im/fcitx: drop as fcitx 4 has been removed from nixpkgs (#3804)

Reference: https://github.com/NixOS/nixpkgs/pull/220776

modules/i18n/input-method/default.nix

@@ -22,8 +22,7 @@ let
   '';
 
 in {
-  imports =
+  imports = [ ./fcitx5.nix ./hime.nix ./kime.nix ./nabi.nix ./uim.nix ];
-    [ ./fcitx.nix ./fcitx5.nix ./hime.nix ./kime.nix ./nabi.nix ./uim.nix ];
 
   options.i18n = {
     inputMethod = {
@@ -31,7 +30,7 @@ in {
         type = types.nullOr
           (types.enum [ "fcitx" "fcitx5" "nabi" "uim" "hime" "kime" ]);
         default = null;
-        example = "fcitx";
+        example = "fcitx5";
         description = ''
           Select the enabled input method. Input methods is a software to input
           symbols that are not available on standard input devices.
@@ -42,17 +41,10 @@ in {
           Currently the following input methods are available in Home Manager:
 
           <variablelist>
-          <varlistentry>
-            <term><literal>fcitx</literal></term>
-            <listitem><para>
-              A customizable lightweight input method
-              extra input engines can be added using
-              <literal>i18n.inputMethod.fcitx.engines</literal>.
-            </para></listitem>
-          </varlistentry>
           <varlistentry>
             <term><literal>fcitx5</literal></term>
             <listitem><para>
+              A customizable lightweight input method.
               The next generation of fcitx,
               addons (including engines, dictionaries, skins) can be added using
               <literal>i18n.inputMethod.fcitx5.addons</literal>.
@@ -97,6 +89,10 @@ in {
   config = mkIf (cfg.enabled != null) {
     assertions = [
       (hm.assertions.assertPlatform "i18n.inputMethod" pkgs platforms.linux)
+      {
+        assertion = cfg.enabled != "fcitx";
+        message = "fcitx has been removed, please use fcitx5 instead";
+      }
     ];
 
     home.packages = [ cfg.package gtk2Cache gtk3Cache ];

modules/i18n/input-method/fcitx.nix

@@ -1,50 +0,0 @@
-{ config, pkgs, lib, ... }:
-
-with lib;
-
-let
-  cfg = config.i18n.inputMethod.fcitx;
-  fcitxPackage = pkgs.fcitx.override { plugins = cfg.engines; };
-  fcitxEngine = types.package // {
-    name = "fcitx-engine";
-    check = x:
-      types.package.check x && attrByPath [ "meta" "isFcitxEngine" ] false x;
-  };
-in {
-  options = {
-
-    i18n.inputMethod.fcitx = {
-      engines = mkOption {
-        type = with types; listOf fcitxEngine;
-        default = [ ];
-        example = literalExpression "with pkgs.fcitx-engines; [ mozc hangul ]";
-        description = let
-          enginesDrv = filterAttrs (const isDerivation) pkgs.fcitx-engines;
-          engines = concatStringsSep ", "
-            (map (name: "<literal>${name}</literal>") (attrNames enginesDrv));
-        in "Enabled Fcitx engines. Available engines are: ${engines}.";
-      };
-    };
-
-  };
-
-  config = mkIf (config.i18n.inputMethod.enabled == "fcitx") {
-    i18n.inputMethod.package = fcitxPackage;
-
-    home.sessionVariables = {
-      GTK_IM_MODULE = "fcitx";
-      QT_IM_MODULE = "fcitx";
-      XMODIFIERS = "@im=fcitx";
-    };
-
-    systemd.user.services.fcitx-daemon = {
-      Unit = {
-        Description = "Fcitx input method editor";
-        PartOf = [ "graphical-session.desktop" ];
-      };
-      Service.ExecStart = "${fcitxPackage}/bin/fcitx";
-      Install.WantedBy = [ "graphical-session.target" ];
-    };
-  };
-
-}