#!/bin/bash

name="mktar-batch"
version="1.0"
read -r -d '' help_message <<-EOF
	Archive utility for scripting
	Usage: mktar-batch [--compress=ALGO] [--encrypt=ALSO --passphrase PASSWD] [--checksum=ALGO] [--name OUTFILE] INFILES
	Options:
	 --compress=ALGO                 compress archive with [none|gzip|xz|zstd|bzip2]
	 --checksum=ALGO                 create checksum with [none|sha1|sha256]
	 --encrypt=ALGO                  encrypt files with [none|gpg|age]
	 -h, --help                      print this message
	 -n FILE, --name FILE            name of backup file (Default: archive.tar)
	 -p PASSWD, --passphrase PASSWD  passphase for encryption
	 -v, --verbose                   show additional messages
	 -V, --version                   print version number and exit
EOF

source /usr/local/lib/mylib.bash

positional=()
verbose=0
compress=-1
encrypt=-1
checksum=-1
archive_fn=""
passphrase=""
while [[ $# -gt 0 ]]; do
  case $1 in

  --compress=no|--compress=none|--compress=0)
    debug_msg "Setting compress option to 0 (=none)"
    compress=0
    shift
    ;;

  --compress=gz|--compress=gzip|--compress=1)
    debug_msg "Setting compress option to 1 (=gzip)"
    compress=1
    shift
    ;;

  --compress=xz|--compress=2)
    debug_msg "Setting compress option to 2 (=xz)"
    compress=2
    shift
    ;;

  --compress=zst|--compress=zstd|--compress=3)
    debug_msg "Setting compress option to 3 (=zstd)"
    compress=3
    shift
    ;;

  --compress=bz2|--compress=bzip2|--compress=4)
    debug_msg "Setting compress option to 4 (=bzip2))"
    compress=4
    shift
    ;;

  --compress=*)
    attempted_compression="$(/usr/bin/printf "%s\n" "$1" | sed -e 's/^.*=//' )"
    error_msg "Bad compress option '${attempted_compression}'"
    ;;

  --checksum=no|--checksum=none|--checksum=0)
    debug_msg "Setting checksum option to 0 (=none)"
    checksum=0
    shift
    ;;

  --checksum=sha1|--checksum=1)
    debug_msg "Setting checksum option to 1 (=sha1)"
    checksum=1
    shift
    ;;

  --checksum=sha256|--checksum=2)
    debug_msg "Setting checksum option to 2 (=sha256)"
    checksum=2
    shift
    ;;

  --checksum=*)
    attempted_checksum="$(/usr/bin/printf "%s\n" "$1" | sed -e 's/^.*=//' )"
    error_msg "Bad checksum option '${attempted_checksum}'"
    ;;

  --encrypt=no|--encrypt=none|--encrypt=0)
    debug_msg "Setting encrypt option to 0 (=none)"
    encrypt=0
    shift
    ;;

  --encrypt=gpg|--encrypt=1)
    debug_msg "Setting encrypt option to 1 (=gpg)"
    encrypt=1
    shift
    ;;

  --encrypt=age|--encrypt=2)
    debug_msg "Setting encrypt option to 2 (=age)"
    encrypt=2
    shift
    ;;

  --encrypt=*)
    attempted_encryption="$(/usr/bin/printf "%s\n" "$1" | sed -e 's/^.*=//' )"
    error_msg "Bad encrypt option '${attempted_encryption}'"
    ;;

  -h|--help)
    help_msg
    shift
    ;;

  -n|--name)
    debug_msg "Setting output filename to ${2}"
    archive_fn="$2"
    shift; shift
    ;;

  -p|--passphrase)
    passphrase="$2"
    shift; shift
    ;;

  -v|--verbose)
    verbose=1
    shift
    ;;

  -V|--version)
    version_msg
    ;;

  *)
    debug_msg "Argument '${1}' added to positional array"
    positional+=("$1")
    shift
    ;;
  esac
done

# error if no input or output filenames given
if [[ "${#positional[@]}" -lt 1 ]]; then
  error_msg "No input filenames given"
elif [[ -z "$archive_fn" ]]; then
  error_msg "No output filename given"
fi

# construct archive action
if [[ "$compress" -eq 1 ]]; then
  archive_action="tar.gz"
elif [[ "$compress" -eq 2 ]]; then
  archive_action="tar.xz"
elif [[ "$compress" -eq 3 ]]; then
  archive_action="tar.zst"
elif [[ "$compress" -eq 4 ]]; then
  archive_action="tar.bz2"
else
  archive_action="tar"
fi
if [[ "$encrypt" -eq 1 ]]; then
  archive_action="${archive_action}.gpg"
elif [[ "$encrypt" -eq 2 ]]; then
  archive_action="${archive_action}.age"
fi

