#!/bin/bash

name="mktar-batch"
version="1.1"
read -r -d '' help_message <<-EOF
	Archive utility for scripting
	Usage: mktar-batch [--compress=ALGO] [--encrypt=ALGO [--passphrase PASS]] [--checksum=ALGO] [--name OUTFILE] INFILES
	Options:
	 --compress=ALGO             compress archive
	 --checksum=ALGO             create checksum
	 --encrypt=ALGO              encrypt archive
	 -h, --help                  print this message
	 -n FILE, --name FILE        name of backup file
	 -p PASS, --passphrase PASS  passphase for encryption
	 -v, --verbose               show additional messages
	 -V, --version               print version number and exit
	
	Compress algorithms and their ALGO codes:
	 n/a    none or no
	 GZip   gzip or gz
	 xz     zx
	 ZStd   zstd or zst
	 bzip2  bz2
	
	Checksum algorithms and their ALGO codes:
	 n/a     none or no
	 SHA1    sha1
	 SHA256  sha256
	
	Encrypt algorithms and their ALGO codes:
	 n/a   none or no
	 GPG   gpg
	 age   age
EOF

# TODO: add support for compress algorithms:
#        WinRAR  rar
#        Ren'Py  rpa
#        PKZip   zip
#        7-Zip   7z

source /usr/local/lib/mylib.bash
source /usr/local/lib/archive.bash

archive_fn=""
checksum=-1
compress=-1
encrypt=-1
passphrase=""
positional=()
verbose=0
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/sed -e 's/^.*=//' <<<"$1")"
    error_msg "Bad encrypt option '${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

# 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 checksum files
if [[ "$checksum" -ge 1 ]]; then
  if contains "$checksum_fn" "${positional[@]}"; then
    error_msg "checksum '${checksum_fn}' cannot be an input file"
  elif ! prompt_overwrite "checksum_fn"; then
    error_msg "checksum '${checksum_fn}' cannot be overwritten"
  fi
fi

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

if ! archive --archive=$archive_action --name "$archive_fn" --passphrase "$passphrase" "${positional[@]}"; then
  exit 1
fi

code=0
if [[ "$checksum" -ge 1 ]]; then
  case "$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
fi

exit "$code"