class Tapioca::Gem::Listeners::ForeignConstants

def ignore?(event)
  event.is_a?(Tapioca::Gem::ForeignScopeNodeAdded)
end

def mixed_in_by_gem?(location)
  @pipeline.gem.contains_path?(location)
end

def on_scope(event)
  mixin = event.constant
  return if Class === mixin # Classes can't be mixed into other constants
  # There are cases where we want to process constants not declared by the current
  # gem, i.e. "foreign constant". These are constants defined in another gem to which
  # this gem is applying a mix-in. This pattern is especially common for gems that add
  # behavior to Ruby standard library classes by mixing in modules to them.
  #
  # The way we identify these "foreign constants" is by asking the mixin tracker which
  # constants have mixed in the current module that we are handling. We add all the
  # constants that we discover to the pipeline to be processed.
  Runtime::Trackers::Mixin.constants_with_mixin(mixin).each do |mixin_type, location_info|
    location_info.each do |constant, location|
      next unless mixed_in_by_gem?(location)
      name = @pipeline.name_of(constant)
      # Calling Tapioca::Gem::Pipeline#name_of on a singleton class returns `nil`.
      # To handle this case, use string parsing to get the name of the singleton class's
      # base constant. Then, generate RBIs as if the base constant is extending the mixin,
      # which is functionally equivalent to including or prepending to the singleton class.
      if !name && constant.singleton_class?
        attached_class = Runtime::Trackers::Mixin.resolve_to_attached_class(constant, mixin, mixin_type)
        next unless attached_class
        constant = attached_class
        name = @pipeline.name_of(constant)
      end
      @pipeline.push_foreign_constant(name, constant) if name
    end
  end
end