untested hm module

flake.nix

@@ -22,7 +22,8 @@
         toolchain = pkgs.rust-bin.fromRustupToolchainFile ./toolchain.toml;
       in 
       rec {
-        packages = flake-utils.lib.flattenTree {
+        packages = flake-utils.lib.flattenTree rec {
+          default = lastfmpris;
           lastfmpris = rustPlatform.buildRustPackage {
             pname = package.name;
             inherit (package) version;
@@ -40,8 +41,6 @@
           };
         };
 
-        defaultPackage = packages.lastfmpris;
-
         devShells.default = pkgs.mkShell {
           buildInputs = with pkgs; [ pkg-config ];
 
@@ -54,5 +53,39 @@
 
           RUST_SRC_PATH = "${toolchain}/lib/rustlib/src/rust/library";
         };
-  });
+  }) // {
+    homeManagerModules = rec {
+      default = lastfmpris;
+      lastfmpris = { config, lib, pkgs, ... }:
+      with lib;
+      let
+        cfg = config.services.lastfmpris;
+      in {
+        options.services.lastfmpris = {
+          enable = mkEnableOption "Enables the lastfmpris mpris scrobbling daemon";
+          package = mkOption {
+            type = types.package;
+            default = self.packages.${pkgs.stdenv.hostPlatform.system}.default;
+          };
+        };
+
+        config = mkIf cfg.enable {
+          systemd.user.services.lastfmpris = {
+            Unit = {
+              Description = "a rust application to scrobble your currently playing song on last.fm with mpris";
+              Requires = ["graphical-session.target"];
+            };
+            Service = {
+              Type = "simple";
+              ExecStart = "${lib.getExe cfg.package}";
+            };
+          };
+
+          home.packages = [
+            cfg.package
+          ];
+        };
+      };
+    };
+  };
 }