module BenchmarkWrapper

# File lib/benchmark_wrapper.rb, line 5
def wrap_with_benchmark(*meths)
  opts = extract_benchmark_receiver_options(meths)
  out = opts[:out]
  out_method = opts[:out_method]

  meths.each do |meth|
    without_bm, with_bm = wrapper_methods(meth)

    define_method(with_bm) do |*args, &blk|
      # obscenely ugly, but Benchmark class seems
      # to have nothing to avoid this
      ret_val = nil
      bm = Benchmark.measure { ret_val = send(without_bm, *args, &blk) }
      out.send(out_method, bm)
      ret_val
    end

    alias_method without_bm, meth
    alias_method meth, with_bm
  end
end

# File lib/benchmark_wrapper.rb, line 34
def default_bm_receiver
  # would love to have this inside a constant,
  # but it would get untestable this way!
  { out: $stdout, out_method: :puts}
end

# File lib/benchmark_wrapper.rb, line 29
def extract_benchmark_receiver_options(arr)
  opts = arr.last.kind_of?(Hash) ? arr.pop : {}
  default_bm_receiver.merge(opts)
end

# File lib/benchmark_wrapper.rb, line 40
def wrapper_methods(meth)
  ['', 'out'].map do |str|
    "#{meth}_with#{str}_benchmark".to_sym
  end
end