main: more detailed --version output

flake.nix

@@ -105,20 +105,27 @@
       default = self.packages.${system}.worblehat;
       worblehat = let
         inherit (pkgs) python3Packages;
+        inherit (self) sourceInfo;
         pyproject = lib.pipe ./pyproject.toml [
           builtins.readFile
           builtins.fromTOML
         ];
       in python3Packages.buildPythonApplication {
         pname = pyproject.project.name;
-        version = pyproject.project.version;
+        version = "0.1";
         src = lib.cleanSource ./.;
 
         format = "pyproject";
 
-        build-system = with python3Packages; [ hatchling ];
+        build-system = with python3Packages; [ setuptools setuptools-scm ];
         dependencies = deps pkgs.python3Packages;
 
+        env.SETUPTOOLS_SCM_PRETEND_METADATA = (x: "{${x}}") (lib.concatStringsSep ", " [
+          "node=\"${sourceInfo.rev or (lib.substring 0 64 sourceInfo.dirtyRev)}\""
+          "node_date=${lib.substring 0 4 sourceInfo.lastModifiedDate}-${lib.substring 4 2 sourceInfo.lastModifiedDate}-${lib.substring 6 2 sourceInfo.lastModifiedDate}"
+          "dirty=${if sourceInfo ? dirtyRev then "true" else "false"}"
+        ]);
+
         meta.mainProgram = "worblehat";
       };
     });