module VCR::RSpec::Metadata

def configure!
  ::RSpec.configure do |config|
    when_tagged_with_vcr = { :vcr => lambda { |v| !!v } }
    config.before(:each, when_tagged_with_vcr) do |ex|
      example = ex.respond_to?(:metadata) ? ex : ex.example
      cassette_name = nil
      options = example.metadata[:vcr]
      options = case options
                when Hash #=> vcr: { cassette_name: 'foo' }
                  options.dup
                when String #=> vcr: 'bar'
                  cassette_name = options.dup
                  {}
                else #=> :vcr or vcr: true
                  {}
                end
      cassette_name ||= options.delete(:cassette_name) ||
                        VCR::RSpec::Metadata.vcr_cassette_name_for(example.metadata)
      VCR.insert_cassette(cassette_name, options)
    end
    config.after(:each, when_tagged_with_vcr) do |ex|
      example = ex.respond_to?(:metadata) ? ex : ex.example
      VCR.eject_cassette(:skip_no_unused_interactions_assertion => !!example.exception)
    end
  end
end

def vcr_cassette_name_for(metadata)
  description = 
    if metadata[:description].empty?
      # we have an "it { is_expected.to be something }" block
      metadata[:scoped_id]
    else
      metadata[:description]
    end
  example_group = 
    if metadata.key?(:example_group)
      metadata[:example_group]
    else
      metadata[:parent_example_group]
    end
  if example_group
    [vcr_cassette_name_for(example_group), description].join('/')
  else
    description
  end
end