tmodloader: add desktop item

pkgs/tmodloader/default.nix

@@ -2,13 +2,26 @@
   lib,
   stdenv,
   fetchzip,
+  fetchurl,
+  makeDesktopItem,
   steam-run,
   dotnet,
   runtimeDir ? "\\$HOME/.local/share/tmodloader",
   ...
 }: let
   pname = "tModLoader";
   version = "2023.11.3.3";
+  description = "A mod to make and play Terraria mods.";
+
+  desktopItem = makeDesktopItem {
+    name = pname;
+    exec = pname;
+    desktopName = pname;
+    genericName = pname;
+    comment = description;
+    icon = pname;
+    categories = ["Game"];
+  };
 in
   stdenv.mkDerivation {
     inherit pname version;
@@ -65,8 +78,19 @@ in
       chmod +x $out/bin/${pname}
     '';
 
+    postInstall = let
+      icon = fetchurl {
+        url = "https://raw.githubusercontent.com/tModLoader/tModLoader/1.4.4/solutions/documentation/tModLoaderIcon-Large.png";
+        hash = "sha256-FXwcoYJwQaG//L0MoJfRp9lHi1MShRssB1HQJy9ZyDg=";
+      };
+    in ''
+      mkdir -p "$out/share/icons/"
+      ln -s ${icon} "$out/share/icons/tModLoader.png"
+      cp -r "${desktopItem}/share/applications/" "$out/share/"
+    '';
+
     meta = {
-      description = "A mod to make and play Terraria mods.";
+      inherit description;
       homepage = "https://github.com/tModLoader/tModLoader";
       license = lib.licenses.mit;
       maintainers = with lib.maintainers; [NotAShelf];