From 035a3088d49e47281575088e25c7079eeb72120c Mon Sep 17 00:00:00 2001
From: Jon Carstens <jjcarstens@me.com>
Date: Tue, 22 Dec 2020 10:39:50 -0700
Subject: [PATCH] Support XDG_DATA_HOME

Resolves https://github.com/nerves-hub/nerves_hub_cli/issues/120
---
 lib/nerves_hub_cli.ex | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/lib/nerves_hub_cli.ex b/lib/nerves_hub_cli.ex
index c996537..a690652 100644
--- a/lib/nerves_hub_cli.ex
+++ b/lib/nerves_hub_cli.ex
@@ -10,6 +10,8 @@ defmodule NervesHubCLI do
   """
   @type fwup_public_key_ref :: String.t() | atom()
 
+  defguard valid_home_dir(dir) when is_binary(dir) and dir != ""
+
   @spec default_description() :: String.t()
   def default_description() do
     {:ok, hostname} = :inet.gethostname()
@@ -20,10 +22,10 @@ defmodule NervesHubCLI do
     override_dir =
       Application.get_env(:nerves_hub_cli, :home_dir) || System.get_env("NERVES_HUB_HOME")
 
-    if override_dir == nil or override_dir == "" do
-      Path.expand("~/.nerves-hub")
-    else
-      override_dir
+    case {override_dir, System.get_env("XDG_DATA_HOME")} do
+      {dir, _} when valid_home_dir(dir) -> dir
+      {_, xdg} when valid_home_dir(xdg) -> Path.join(xdg, "nerves-hub")
+      _ -> Path.expand("~/.nerves-hub")
     end
   end