plasma-manager/modules/panels.nix

{
  lib,
  config,
  pkgs,
  ...
}@args:
let
  cfg = config.programs.plasma;
  desktopWidgets = if cfg.desktop.widgets != null then cfg.desktop.widgets else [ ];
  hasWidget =
    widgetName:
    builtins.any (panel: builtins.any (widget: widget.name == widgetName) panel.widgets) cfg.panels
    || builtins.any (widget: widget.name == widgetName) desktopWidgets;

  # An attrset keeping track of the packages which should be added when a
  # widget is present in the config.
  additionalWidgetPackages = with pkgs; {
    "com.github.antroids.application-title-bar" = [ application-title-bar ];
    plasmusic-toolbar = [ plasmusic-toolbar ];
    "luisbocanegra.panel.colorizer" = [ plasma-panel-colorizer ];
    "org.kde.windowbuttons" = [ kdePackages.applet-window-buttons6 ];
    "org.dhruv8sh.kara" = [ kara ];
  };
  # An attrset of service-names and widgets/conditions. If any of the
  # conditions (given in cond) evaluate to true for any of the widgets with the
  # name given in the widget attribute, the service is marked for restart in
  # the panel-script.
  serviceRestarts = {
    "plasma-plasmashell" = [
      {
        widget = "org.kde.plasma.systemmonitor";
        cond =
          widget:
          (
            (builtins.hasAttr "org.kde.ksysguard.piechart/General" widget.config)
            && (builtins.hasAttr "showLegend" widget.config."org.kde.ksysguard.piechart/General")
          );
      }
    ];
  };
  widgetsOfName =
    name: (lib.filter (w: w.name == name) (lib.flatten (map (panel: panel.widgets) cfg.panels)));
  shouldRestart =
    service:
    (
      let
        candidates = serviceRestarts."${service}";
      in
      (builtins.any (x: x) (map (v: (builtins.any v.cond (widgetsOfName v.widget))) candidates))
    );

  widgets = import ./widgets args;

  panelType = lib.types.submodule (
    { config, ... }:
    {
      options = {
        height = lib.mkOption {
          type = lib.types.int;
          default = 44;
          description = "The height of the panel.";
        };
        offset = lib.mkOption {
          type = with lib.types; nullOr int;
          default = null;
          example = 100;
          description = "The offset of the panel from the anchor-point.";
        };
        minLength = lib.mkOption {
          type = with lib.types; nullOr int;
          default = null;
          example = 1000;
          description = "The minimum required length/width of the panel.";
        };
        maxLength = lib.mkOption {
          type = with lib.types; nullOr int;
          default = null;
          example = 1600;
          description = "The maximum allowed length/width of the panel.";
        };
        lengthMode = lib.mkOption {
          type =
            with lib.types;
            nullOr (enum [
              "fit"
              "fill"
              "custom"
            ]);
          default = if config.minLength != null || config.maxLength != null then "custom" else null;
          example = "fit";
          description = "The length mode of the panel. Defaults to `custom` if either `minLength` or `maxLength` is set.";
        };
        location = lib.mkOption {
          type =
            with lib.types;
            nullOr (enum [
              "top"
              "bottom"
              "left"
              "right"
              "floating"
            ]);
          default = "bottom";
          example = "left";
          description = "The location of the panel.";
        };
        alignment = lib.mkOption {
          type =
            with lib.types;
            nullOr (enum [
              "left"
              "center"
              "right"
            ]);
          default = "center";
          example = "right";
          description = "The alignment of the panel.";
        };
        hiding = lib.mkOption {
          type =
            with lib.types;
            nullOr (enum [
              "none"
              "autohide"
              # Plasma 5 only
              "windowscover"
              "windowsbelow"
              # Plasma 6 only
              "dodgewindows"
              "normalpanel"
              "windowsgobelow"
            ]);
          default = null;
          example = "autohide";
          description = ''
            The hiding mode of the panel. Here windowscover and windowsbelow are
            plasma 5 only, while dodgewindows, windowsgobelow and normalpanel are
            plasma 6 only.
          '';
        };
        floating = lib.mkEnableOption "Enable or disable floating style.";
        widgets = lib.mkOption {
          type = lib.types.listOf widgets.type;
          default = [
            "org.kde.plasma.kickoff"
            "org.kde.plasma.pager"
            "org.kde.plasma.icontasks"
            "org.kde.plasma.marginsseparator"
            "org.kde.plasma.systemtray"
            "org.kde.plasma.digitalclock"
            "org.kde.plasma.showdesktop"
          ];
          example = [
            "org.kde.plasma.kickoff"
            "org.kde.plasma.icontasks"
            "org.kde.plasma.marginsseparator"
            "org.kde.plasma.digitalclock"
          ];
          description = ''
            The widgets to use in the panel. To get the names, it may be useful
            to look in the share/plasma/plasmoids folder of the nix-package the
            widget/plasmoid is from. Some packages which include some
            widgets/plasmoids are for example plasma-desktop and
            plasma-workspace.
          '';
          apply = map widgets.convert;
        };
        screen = lib.mkOption {
          type =
            with lib.types;
            nullOr (oneOf [
              ints.unsigned
              (listOf ints.unsigned)
              (enum [ "all" ])
            ]);
          default = null;
          description = ''
            The screen the panel should appear on. Can be an int, or a list of ints,
            starting from 0, representing the ID of the screen the panel should
            appear on. Alternatively it can be set to "all" if the panel should
            appear on all the screens.
          '';
        };
        extraSettings = lib.mkOption {
          type = with lib.types; nullOr str;
          default = null;
          description = ''
            Extra lines to add to the layout.js. See
            https://develop.kde.org/docs/plasma/scripting/ for inspiration.
          '';
        };
      };
    }
  );

