Add desktop item and icon, format flake code

flake.nix

@@ -5,8 +5,15 @@
     utils.url = "github:numtide/flake-utils";
   };
 
-  outputs = { self, nixpkgs, utils, naersk }:
-    utils.lib.eachDefaultSystem (system:
+  outputs =
+    {
+      self,
+      nixpkgs,
+      utils,
+      naersk,
+    }:
+    utils.lib.eachDefaultSystem (
+      system:
       let
         pkgs = import nixpkgs { inherit system; };
         naersk-lib = pkgs.callPackage naersk { };
@@ -22,20 +29,36 @@
         ];
         # Needed at runtime (on run system)
         buildInputs = with pkgs; [ ];
-      in rec {
+      in
+      rec {
         defaultPackage = naersk-lib.buildPackage {
           src = ./.;
           inherit buildInputs;
           inherit nativeBuildInputs;
+
+          postInstall = ''
+            mkdir -p $out/share/applications
+            cp ${./music-reader.desktop} $out/share/applications/music-reader.desktop
+
+            mkdir -p $out/share/icons
+            cp ${./music-reader.png} $out/share/icons/music-reader.png
+          '';
         };
-        devShell = with pkgs;
+        devShell =
+          with pkgs;
           mkShell {
-            buildInputs =
-              [ cargo rustc rustfmt pre-commit rustPackages.clippy ];
+            buildInputs = [
+              cargo
+              rustc
+              rustfmt
+              pre-commit
+              rustPackages.clippy
+            ];
             # Without inheriting nativeBuildinputs, cargo build will fail but that is good since we want to use only nix build
             # inherit nativeBuildInputs;
 
             RUST_SRC_PATH = rustPlatform.rustLibSrc;
           };
-      });
+      }
+    );
 }

music-reader.desktop

@@ -0,0 +1,9 @@
+[Desktop Entry]
+Type=Application
+Terminal=false
+Name=Music Reader
+Icon=music-reader
+Categories=Viewer;Utility;
+Keywords=viewer;document;pdf;
+Exec=music-reader %F
+MimeType=application/pdf;