setup

#!/usr/bin/env sh
#
# Manage dotfiles with GNU Stow.
#
# Running without arguments stows all packages. The `add` subcommand
# automates adopting existing config files into a new stow package
# by creating the package directory, moving the files, and stowing.
#
set -e

DOTFILES="$(cd "$(dirname "$0")" && pwd)"

usage() {
  cat <<EOF
Manage dotfiles with GNU Stow.

Usage: ./setup                        install all packages
       ./setup add <name>             adopt ~/.<name>
       ./setup add .config <name>     adopt ~/.config/<name>
       ./setup add .config            scan ~/.config for unmanaged dirs

The add command moves config files into a new stow package and
creates symlinks back to their original locations.
EOF
}

add_package() {
  package="$1"
  source="$2"

  if [ ! -e "$source" ]; then
    echo "error: $source does not exist" >&2
    return 1
  fi

  if [ -d "$DOTFILES/$package" ]; then
    echo "skip: $package already managed" >&2
    return 1
  fi

  relative="${source#$HOME/}"
  dest="$DOTFILES/$package/$relative"

  mkdir -p "$(dirname "$dest")"
  mv "$source" "$dest"
  cd "$DOTFILES" && stow "$package"
  echo "added $package: ~/$relative"
}

# Check if a name is already managed by any stow package:
# either as a top-level package or as .config/<name> inside
# a differently-named package, for example ruby/.config/gem
is_managed() {
  [ -d "$DOTFILES/$1" ] && return 0
  for package in "$DOTFILES"/[!.]*/; do
    [ -d "${package}.config/$1" ] && return 0
  done
  return 1
}

scan_dotconfig() {
  for dir in "$HOME"/.config/*/; do
    [ -L "$dir" ] && continue
    name="$(basename "$dir")"
    is_managed "$name" && continue

    printf "Add %s? [y/N] " "$name"
    read -r answer
    case "$answer" in
      [yY]*) add_package "$name" "$dir" ;;
    esac
  done
}

case "${1:-}" in
  help|--help|-h)
    usage
    ;;
  add)
    case "${2:-}" in
      .config)
        if [ -n "${3:-}" ]; then
          add_package "$3" "$HOME/.config/$3"
        else
          scan_dotconfig
        fi
        ;;
      .config/*)
        name="${2#.config/}"
        add_package "$name" "$HOME/.config/$name"
        ;;
      "")
        usage >&2
        exit 1
        ;;
      .*)
        echo "error: package name must not start with '.'" >&2
        exit 1
        ;;
      *)
        add_package "$2" "$HOME/.$2"
        ;;
    esac
    ;;
  "")
    cd "$DOTFILES"
    # [!.]*/ excludes hidden directories (.git, .claude, et cetera)
    # because when bash dotglob is set */ matches dotfiles as well
    output="$(stow --verbose [!.]*/ 2>&1)" || { echo "$output" >&2; exit 1; }
    if [ -n "$output" ]; then
      echo "$output"
    else
      echo "all packages up to date"
    fi
    ;;
  *)
    echo "unknown command: $1" >&2
    usage >&2
    exit 1
    ;;
esac