# construct checksum action
if [[ "$checksum" -eq 1 ]]; then
  checksum_action="sha1"
elif [[ "$checksum" -eq 2 ]]; then
  checksum_action="sha256"
fi

# construct checksum filename
checksum_fn="$(fn_basename "$archive_fn").${checksum_action}"

# check files
if contains "$archive_fn" "${positional[@]}"; then
  error_msg "Output file cannot also be input file ('${archive_fn}')"
elif [[ "$checksum" -ge 1 ]] && contains "$checksum_fn" "${positional[@]}"; then
  error_msg "Output file cannot also be input file ('${checksum_fn}')"
elif [[ -f "$archive_fn" ]]; then
  error_msg "Output file already exists ('${archive_fn}')"
elif [[ "$checksum" -ge 1 && -f "$checksum_fn" ]]; then
  error_msg "Output file already exists ('${checksum_fn}')"
fi
for target in "${positional[@]}"; do
  if [[ ! -f "$target" ]] && [[ ! -d "$target" ]]; then
    error_msg "No such file '${target}'"
  fi
done

# check passphrase
if [[ "$checksum" -ge 1 && -z "$passphrase" ]]; then
  error_msg "No passphrase given"
fi

# main routine
code=0
case "$archive_action" in
tar)
  if ! /usr/bin/tar -cf "$archive_fn" "${positional[@]}"; then
    code=1
  fi
  ;;

tar.gpg)
  if ! /usr/bin/tar -c "${positional[@]}" | /usr/bin/gpg --symmetric --batch --passphrase "$passphrase" --output "$archive_fn"; then
    code=1
  fi
  ;;

tar.age)
  if ! /usr/bin/tar -c "${positional[@]}" | /usr/bin/age --encrypt --passphrase --output "$archive_fn"; then
    code=1
  fi
  ;;

tar.gz)
  if ! /usr/bin/tar -czf "$archive_fn" "${positional[@]}"; then
    code=1
  fi
  ;;

tar.gz.gpg)
  if ! /usr/bin/tar -cz "${positional[@]}" | /usr/bin/gpg --symmetric --batch --passphrase "$passphrase" --output "$archive_fn"; then
    code=1
  fi
  ;;

tar.gz.age)
  if ! /usr/bin/tar -cz "${positional[@]}" | /usr/bin/age --encrypt --passphrase --output "$archive_fn"; then
    code=1
  fi
  ;;

tar.xz)
  if ! /usr/bin/tar -cJf "$archive_fn" "${positional[@]}"; then
    code=1
  fi
  ;;

tar.xz.gpg)
  if ! /usr/bin/tar -cJ "${positional[@]}" | /usr/bin/gpg --symmetric --batch --passphrase "$passphrase" --output "$archive_fn"; then
    code=1
  fi
  ;;

tar.xz.age)
  if ! /usr/bin/tar -cJ "${positional[@]}" | /usr/bin/age --encrypt --passphrase --output "$archive_fn"; then
    code=1
  fi
  ;;

tar.zst)
  if ! /usr/bin/tar --zstd -cf "$archive_fn" "${positional[@]}"; then
    code=1
  fi
  ;;

tar.zst.gpg)
  if ! /usr/bin/tar --zstd -c "${positional[@]}" | /usr/bin/gpg --symmetric --batch --passphrase "$passphrase" --output "$archive_fn"; then
    code=1
  fi
  ;;

tar.zst.age)
  if ! /usr/bin/tar --zstd -c "${positional[@]}" | /usr/bin/age --encrypt --passphrase --output "$archive_fn"; then
    code=1
  fi
  ;;

tar.bz2)
  if ! /usr/bin/tar -cjf "$archive_fn" "${positional[@]}"; then
    code=1
  fi
  ;;

tar.bz2.gpg)
  if ! /usr/bin/tar -cj "${positional[@]}" | /usr/bin/gpg --symmetric --batch --passphrase "$passphrase" --output "$archive_fn"; then
    code=1
  fi
  ;;

tar.bz2.age)
  if ! /usr/bin/tar -cj "${positional[@]}" | /usr/bin/age --encrypt --passphrase --output "$archive_fn"; then
    code=1
  fi
  ;;
esac

# checksum routine
if [[ "$checksum" -ge 1 ]]; then
  if [[ -f "$archive_fn" ]]; then
    case "$checksum_action" in
    sha1)
      if ! /usr/bin/sha1sum "$archive_fn" | /usr/bin/awk '{print $1}' > "$checksum_fn"; then
        code=1
      fi
      ;;

    sha256)
      if ! /usr/bin/sha256sum "$archive_fn" | /usr/bin/awk '{print $1}' > "$checksum_fn"; then
        code=1
      fi
      ;;
    esac
  else
    error_msg "No such file '${archive_fn}'"
  fi
fi

# return stored code
exit "$code"