Twisted Countdown Etude 3

# A solution to the Twisted tutorial exercise suggested in the comment at
# http://krondo.com/?p=1333&cpage=1#comment-20927

import time
from twisted.internet.task import LoopingCall

class CountdownMonitor(object):

    def __init__(self, rate=.2):
        self.rate = .2
        self.countdowns = []
        self.finishedCountdowns = []
        self.looper = LoopingCall(self.poll)

    def register(self, ctdn):
        self.countdowns.append(ctdn)
        reactor.callWhenRunning(ctdn.start)

    def start(self):
        self.startTime = time.time()
        self.looper.start(self.rate)

    def poll(self):
        for ctdn in self.countdowns:
            endTime = ctdn.endTime
            if endTime:
                self.countdowns.remove(ctdn)
                self.finishedCountdowns.append((ctdn.name, endTime - self.startTime))

        if not self.countdowns:
            for c, t in self.finishedCountdowns:
                print 'Countdown {} finished in {:.3f} sec'.format(c,t)
            reactor.callLater(0, reactor.stop)

class Countdown(object):

    def __init__(self, name, ticks, rate):
        self.name, self.counter, self.rate = name, ticks, rate
        self.looper = LoopingCall(self.count)
        self.endTime = None

    def start(self):
        self.looper.start(self.rate)

    def count(self):
        if self.counter == 0:
            self.endTime = time.time()
            self.looper.stop()
            print 'Counter {} complete!'.format(self.name)
        else:
            print '{}: {:>2} ticks left at {} sec/tick ...'.format(self.name, self.counter, self.rate)
            self.counter -= 1

from twisted.internet import reactor

monitor = CountdownMonitor()
reactor.callWhenRunning(monitor.start)

data = [['one', 5, 1.0], ['two', 13, .3], ['tri', 8, .8]]
for name, ticks, rate in data:
    monitor.register(Countdown(name, ticks, rate))

print 'Start!'
reactor.run()
print 'Stop!'



#### Output ####

Start!
one:  5 ticks left at 1.0 sec/tick ...
two: 13 ticks left at 0.3 sec/tick ...
tri:  8 ticks left at 0.8 sec/tick ...
two: 12 ticks left at 0.3 sec/tick ...
two: 11 ticks left at 0.3 sec/tick ...
tri:  7 ticks left at 0.8 sec/tick ...
two: 10 ticks left at 0.3 sec/tick ...
one:  4 ticks left at 1.0 sec/tick ...
two:  9 ticks left at 0.3 sec/tick ...
two:  8 ticks left at 0.3 sec/tick ...
tri:  6 ticks left at 0.8 sec/tick ...
two:  7 ticks left at 0.3 sec/tick ...
one:  3 ticks left at 1.0 sec/tick ...
two:  6 ticks left at 0.3 sec/tick ...
two:  5 ticks left at 0.3 sec/tick ...
tri:  5 ticks left at 0.8 sec/tick ...
two:  4 ticks left at 0.3 sec/tick ...
one:  2 ticks left at 1.0 sec/tick ...
two:  3 ticks left at 0.3 sec/tick ...
tri:  4 ticks left at 0.8 sec/tick ...
two:  2 ticks left at 0.3 sec/tick ...
two:  1 ticks left at 0.3 sec/tick ...
Counter two complete!
one:  1 ticks left at 1.0 sec/tick ...
tri:  3 ticks left at 0.8 sec/tick ...
tri:  2 ticks left at 0.8 sec/tick ...
Counter one complete!
tri:  1 ticks left at 0.8 sec/tick ...
Counter tri complete!
Countdown two finished in 3.900 sec
Countdown one finished in 5.000 sec
Countdown tri finished in 6.400 sec
Stop!