class Nettle < Formula
  desc "Low-level cryptographic library"
  homepage "https://www.lysator.liu.se/~nisse/nettle/"
  url "https://ftp.gnu.org/gnu/nettle/nettle-3.6.tar.gz"
  mirror "https://ftpmirror.gnu.org/nettle/nettle-3.6.tar.gz"
  sha256 "d24c0d0f2abffbc8f4f34dcf114b0f131ec3774895f3555922fe2f40f3d5e3f1"
  # license ["GPL-2.0", "GPL-3.0", "LGPL-3.0"] - pending https://github.com/Homebrew/brew/pull/7953
  license "GPL-2.0"

  livecheck do
    url :stable
  end

  bottle do
    cellar :any
    sha256 "7ac7677ba653dbef81dd83ed8cde3dfcb7b464d04442886c396179932f4f9faa" => :catalina
    sha256 "d378b026725d8d449ca6497ce2158b93c991a0e0326921a5f914bc4847da3a92" => :mojave
    sha256 "07c65cb4d172b05065dcceb702b41ca3408b31b6154690c7a4cfa430b2de074d" => :high_sierra
  end

  depends_on "gmp"

  uses_from_macos "m4" => :build

  def install
    # The LLVM shipped with Xcode/CLT 10+ compiles binaries/libraries with
    # ___chkstk_darwin, which upsets nettle's expected symbol check.
    # https://github.com/Homebrew/homebrew-core/issues/28817#issuecomment-396762855
    # https://lists.lysator.liu.se/pipermail/nettle-bugs/2018/007300.html
    if DevelopmentTools.clang_build_version >= 1000
      inreplace "testsuite/symbols-test", "get_pc_thunk",
                                          "get_pc_thunk|(_*chkstk_darwin)"
    end

    args = []
    args << "--build=aarch64-apple-darwin#{OS.kernel_version}" if Hardware::CPU.arm?

    system "./configure", "--disable-dependency-tracking",
                          "--prefix=#{prefix}",
                          "--enable-shared",
                          *args
    system "make"
    system "make", "install"
    system "make", "check"
  end

  test do
    (testpath/"test.c").write <<~EOS
      #include <nettle/sha1.h>
      #include <stdio.h>

      int main()
      {
        struct sha1_ctx ctx;
        uint8_t digest[SHA1_DIGEST_SIZE];
        unsigned i;

        sha1_init(&ctx);
        sha1_update(&ctx, 4, "test");
        sha1_digest(&ctx, SHA1_DIGEST_SIZE, digest);

        printf("SHA1(test)=");

        for (i = 0; i<SHA1_DIGEST_SIZE; i++)
          printf("%02x", digest[i]);

        printf("\\n");
        return 0;
      }
    EOS
    system ENV.cc, "test.c", "-L#{lib}", "-lnettle", "-o", "test"
    system "./test"
  end
end