Quick attempt at Bubble Sort implementation in Ruby (needs to be improved)

bubble_sort.rb

def bubble_sort(arr, swap_count = 0)
	time_start = Time.now
	total_swap_count = 0

	swap_count = nil
	while swap_count.nil? || swap_count > 0
		swap_count = 0

		arr.each_with_index do |i, index|
			pos = index
			next_item = arr[pos+1]
			item = i
			while !next_item.nil? && item > next_item do
				if item > next_item
					arr[pos], arr[pos+1] = next_item, item
					swap_count += 1
				end
				pos += 1

				item = arr[pos]
				next_item = arr[pos+1]
			end
		end

		total_swap_count += swap_count
	end

	puts "Sorted in #{total_swap_count} swaps"
	puts "Sorted in #{Time.now - time_start} seconds"

	return arr
end

bubble_sort([*0..10000].shuffle)