{ lib
, stdenv
, python3
, fetchPypi
, fetchFromBitbucket
, fetchpatch
, substituteAll
, geos
}:

let
  python = python3.override {
    packageOverrides = self: super: {
      shapely = super.shapely.overridePythonAttrs (old: rec {
        version = "1.8.4";
        src = fetchPypi {
          pname = "Shapely";
          inherit version;
          hash = "sha256-oZXlHKr6IYKR8suqP+9p/TNTyT7EtlsqRyLEz0DDGYw=";
        };
        # Environment variable used in shapely/_buildcfg.py
        GEOS_LIBRARY_PATH = "${geos}/lib/libgeos_c${stdenv.hostPlatform.extensions.sharedLibrary}";
        patches = [
          # Patch to search form GOES .so/.dylib files in a Nix-aware way
          (substituteAll {
            src = ./shapely-library-paths.patch;
            libgeos_c = GEOS_LIBRARY_PATH;
            libc = lib.optionalString (!stdenv.isDarwin) "${stdenv.cc.libc}/lib/libc${stdenv.hostPlatform.extensions.sharedLibrary}.6";
          })
        ];
      });
    };
  };
in
python.pkgs.buildPythonApplication rec {
  pname = "flatcam";
  version = "8.5";

  src = fetchFromBitbucket {
    owner = "jpcgt";
    repo = pname;
    rev = "533afd6a1772857cb633c011b5e0a15b60b1e92e"; # 8.5 with Red Hat packaging.
    sha256 = "199kiiml18k34z1zhk2hbhibphmnv0kb11kxiajq52alps0mjb3m";
  };

  propagatedBuildInputs = with python.pkgs; [
    matplotlib
    numpy
    packaging
    pyqt4
    rtree
    scipy
    setuptools
    shapely
    simplejson
    six
    svg-path
  ];

  packaging_fix_pull_request_patch = fetchpatch {
    name = "packaging_fix_pull_request.patch";
    url = "https://bitbucket.org/trepetti/flatcam/commits/5591ed889d1f48a5190fe237b562cb932cb5876c/raw";
    sha256 = "19rhjdrf1n1q29cgpcry6pl2kl90zq0d613hhkwdir9bhq5bkknp";
  };

  patches = [
    packaging_fix_pull_request_patch
    ./release.patch
  ];

  postPatch = ''
    substituteInPlace setup.py --replace "'shapely>=1.3'" "'shapely>=1.3',"
  '';

  # Only non-GUI tests can be run deterministically in the Nix build environment.
  checkPhase = ''
    python -m unittest tests.test_excellon
    python -m unittest tests.test_gerber_buffer
    python -m unittest tests.test_paint
    python -m unittest tests.test_pathconnect
  '';

  meta = with lib; {
    description = "2-D post processing for PCB fabrication on CNC routers";
    homepage = "https://bitbucket.org/jpcgt/flatcam";
    license = licenses.mit;
    maintainers = with maintainers; [ trepetti ];
  };
}