{
  lib,
  testers,
  stdenv,
  fetchFromGitHub,
  openssl,
  libsamplerate,
  swig,
  alsa-lib,
  AppKit,
  CoreFoundation,
  Security,
  python3,
  pythonSupport ? true,
  runCommand,
}:
stdenv.mkDerivation (finalAttrs: {
  pname = "pjsip";
  version = "2.14.1";

  src = fetchFromGitHub {
    owner = "pjsip";
    repo = "pjproject";
    tag = finalAttrs.version;
    hash = "sha256-LDA3o1QMrAxcGuOi/YRoMzXmw/wFkfDs2wweZuIJ2RY=";
  };

  patches = [ ./fix-aarch64.patch ];

  postPatch = ''
    substituteInPlace \
      pjsip-apps/src/py_pjsua/setup.py \
      pjsip-apps/src/swig/python/setup.py \
      pjsip-apps/src/python/setup.py \
      pjsip-apps/src/python/setup-vc.py \
      --replace-fail "distutils.core" "setuptools"
  '';

  nativeBuildInputs = lib.optionals pythonSupport [
    swig
    python3
    python3.pkgs.build
    python3.pkgs.installer
    python3.pkgs.setuptools
    python3.pkgs.wheel
  ];

  buildInputs =
    [
      openssl
      libsamplerate
    ]
    ++ lib.optional stdenv.hostPlatform.isLinux alsa-lib
    ++ lib.optionals stdenv.hostPlatform.isDarwin [
      AppKit
      CoreFoundation
      Security
    ];

  env =
    lib.optionalAttrs stdenv.cc.isClang { CXXFLAGS = "-std=c++11"; }
    // lib.optionalAttrs stdenv.hostPlatform.isDarwin {
      NIX_CFLAGS_LINK = "-headerpad_max_install_names";
    };

  preConfigure = ''
    export LD=$CC
  '';

  postBuild = lib.optionalString pythonSupport ''
    make -C pjsip-apps/src/swig/python
  '';

  configureFlags = [ "--enable-shared" ];

  outputs = [ "out" ] ++ lib.optional pythonSupport "py";

  postInstall =
    ''
      mkdir -p $out/bin
      cp pjsip-apps/bin/pjsua-* $out/bin/pjsua
      mkdir -p $out/share/${finalAttrs.pname}-${finalAttrs.version}/samples
      cp pjsip-apps/bin/samples/*/* $out/share/${finalAttrs.pname}-${finalAttrs.version}/samples
    ''
    + lib.optionalString pythonSupport ''
      (cd pjsip-apps/src/swig/python && \
          python -m build --no-isolation --outdir dist/ --wheel
          python -m installer --prefix $py dist/*.whl
      )
    ''
    + lib.optionalString stdenv.hostPlatform.isDarwin ''
      # On MacOS relative paths are used to refer to libraries. All libraries use
      # a relative path like ../lib/*.dylib or ../../lib/*.dylib. We need to
      # rewrite these to use absolute ones.

      # First, find all libraries (and their symlinks) in our outputs to define
      # the install_name_tool -change arguments we should pass.
      readarray -t libraries < <(
        for outputName in $(getAllOutputNames); do
          find "''${!outputName}" \( -name '*.dylib*' -o -name '*.so*' \)
        done
      )

      # Determine the install_name_tool -change arguments that are going to be
      # applied to all libraries.
      change_args=()
      for lib in "''${libraries[@]}"; do
        lib_name="$(basename $lib)"
        change_args+=(-change ../lib/$lib_name $lib)
        change_args+=(-change ../../lib/$lib_name $lib)
      done

      # Rewrite id and library refences for all non-symlinked libraries.
      for lib in "''${libraries[@]}"; do
        if [ -f "$lib" ]; then
          install_name_tool -id $lib "''${change_args[@]}" $lib
        fi
      done

      # Rewrite library references for all executables.
      find "$out" -executable -type f | while read executable; do
        install_name_tool "''${change_args[@]}" "$executable"
      done
    '';

  # We need the libgcc_s.so.1 loadable (for pthread_cancel to work)
  dontPatchELF = true;

  passthru.tests.version = testers.testVersion {
    package = finalAttrs.finalPackage;
    command = "pjsua --version";
  };

  passthru.tests.pkg-config = testers.hasPkgConfigModules { package = finalAttrs.finalPackage; };

  passthru.tests.python-pjsua2 = runCommand "python-pjsua2" { } ''
    ${(python3.withPackages (pkgs: [ pkgs.pjsua2 ])).interpreter} -c "import pjsua2" > $out
  '';

  meta = with lib; {
    description = "Multimedia communication library written in C, implementing standard based protocols such as SIP, SDP, RTP, STUN, TURN, and ICE";
    homepage = "https://pjsip.org/";
    license = licenses.gpl2Plus;
    maintainers = with maintainers; [ olynch ];
    mainProgram = "pjsua";
    platforms = platforms.linux ++ platforms.darwin;
    pkgConfigModules = [ "libpjproject" ];
  };
})
