class Rake::ExtensionTask

def define_cross_platform_tasks_with_version(for_platform, ruby_ver)
  config_path = File.expand_path("~/.rake-compiler/config.yml")
  # warn the user about the need of configuration to use cross compilation.
  unless File.exist?(config_path)
    define_dummy_cross_platform_tasks
    return
  end
  rbconfig_file = Rake::CompilerConfig.new(config_path).find(ruby_ver, for_platform)
  unless rbconfig_file
    warn "no configuration section for specified version of Ruby (rbconfig-#{for_platform}-#{ruby_ver})"
    return
  end
  # tmp_path
  tmp_path = "#{@tmp_dir}/#{for_platform}/#{@name}/#{ruby_ver}"
  # lib_path
  lib_path = lib_dir
  # lib_binary_path
  lib_binary_path = "#{lib_path}/#{File.basename(binary(for_platform))}"
  # mkmf
  mkmf_file = File.expand_path(File.join(File.dirname(rbconfig_file), '..', 'mkmf.rb'))
  # define compilation tasks for cross platform!
  define_compile_tasks(for_platform, ruby_ver)
  # chain fake.rb and mkmf.rb to Makefile generation
  file "#{tmp_path}/Makefile" => ["#{tmp_path}/fake.rb",
                                  "#{tmp_path}/mkmf.rb"]
  # copy the rbconfig from the cross-ruby location and
  # genearte fake.rb for different ruby versions
  file "#{tmp_path}/fake.rb" => [rbconfig_file] do |t|
    File.open(t.name, 'w') do |f|
      # Keep the original RbConfig::CONFIG["ENABLE_SHARED"] to use
      # the same RubyGems extension directory. See also
      # Gem::BasicSpecificaion#extenions_dir and
      # Gem.extension_api_version.
      #
      # if RbConfig::CONFIG["ENABLE_SHARED"] == "no"
      #   "extensions/x86_64-linux/2.5.0-static"
      # else
      #   "extensions/x86_64-linux/2.5.0"
      # end
      f.puts("require 'rbconfig'")
      f.puts("original_enable_shared = RbConfig::CONFIG['ENABLE_SHARED']")
      f.puts(fake_rb(for_platform, ruby_ver))
      f.puts("require #{t.prerequisites.first.dump}")
      f.puts("RbConfig::CONFIG['ENABLE_SHARED'] = original_enable_shared")
    end
  end
  # copy mkmf from cross-ruby location
  file "#{tmp_path}/mkmf.rb" => [mkmf_file] do |t|
    File.open(t.name, 'w') do |f|
      content = File.read(t.prerequisites.first)
      content.sub!(/^(require ')rbconfig(')$/, '\\1fake\\2')
      if ruby_ver < "1.9" && "1.9" <= RUBY_VERSION
        content.sub!(/^(      break )\*(defaults)$/, '\\1\\2.first')
        content.sub!(/^(    return )\*(defaults)$/, '\\1\\2.first')
        content.sub!(/^(  mfile\.)print( configuration\(srcprefix\))$/, '\\1puts\\2')
      end
      f.write content
    end
  end
  # now define native tasks for cross compiled files
  if @gem_spec && @gem_spec.platform == 'ruby' then
    define_native_tasks(for_platform, ruby_ver, @cross_compiling)
  end
  # create cross task
  task 'cross' do
    # clear compile dependencies
    Rake::Task['compile'].prerequisites.reject! { |t| !compiles_cross_platform.include?(t) }
    # chain the cross platform ones
    task 'compile' => ["compile:#{for_platform}"]
    # clear lib/binary dependencies and trigger cross platform ones
    # check if lib/binary is defined (damn bundle versus so versus dll)
    if Rake::Task.task_defined?(lib_binary_path) then
      Rake::Task[lib_binary_path].prerequisites.clear
    end
    # FIXME: targeting multiple platforms copies the file twice
    file lib_binary_path => ["copy:#{@name}:#{for_platform}:#{ruby_ver}"]
    # if everything for native task is in place
    if @gem_spec && @gem_spec.platform == 'ruby' then
      # double check: only cross platform native tasks should be here
      # FIXME: Sooo brittle
      Rake::Task['native'].prerequisites.reject! { |t| !natives_cross_platform.include?(t) }
      task 'native' => ["native:#{for_platform}"]
    end
  end
end