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

let

  inherit (nixpkgs) pkgs;

  pg-transact = with haskellPackages; callPackage(
    { mkDerivation, async, base, bytestring, exceptions, hspec
    , hspec-expectations-lifted, lib, monad-control, postgresql-libpq
    , postgresql-simple, tmp-postgres, transformers
    }:
    mkDerivation {
      pname = "pg-transact";
      version = "0.3.1.1";
      sha256 = "8d5d61ebafdcb8e94d563e74bc9646519e45a2fddf327a708b0a59e5160c20fc";
      libraryHaskellDepends = [
        base bytestring exceptions monad-control postgresql-simple
        transformers
      ];
      testHaskellDepends = [
        async base bytestring exceptions hspec hspec-expectations-lifted
        postgresql-libpq postgresql-simple tmp-postgres
      ];
      doCheck = false;
      homepage = "https://github.com/jfischoff/pg-transact#readme";
      description = "A postgresql-simple transaction monad";
      license = lib.licenses.bsd3;
    }) {};

  f = { mkDerivation, aeson, base, base16-bytestring
      , base64-bytestring, bytestring, case-insensitive, clock
      , containers, directory, extra, haskell-gettext, hspec
      , hspec-discover, hspec-wai, hspec-wai-json, http-api-data
      , http-types, iproute, lib, mime-mail, mtl, network, opaleye
      , optparse-applicative, postgresql-simple
      , postgresql-simple-migration, product-profunctors, profunctors
      , pureMD5, random-bytestring, resource-pool, servant, servant-rawm
      , servant-rawm-server, servant-server, stm, text, time
      , tmp-postgres, wai, wai-logger, wai-middleware-throttle, warp
      , yaml
      }:
      mkDerivation {
        pname = "mateamt";
        version = "0.0.0.0";
        src = ./.;
        isLibrary = true;
        isExecutable = true;
        libraryHaskellDepends = [
          aeson base base16-bytestring base64-bytestring bytestring
          containers directory extra haskell-gettext http-api-data http-types
          mime-mail mtl opaleye postgresql-simple product-profunctors
          profunctors pureMD5 random-bytestring servant servant-rawm
          servant-rawm-server servant-server stm text time wai wai-logger
          warp
        ];
        executableHaskellDepends = [
          base base16-bytestring bytestring case-insensitive clock containers
          iproute mtl network opaleye optparse-applicative postgresql-simple
          postgresql-simple-migration servant servant-server stm text time
          wai wai-logger wai-middleware-throttle warp yaml
        ];
        testHaskellDepends = [
          base bytestring containers hspec hspec-wai hspec-wai-json mtl
          pg-transact postgresql-simple resource-pool text time tmp-postgres
          wai warp
        ];
        testToolDepends = [ hspec-discover ];
        homepage = "https://gitea.nek0.eu/nek0/mateamt/";
        description = "A whole new matemat";
        license = lib.licenses.agpl3Plus;
      };

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

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

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

in

  if pkgs.lib.inNixShell then drv.env else drv