l: add themes.nix

lass/2configs/baseX.nix

@@ -13,6 +13,7 @@ in {
     ./pipewire.nix
     ./tmux.nix
     ./xmonad.nix
+    ./themes.nix
     {
       krebs.per-user.lass.packages = [
         pkgs.sshuttle

lass/2configs/themes.nix

@@ -0,0 +1,46 @@
+{ config, lib, pkgs, ... }: let
+
+    switch-theme = pkgs.writers.writeDashBin "switch-theme" ''
+      if test -e "/etc/themes/$1"; then
+        ${pkgs.rsync}/bin/rsync --chown=lass:users -a --delete "/etc/themes/$1/" /var/theme/config/
+        echo "$1" > /var/theme/current_theme
+        chown lass:users /var/theme/current_theme
+        ${pkgs.procps}/bin/pkill -HUP xsettingsd
+
+      else
+        echo "theme $1 not found"
+      fi
+    '';
+
+in {
+  systemd.services.xsettingsd = {
+    wantedBy = [ "multi-user.target" ];
+    environment.DISPLAY = ":0";
+    serviceConfig = {
+      ExecStart = "${pkgs.xsettingsd}/bin/xsettingsd -c /var/theme/config/xsettings.conf";
+      User = "lass";
+    };
+  };
+  systemd.tmpfiles.rules = [
+    "d /var/theme/ 755 lass users"
+  ];
+  environment.systemPackages = [
+    switch-theme
+  ];
+  environment.etc = {
+    "themes/light/xsettings.conf".text = ''
+      Net/ThemeName "Adwaita" 
+    '';
+    "themes/dark/xsettings.conf".text = ''
+      Net/ThemeName "Adwaita-dark" 
+    '';
+  };
+  system.activationScripts.theme.text = ''
+    if test -e /var/theme/current_theme; then
+      ${switch-theme}/bin/switch-theme "$(cat /var/theme/current_theme)" ||
+      ${switch-theme}/bin/switch-theme dark
+    else
+      ${switch-theme}/bin/switch-theme dark
+    fi
+  '';
+}