#!/usr/bin/ruby
 
require 'find'
 
directory = "/home/peter/Ruby/test_data"
files = Array.new
 
#first get a list of the files
 
Find.find(directory) do |filename|
	filename.each do |f|
		files << f if /\.dat/ =~ f
	end
end
 
#to hold the difference, closest file name and its difference in time from today
diff, closest, closest_diff = nil
 
files.each do |f|
	#get the part of the string following the last /  
	filename = f.split("/")[-1]
	#create a time using the info in the filename
	x = Time.utc(filename.slice(17,4), filename.slice(15,2), filename.slice(13,2))
	#if the time is greater than now
	if x > Time.now
		#calculate the difference
		diff = x - Time.now
		if closest.nil?
		#if closest is empty (ie we are checking the first file)
			closest = f
			closest_diff = diff
		else
		#otherwise if the difference is smaller than the closest diff update our variables
			closest = f if diff < closest_diff
			closest_diff = diff
		end
	end
 
end
 
puts closest