class R < Formula
  desc "Software environment for statistical computing"
  homepage "https://www.r-project.org/"
  url "https://cran.r-project.org/src/base/R-4/R-4.1.3.tar.gz"
  sha256 "15ff5b333c61094060b2a52e9c1d8ec55cc42dd029e39ca22abdaa909526fed6"
  license "GPL-2.0-or-later"

  livecheck do
    url "https://cran.rstudio.com/banner.shtml"
    regex(%r{href=(?:["']?|.*?/)R[._-]v?(\d+(?:\.\d+)+)\.t}i)
  end

  bottle do
    sha256 arm64_monterey: "a34f069127fda71f97b119036520d56703212ab38137b79b7e92cf351f69292e"
    sha256 arm64_big_sur:  "5f1088340bcd5f8bfc75d2dee84212f8eda0769464e06c24c0819612fb415ee7"
    sha256 monterey:       "edae2c1cd7044eca95092fdf6f370991db60393baf902acf35844f7fd8203e0c"
    sha256 big_sur:        "28f9d5c6639eca65d2556b20e8816e04353c5d879ac21ff0186843ced832096e"
    sha256 catalina:       "bda2b0bd71f0922a8c275b03c8191b4e54acff3a9a8e572df708b096fc17324b"
    sha256 x86_64_linux:   "39c7d343bb57f8804402e5322bcf97ac49e06933d048d73e2ab0adfa14a8c80a"
  end

  depends_on "pkg-config" => :build
  depends_on "cairo"
  depends_on "gcc" # for gfortran
  depends_on "gettext"
  depends_on "jpeg"
  depends_on "libffi"
  depends_on "libpng"
  depends_on "openblas"
  depends_on "pcre2"
  depends_on "readline"
  depends_on "tcl-tk"
  depends_on "xz"

  uses_from_macos "curl"
  uses_from_macos "icu4c"

  on_linux do
    depends_on "pango"
    depends_on "libice"
    depends_on "libx11"
    depends_on "libxt"
    depends_on "libtirpc"
  end

  # needed to preserve executable permissions on files without shebangs
  skip_clean "lib/R/bin", "lib/R/doc"

  def install
    # BLAS detection fails with Xcode 12 due to missing prototype
    # https://bugs.r-project.org/bugzilla/show_bug.cgi?id=18024
    ENV.append "CFLAGS", "-Wno-implicit-function-declaration"

    args = [
      "--prefix=#{prefix}",
      "--enable-memory-profiling",
      "--with-tcl-config=#{Formula["tcl-tk"].opt_lib}/tclConfig.sh",
      "--with-tk-config=#{Formula["tcl-tk"].opt_lib}/tkConfig.sh",
      "--with-blas=-L#{Formula["openblas"].opt_lib} -lopenblas",
      "--enable-R-shlib",
      "--disable-java",
      "--with-cairo",
    ]

    if OS.mac?
      args << "--without-x"
      args << "--with-aqua"
    else
      args << "--libdir=#{lib}" # avoid using lib64 on CentOS

      # Avoid references to homebrew shims
      args << "LD=ld"

      # If LDFLAGS contains any -L options, configure sets LD_LIBRARY_PATH to
      # search those directories. Remove -LHOMEBREW_PREFIX/lib from LDFLAGS.
      ENV.remove "LDFLAGS", "-L#{HOMEBREW_PREFIX}/lib"

      ENV.append "CPPFLAGS", "-I#{Formula["libtirpc"].opt_include}/tirpc"
      ENV.append "LDFLAGS", "-L#{Formula["libtirpc"].opt_lib}"
    end

    # Help CRAN packages find gettext and readline
    ["gettext", "readline", "xz"].each do |f|
      ENV.append "CPPFLAGS", "-I#{Formula[f].opt_include}"
      ENV.append "LDFLAGS", "-L#{Formula[f].opt_lib}"
    end

    system "./configure", *args
    system "make"
    ENV.deparallelize do
      system "make", "install"
    end

    cd "src/nmath/standalone" do
      system "make"
      ENV.deparallelize do
        system "make", "install"
      end
    end

    r_home = lib/"R"

    # make Homebrew packages discoverable for R CMD INSTALL
    inreplace r_home/"etc/Makeconf" do |s|
      s.gsub!(/^CPPFLAGS =.*/, "\\0 -I#{HOMEBREW_PREFIX}/include")
      s.gsub!(/^LDFLAGS =.*/, "\\0 -L#{HOMEBREW_PREFIX}/lib")
      s.gsub!(/.LDFLAGS =.*/, "\\0 $(LDFLAGS)")
    end

    include.install_symlink Dir[r_home/"include/*"]
    lib.install_symlink Dir[r_home/"lib/*"]

    # avoid triggering mandatory rebuilds of r when gcc is upgraded
    check_replace = OS.mac?
    inreplace lib/"R/etc/Makeconf", Formula["gcc"].prefix.realpath,
                                    Formula["gcc"].opt_prefix,
                                    check_replace
  end

  def post_install
    short_version =
      `#{bin}/Rscript -e 'cat(as.character(getRversion()[1,1:2]))'`.strip
    site_library = HOMEBREW_PREFIX/"lib/R/#{short_version}/site-library"
    site_library.mkpath
    ln_s site_library, lib/"R/site-library"
  end

  test do
    assert_equal "[1] 2", shell_output("#{bin}/Rscript -e 'print(1+1)'").chomp
    assert_equal shared_library(""), shell_output("#{bin}/R CMD config DYLIB_EXT").chomp
    system bin/"Rscript", "-e", "if(!capabilities('cairo')) stop('cairo not available')"

    system bin/"Rscript", "-e", "install.packages('gss', '.', 'https://cloud.r-project.org')"
    assert_predicate testpath/"gss/libs/gss.so", :exist?,
                     "Failed to install gss package"

    winsys = "[1] \"aqua\""
    on_linux do
      # Fails in Linux CI with: no DISPLAY variable so Tk is not available
      return if ENV["HOMEBREW_GITHUB_ACTIONS"]

      winsys = "[1] \"x11\""
    end
    assert_equal winsys,
                 shell_output("#{bin}/Rscript -e 'library(tcltk)' -e 'tclvalue(.Tcl(\"tk windowingsystem\"))'").chomp
  end
end
