	   exit 1
    fi
}


# Execute this tool
# Caution: Use "\"text with spaces\"" to escape spaces
function exec_tool() {
    echo "$@"
   if [[ -z "$TESTMODE" ]]; then
       eval "$@"
       abort_on_error $?
   fi
}

root_check() {
  if [[ $EUID -ne 0 ]]; then
      echo "This script must be run as root" 1>&2
      if [[ -z "$TESTMODE" ]]; then # Ignore in testmode
	  exit 1
      fi
 fi
}


# Mount encrypted volume
do_mount() {
    if [[ ! -d "$MNT_DEST" ]]; then 
	echo "Create mount directory"
	exec_tool mkdir -v $MNT_DEST
    fi

    echo "Open encrypted volume $MNT_SRC as $MNT_CRYPT ..."
    if [[ "$MNT_DERIVE" == "gnupg" ]]; then
	echo "Get password from GnuPG file ${GPG_PWDFILE}"
	exec_tool gpg --homedir ${GPG_HOME} --decrypt --quiet ${GPG_PWDFILE} \| \
	          cryptsetup open --type luks $MNT_SRC $MNT_CRYPT --key-file -
    elif [[ -n "$MNT_DERIVE" ]]; then
	echo "Derive password from device $MNT_DERIVE"
	exec_tool /lib/cryptsetup/scripts/decrypt_derived $MNT_DERIVE \| \
	          cryptsetup open --type luks $MNT_SRC $MNT_CRYPT
    else
	echo "Ask for password"
	exit 1
	exec_tool cryptsetup open --type luks $MNT_SRC $MNT_CRYPT
    fi

    echo "Now mount device with btrs to $MNT_DEST"
    exec_tool mount -t btrfs -o async,noatime,nodev,nosuid,compress=zlib,noexec /dev/mapper/$MNT_CRYPT $MNT_DEST
}

# Un-Mount encrypted volume
do_umount() {
  echo "Unmounting device ..."
  exec_tool umount $MNT_DEST

  echo "Closing encrypted volume"
  exec_tool cryptsetup luksClose $MNT_CRYPT

  echo "Remove mount directory"
  exec_tool rmdir -v $MNT_DEST
}


# Run standard backup
do_backup() {
  echo "Do the backup on $HOSTNAME"

  # Preparation
  exec_tool aptitude clean


  # Create user readable logfile
  exec_tool touch $RS_LOG
  exec_tool chmod u=rw,og=r $RS_LOG

  # Run backup
  exec_tool btrfs-backup -c ../../../etc/btrfs-backup/backup-full.conf snap rotate \|\& tee $RS_LOG

  echo "Done - Logfile in $RS_LOG"
}

# Run Virtualbox backup
do_vbox_backup() {
  echo "Do the Virtualbox backup on $HOSTNAME"
  local file
  local outfile


  # Check for input and output directory existance
  if [ ! -d "$VBOX_IN_DIR" ]; then
    echo "Input directory $VBOX_IN_DIR not found!"
    exit 1
  fi
  if [ ! -d "$VBOX_OUT_DIR" ]; then
    echo "Output directory $VBOX_OUT_DIR not existing!"
    exit 1
  fi

  # Run rsync backup
  # This call checks the file(s) and only transfers differences
  # exec_tool rsync -aHAXER -hvv --progress --numeric-ids --inplace --no-whole-file \
  #           --delete-delay \"$VBOX_IN_DIR\" \"$VBOX_OUT_DIR/\"
  # When the files are always different (like the Work Windows VM) then the
  # checking takes longer as the actual transfer. So just transfer the files
  exec_tool rsync -aHAXER -hvv --progress --numeric-ids --inplace --whole-file \
            --partial --delete-delay \"$VBOX_IN_DIR\" \"$VBOX_OUT_DIR/\"

  # Update timestamp
  echo "Update Backup timestamp"
  echo "   date -I > ${VBOX_OUT_DIR}/backup_timestamp.txt"
  [ -z "$TESTMODE" ] && date -I > ${VBOX_OUT_DIR}/backup_timestamp.txt

  echo "Done"
}


# Check backup size
do_check_backup_size() {
  echo "Check backup size"
  # local TASKS

  # echo "rsnapshot du - DISABLED RUNS TOO LONG"
  # [ -z "$TESTMODE" ] && rsnapshot du
  btrfs fi usage ${MNT_DEST}
}

# Wait for keypress
do_wait() {
    echo "Waiting for keypress to continue ..."
    read -n 1
}



# *** Kommandozeile auswerten
get_options() {
  local opt
  local argcounter=1

  while [ -n "$*" ] ; do
      opt="$1"
      shift
      case $opt in
          -t|--test|--dry-run)
          # Test Mode
       	  TESTMODE=1
      	;;
          -V|--version)
          # Version output
          echo "$PROGNAME"
          echo "(c) by Robert Lange (sd2k9@sethdepot.org)"
	  echo "Project URL: https://github.com/sd2k9/documentation"
          exit 0
          ;;
          -h|--help|'-?')
          # Hilfetext
          echo "$PROGNAME - Prepare and Handle USB-Disk for encrypted Backup"
          echo
          echo "Call: $PROGNAME command [options]"
          echo
          echo "General Options:"
          echo "[-t|--test|--dry-run] - Do not execute commands/burning, only echo"
          echo "       [-V|--version] - Print program version and exit"
          echo
	  echo "Command: mount"
	  echo "   Mount encrypted disk only"
	  echo
	  echo "Command: umount"
	  echo "   Un-Mount encrypted disk only"
	  echo
	  echo "Command: backup"
	  echo "   Mount, run backup, run virtualbox backup, check size, Wait, Un-Mount"
	  echo
	  echo "Command: backup-only"
	  echo "   Run only the backup itself"
	  echo
	  echo "Command: vbox-only"
	  echo "   Run only the Virtualbox backup"
	  echo
          exit 0
        ;;
          *)
          # Store arguments in variables
     	  case $argcounter in
      	    1)
      		COMMAND_MODE="$opt"
      		;;
      	    2)
      		COMMAND_1P="$opt"
      		;;
      	    3)
      		COMMAND_2P="$opt"
      		;;
      	    *)
                  # Too many arguments
  	        echo "Too many arguments! See help text for usage"
  		exit 1
  		;;
      	  esac
          #increment argument counter
          let argcounter++
      	;;
      esac
  done
}

# *** Call Command Line Parsing
# When no options supplied then call help
if [ -z "$*" ]; then
    get_options "--help"
else
    get_options "$@"
fi

# echo $COMMAND_MODE
# *** Select working mode ***
case "$COMMAND_MODE" in
 mount)
   root_check
   do_mount
   ;;
 umount)
   root_check
   do_umount
   ;;
 backup)
   root_check
   do_mount
   do_backup
   do_vbox_backup
   do_check_backup_size
   do_wait
   do_umount
   ;;
 backup-only)
   root_check
   do_backup
   ;;
 vbox-only)
   root_check
   do_vbox_backup
   ;;
 *)
   echo "Unknown Function \"$COMMAND_MODE\" requested!"
   exit 1
   ;;
esac


echo
echo "Done"