#My implementation of a (mostly) functional version of a CircularBuffer data structure

class CircularBuffer
	def initialize (size,arr,head,tail)
		@cbuff = arr
		@size = size
		@head = head
		@tail = tail
	end

	def push(elem)
		#when the buffer is full, just return a copy of this instance
		if @head + 1 % @size == @tail return CiruclarBuffer.new(@size,@cbuff,@head,@tail) end
		CiruclarBuffer.new(@size,@cbuff.insert(@head,elem),(@head+1) % @size,@tail)
	end

	def take()
		if @head == @tail CiruclarBuffer.new(@size,@cbuff,@head,@tail) end
		CiruclarBuffer.new(@size,@cbuff.delete_at(@tail),@head,(@tail + 1) % @size)
	end

	def size
		@size
	end

	#this method returns the distance between head and tail, i.e. the number
	#of indices which hold actual values
	def length
		if @head > @tail
			return @head - @tail
		elsif @tail > @head
			return (@head + @size) - @tail
		else
			return 0
		end
	end

	def peek
		@cbuff[@head]
	end

	def head
		@head
	end

	def tail
		@tail
	end
end