Add packwiz-wrapper package

this searches up the directory tree for a pack.toml before executing
packwiz

flake.nix

@@ -7,7 +7,7 @@
     devShells = eachSystem (system: let pkgs = import nixpkgs { inherit system; };
     in {
       default = pkgs.mkShell {
-        buildInputs = with pkgs; [ packwiz nix-update ];
+        buildInputs = with pkgs; [ self.packages.${system}.packwiz-wrapper nix-update ];
       };
     });
     packages = eachSystem (system: let pkgs = import nixpkgs { inherit system; };

nix/packages/default.nix

@@ -3,4 +3,5 @@ let
   shaders = callPackage ./shaders.nix {};
 in {
   inherit (shaders) bliss-dh complementary-reimagined-dh rethinking-voxels-dh;
+  packwiz-wrapper = callPackage ./packwiz-wrapper { };
 }

nix/packages/packwiz-wrapper/default.nix

@@ -0,0 +1,25 @@
+{ lib,
+  stdenvNoCC,
+  python3,
+  makeWrapper,
+  packwiz }:
+let
+  wrappedPath = lib.makeBinPath [ packwiz ];
+in stdenvNoCC.mkDerivation {
+  pname = "packwiz-wrapper";
+  version = "0.0.0";
+  buildInputs = [
+    python3
+    makeWrapper
+    packwiz
+  ];
+
+  src = ./.;
+
+  installPhase = ''
+    install -Dm555 packwiz-wrapper.py $out/libexec/packwiz-wrapper.py
+    mkdir -p $out/bin
+    makeShellWrapper $out/libexec/packwiz-wrapper.py $out/bin/packwiz \
+      --prefix PATH : "${wrappedPath}"
+  '';
+}

nix/packages/packwiz-wrapper/packwiz-wrapper.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+import sys, os
+from pathlib import Path
+
+# Returns a parent path with pack.toml, or None if it can't be found
+def search_recursive(dir: str | os.PathLike) -> Path | None:
+    dir = Path(dir)
+    pack = dir / "pack.toml"
+
+    if pack.is_file():
+        return dir
+
+    # If we've made it to / without finding it, return None
+    if dir.samefile("/"):
+        return None
+
+    # Otherwise, recurse
+    return search_recursive(dir / "..")
+
+def search(dir: str | os.PathLike) -> Path:
+    new_dir = search_recursive(dir)
+    if new_dir is not None:
+        return new_dir
+    else:
+        return Path(dir)
+
+def main():
+    args = ["packwiz"] + sys.argv[1:]
+    os.chdir(search("."))
+    os.execvp("packwiz", args)
+
+
+if __name__ == "__main__":
+    main()