#!/bin/bash

name="mktar"
version="1.3"
read -r -d '' help_message <<-EOF
	Archive utility
	Usage: mktar [OPTIONS] INFILES
	Options:
	 -c, --compress        compress archive with gzip
	 --compress=ALGO       compress archive with [none|gzip|xz|zstd|bzip2]
	 -C, --checksum        create checksum with SHA1
	 --checksum=ALGO       create checksum with [none|sha1|sha256]
	 -e, --encrypt         encrypt files with GPG
	 --encrypt=ALGO        encrypt files with [none|gpg|age]
	 -h, --help            print this message
	 -n FILE, --name FILE  name of backup file (Default: archive.tar)
	 -q, --quiet           suppress error messages and prompts
	 -v, --verbose         show additional messages
	 -V, --version         print version number and exit
EOF

source /usr/local/lib/mylib.bash

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

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

  --compress=xz|--compress=2)
    debug_msg "Setting compress option to 2 (=xz) (was ${compress})"
    compress=2
    shift
    ;;

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

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

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

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

  -c|--compress)
    debug_msg "Setting compress option to 1 (=gzip) (was ${compress})"
    compress=1
    shift
    ;;

  --checksum=sha1|--checksum=1)
    debug_msg "Setting checksum option to 1 (=sha1) (was ${checksum})"
    checksum=1
    shift
    ;;

  --checksum=sha256|--checksum=2)
    debug_msg "Setting checksum option to 2 (=sha256) (was ${checksum})"
    checksum=2
    shift
    ;;

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

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

  -C|--checksum)
    debug_msg "Setting checksum option to 1 (=SHA1) (was ${checksum})"
    checksum=1
    shift
    ;;

  --encrypt=gpg|--encrypt=1)
    debug_msg "Setting encrypt option to 1 (=GPG) (was ${encrypt})"
    encrypt=1
    shift
    ;;

  --encrypt=age|--encrypt=2)
    debug_msg "Setting encrypt option to 2 (=Age) (was ${encrypt})"
    encrypt=2
    shift
    ;;

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

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

  -e|--encrypt)
    debug_msg "Setting encrypt option to 1 (=GPG) (was ${encrypt})"
    encrypt=1
    shift
    ;;

  -h|--help)
    help_msg
    shift
    ;;

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

  -q|--quiet)
    debug_msg "Setting quiet option to 1 (was ${quiet})"
    quiet=1
    shift
    ;;

  -v|--verbose)
    debug_msg "Setting verbose option to 1 (was ${verbose})"
    verbose=1
    shift
    ;;

  -V|--version)
    version_msg
    ;;

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

# error if no filenames given
if [[ "${#positional[@]}" -lt 1 ]]; then
  debug_msg "No input filenames were given"
  usage_msg
fi

# determine compress 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"
elif [[ "$compress" -eq -1 ]]; then
  debug_msg "No explicit compress option; parsing archive name..."
  case "$archive_fn" in
  *.tar)
    debug_msg "Detected tarball (no compress)"
    archive_action="tar"
    ;;

  *.tar.gz)
    debug_msg "Detected gzip compress"
    archive_action="tar.gz"
    ;;

  *.tar.xz)
    debug_msg "Detected xz compress"
    archive_action="tar.xz"
    ;;

  *.tar.zst)
    debug_msg "Detected zstandard compress"
    archive_action="tar.zst"
    ;;

  *.tar.bz2)
    debug_msg "Detected bz2 compress"
    archive_action="tar.bz2"
    ;;

  *)
    debug_msg "Could not parse archive name; defaulting to no compress"
    archive_action="tar"
    ;;
  esac
else
  archive_action="tar"
fi

# determine encrypt action
if [[ "$encrypt" -eq 1 ]]; then
  archive_action="${archive_action}.gpg"
elif [[ "$encrypt" -eq 2 ]]; then
  archive_action="${archive_action}.age"
elif [[ "$encrypt" -eq -1 ]]; then
  debug_msg "No explicit encrypt option; parsing archive name..."
  case "$archive_fn" in
  *.gpg)
    debug_msg "Detected gpg encrypt"
    archive_action="${archive_action}.gpg"
    ;;

  *.age)
    debug_msg "Detected age encrypt"
    archive_action="${archive_action}.age"
    ;;

  *)
    debug_msg "No explicit encrypt option and could not parse archive name; defaulting to no encrypt"
    archive_action="${archive_action}"
    ;;
  esac
else
  archive_action="${archive_action}"
fi

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

# output filename
if [[ -z "$archive_fn" ]]; then
  archive_fn="archive.${archive_action}"
  checksum_fn="archive.${checksum_action}"
  debug_msg "No output filename was given, defaulting to '${archive_fn}'"
else
  checksum_fn="$(fn_basename "$archive_fn").${checksum_action}"
fi

# 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 ('${checksum_fn}')"
fi
if ! prompt_overwrite "$archive_fn"; then
  exit 1
elif [[ "$checksum" -ge 1 ]] && ! prompt_overwrite "$checksum_fn"; then
  exit 1
fi
for target in "${positional[@]}"; do
  if [[ ! -f "$target" ]] && [[ ! -d "$target" ]]; then
    error_msg "No such file '${target}'"
  fi
done

# 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 "${positional[@]}" | /usr/bin/gpg --symmetric --output "$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 "${positional[@]}" | /usr/bin/gpg --symmetric --output "$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 "${positional[@]}" | /usr/bin/gpg --symmetric --output "$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 "${positional[@]}" | /usr/bin/gpg --symmetric --output "$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 "${positional[@]}" | /usr/bin/gpg --symmetric --output "$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"