class RSpec::Core::SharedExampleGroup::Registry

def add(context, name, *metadata_args, &block)
  ensure_block_has_source_location(block) { CallerFilter.first_non_rspec_line }
  if valid_name?(name)
    warn_if_key_taken context, name, block
    shared_example_groups[context][name] = block
  else
    metadata_args.unshift name
  end
  return if metadata_args.empty?
  mod = Module.new
  (class << mod; self; end).__send__(:define_method, :included) do |host|
    host.class_exec(&block)
  end
  RSpec.configuration.include mod, *metadata_args
end

def ensure_block_has_source_location(_block); end

def ensure_block_has_source_location(block)
  source_location = yield.split(':')
  block.extend Module.new { define_method(:source_location) { source_location } }
end

def find(lookup_contexts, name)
  lookup_contexts.each do |context|
    found = shared_example_groups[context][name]
    return found if found
  end
  shared_example_groups[:main][name]
end

def formatted_location(block)
  block.source_location.join ":"
end

def shared_example_groups
  @shared_example_groups ||= Hash.new { |hash, context| hash[context] = {} }
end

def valid_name?(candidate)
  case candidate
  when String, Symbol, Module then true
  else false
  end
end

def warn_if_key_taken(context, key, new_block)
  existing_block = shared_example_groups[context][key]
  return unless existing_block
  RSpec.warn_with <<-WARNING.gsub(/^ +\|/, ''), :call_site => nil
    |WARNING: Shared example group '#{key}' has been previously defined at:
    |  #{formatted_location existing_block}
    |...and you are now defining it at:
    |  #{formatted_location new_block}
    |The new definition will overwrite the original one.
  WARNING
end