nix: update package and remove meta section since we are not on nixpkgs

packages/nix/polymc/default.nix

@@ -1,49 +1,73 @@
-{ lib, mkDerivation, fetchFromGitHub, cmake, jdk8, jdk, zlib, file, makeWrapper, xorg, libpulseaudio, qtbase, libGL, msaClientID ? "" }:
+{ lib
+, mkDerivation
+, fetchFromGitHub
+, makeDesktopItem
+, substituteAll
+, fetchpatch
+, cmake
+, jdk8
+, jdk
+, zlib
+, file
+, makeWrapper
+, xorg
+, libpulseaudio
+, qtbase
+, libGL
+, self
+, msaClientID ? ""
+}:
 
 let
-  libpath = with xorg; lib.makeLibraryPath [ libX11 libXext libXcursor libXrandr libXxf86vm libpulseaudio libGL ];
-in 
+  gameLibraryPath = with xorg; lib.makeLibraryPath [
+    libX11
+    libXext
+    libXcursor
+    libXrandr
+    libXxf86vm
+    libpulseaudio
+    libGL
+  ];
+in
+
 mkDerivation rec {
   pname = "polymc";
-  version = "1.0.4";
-  src = fetchFromGitHub {
-    owner = "PolyMC";
-    repo = "PolyMC";
-    rev = "${version}";
-    sha256 = "sha256-8aya0KfV9F+i2qBpweWcR9hwyTSQkqn2wHdtkCEeNvk=";
-    fetchSubmodules = true;
-  };
+  version = "nightly";
+
+  src = lib.cleanSource self;
+
   nativeBuildInputs = [ cmake file makeWrapper ];
   buildInputs = [ qtbase jdk8 zlib ];
 
-  patches = [ ./0001-pick-latest-java-first.patch ];
-
   postPatch = ''
-    # hardcode jdk paths
-    substituteInPlace launcher/java/JavaUtils.cpp \
-      --replace 'scanJavaDir("/usr/lib/jvm")' 'javas.append("${jdk}/lib/openjdk/bin/java")' \
-      --replace 'scanJavaDir("/usr/lib32/jvm")' 'javas.append("${jdk8}/lib/openjdk/bin/java")'
+    # add client ID
+    substituteInPlace notsecrets/Secrets.cpp \
+      --replace 'QString MSAClientID = "";' 'QString MSAClientID = "${msaClientID}";'
   '';
 
-  cmakeFlags = [ "-DLauncher_LAYOUT=lin-system" ];
+  cmakeFlags = [
+    "-DLauncher_LAYOUT=lin-system"
+  ];
+
+  desktopItem = makeDesktopItem {
+    name = "polymc";
+    exec = "polymc";
+    icon = "polymc";
+    desktopName = "PolyMC";
+    genericName = "Minecraft Launcher";
+    comment = "A custom launcher for Minecraft";
+    categories = "Game;";
+    extraEntries = ''
+      Keywords=game;Minecraft;
+    '';
+  };
 
   postInstall = ''
+    install -Dm644 ../launcher/resources/multimc/scalable/launcher.svg $out/share/pixmaps/multimc.svg
+    install -Dm755 ${desktopItem}/share/applications/polymc.desktop -t $out/share/applications
     # xorg.xrandr needed for LWJGL [2.9.2, 3) https://github.com/LWJGL/lwjgl/issues/128
     wrapProgram $out/bin/polymc \
-      --set GAME_LIBRARY_PATH /run/opengl-driver/lib:${libpath} \
-      --prefix PATH : ${lib.makeBinPath [ xorg.xrandr ]}
-
-    substituteInPlace $out/share/applications/org.polymc.PolyMC.desktop --replace 'Exec=' 'Exec=${placeholder "out"}/bin/polymc'
+      --set GAME_LIBRARY_PATH /run/opengl-driver/lib:${gameLibraryPath} \
+      --prefix PATH : ${lib.makeBinPath [ xorg.xrandr jdk ]}
   '';
-
-  meta = with lib; {
-    homepage = "https://github.com/PolyMC/PolyMC";
-    description = "A free, open source launcher for Minecraft";
-    longDescription = ''
-      Allows you to have multiple, separate instances of Minecraft (each with their own mods, texture packs, saves, etc) and helps you manage them and their associated options with a simple interface.
-    '';
-    platforms = platforms.linux;
-    license = licenses.gpl3;
-    maintainers = with maintainers; [ cidkid ];
-  };
-}
+}