Add steam games directory sync

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

hosts/common/user/configs/gui/gaming/default.nix

@@ -2,7 +2,12 @@
   user ? throw "user argument is required",
   home ? throw "home argument is required",
 }:
-{ pkgs, ... }:
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
 {
   environment.persistence."/persist" = {
     "${home}/.steam" = { };
@@ -29,6 +34,49 @@
   };
 
   home-manager.users.${user} = {
+    systemd.user = {
+      tmpfiles.rules = [ "d ${home}/.local/share/Steam/steamapps/common 0755 ${user} users -" ];
+
+      services.steam-ln =
+        let
+          steamLn = lib.meta.getExe (
+            pkgs.writeShellApplication {
+              name = "steam-ln";
+              runtimeInputs = with pkgs; [ coreutils ];
+              text = builtins.readFile ./scripts/steam-ln.sh;
+            }
+          );
+        in
+        {
+          Unit = {
+            Description = "Sync Steam games with Games directory";
+            After = [
+              config.environment.persistence."/persist"."${home}/.local/share/Steam".mount
+              config.environment.persistence."/persist"."${home}/Games".mount
+            ];
+            DefaultDependencies = false;
+          };
+
+          Service = {
+            ExecStart = steamLn;
+            Type = "oneshot";
+          };
+        };
+
+      paths.steam-ln = {
+        Unit = {
+          Description = "Monitor Steam games directory for changes";
+          After = [
+            config.environment.persistence."/persist"."${home}/.local/share/Steam".mount
+            config.environment.persistence."/persist"."${home}/Games".mount
+          ];
+        };
+
+        Path.PathChanged = "${home}/.local/share/Steam/steamapps/common";
+        Install.WantedBy = [ "graphical-session.target" ];
+      };
+    };
+
     home = {
       packages = with pkgs; [ protonup ];
       sessionVariables.STEAM_EXTRA_COMPAT_TOOLS_PATHS = "${home}/.steam/root/compatibilitytools.d";