# Almost 1:1 copy of idris2's nix/package.nix. Some work done in their flake.nix
# we do here instead.
{ stdenv
, lib
, chez
, chez-racket
, clang
, gmp
, fetchFromGitHub
, makeWrapper
, gambit
, nodejs
, zsh
, callPackage
}:

# NOTICE: An `idris2WithPackages` is available at: https://github.com/claymager/idris2-pkgs

let
  # Taken from Idris2/idris2/flake.nix. Check if the idris2 project does it this
  # way, still, every now and then.
  platformChez = if stdenv.system == "x86_64-linux" then chez else chez-racket;
# Uses scheme to bootstrap the build of idris2
in stdenv.mkDerivation rec {
  pname = "idris2";
  version = "0.7.0";

  src = fetchFromGitHub {
    owner = "idris-lang";
    repo = "Idris2";
    rev = "v${version}";
    sha256 = "sha256-VwveX3fZfrxEsytpbOc5Tm6rySpLFhTt5132J6rmrmM=";
  };

  strictDeps = true;
  nativeBuildInputs = [ makeWrapper clang platformChez ]
    ++ lib.optionals stdenv.isDarwin [ zsh ];
  buildInputs = [ platformChez gmp ];

  prePatch = ''
    patchShebangs --build tests
  '';

  makeFlags = [ "PREFIX=$(out)" ]
    ++ lib.optional stdenv.isDarwin "OS=";

  # The name of the main executable of pkgs.chez is `scheme`
  buildFlags = [ "bootstrap" "SCHEME=scheme" ];

  checkTarget = "test";
  nativeCheckInputs = [ gambit nodejs ]; # racket ];
  checkFlags = [ "INTERACTIVE=" ];

  # TODO: Move this into its own derivation, such that this can be changed
  #       without having to recompile idris2 every time.
  postInstall = let
    name = "${pname}-${version}";
    globalLibraries = [
      "\\$HOME/.nix-profile/lib/${name}"
      "/run/current-system/sw/lib/${name}"
      "$out/${name}"
    ];
    globalLibrariesPath = builtins.concatStringsSep ":" globalLibraries;
  in ''
    # Remove existing idris2 wrapper that sets incorrect LD_LIBRARY_PATH
    rm $out/bin/idris2
    # The only thing we need from idris2_app is the actual binary
    mv $out/bin/idris2_app/idris2.so $out/bin/idris2
    rm $out/bin/idris2_app/*
    rmdir $out/bin/idris2_app
    # idris2 needs to find scheme at runtime to compile
    # idris2 installs packages with --install into the path given by
    #   IDRIS2_PREFIX. We set that to a default of ~/.idris2, to mirror the
    #   behaviour of the standard Makefile install.
    # TODO: Make support libraries their own derivation such that
    #       overriding LD_LIBRARY_PATH is unnecessary
    wrapProgram "$out/bin/idris2" \
      --set-default CHEZ "${platformChez}/bin/scheme" \
      --run 'export IDRIS2_PREFIX=''${IDRIS2_PREFIX-"$HOME/.idris2"}' \
      --suffix IDRIS2_LIBS ':' "$out/${name}/lib" \
      --suffix IDRIS2_DATA ':' "$out/${name}/support" \
      --suffix IDRIS2_PACKAGE_PATH ':' "${globalLibrariesPath}" \
      --suffix DYLD_LIBRARY_PATH ':' "$out/${name}/lib" \
      --suffix LD_LIBRARY_PATH ':' "$out/${name}/lib"
  '';

  # Run package tests
  passthru.tests = callPackage ./tests.nix { inherit pname; };

  meta = {
    description = "A purely functional programming language with first class types";
    mainProgram = "idris2";
    homepage = "https://github.com/idris-lang/Idris2";
    license = lib.licenses.bsd3;
    maintainers = with lib.maintainers; [ fabianhjr wchresta mattpolzin ];
    inherit (chez.meta) platforms;
  };
}