{ stdenv, python, fetchPypi, makeWrapper, unzip }:

let
  wheel_source = fetchPypi {
    pname = "wheel";
    version = "0.33.4";
    format = "wheel";
    sha256 = "5e79117472686ac0c4aef5bad5172ea73a1c2d1646b808c35926bd26bdfb0c08";
  };
  setuptools_source = fetchPypi {
    pname = "setuptools";
    version = "41.0.1";
    format = "wheel";
    sha256 = "c7769ce668c7a333d84e17fe8b524b1c45e7ee9f7908ad0a73e1eda7e6a5aebf";
  };

in stdenv.mkDerivation rec {
  pname = "pip";
  version = "19.1.1";
  name = "${python.libPrefix}-bootstrapped-${pname}-${version}";

  src = fetchPypi {
    inherit pname version;
    format = "wheel";
    sha256 = "993134f0475471b91452ca029d4390dc8f298ac63a712814f101cd1b6db46676";
  };

  unpackPhase = ''
    mkdir -p $out/${python.sitePackages}
    unzip -d $out/${python.sitePackages} $src
    unzip -d $out/${python.sitePackages} ${setuptools_source}
    unzip -d $out/${python.sitePackages} ${wheel_source}
  '';

  patchPhase = ''
    mkdir -p $out/bin
  '';

  nativeBuildInputs = [ makeWrapper unzip ];
  buildInputs = [ python ];

  installPhase = ''

    # install pip binary
    echo '#!${python.interpreter}' > $out/bin/pip
    echo 'import sys;from pip._internal import main' >> $out/bin/pip
    echo 'sys.exit(main())' >> $out/bin/pip
    chmod +x $out/bin/pip

    # wrap binaries with PYTHONPATH
    for f in $out/bin/*; do
      wrapProgram $f --prefix PYTHONPATH ":" $out/${python.sitePackages}/
    done
  '';
}