{ nixpkgs ? import <nixpkgs> {}, compiler ? "default", doBenchmark ? false }:

let

  inherit (nixpkgs) pkgs;

  conftrack =
    { mkDerivation, aeson, base, bytestring, containers, directory
    , file-io, filepath, lib, mtl, QuickCheck, quickcheck-instances
    , scientific, template-haskell, text, transformers, yaml
    }:
    mkDerivation {
      pname = "conftrack";
      version = "0.0.1";
      src = nixpkgs.fetchgit {
        url = "https://stuebinm.eu/git/conftrack";
        rev = "3e71d0ab05c7f5fd71a75b86eeac6f8a1edc3a44";
        hash = "sha256-gBkzbvKFNhut2XbruqisXLSHFwJPIsf8e5bjrSUgHsI=";
      };
      libraryHaskellDepends = [
        aeson base bytestring containers directory file-io filepath mtl
        scientific template-haskell text transformers yaml
      ];
      testHaskellDepends = [
        aeson base containers QuickCheck quickcheck-instances text
      ];
      description = "Tracable multi-source config management";
      license = lib.licenses.bsd3;
    };

  f = { mkDerivation, aeson, base, blaze-html, blaze-markup
      , bytestring, cassava, conduit, conftrack, containers, data-default-class
      , directory, either, exceptions, extra, filepath, fmt, hoauth2, http-api-data
      , http-media, insert-ordered-containers, lens, lib, monad-logger
      , mtl, path-pieces, persistent, persistent-postgresql
      , prometheus-client, prometheus-metrics-ghc, proto-lens
      , proto-lens-runtime, regex-tdfa, resource-pool, servant
      , servant-docs, servant-server, servant-swagger, servant-websockets
      , shakespeare, stm, swagger2, text, time, timezone-olson
      , timezone-series, transformers, unliftio-core, uri-bytestring
      , uuid, vector, vector-algorithms, wai-extra, warp, websockets
      , yesod, yesod-auth, yesod-auth-oauth2, yesod-core, yesod-form
      , zip-archive
      }:
      mkDerivation {
        pname = "tracktrain";
        version = "0.1.0.0";
        src = ./.;
        isLibrary = true;
        isExecutable = true;
        libraryHaskellDepends = [
          aeson base blaze-html blaze-markup bytestring cassava conduit
          conftrack containers either exceptions extra fmt filepath
          hoauth2 http-api-data http-media insert-ordered-containers lens
          monad-logger mtl path-pieces persistent persistent-postgresql
          prometheus-client prometheus-metrics-ghc proto-lens
          proto-lens-runtime regex-tdfa resource-pool servant servant-docs
          servant-server servant-swagger servant-websockets shakespeare stm
          swagger2 text time timezone-olson timezone-series transformers
          unliftio-core uri-bytestring uuid vector vector-algorithms warp
          websockets yesod yesod-auth yesod-auth-oauth2 yesod-core yesod-form
          zip-archive
        ];
        executableHaskellDepends = [
          aeson base bytestring conftrack
          data-default-class directory extra fmt monad-logger
          persistent-postgresql proto-lens time wai-extra warp
        ];
        doHaddock = false;
        postInstall = ''
          cp -r $src/assets $out/assets
        '';
        description = "tracktrain tracks trains on their traintracks";
        license = "unknown";
        mainProgram = "tracktrain";
      };

  haskellPackages = if compiler == "default"
                       then pkgs.haskellPackages
                       else pkgs.haskell.packages.${compiler};

  variant = if doBenchmark then pkgs.haskell.lib.doBenchmark else pkgs.lib.id;

  # we can override haskell packages in nix here; but attempt to minimise that
  # since builds get pretty expensive when we do.
  # (currently kept as a dummy)
  hpkgs = haskellPackages.override {
    overrides = self: super: with pkgs.haskell.lib.compose; {
      conftrack = self.callPackage conftrack {};
      # filepath = self.filepath_1_4_100_4;
      # conferer-warp = markUnbroken super.conferer-warp;
    };
  };

  drv = variant (hpkgs.callPackage f {});

in with pkgs.haskell.lib;
  justStaticExecutables drv