shopt -s extglob

[ -z "$DF_DIR" ] && DF_DIR="${XDG_DATA_HOME:-$HOME/.local/share}/df_linux"
env_dir="@env@"
exe="$env_dir/@exe@"

update_path() {
  local path="$1"

  mkdir -p "$DF_DIR/$(dirname "$path")"
  # If user has replaced these data directories, let them stay.
  if [ ! -e "$DF_DIR/$path" ] || [ -L "$DF_DIR/$path" ]; then
    rm -f "$DF_DIR/$path"
    ln -s "$env_dir/$path" "$DF_DIR/$path"
  fi
}

forcecopy_path() {
  local path="$1"

  mkdir -p "$DF_DIR/$(dirname "$path")"
  rm -rf "$DF_DIR/$path"
  cp -rL --no-preserve=all "$env_dir/$path" "$DF_DIR/$path"
}

mkdir -p "$DF_DIR"

cat <<EOF >&2
Using $DF_DIR as Dwarf Fortress overlay directory.
If you do any changes in it, don't forget to clean it when updating the game version!
We try to detect changes based on data directories being symbolic links -- keep this in mind.

EOF

cd "$env_dir"
for i in data/init/* data/!(init|index|announcement) raw; do
  update_path "$i"
done

forcecopy_path data/index
# For some reason, it's needed to be writable...
forcecopy_path data/announcement
forcecopy_path data/help
forcecopy_path data/dipscript