add screen rotation

mum/configuration.nix

@@ -5,8 +5,8 @@
 { config, pkgs, ... }:
 
 {
-  imports =
+  imports = [
-    [ # Include the results of the hardware scan.
+    # Include the results of the hardware scan.
     ./hardware-configuration.nix
   ];
 
@@ -56,7 +56,10 @@
   users.users.kemp = {
     isNormalUser = true;
     description = "kemp";
-    extraGroups = [ "networkmanager" "wheel" ];
+    extraGroups = [
+      "networkmanager"
+      "wheel"
+    ];
     packages = with pkgs; [ ];
 
     openssh.authorizedKeys.keys = [
@@ -81,17 +84,19 @@
     git
     nil
     nixd
+    wlr-randr
+    kmsxx
   ];
   programs.firefox = {
     enable = true;
   };
 
-
   systemd.services.cage-tty1 = {
     after = [
       "network-online.target"
       #"systemd-resolved.service"
-  ];serviceConfig = {
+    ];
+    serviceConfig = {
       Restart = "always";
       RestartSec = "1s";
     };
@@ -101,7 +106,16 @@
   services.cage = {
     enable = true;
     user = "kemp";
-    program = "${pkgs.firefox}/bin/firefox";
+    program = "${pkgs.writeScriptBin "start-cage-app" ''
+      #!/usr/bin/env bash
+      kmsprint |
+        grep '(connected)' |
+        sed -E 's/.* ([^ ]+) \(connected\).*/\1/' |
+        while read -r output; do
+          wlr-randr --output "$output" --transform 180
+        done
+      exec ${pkgs.firefox}/bin/firefox
+    ''}/bin/start-cage-app";
   };
   services.getty.loginProgram = "${pkgs.coreutils}/bin/true";