sway: integrate with systemd

            # Import the most important environment variables into the D-Bus and systemd

            # user environments (e.g. required for screen sharing and Pinentry prompts):

            exec dbus-update-activation-environment --systemd DISPLAY WAYLAND_DISPLAY SWAYSOCK XDG_CURRENT_DESKTOP

            # enable systemd-integration

            exec "systemctl --user import-environment {,WAYLAND_}DISPLAY SWAYSOCK; systemctl --user start sway-session.target"

            exec swaymsg -t subscribe '["shutdown"]' && systemctl --user stop sway-session.target

          '';

        } // lib.optionalAttrs (cfg.package != null) {

          "sway/config".source = lib.mkOptionDefault "${cfg.package}/etc/sway/config";

        };

      };

      systemd.user.targets.sway-session = {

        description = "sway compositor session";

        documentation = [ "man:systemd.special(7)" ];

        bindsTo = [ "graphical-session.target" ];

        wants = [ "graphical-session-pre.target" ];

        after = [ "graphical-session-pre.target" ];

      };

      # To make a Sway session available if a display manager like SDDM is enabled:

      services.displayManager.sessionPackages = lib.optional (cfg.package != null) cfg.package;