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require 'socket'
server = TCPServer.open(2000) 			# Listen on port 2000
sockets = [server] 						# An array of sockets we'll monitor
log = STDOUT 							# Send log messages to standard out
while true 								# Servers loop forever
	ready = select(sockets) 				# Wait for a socket to be ready
	readable = ready[0] 					# These sockets are readable
	readable.each do |socket| 				# Loop through readable sockets
		if socket == server 				# If the server socket is ready
			client = server.accept 		# Accept a new client
			sockets << client 			# Add it to the set of sockets
										# Tell the client what and where it has connected.
			client.puts "Reversal service v0.01 running on #{Socket.gethostname}"
										# And log the fact that the client connected
			log.puts "Accepted connection from #{client.peeraddr[2]}"
		else 							# Otherwise, a client is ready
			input = socket.gets 			# Read input from the client
										# If no input, the client has disconnected
			if !input
				log.puts "Client on #{socket.peeraddr[2]} disconnected."
				sockets.delete(socket) 	# Stop monitoring this socket
				socket.close 			# Close it
				next					# And go on to the next
			end
			input.chop! 					# Trim client's input
			if (input == "quit") 			# If the client asks to quit
				socket.puts("Bye!"); 		# Say goodbye
				log.puts "Closing connection to #{socket.peeraddr[2]}"
				sockets.delete(socket) 	# Stop monitoring the socket
				socket.close 			# Terminate the session
			else 						# Otherwise, client is not quitting
				socket.puts(input.reverse) # So reverse input and send it back
			end
		end
	end
end