Getting more idomatic nix modules setup... will tackle users dir later

modules/de/cosmic.nix

@@ -0,0 +1,32 @@
+{
+  cosmic,
+  config,
+  lib,
+  settings,
+  ...
+}:
+with lib;
+let
+  name = "de_cosmic";
+  cfg = config.mods.${name};
+in
+{
+
+  options = {
+    mods.${name} = {
+      enable = mkEnableOption (lib.mdDoc "Enable COSMIC desktop environment");
+    };
+  };
+
+  config = mkIf cfg.enable {
+    # Use cosmic binary cache
+    nix.settings = {
+      substituters = [ "https://cosmic.cachix.org/" ];
+      trusted-public-keys = [ "cosmic.cachix.org-1:Dya9IyXD4xdBehWjrkPv6rtxpmMdRel02smYzA85dPE=" ];
+    };
+
+    # Enable cosmic
+    services.desktopManager.cosmic.enable = true;
+    services.displayManager.cosmic-greeter.enable = true;
+  };
+}