class Boost < Formula
  desc "Collection of portable C++ source libraries"
  homepage "https://www.boost.org/"
  revision 5

  stable do
    url "https://downloads.sourceforge.net/project/boost/boost/1.63.0/boost_1_63_0.tar.bz2"
    sha256 "beae2529f759f6b3bf3f4969a19c2e9d6f0c503edcb2de4a61d1428519fcb3b0"
  end

  devel do
    url "https://dl.bintray.com/boostorg/release/1.68.0/source/boost_1_68_0.tar.bz2"
    sha256 "7f6130bc3cf65f56a618888ce9d5ea704fa10b462be126ad053e80e553d6d8b7"
  end

  depends_on "icu4c"

  unless OS.mac?
    depends_on "bzip2"
    depends_on "zlib"
  end

  def install
    # Reduce memory usage below 4 GB for Circle CI.
    ENV["HOMEBREW_MAKE_JOBS"] = "6" if ENV["CIRCLECI"]

    # Force boost to compile with the desired compiler
    open("user-config.jam", "a") do |file|
      if OS.mac?
        file.write "using darwin : : #{ENV.cxx} ;\n"
      else
        file.write "using gcc : : #{ENV.cxx} ;\n"
      end
      file.write "using mpi ;\n" if build.with? "mpi"
    end

    # libdir should be set by --prefix but isn't
    bootstrap_args = ["--prefix=#{prefix}", "--libdir=#{lib}"]

    icu4c_prefix = Formula["icu4c"].opt_prefix
    bootstrap_args << "--with-icu=#{icu4c_prefix}"

    # Handle libraries that will not be built.
    without_libraries = ["python", "mpi"]

    # Boost.Log cannot be built using Apple GCC at the moment. Disabled
    # on such systems.
    without_libraries << "log" if ENV.compiler == :gcc

    bootstrap_args << "--without-libraries=#{without_libraries.join(",")}"

    # layout should be synchronized with boost-python and boost-mpi
    args = ["--prefix=#{prefix}",
            "--libdir=#{lib}",
            "-d2",
            "-j#{ENV.make_jobs}",
            "--layout=tagged",
            "--user-config=user-config.jam",
            "install"]

    # Only build MT shared variants
    args << "threading=multi"
    args << "link=shared"

    # Trunk starts using "clang++ -x c" to select C compiler which breaks C++11
    # handling using ENV.cxx11. Using "cxxflags" and "linkflags" still works.
    args << "cxxflags=-std=c++11"
    if ENV.compiler == :clang
      args << "cxxflags=-stdlib=libc++" << "linkflags=-stdlib=libc++"
    end

    # Fix error: bzlib.h: No such file or directory
    # and /usr/bin/ld: cannot find -lbz2
    args += ["include=#{HOMEBREW_PREFIX}/include", "linkflags=-L#{HOMEBREW_PREFIX}/lib"] unless OS.mac?

    system "./bootstrap.sh", *bootstrap_args
    system "./b2", "headers"
    system "./b2", *args
  end

  def caveats
    s = ""
    # ENV.compiler doesn't exist in caveats. Check library availability
    # instead.
    if Dir["#{lib}/libboost_log*"].empty?
      s += <<~EOS
        Building of Boost.Log is disabled because it requires newer GCC or Clang.
      EOS
    end

    s
  end

  test do
    (testpath/"test.cpp").write <<~EOS
      #include <boost/algorithm/string.hpp>
      #include <string>
      #include <vector>
      #include <assert.h>
      using namespace boost::algorithm;
      using namespace std;

      int main()
      {
        string str("a,b");
        vector<string> strVec;
        split(strVec, str, is_any_of(","));
        assert(strVec.size()==2);
        assert(strVec[0]=="a");
        assert(strVec[1]=="b");
        return 0;
      }
    EOS
    system ENV.cxx, "test.cpp", "-std=c++1y", "-L#{lib}", "-lboost_system-mt", "-o", "test"
    system "./test"
  end
end
