class Xcodegen < Formula
  desc "Tool that generates your Xcode project from a project spec"
  homepage "https://github.com/yonaskolb/XcodeGen"
  url "https://github.com/yonaskolb/XcodeGen/archive/1.8.0.tar.gz"
  sha256 "fed2da98f176f18d3b761b76def4c3324d4a9a5c77cc7392388042db33dc9cee"
  head "https://github.com/yonaskolb/XcodeGen.git"

  depends_on :xcode

  def install
    # libxml2 has to be included in ISYSTEM_PATH for building one of
    # dependencies. It didn't happen automatically before Xcode 9.3
    # so homebrew patched environment variable to get it work.
    # But since Xcode 9.3 includes it already, the build will fail
    # because of redefinition of libxml2 module.
    # It's a bug of homebrew but before it's fixed, it's easier
    # to provide in-place workaround for now.
    # Please remove this once homebrew is patched.

    # step 1: capture old value and patch environment
    if OS::Mac::Xcode.version >= Version.new("9.3") then
      old_isystem_paths = ENV["HOMEBREW_ISYSTEM_PATHS"]
      ENV["HOMEBREW_ISYSTEM_PATHS"] = old_isystem_paths.gsub("/usr/include/libxml2", "")
    end

    # step 2: usual build
    system "make", "install", "PREFIX=#{prefix}"

    # step 3: restoring environment to pristine state
    ENV["HOMEBREW_ISYSTEM_PATHS"] = old_isystem_paths if defined? old_isystem_paths
  end

  test do
    (testpath/"xcodegen.yml").write <<-EOS.undent
      name: GeneratedProject
      targets:
        TestProject:
          type: application
          platform: iOS
          sources: TestProject
          settings:
            PRODUCT_BUNDLE_IDENTIFIER: com.test
            PRODUCT_NAME: TestProject
    EOS
    Dir.mkdir(File.join(testpath, "TestProject"))
    system("#{bin}/XcodeGen --spec #{File.join(testpath, "xcodegen.yml")}")
    system("xcodebuild --project #{File.join(testpath, "GeneratedProject.xcodeproj")}")
  end
end