templates/system/modules/ui/desktops/kde.nix

# Enables the KDE desktop environment.
{
  pkgs,
  config,
  lib,
  ...
}:

let
  cfg = config.aux.system.ui.desktops.kde;
in
{
  options = {
    aux.system.ui.desktops.kde = {
      enable = lib.mkEnableOption (lib.mdDoc "Enables the KDE Desktop Environment.");
      useX11 = lib.mkEnableOption (lib.mdDoc "Uses X11 instead of Wayland.");
    };
  };

  config = lib.mkIf cfg.enable {
    aux.system.ui.desktops = {
      enable = true;
      displayManager = if cfg.useX11 then lib.mkDefault "sddm" else lib.mkDefault "sddm_wayland";
    };

    programs.dconf.enable = true;

    # Fix blank messages in KMail. See https://nixos.wiki/wiki/KDE#KMail_Renders_Blank_Messages
    environment.sessionVariables = {
      NIX_PROFILES = "${pkgs.lib.concatStringsSep " " (
        pkgs.lib.reverseList config.environment.profiles
      )}";
    };

    services = {
      desktopManager.plasma6.enable = true;

      xserver.displayManager = lib.mkIf cfg.useX11 { defaultSession = "plasmaX11"; };
    };

    # Enable Gnome integration
    qt = {
      enable = true;
      platformTheme = "gnome";
      style = "adwaita-dark";
    };
  };
}