Set up an ibus switch

home/modules/linux/graphical/alacritty.nix

@@ -7,7 +7,7 @@ with lib;
     package = pkgs.unstable.alacritty;
 
     settings = {
-      window.opacity = 0.95;
+      window.opacity = 0.8;
       font = {
         size = 14.0;
         normal.family = "Fantasque Sans Mono Nerd Font";

home/modules/programs/my-sway/default.nix

@@ -31,6 +31,8 @@ let
 
 in
 {
+  imports = [ ./ibus.nix ];
+
   options.programs.my-sway = {
     enable = mkEnableOption "Enable the sway configuration";
     fontSize = mkOption {

home/modules/programs/my-sway/ibus.nix

@@ -0,0 +1,49 @@
+{ pkgs, config, lib, ... }:
+with lib;
+let
+  cfg = config.programs.my-sway;
+
+  # Set up an ibus script
+  ibusNext = (
+    let
+      input-methods = [ "xkb:us::eng" "mozc-jp" "Bamboo" ];
+      next = m:
+        let
+          nextRec = l:
+            if (length l == 1)
+            then head input-methods
+            else if (m == head l)
+            then (head (tail l))
+            else nextRec (tail l);
+        in
+        nextRec input-methods;
+      inputCase = m: ''
+        if test $current = "${m}"
+          ${pkgs.libnotify}/bin/notify-send \
+            -a ibus \
+            -u low \
+            -t 3000 \
+            "${next m}" \
+            "Input engine changed"
+          ${pkgs.ibus}/bin/ibus engine ${next m}
+        end
+      '';
+    in
+    pkgs.writeScriptBin "ibus-next-engine" ''
+      #! ${pkgs.fish}/bin/fish
+
+      set current (${pkgs.ibus}/bin/ibus engine)
+
+      ${strings.concatMapStrings inputCase input-methods}
+    ''
+  );
+
+in
+{
+  config = mkIf cfg.enable {
+    wayland.windowManager.sway.config.keybindings = mkOptionDefault {
+      "${config.wayland.windowManager.sway.config.modifier}+z" = "exec ${ibusNext}/bin/ibus-next-engine";
+    };
+  };
+}
+