  anyPanelSet = (builtins.length cfg.panels) > 0;
in
{
  imports = [
    (lib.mkRemovedOptionModule [
      "programs"
      "plasma"
      "extraWidgets"
    ] "Place the widget packages in home.packages or environment.systemPackages instead.")
  ];

  options.programs.plasma.panels = lib.mkOption {
    type = lib.types.listOf panelType;
    default = [ ];
  };

  config = (
    lib.mkIf cfg.enable {
      home.packages = (
        lib.flatten (
          lib.filter (x: x != null) (
            lib.mapAttrsToList (
              widgetName: packages: if (hasWidget widgetName) then packages else null
            ) additionalWidgetPackages
          )
        )
      );

      programs.plasma.startup.desktopScript."panels" = (
        lib.mkIf anyPanelSet (
          let
            anyNonDefaultScreens = ((builtins.any (panel: panel.screen != null)) cfg.panels);
            panelPreCMD = ''
              # We delete plasma-org.kde.plasma.desktop-appletsrc to hinder it
              # growing indefinitely. See:
              # https://github.com/nix-community/plasma-manager/issues/76
              [ -f ${config.xdg.configHome}/plasma-org.kde.plasma.desktop-appletsrc ] && rm ${config.xdg.configHome}/plasma-org.kde.plasma.desktop-appletsrc
            '';
            panelLayoutStr = (
              import ../lib/panel.nix {
                inherit lib;
                inherit config;
              }
            );
            panelPostCMD = (
              if anyNonDefaultScreens then
                ''
                  sed -i 's/^lastScreen\\x5b$i\\x5d=/lastScreen[$i]=/' ${config.xdg.configHome}/plasma-org.kde.plasma.desktop-appletsrc
                ''
              else
                ""
            );
          in
          {
            preCommands = panelPreCMD;
            text = panelLayoutStr;
            postCommands = panelPostCMD;
            restartServices = (
              lib.unique (if anyNonDefaultScreens then [ "plasma-plasmashell" ] else [ ])
              ++ (lib.filter (service: shouldRestart service) (builtins.attrNames serviceRestarts))
            );
            priority = 2;
          }
        )
      );
    }
  );
}