{ config, pkgs, lib, username, ... }: {
  services.xserver = {
    enable = true;
    displayManager.gdm.enable = true;
    desktopManager.gnome.enable = true;
  };

  environment = {
    systemPackages = (with pkgs;[
      gnome-tweaks
      gnome-shell-extensions
    ]) ++ (with pkgs.gnomeExtensions;[
      dash-to-dock
      appindicator # tray icon
    ]);

    gnome.excludePackages = (with pkgs; [
      atomix # puzzle game
      cheese # webcam tool
      gnome-photos
      gnome-tour
      gnome-text-editor
      epiphany # web browser
      geary # email reader
      evince # document viewer
      gedit # text editor
      gnome-contacts
      gnome-maps
      gnome-weather
      gnome-music
      gnome-characters
      # gnome-terminal
      hitori # sudoku game
      iagno # go game
      simple-scan
      totem # video player
      tali # poker game
      yelp # help viewer
    ]);

    variables = {
      "GTK_IM_MODULE" = "fcitx";
      "QT_IM_MODULE" = "fcitx";
      "XMODIFIERS" = "@im=fcitx";
      "SDL_IM_MODULE" = "fcitx";
      "GLFW_IM_MODULE" = "ibus";
    };
  };

  programs = {
    dconf = {
      enable = true;
      profiles = {
        # TODO: Investigate customizing gdm greeter.
        user.databases = [{
          settings = with lib.gvariant; {

            "org/gnome/desktop/interface" = {
              clock-show-weekday = true;
              cursor-size = mkUint32 16;
              cursor-theme = "capitaine-cursors";
              enable-hot-corners = false;
              icon-theme = "Papirus-Dark";
              locate-pointer = false;
              monospace-font-name = "JetBrainsMono Nerd Font Mono 10";
              overlay-scrolling = true;
            };

            "org/gnome/mutter" = {
              edge-tiling = true;
              attach-modal-dialogs = true;
              experimental-features = [ "scale-monitor-framebuffer" ];
            };

            "org/gnome/shell" = {
              last-selected-power-profile = "power-saver";
            };

            "org/gnome/desktop/session" = {
              idle-delay = mkUint32 900;
            };

            "org/gnome/settings-daemon/plugins/power" = {
              power-button-action = "interactive";
              sleep-inactive-ac-timeout = mkUint32 7200;
              sleep-inactive-ac-type = "nothing";
            };

            "org/gtk/gtk4/settings/file-chooser" = {
              sort-directories-first = true;
              # show-hidden = true;
              view-type = "list";
            };

            "org/gnome/desktop/wm/keybindings" = {
              minimize = mkEmptyArray type.string;
              move-to-workspace-1 = [ "<Shift><Super>1" ];
              move-to-workspace-2 = [ "<Shift><Super>2" ];
              move-to-workspace-3 = [ "<Shift><Super>3" ];
              move-to-workspace-4 = [ "<Shift><Super>4" ];
              switch-to-workspace-1 = [ "<Super>1" ];
              switch-to-workspace-2 = [ "<Super>2" ];
              switch-to-workspace-3 = [ "<Super>3" ];
              switch-to-workspace-4 = [ "<Super>4" ];
              switch-to-workspace-left = [ "<Control><Super>h" ];
              switch-to-workspace-right = [ "<Control><Super>l" ];
              switch-windows = [ "<Alt>Tab" ];
              switch-windows-backward = [ "<Shift><Alt>Tab" ];
              switch-applications = [ "<Super>Tab" ];
              switch-applications-backward = [ "<Shift><Super>Tab" ];
            };

            "org/gnome/shell/keybindings" = {
              # Following binds are replaced by the ones above.
              switch-to-application-1 = mkEmptyArray type.string;
              switch-to-application-2 = mkEmptyArray type.string;
              switch-to-application-3 = mkEmptyArray type.string;
              switch-to-application-4 = mkEmptyArray type.string;
            };

            "org/gnome/shell" = {
              enabled-extensions = [
                "appindicatorsupport@rgcjonas.gmail.com"
                "dash-to-dock@micxgx.gmail.com"
                "status-icons@gnome-shell-extensions.gcampax.github.com"
                "system-monitor@gnome-shell-extensions.gcampax.github.com"
              ];
            };

            "org/gnome/shell/extensions/dash-to-panel" = {
              apply-custom-theme = false;
              background-opacity = 0.8;
              click-action = "previews";
              custom-background-color = false;
              custom-theme-shrink = true;
              dash-max-icon-size = mkUint32 40;
              dock-position = "BOTTOM";
              extend-height = false;
              height-fraction = 0.9;
              hot-keys = false;
              icon-size-fixed = true;
              isolate-monitors = true;
              max-alpha = 0.8;
              multi-monitor = true;
              preview-size-scale = 0.0;
              running-indicator-style = "DOTS";
              scroll-action = "cycle-windows";
              show-mounts = false;
              show-mounts-only-mounted = true;
              transparency-mode = "DYNAMIC";
            };
            "org/gnome/shell/extensions/system-monitor" = {
              show-download = true;
              show-swap = false;
              show-upload = false;
            };
          };
        }];
      };
    };
  };
}