module Phlex::Collection

def first?
	raise ArgumentError unless @item
	@first
end

def initialize(collection: nil, item: nil)
	unless collection || item
		raise ArgumentError, "You must pass a collection or an item as a keyword argument."
	end
	@collection = collection
	@item = item
end

def last?
	raise ArgumentError unless @item
	@last
end

def template
	if @item
		item_template
	else
		collection_template { yield_items }
	end
end

def yield_items
	if @item
		raise ArgumentError, "You can only yield_items when rendering a collection. You are currently rendering an item."
	end
	@collection.each_with_index do |item, index|
		@item = item
		@index = index
		@position = (index + 1)
		@first = (index == 0)
		@last = (@position == @collection.size)
		item_template
	end
	@item = nil
	@index = nil
	@first = nil
	@last = nil
	@position = nil
end