install

#!/bin/sh

# Helper to install symlinks to `src` directory.

# Remove any existing file/symlink at $2, then symlink $2 -> $1.
install_symlink() {
  echo "Symlinking:  $2 -> $1"
  rm -rf "$2"
  ln -s "$1" "$2"
}

# Directories (relative to src/) whose *contents* are symlinked individually into ~/<dir>/ rather
# than symlinking the directory itself. This is needed for `.config` and `.local/bin` where
# AppArmor allows `~/.config` or `~/.local/bin` but doesn't follow symlinks to them. Entries may
# be nested paths; ancestor directories are mkdir -p'd as needed.
EXPAND_DIRS=".config .local/bin"

# Check whether $1 exactly matches an entry in EXPAND_DIRS.
is_expand_dir() {
  for d in $EXPAND_DIRS; do
    if [ "$1" = "$d" ]; then return 0; fi
  done
  return 1
}

# Check whether $1 is a strict ancestor (path prefix) of some EXPAND_DIRS entry.
is_expand_ancestor() {
  for d in $EXPAND_DIRS; do
    case "$d" in
      "$1"/*) return 0 ;;
    esac
  done
  return 1
}

# Walk src/$1 and install entries into ~/$1. Pass "" to process the src root.
install_dir() {
  local rel="$1"
  local src_dir home_dir entry_path entry child_rel

  if [ -z "$rel" ]; then
    src_dir="`pwd`/src"
    home_dir="$HOME"
  else
    src_dir="`pwd`/src/$rel"
    home_dir="$HOME/$rel"

    # If a previous install symlinked this dir, remove the symlink and warn.
    if [ -L "$home_dir" ]; then
      echo "Found existing symlink!"
      echo "Removing:    $home_dir symlink"
      rm -rf "$home_dir"
      echo "WARNING: Move any untracked files out of the dotfiles tree and re-run this script."
      exit 1
    fi

    mkdir -p "$home_dir"
  fi

  for entry_path in "$src_dir"/.* "$src_dir"/*; do
    [ -e "$entry_path" ] || continue
    entry=$(basename "$entry_path")
    if [ "$entry" = "." ] || [ "$entry" = ".." ]; then continue; fi

    if [ -z "$rel" ]; then
      child_rel="$entry"
    else
      child_rel="$rel/$entry"
    fi

    if is_expand_dir "$child_rel" || is_expand_ancestor "$child_rel"; then
      install_dir "$child_rel"
    else
      install_symlink "$entry_path" "$home_dir/$entry"
    fi
  done
}

# Ensure current directory is the script location.
cd "`dirname "$0"`"

install_dir ""