#!/bin/python

import time
import logging

logger = logging.getLogger(__name__)

class Clock(object):
    def __init__(self, stopped=False):
        self._base = time.time()
        logging.info('Clock created. ' + 'Stopped = ' + str(stopped) + ', Base = ' + str(self._base))
        self.stopped = stopped

    def stop(self):
        if not self.stopped:
            self.stopped_raw_time = time.time()
            logging.info('Clock stopped at ' + str(self.time))
            self.stopped = True
        else:
            logging.warning('Attempt to stop the clock at ' + str(self.time) + ' - Clock already stopped!')

    def start(self):
        if self.stopped:
            logging.info('Clock started at ' + str(self.time))
            delta = time.time() - self.stopped_raw_time
            self._base += delta
            self.stopped = False
        else:
            logging.warning('Attempted clock start at ' + str(self.time) + ' - Clock already running!')

    @property
    def time(self):
        if self.stopped:
            return self.stopped_raw_time - self._base
        else:
            return time.time() - self._base


if __name__ == '__main__':
    logging.basicConfig(level=logging.INFO)
    clock = Clock()
    print 'Base = ', clock._base
    print clock.time
    print 'started, wait 5'
    time.sleep(5)
    print clock.time, '\n'

    clock.stop()
    print 'stopped, wait 5'
    time.sleep(5)
    print clock.time, '\n'

    print 'Stopping, but already stopped'
    clock.stop()
    print 'waiting 3 sec'
    time.sleep(3)
    print 'after 3 sec - ', clock.time, '\n'

    clock.start()
    print 'Started, wait 5'
    time.sleep(5)
    print clock.time, '\n'

    print 'Starting, but already started'
    clock.start()
    print 'waiting 3 sec'
    time.sleep(3)
    print 'After 3 -', clock.time