class ErlangAT21 < Formula
  desc "Programming language for highly scalable real-time systems"
  homepage "https://www.erlang.org/"
  # Download tarball from GitHub; it is served faster than the official tarball.
  url "https://github.com/erlang/otp/archive/OTP-21.3.8.6.tar.gz"
  sha256 "7d96d11143b8ad71448acc0427c2c34756712aa2972d9aaa6d100f87f29918c6"
  revision 1

  bottle do
    cellar :any
    sha256 "f732d5fd9fa777892f830de91b82506b07848fdc4a08d37016dd4f54d8e910be" => :mojave
    sha256 "1eae10e8e2701f7da2c933c2b136cf6e5f9564007a41364574835cc5c7f65043" => :high_sierra
    sha256 "9f27267e896b026e32eec00e97a70c09ec057746ad8d8ae1f3d05553eb9fea55" => :sierra
  end

  keg_only :versioned_formula

  depends_on "autoconf" => :build
  depends_on "automake" => :build
  depends_on "libtool" => :build
  depends_on "openssl@1.1"
  depends_on "wxmac" # for GUI apps like observer

  resource "man" do
    url "https://www.erlang.org/download/otp_doc_man_21.3.tar.gz"
    mirror "https://fossies.org/linux/misc/otp_doc_man_21.3.tar.gz"
    sha256 "f5464b5c8368aa40c175a5908b44b6d9670dbd01ba7a1eef1b366c7dc36ba172"
  end

  resource "html" do
    url "https://www.erlang.org/download/otp_doc_html_21.3.tar.gz"
    mirror "https://fossies.org/linux/misc/otp_doc_html_21.3.tar.gz"
    sha256 "258b1e0ed1d07abbf08938f62c845450e90a32ec542e94455e5d5b7c333da362"
  end

  def install
    # Unset these so that building wx, kernel, compiler and
    # other modules doesn't fail with an unintelligable error.
    %w[LIBS FLAGS AFLAGS ZFLAGS].each { |k| ENV.delete("ERL_#{k}") }

    # Do this if building from a checkout to generate configure
    system "./otp_build", "autoconf" if File.exist? "otp_build"

    args = %W[
      --disable-debug
      --disable-silent-rules
      --prefix=#{prefix}
      --enable-dynamic-ssl-lib
      --enable-hipe
      --enable-sctp
      --enable-shared-zlib
      --enable-smp-support
      --enable-threads
      --enable-wx
      --with-ssl=#{Formula["openssl@1.1"].opt_prefix}
      --without-javac
      --enable-darwin-64bit
    ]

    args << "--enable-kernel-poll" if MacOS.version > :el_capitan
    args << "--with-dynamic-trace=dtrace" if MacOS::CLT.installed?

    system "./configure", *args
    system "make"
    system "make", "install"

    (lib/"erlang").install resource("man").files("man")
    doc.install resource("html")
  end

  def caveats; <<~EOS
    Man pages can be found in:
      #{opt_lib}/erlang/man

    Access them with `erl -man`, or add this directory to MANPATH.
  EOS
  end

  test do
    system "#{bin}/erl", "-noshell", "-eval", "crypto:start().", "-s", "init", "stop"
  end
end