hydrus: add desktop file

The flatpak package for Hydrus Network install a .desktop file.
I updated this file so that the Nix package also generate a .desktop file on install.

pkgs/applications/graphics/hydrus/default.nix

@@ -8,6 +8,8 @@
 , python3Packages
 , qtbase
 , qtcharts
+, makeDesktopItem
+, copyDesktopItems
 }:
 
 python3Packages.buildPythonPackage rec {
@@ -25,6 +27,7 @@ python3Packages.buildPythonPackage rec {
   nativeBuildInputs = [
     wrapQtAppsHook
     python3Packages.mkdocs-material
+    copyDesktopItems
   ];
 
   buildInputs = [
@@ -32,6 +35,20 @@ python3Packages.buildPythonPackage rec {
     qtcharts
   ];
 
+  desktopItems = [
+    (makeDesktopItem {
+      name = "hydrus-client";
+      exec = "hydrus-client";
+      desktopName = "Hydrus Client";
+      icon = "hydrus-client";
+      comment = meta.description;
+      terminal = false;
+      type = "Application";
+      categories = [ "FileTools" "Utility" ];
+    })
+  ];
+
+
   propagatedBuildInputs = with python3Packages; [
     beautifulsoup4
     cbor2
@@ -104,6 +121,8 @@ python3Packages.buildPythonPackage rec {
   outputs = [ "out" "doc" ];
 
   installPhase = ''
+    runHook preInstall
+
     # Move the hydrus module and related directories
     mkdir -p $out/${python3Packages.python.sitePackages}
     mv {hydrus,static,db} $out/${python3Packages.python.sitePackages}
@@ -118,12 +137,18 @@ python3Packages.buildPythonPackage rec {
     mkdir -p $out/bin
     install -m0755 hydrus_server.py $out/bin/hydrus-server
     install -m0755 hydrus_client.py $out/bin/hydrus-client
+
+    # desktop item
+    mkdir -p "$out/share/icons/hicolor/scalable/apps"
+    ln -s "$doc/share/doc/hydrus/assets/hydrus-white.svg" "$out/share/icons/hicolor/scalable/apps/hydrus-client.svg"
   '' + lib.optionalString enableSwftools ''
     mkdir -p $out/${python3Packages.python.sitePackages}/bin
     # swfrender seems to have to be called sfwrender_linux
     # not sure if it can be loaded through PATH, but this is simpler
     # $out/python3Packages.python.sitePackages/bin is correct NOT .../hydrus/bin
     ln -s ${swftools}/bin/swfrender $out/${python3Packages.python.sitePackages}/bin/swfrender_linux
+  '' + ''
+    runHook postInstall
   '';
 
   dontWrapQtApps = true;