class Stats:
	received=0
	sent=0
	exchangedNodes=0
	transferredBlocks=0


def logReceived(data):
	Stats.received+=len(data)


def logSent(data):
	Stats.sent+=len(data)


def logExchangedNode(k=1):
	Stats.exchangedNodes+=k


def logTransferredBlock():
	Stats.transferredBlocks+=1


def report():
	return """received {r}B
sent {s}B
exchanged {nodes} hash tree nodes
transferred {blocks} blocks""".format(r=Stats.received, s=Stats.sent, nodes=Stats.exchangedNodes, blocks=Stats.transferredBlocks)