dotf

#!/usr/bin/env bash

# Link or unlink dotfiles

set -o errexit
set -o nounset
set -o pipefail

usage() {
  echo "Usage: $0 <link | unlink> [--dry-run] PACKAGES..."
  exit 1
}

# Text colors
color_reset='\033[0m'
color_green='\033[1;32m'
color_red='\033[1;31m'

DOTFILES_PATH="$(cd "$(dirname "$0")"; pwd)" # get absolute path
PACKAGES_PATH="$DOTFILES_PATH/packages"
DRYRUN=0

main() {
  local positional_args=()

  while [[ "$#" -gt 0 ]]; do
    case "$1" in
      --dry-run)
        DRYRUN=1
        shift
        ;;
      -*|--*)
        echo "Unknown option $1"
        exit 1
        ;;
      *)
        positional_args+=("$1")
        shift
        ;;
    esac
  done

  set -- "${positional_args[@]}" # restore positional parameters

  if [[ "$#" -lt 2 ]]; then
    usage
  fi

  local action="$1"
  if [[ "$action" != link && "$action" != unlink ]]; then
    usage
  fi
  shift

  for package in "$@"; do
    local path="$PACKAGES_PATH/$package"
    if [ ! -d "$path" ]; then
      echo -e "No such package ${color_red}${package}${color_reset}"
      continue
    fi

    echo -e "Package: ${color_green}${package}${color_reset}"
    do_package "$action" "$path"
  done
}

do_package() {
  local action="$1"
  local package_path="$2" # must be absolute

  while IFS= read -r -d '' src; do
    # we could more easily get src_pruned using `find -printf "%P\0`, but -printf is not supported by MacOS find.
    local src_pruned="${src#"$package_path/"}"
    local target="$HOME"/"$src_pruned"

    if [ -L "$target" ]; then
      if [ "$target" -ef "$src" ]; then
        # This link points to the right src
        if [ "$action" = "unlink" ]; then
          if [ "$DRYRUN" = 1 ]; then
            echo "- dry run: rm '$target'"
          else
            echo -en "${color_green}✓ ${color_reset}"
            rm -v "$target"
          fi
        elif [ "$action" = "link" ]; then
          echo "- '$target' is already symlinked to '$src'"
        fi
      else
        echo -e "${color_red}x ${color_reset}'$target' exists and is not a symlink to '$src'"
        continue
      fi
    elif [ -e "$target" ]; then
      # target is a file/directory that is not a symlink
      echo -e "${color_red}x ${color_reset}'$target' exists and is not a symlink to '$src'"
      continue
    else
      if [ "$action" = "link" ]; then
        if [ "$DRYRUN" = 1 ]; then
          echo "- dry run: ln -s '$src' '$target'"
        else
          mkdir -v -p "$(dirname "$target")"
          echo -en "${color_green}✓ ${color_reset}"
          ln -sv "$src" "$target"
        fi
      fi
    fi
  done < <(find "$package_path" -type f -print0 | sort --zero-terminated) # sort for deterministic order
}

main "$@"