class Libtorch < Formula
  include Language::Python::Virtualenv

  desc "Tensors and dynamic neural networks"
  homepage "https://pytorch.org/"
  url "https://github.com/pytorch/pytorch.git",
      tag:      "v1.10.2",
      revision: "71f889c7d265b9636b93ede9d651c0a9c4bee191"
  license "BSD-3-Clause"

  livecheck do
    url :stable
    regex(/^v?(\d+(?:\.\d+)+)$/i)
  end

  bottle do
    sha256 cellar: :any,                 arm64_monterey: "5ce1f2a40f787dc61b762bde001027393cef039ffd94b0a63d800a78d0601d9d"
    sha256 cellar: :any,                 arm64_big_sur:  "8122c594fe8d1cd192542bc0c7f7d458253d9e105743101d37b9a2cb885dad98"
    sha256 cellar: :any,                 monterey:       "95cec86cdc2c96c18955058fa918b2a6d0b9e6ac536814a6866cd56f94fe6c25"
    sha256 cellar: :any,                 big_sur:        "238dc4802a6684e19c4036e80313305be83ff65a8514606ddd815426fe15e397"
    sha256 cellar: :any,                 catalina:       "834b65640273592324e8c718c0770be73b972ea3c25a67f71dd239946aaa220b"
    sha256 cellar: :any_skip_relocation, x86_64_linux:   "c2ea263eb6e8fecdbba9689cdc5254191bd3f6de32fa7af0720f7cfc482fa044"
  end

  depends_on "cmake" => :build
  depends_on "python@3.9" => :build
  depends_on "eigen"
  depends_on "libomp"
  depends_on "libyaml"
  depends_on "protobuf"
  depends_on "pybind11"

  resource "PyYAML" do
    url "https://files.pythonhosted.org/packages/36/2b/61d51a2c4f25ef062ae3f74576b01638bebad5e045f747ff12643df63844/PyYAML-6.0.tar.gz"
    sha256 "68fb519c14306fec9720a2a5b45bc9f0c8d1b9c72adf45c37baedfcd949c35a2"
  end

  resource "typing-extensions" do
    url "https://files.pythonhosted.org/packages/0d/4a/60ba3706797b878016f16edc5fbaf1e222109e38d0fa4d7d9312cb53f8dd/typing_extensions-4.0.1.tar.gz"
    sha256 "4ca091dea149f945ec56afb48dae714f21e8692ef22a395223bcd328961b6a0e"
  end

  def install
    venv = virtualenv_create(buildpath/"venv", Formula["python@3.9"].opt_bin/"python3")
    venv.pip_install resources

    args = %W[
      -DBUILD_CUSTOM_PROTOBUF=OFF
      -DBUILD_PYTHON=OFF
      -DPYTHON_EXECUTABLE=#{buildpath}/venv/bin/python
      -DUSE_CUDA=OFF
      -DUSE_METAL=OFF
      -DUSE_MKLDNN=OFF
      -DUSE_NNPACK=OFF
      -DUSE_OPENMP=OFF
      -DUSE_SYSTEM_EIGEN_INSTALL=ON
      -DUSE_SYSTEM_PYBIND11=ON
    ]
    # Remove when https://github.com/pytorch/pytorch/issues/67974 is addressed
    args << "-DUSE_SYSTEM_BIND11=ON"

    mkdir "build" do
      system "cmake", "..", *std_cmake_args, *args

      # Avoid references to Homebrew shims
      inreplace "caffe2/core/macros.h", Superenv.shims_path/ENV.cxx, ENV.cxx

      system "make"
      system "make", "install"
    end
  end

  test do
    (testpath/"test.cpp").write <<~EOS
      #include <torch/torch.h>
      #include <iostream>

      int main() {
        torch::Tensor tensor = torch::rand({2, 3});
        std::cout << tensor << std::endl;
      }
    EOS
    system ENV.cxx, "-std=c++14", "test.cpp", "-o", "test",
                    "-I#{include}/torch/csrc/api/include",
                    "-L#{lib}", "-ltorch", "-ltorch_cpu", "-lc10"
    system "./test"
  end
end