class Mocha::StubbedMethod

def define_new_method
  self_in_scope = self
  method_name_in_scope = method_name
  stub_method_owner.send(:define_method, method_name) do |*args, &block|
    self_in_scope.mock.method_missing(method_name_in_scope, *args, &block)
  end
  retain_original_visibility(stub_method_owner)
end

def hide_original_method
  return unless original_method_owner.__method_exists__?(method_name)
  store_original_method_visibility
  if use_prepended_module_for_stub_method?
    use_prepended_module_for_stub_method
  else
    begin
      store_original_method
    # rubocop:disable Lint/HandleExceptions
    rescue NameError
      # deal with nasties like ActiveRecord::Associations::AssociationProxy
    end
    # rubocop:enable Lint/HandleExceptions
    if stub_method_overwrites_original_method?
      remove_original_method_from_stubbee
    end
  end
end

def initialize(stubbee, method_name)
  @stubbee = stubbee
  @original_method = nil
  @original_visibility = nil
  @method_name = PRE_RUBY_V19 ? method_name.to_s : method_name.to_sym
end

def matches?(other)
  return false unless other.class == self.class
  (stubbee.object_id == other.stubbee.object_id) && (method_name == other.method_name)
end

def mock
  mock_owner.mocha
end

def remove_new_method
  stub_method_owner.send(:remove_method, method_name)
end

def remove_original_method_from_stubbee
  original_method_owner.send(:remove_method, method_name)
end

def reset_mocha
  mock_owner.reset_mocha
end

def restore_original_method
  return if use_prepended_module_for_stub_method?
  if stub_method_overwrites_original_method?
    original_method_owner.send(:define_method, method_name, method_body(@original_method))
  end
  retain_original_visibility(original_method_owner)
end

def retain_original_visibility(method_owner)
  return unless @original_visibility
  Module.instance_method(@original_visibility).bind(method_owner).call(method_name)
end

def store_original_method
  @original_method = stubbee_method(method_name)
end

def store_original_method_visibility
  @original_visibility = original_method_owner.__method_visibility__(method_name)
end

def stub
  hide_original_method
  define_new_method
end

def stub_method_overwrites_original_method?
  @original_method && @original_method.owner == original_method_owner
end

def stub_method_owner
  @stub_method_owner ||= original_method_owner
end

def to_s
  "#{stubbee}.#{method_name}"
end

def unstub
  remove_new_method
  restore_original_method
  mock.unstub(method_name.to_sym)
  return if mock.any_expectations?
  reset_mocha
end

def use_prepended_module_for_stub_method
  @stub_method_owner = PrependedModule.new
  original_method_owner.__send__ :prepend, @stub_method_owner
end

def use_prepended_module_for_stub_method?
  RUBY_V2_PLUS
end