gui/kde: add tile-gaps package

gui/kde.nix

@@ -1,20 +1,21 @@
 { config, lib, pkgs, ... }:
-with lib; {
-  options = { kde = { enable = mkEnableOption "Enable KDE desktop."; }; };
+let inherit (pkgs.libsForQt5) callPackage; in {
+  options = { kde = { enable = lib.mkEnableOption "Enable KDE desktop."; }; };
 
-  config = mkIf config.kde.enable {
+  config = lib.mkIf config.kde.enable {
     services.xserver.displayManager.sddm.enable = true;
     services.xserver.desktopManager.plasma5.enable = true;
 
     # Listen for KDE Connect connections on the tailnet
     networking.firewall.interfaces = {
       "tailscale0" = {
-        allowedTCPPorts = range 1714 1764;
-        allowedUDPPorts = range 1714 1764;
+        allowedTCPPorts = lib.range 1714 1764;
+        allowedUDPPorts = lib.range 1714 1764;
       };
     };
 
     environment.systemPackages = with pkgs; [
+      (callPackage ../pkgs/tile-gaps.nix { })
       akonadi
       plasma5Packages.akonadiconsole
       plasma5Packages.akonadi-contacts

pkgs/tile-gaps.nix

@@ -0,0 +1,39 @@
+{ lib, mkDerivation, fetchFromGitHub
+, kcoreaddons, kwindowsystem, plasma-framework, systemsettings }:
+
+mkDerivation rec {
+  pname = "tile-gaps";
+  version = "7.1";
+
+  src = fetchFromGitHub {
+    owner = "nclarius";
+    repo = "tile-gaps";
+    rev = "window-gaps_v${version}";
+    sha256 = "sha256-7tW098kP50rQApn0SW538NrJT0YArpkw/njYWavMvLo=";
+  };
+
+  buildInputs = [
+    kcoreaddons kwindowsystem plasma-framework systemsettings
+  ];
+
+  dontBuild = true;
+
+  # 1. --global still installs to $HOME/.local/share so we use --packageroot
+  # 2. plasmapkg2 doesn't copy metadata.desktop into place, so we do that manually
+  installPhase = ''
+    runHook preInstall
+
+    plasmapkg2 --type kwinscript --install ${src} --packageroot $out/share/kwin/scripts
+    install -Dm644 ${src}/metadata.desktop $out/share/kservices5/tilegaps.desktop
+
+    runHook postInstall
+  '';
+
+  meta = with lib; {
+    description = "Tiling script for kwin";
+    license = licenses.gpl3;
+    maintainers = with maintainers; [ qbit ];
+    inherit (src.meta) homepage;
+    inherit (kwindowsystem.meta) platforms;
+  };
+}