refactor(waybar): register owned modules

configs/nixos/modules/desktop/session/mako.nix

@@ -2,9 +2,24 @@
   config,
   lib,
   pkgs,
+  util,
   ...
 }:
 # mako as the notification daemon: toasts, a do-not-disturb mode, and history recall.
+let
+  dndStatus = pkgs.writeShellScript "waybar-dnd-status" ''
+    if ${lib.getExe' pkgs.mako "makoctl"} mode 2>/dev/null | ${lib.getExe pkgs.gnugrep} -qx dnd; then
+      printf '{"text":"${util.glyph "f1f6"}","tooltip":"Do not disturb: on","class":"dnd"}\n'
+    else
+      printf '{"text":"${util.glyph "f0f3"}","tooltip":"Notifications on","class":"active"}\n'
+    fi
+  '';
+
+  dndToggle = pkgs.writeShellScript "waybar-dnd-toggle" ''
+    ${lib.getExe' pkgs.mako "makoctl"} mode -t dnd >/dev/null 2>&1
+    ${lib.getExe' pkgs.procps "pkill"} -RTMIN+8 waybar
+  '';
+in
 {
   options.modules.desktop.session.mako.enable = lib.mkEnableOption "the mako notification daemon";
 
@@ -35,5 +50,16 @@
         command = "${lib.getExe' pkgs.mako "makoctl"} restore";
       };
     };
+
+    registry.waybar.${config.networking.hostName}."custom/dnd" = {
+      order = 80;
+      settings = {
+        return-type = "json";
+        exec = "${dndStatus}";
+        on-click = "${dndToggle}";
+        interval = "once";
+        signal = 8;
+      };
+    };
   };
 }