class ViewComponent::Collection

def collection_variable(object)
  if object.respond_to?(:to_ary)
    object.to_ary
  else
    raise InvalidCollectionArgumentError
  end
end

def component_options(item, iterator)
  item_options = {component.__vc_collection_parameter => item}
  item_options[component.__vc_collection_counter_parameter] = iterator.index if component.__vc_counter_argument_present?
  item_options[component.__vc_collection_iteration_parameter] = iterator.dup if component.__vc_iteration_argument_present?
  @options.merge(item_options)
end

def components
  return @components if defined? @components
  iterator = ActionView::PartialIteration.new(@collection.size)
  component.__vc_validate_collection_parameter!(validate_default: true)
  @components = @collection.map do |item|
    component.new(**component_options(item, iterator)).tap do |component|
      iterator.iterate!
    end
  end
end

def each(&block)
  components.each(&block)
end

def initialize(component, object, spacer_component, **options)
  @component = component
  @collection = collection_variable(object || [])
  @spacer_component = spacer_component
  @options = options
end

def render_in(view_context, &block)
  components.map do |component|
    component.render_in(view_context, &block)
  end.join(rendered_spacer(view_context)).html_safe
end

def rendered_spacer(view_context)
  if @spacer_component
    @spacer_component.render_in(view_context)
  else
    ""
  end
end