embed-script

#!/bin/bash

# SPDX-FileCopyrightText: 2024 sudorook <daemon@nullcodon.com>
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
# for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program. If not, see <https://www.gnu.org/licenses/>.

set -Eeuo pipefail

ROOT="$(dirname "${0}")"

source "${ROOT}"/globals

function make_single_file {
  local contents
  contents="$(tar -cz -O "${SOURCES[@]}" | base64 -w 0)"
  cat << EOF
#!/bin/bash
set -eu
TMP="\$(mktemp -d)"
trap 'rm -rf "\${TMP}"; exit' INT TERM ERR EXIT
cd "\${TMP}"
tar -m -xzf <(base64 -d <<< ${contents})
${CMD}
EOF
}

function generate_output_name {
  local in
  local name
  local ext

  in="$(basename "${CMD}")"
  name="${in%.*}"
  ext="${in##*.}"

  if [ -n "${ext}" ] && [[ "${name}" != "${ext}" ]]; then
    echo "${name}_single_file.${ext}"
  else
    echo "${in}_single_file"
  fi
}

#
# Globals
#

SOURCES=()

#
# Main
#

OPTIONS=c:ho:
LONGOPTIONS=command:,help,output:
PARSED=$(getopt -o "${OPTIONS}" --long "${LONGOPTIONS}" -n "${0}" -- "${@}")
eval set -- "${PARSED}"

while [ ${#} -ge 1 ]; do
  case "${1}" in
    -c | --command)
      CMD="${2}"
      shift 2
      ;;
    -o | --output)
      OUTFILE="${2}"
      shift 2
      ;;
    --)
      shift
      break
      ;;
    *)
      show_error "ERROR: Invalid flag ${1@Q}."
      exit 3
      ;;
  esac
done

if ! [[ -v CMD ]]; then
  show_error "ERROR: Input ${CMD@Q} not specified. Exiting."
  exit 3
fi

SOURCES=("${@}")
if [ "${#SOURCES[@]}" -eq 0 ]; then
  show_warning "Input is already a single file. What's the point?"
  exit
else
  if [ -f "${CMD}" ]; then
    SOURCES+=("${CMD}")
    if [[ "${CMD:0:2}" != "./" ]]; then
      CMD="./${CMD}"
    fi
  # Don't quote variable expansion. Otherwise command will interpret the entire
  # string as the identity of a single executable.
  elif ! command -v ${CMD} > /dev/null 2>&1; then
    show_error "ERROR: No file or command ${CMD@Q} found. Exiting."
    exit 3
  fi
fi

OUTFILE="${OUTFILE:-"$(generate_output_name)"}"

make_single_file > "${OUTFILE}"
chmod +x "${OUTFILE}"