{ config, lib, pkgs, ... }:

let
  cfg = config.libkookie.rustup;
  rustupSettings = pkgs.writeTextDir "settings.toml" ''
    default_toolchain = "{cfg.defaulttoolchain}"
    profile = "default"
    version = "12"

    [overrides]
    # TODO: Add overrides to module
  '';
  rustupDir = pkgs.symlinkJoin {
    name = "rustup-state";
    paths = [ rustupSettings ];
  };

  pkgs.stdenv.mkDerivation {
    name = "rustup";
    buildInputs = [ pkgs.rustup ];
    dontUnpack = true;
    installPhase = ''
      mkdir -p $out
      echo "${(buildSettingsBase cfg.defaultToolchain)}" > $out/settings.toml

      export $RUSTUP_HOME=$out
      ${pkgs.rustup}/bin/rustup default stable
    '';
  };
in
{
  options.libkookie.rustup = with lib; {
    enable = mkEnableOption "The Rust version manager";

    defaultToolchain = mkOption {
      type = types.str;
      description = "The default Rust toolchain to use";
      default = "stable-x86_64-unknown-linux-gnu";
    };

  };
  
  config = lib.mkIf cfg.rustup.enable {
    home.packages = with pkgs; [
      (writeShellScriptBin "rustup" ''
          RUSTUP_HOME=${rustupDir} ${rustup}/bin/rustup
        '')
    ];
  };
}