{ stdenvNoCC, lib, kubernetes-helm, cacert }:
let
  cleanName = lib.replaceStrings [ "/" ] [ "-" ];
in
{
  # name of the chart
  chart
, # chart url to fetch from custom location
  chartUrl ? null
, # version of the chart
  version ? null
, # chart hash
  sha256
, # whether to extract chart
  untar ? true
, # use custom charts repo
  repo ? null
, # pass --verify to helm chart
  verify ? false
, # pass --devel to helm chart
  devel ? false
,
}:
stdenvNoCC.mkDerivation {
  name = "${cleanName chart}-${ if version == null then "dev" else version }";

  buildCommand = ''
    export HOME="$PWD"
    echo "adding helm repo"
    ${ if repo == null then "" else "helm repo add repository ${repo}" }
    echo "fetching helm chart"
    helm fetch -d ./chart \
      ${ if untar then "--untar" else ""} \
      ${ if version == null then "" else "--version ${version}" } \
      ${ if devel then "--devel" else "" } \
      ${ if verify then "--verify" else "" } \
      ${ if chartUrl == null then  (
        if repo == null
        then chart
        else "repository/${chart}"
      ) else chartUrl}
    cp -r chart/*/ $out
  '';
  outputHashMode = "recursive";
  outputHashAlgo = "sha256";
  outputHash = sha256;
  nativeBuildInputs = [ kubernetes-helm cacert ];
}