WIP: feat(sway): Add basic tray with EWW

WIP because this needs to handle systems without a battery, and maybe
have a network icon.

home-config/config/desktop/sway.nix

@@ -91,6 +91,25 @@ in
     };
   };
 
+  programs.eww = {
+    enable = true;
+    configDir = ../../dotfiles/eww;
+  };
+
+  systemd.user.services.eww = {
+    Unit = {
+      Description = "System tray";
+      After = [ "graphical-session-pre.target" ];
+      PartOf = [ "graphical-session.target" ];
+    };
+
+    Service = {
+      ExecStart = "${config.programs.eww.package}/bin/eww daemon --no-daemonize";
+      ExecStartPost = "${config.programs.eww.package}/bin/eww open tray";
+    };
+    Install.WantedBy = [ "graphical-session.target" ];
+  };
+
   systemd.user.services.swaylock = {
     Unit.Description = "Lock screen";
     Service.ExecStart = "${config.programs.swaylock.package}/bin/swaylock";

home-config/dotfiles/eww/eww.scss

@@ -0,0 +1,5 @@
+* { all: unset; }
+
+.tray-items {
+    font-size: 1.35em;
+}

home-config/dotfiles/eww/eww.yuck

@@ -0,0 +1,47 @@
+(defwindow tray
+           :monitor 0
+           :geometry (geometry :height "0%"
+                               :width "0%"
+                               :anchor "bottom left")
+           :stacking "bottom"
+           :exclusive true
+           :focusable false
+
+           (_tray_items))
+
+(defwidget _tray_items []
+           (box :class "tray-items"
+
+                :spacing 3
+                :vexpand true
+                :hexpand true
+                :valign "center"
+                :halign "start"
+                :space-evenly false
+
+                (_battery_icon)
+                (_clock)
+                "|"
+                (systray :spacing 5
+                         :orientation "horizontal"
+                         :space-evenly false)))
+
+(defvar battery_icons `[
+  "",
+  "",
+  "",
+  "",
+  ""
+]`)
+
+(defwidget _battery_icon []
+           (label :text {
+                    jq(EWW_BATTERY, "first(.[])").status == "Charging" ?
+                    "" :
+                    battery_icons[round(jq(EWW_BATTERY, "first(.[])").capacity / 25, 0)]
+                    }
+                  :tooltip "${jq(EWW_BATTERY, "first(.[])").capacity}%"))
+
+(defwidget _clock []
+           (label :text { formattime(EWW_TIME, "%R") }
+                  :tooltip { formattime(EWW_TIME, "%F") }))