{
  pkgs ? import <nixpkgs> { },
}:

let
  # First, select the rust toolchain attribute set from pkgs.
  # This set contains cargo, rustc, rust-std, rust-src, etc.
  # Using `pkgs.rust-toolchain` will select the default stable toolchain.
  rust-toolchain = pkgs.rust-toolchain;
in
pkgs.mkShell {
  # nativeBuildInputs are tools you run on your machine during development.
  nativeBuildInputs = with pkgs; [
    # 1. Add the main toolchain components (cargo, rustc).
    rust-toolchain

    # 2. Add the Rust standard library for our specific WebAssembly target.
    #    We get `rust-std` from the `rust-toolchain` set we defined above
    #    to guarantee version consistency.
    (rust-toolchain.rust-std.override {
      targets = [ "wasm32-unknown-unknown" ];
    })

    # 3. Add the other necessary tools.
    wasm-bindgen-cli
    bun
    clang # Recommended linker for wasm on NixOS
    pkg-config
    openssl
  ];

  # Environment variables that will be set when you enter the shell.
  shellHook = ''
    # Set the linker for the wasm target to avoid potential issues.
    export CARGO_TARGET_WASM32_UNKNOWN_UNKNOWN_LINKER="${pkgs.clang}/bin/clang"

    # Set the path to the Rust standard library source code.
    # This is used by tools like rust-analyzer for "go to definition", etc.
    export RUST_SRC_PATH="${rust-toolchain}/lib/rustlib/src/rust/library"

    echo "✅ Nix shell is ready with Rust (wasm target), wasm-bindgen, and Bun."
  '';
}