{
  description = "The PrivateStorage Mobile application";
  inputs = {
    nixpkgs = {
      url = "github:NixOS/nixpkgs?ref=nixos-22.05";
    };
    flake-utils.url = "github:numtide/flake-utils";
    pypi-deps-db = {
      flake = false;
      url = "github:DavHau/pypi-deps-db";
    };
    mach-nix-flake = {
      flake = true;
      url = "github:DavHau/mach-nix";
      inputs = {
        nixpkgs.follows = "nixpkgs";
        flake-utils.follows = "flake-utils";
        pypi-deps-db.follows = "pypi-deps-db";
      };
    };
    buildozerSrc = {
      flake = false;
      url = "github:PrivateStorageio/buildozer?ref=build-without-installing";
    };
    pythonForAndroidSrc = {
      flake = false;
      url = "github:PrivateStorageio/python-for-android?ref=work-on-nixos";
    };
  };
  outputs = { self, nixpkgs, flake-utils, mach-nix-flake, buildozerSrc, pythonForAndroidSrc, ... }:
    flake-utils.lib.eachSystem [
      "x86_64-linux"
    ] (system: let

      mach-nix = mach-nix-flake.lib.${system};
      pkgs = import nixpkgs {
        inherit system;
        config = {
          allowUnfree = true;
          android_sdk.accept_license = true;
        };
      };
      lib = pkgs.lib;

      python-for-android = mach-nix.buildPythonPackage {
        src = pythonForAndroidSrc;
        requirementsExtra = ''
        sh>=1.10
        '';
      };
      buildozer = mach-nix.buildPythonPackage {
        src = buildozerSrc;
        packagesExtra = [ ];
      };

      kivy-env = mach-nix.mkPython {
        python = "python39";
        requirements = ''
          kivy
          Pillow
          cython
        '';
        packagesExtra = [ python-for-android buildozer ];

      };

      cmakeVersion = "3.10.2";

      # Also includes ndk
      androidComposition = pkgs.callPackage ./android.nix { inherit cmakeVersion; };

      getBuildInputs = getInputs: xs: builtins.foldl' (accum: drv: (getInputs drv) ++ accum) [] xs;

      chaquopy-env = mach-nix.mkPython {
        python = "python39";
        requirements = ''
          chaquopy
        '';
      };
    in {

      packages.default = pkgs.androidenv.buildApp {
        name = "PrivateStorage Mobile";
        src = ./app;
        release = false;

        platformVersions = [ "27" ];
        includeNDK = false;
      };

      apps.emulator = {
        type = "app";
        program = let
          emulator = pkgs.androidenv.emulateApp {
            name = "PrivateStorage Mobile";
            platformVersion = "27";
            abiVersion = "x86_64";
            systemImageType = "default";
            app = ./app/app/build/outputs/apk/debug/app-debug.apk;
            package = "MyApp";
            activity = "MainActivity";
          };
        in
          "${emulator}/bin/emulate-it???";
      };
      devShells.gradle = pkgs.mkShell rec {
        name = "nix-native";
        version = "2022.11.09";

        ANDROIDSDK = "${androidComposition.androidsdk}/libexec/android-sdk";
        ANDROIDNDK = "${ANDROIDSDK}/ndk-bundle";

        buildInputs = with pkgs; [

          # XXXX
          # gradle finds an aapk2 from some random tgz it downloads from internet instead of from our ANDROIDSDK!  GREAT!!!!!!!!!!11111
          #
          # Fix the one it downloads, if it didn't already root you, with:
          #
          #  patchelf --set-interpreter <correct ld.so> ~/.gradle/<...path to aapt2>

          gradle
          ant
          # openjdk8
          android-studio
          android-tools
          python39
        ];
      };

      devShells.default = self.devShells.${system}.gradle;

      # https://github.com/NixOS/nixpkgs/blob/master/doc/languages-frameworks/android.section.md
      # is a good reference for this stuff.
      devShells.kivy = pkgs.mkShell rec {
        name = "ps-mobile";
        version = "2022.10.21";

        # The docs talk about ANDROID_SDK_ROOT but apparently it has been
        # renamed yet again.
        ANDROIDSDK = "${androidComposition.androidsdk}/libexec/android-sdk";
        ANDROIDNDK = "${ANDROIDSDK}/ndk-bundle";

        shellHook = ''
        export PATH="$(echo "$ANDROIDSDK/cmake/${cmakeVersion}".*/bin):$PATH"
        '';

        buildInputs = with pkgs; [
          android-studio
          android-tools
          kivy-env

          # Kivy and python-for-android depend on:
          # https://github.com/kivy/python-for-android/blob/v2020.04.29/doc/source/troubleshooting.rst#errors-related-to-java-version
          openjdk8
          ant

          # python-for-android recipes all want to download and unpack their
          # own sources!  aaaaaa
          unzip
        ] ++

        # Also we need build dependencies for all of the things it is going to
        # build!
        (getBuildInputs (drv: drv.buildInputs) [ openssl libffi python39 ]);

        nativeBuildInputs =
          with pkgs; getBuildInputs (drv: drv.nativeBuildInputs) [ openssl libffi python39 ];
      };
    });
}