{
  description = "animator-as-crab: Animator Controllers described in Rhai, generated from Rust into Unity";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    crane.url = "github:ipetkov/crane";
    rust-overlay = {
      url = "github:oxalica/rust-overlay";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs =
    {
      self,
      nixpkgs,
      crane,
      rust-overlay,
    }:
    let
      systems = [
        "x86_64-linux"
        "aarch64-linux"
        "x86_64-darwin"
        "aarch64-darwin"
      ];
      forAllSystems = nixpkgs.lib.genAttrs systems;

      perSystem =
        system:
        let
          pkgs = import nixpkgs {
            inherit system;
            overlays = [ (import rust-overlay) ];
          };
          rustToolchain = pkgs.rust-bin.stable.latest.default.override {
            extensions = [
              "rust-src"
              "rust-analyzer"
              "clippy"
              "rustfmt"
            ];
          };
          craneLib = (crane.mkLib pkgs).overrideToolchain rustToolchain;

          # Name Unity expects on the current platform; AacCrabNative.cs imports "libaac".
          nativeLib =
            if pkgs.stdenv.hostPlatform.isDarwin then
              "libaac.dylib"
            else if pkgs.stdenv.hostPlatform.isWindows then
              "aac.dll"
            else
              "libaac.so";

          # The Rust core: evaluates the Rhai DSL and emits the graph as JSON for Unity.
          aac = craneLib.buildPackage {
            src = ./rust;
            strictDeps = true;
            doCheck = true;
            # crane's default install only copies binaries; install the cdylib explicitly.
            installPhase = ''
              runHook preInstall
              mkdir -p $out/lib $out/bin
              cp target/release/${nativeLib} $out/lib/
              cp target/release/aac-dump $out/bin/
              runHook postInstall
            '';
          };

          # Unity-importable bundle: native library plus the C# packages, as a single zip.
          bundle =
            pkgs.runCommand "animator-as-crab-${system}.zip"
              {
                nativeBuildInputs = [ pkgs.zip ];
                meta.description = "Unity plugin bundle for animator-as-crab";
              }
              ''
                mkdir -p root/Plugins root/bin
                cp ${aac}/lib/${nativeLib} root/Plugins/
                cp ${aac}/bin/aac-dump root/bin/
                cp -r ${./csharp}/dev.doloro.animator-as-crab root/
                cp -r ${./csharp}/dev.hai-vr.animator-as-code.v1.base.test root/
                (cd root && zip -q -r $out .)
              '';
        in
        {
          packages = {
            inherit aac bundle;
            default = bundle;
          };

          devShells.default = craneLib.devShell {
            inputsFrom = [ aac ];
            packages = [
              rustToolchain
              pkgs.jq
              pkgs.zip
            ];
          };

          formatter = pkgs.nixfmt-rfc-style;
        };
    in
    {
      packages = forAllSystems (system: (perSystem system).packages);
      devShells = forAllSystems (system: (perSystem system).devShells);
      formatter = forAllSystems (system: (perSystem system).formatter);
    };
}