restructuring

lib/xlib/device.nix

@@ -0,0 +1,65 @@
+{
+  lib,
+  ...
+}:
+# Supported device types and the identity record built from one.
+#
+# Single source of truth for host identity: hostname, type, username and the
+# capability flags derived from the type. Replaces the old `lib.types.enum`
+# in modules/options.nix and the hand-written type lists in modules/default.nix
+# and home/home.nix.
+let
+  devices = {
+    minimal = {
+      desktop = false;
+      headless = false;
+    };
+    primary = {
+      desktop = true;
+      headless = false;
+    };
+    secondary = {
+      desktop = true;
+      headless = false;
+    };
+    server = {
+      desktop = false;
+      headless = true;
+    };
+    vds = {
+      desktop = false;
+      headless = true;
+    };
+    wsl = {
+      desktop = false;
+      headless = true;
+    };
+    termux = {
+      desktop = false;
+      headless = true;
+    };
+  };
+in
+{
+  inherit devices;
+
+  # Unknown device type fails here, at flake level, with the valid list.
+  mkDevice =
+    {
+      hostname,
+      type,
+      username ? "oqyude",
+    }:
+    let
+      capabilities = devices.${type} or (throw "xlib: unknown device type '${type}', expected one of ${lib.concatStringsSep ", " (builtins.attrNames devices)}");
+    in
+    {
+      inherit
+        hostname
+        type
+        username
+        ;
+      isDesktop = capabilities.desktop;
+      isHeadless = capabilities.headless;
+    };
+}