{ pkgs, buildPackages, stdenv, lib, haskellLib, ghc, fetchurl, runCommand, comp-builder, setup-builder }:

config:
{ flags
, package
, components
, cabal-generator

, name
, sha256
, src
, revision
, revisionSha256
, patches

, shellHook

, ...
}@pkg:

assert (if ghc.isHaskellNixCompiler or false then true
  else throw ("It is likely you used `haskell.compiler.X` instead of `haskell-nix.compiler.X`"
    + pkgs.lib.optionalString (name != null) (" for " + name)));

let
  cabalFile = if revision == null || revision == 0 then null else
    fetchurl {
      name = "${name}-${toString revision}.cabal";
      url = "https://hackage.haskell.org/package/${name}/revision/${toString revision}.cabal";
      sha256 = revisionSha256;
    };

  defaultSetupSrc = builtins.toFile "Setup.hs" ''
    import Distribution.Simple
    main = defaultMain
  '';
  defaultSetup = setup-builder {
    name = "${ghc.targetPrefix}default-Setup";
    component = {
      depends = config.setup-depends;
      libs = [];
      frameworks = [];
      doExactConfig = false;
      includeDirs = [];
      asmSources = [];
      cSources = [];
      cmmSources = [];
      cxxSources = [];
      jsSources = [];
      extraSrcFiles = [ "Setup.hs" "Setup.lhs" ];
      pkgconfig = [];
      build-tools = [];

      platforms = null;
      preBuild = null;   postBuild = null;
      preInstall = null; postInstall = null;
      preUnpack = null;  postUnpack = null;
    };
    package = {
      identifier = {
        name = "default-Setup";
        version = "1.0";
      };
      homepage = null;
      synopsis = null;
      license = "MIT";
    };
    src = null; cleanSrc = buildPackages.runCommand "default-Setup-src" {} ''
      mkdir $out
      cat ${defaultSetupSrc} > $out/Setup.hs
    '';
    inherit defaultSetupSrc;
  };

  # buildPackages.runCommand "default-Setup" { nativeBuildInputs = [(ghc.passthru.buildGHC or ghc)]; } ''
  #   cat ${defaultSetupSrc} > Setup.hs
  #   mkdir -p $out/bin
  #   ${(ghc.passthru.buildGHC or ghc).targetPrefix}ghc Setup.hs --make -o $out/bin/Setup
  # '';

  setup = if package.buildType == "Simple"
    then defaultSetup
    else setup-builder {
      component = components.setup // {
        depends = config.setup-depends ++ components.setup.depends ++ package.setup-depends;
        extraSrcFiles = components.setup.extraSrcFiles ++ [ "Setup.hs" "Setup.lhs" ];
        pkgconfig = if components ? library then components.library.pkgconfig or [] else [];
      };
      inherit package name src flags revision patches defaultSetupSrc;
      inherit (pkg) preUnpack postUnpack;
    };

  buildComp = componentId: component: comp-builder {
    inherit componentId component package name src flags setup cabalFile cabal-generator patches revision
            shellHook
            ;
  };

in rec {
  components = haskellLib.applyComponents buildComp pkg;
  checks = pkgs.recurseIntoAttrs (builtins.mapAttrs
    (_: d: haskellLib.check d)
      (lib.filterAttrs (_: d: d.config.doCheck) components.tests));
  inherit (package) identifier detailLevel isLocal;
  inherit setup cabalFile;
  isHaskell = true;
  inherit src;
}