#!/usr/bin/env bash
#
# autostow.sh
#
# Stow automatic symlinking script
#
# Invokes stow for every folder within this repository, and that's it.

ignore="${AUTOSTOW_IGNORED_DIRS:-"bootstrap:assets"}"

main() {
  case "$1" in
  -s | --stow)
    have_stow
    echo "Creating dotfile symlinks ................................................."
    stow_dirs
    echo "Done creating symlinks ...................................................."
    exit 0
    ;;
  -d | --delete)
    have_stow
    echo "Removing dotfile symlinks ................................................."
    unstow_dirs
    echo "Done removing symlinks ...................................................."
    exit 0
    ;;
  -n | --dry-run)
    have_stow
    echo "Printing processed directories ............................................"
    dryrun
    echo "Done printing directories ................................................."
    exit 0
    ;;
  -v | --version)
    printf "System bootstrap script.\n\n©Marty Oehme\n\nVersion: 0.2\n"
    ;;
  -h | --help | *)
    usage
    exit 0
    ;;
  esac
  shift
}

stow_dirs() {
  for d in */; do

    if is_ignored "$d"; then
      printf "ignoring %s\n" "$d"
      continue
    fi

    printf "stowing %s\n" "$d"
    stow -S -t ~ "$d"
  done
}

unstow_dirs() {
  for d in */; do

    if is_ignored "$d"; then
      printf "ignoring %s\n" "$d"
      continue
    fi

    printf "unstowing %s\n" "$d"
    stow -D -t ~ "$d"
  done
}

dryrun() {
  for d in */; do

    if is_ignored "$d"; then
      printf "ignoring %s\n" "$d"
      continue
    fi

    printf "processing %s\n" "$d"
  done
}

is_ignored() {
  IFS=":"
  for ign in $ignore; do
    # it is either passed in through our environment variable
    # or it starts with a _ which is ignored by default (that's the regex).
    # (using herestring to avoid cat>grep)
    if [ "$ign" = "$1" ] || [ "$ign/" = "$1" ] || grep -q -e '^_[[:alnum:]]\{1,\}' <<<"$1"; then
      return 0
    fi
  done
  return 1
}

have_stow() {
  if ! type stow >/dev/null 2>&1; then
    printf "GNU stow needs to be installed for this script to function. Please install stow through your package manager.\n"
    exit 1
  fi
}

usage() {
  printf "%s\n" \
    "" \
    " autostow.sh - Automatically stow your dotfiles." \
    "               Uses GNU stow to set up automatic links to any dotfiles in subdirectories of this directory." \
    "" \
    " Usage: stow.sh -dhsn" \
    "" \
    " Options:" \
    "" \
    "     -h | --help     Print out this help." \
    "" \
    "     -s | --stow     Install dotfiles, by symlinking any directory found next to stow.sh using GNU stow." \
    "" \
    "     -d | --delete   Remove dotfiles, by unlinking any directory found next to stow.sh using GNU stow." \
    "" \
    "     -n | --dry-run  Do not invoke any operation but print out directories affected, simulating a dry-run." \
    "" \
    " Note, by default any directory starting with an underscore _directoryname will be ignored." \
    " Additional folders to ignore can be set through the environment variable AUTOSTOW_IGNORED_DIRS " \
    " using a colon-separated string: AUTOSTOW_IGNORED_DIRS=\"directories:to:ignore\"   " \
    "" \
    ""
}

main "$@"