from datetime import datetime, timedelta
import threading
import time

from app.EventBus import Event
from app.util import ensure_list, matcher

TIME_INTERVAL = 10 # seconds

assert 60 % TIME_INTERVAL == 0, "60 % TIME_INTERVAL should be 0!"

EVENT_TIME_CHANGED = "time_changed"

class Timer(threading.Thread):
	def __init__(self, eventbus):
		threading.Thread.__init__(self)

		self.eventbus = eventbus
		self._stop = threading.Event()

	def stop(self):
		self._stop.set()

	def run(self):
		now = datetime.now()

		while True:
			if self._stop.isSet():
				break

			self.eventbus.fire(Event(EVENT_TIME_CHANGED, {'now':now}))

			while True:
				time.sleep(1)

				now = datetime.now()

				if self._stop.isSet() or now.second % TIME_INTERVAL == 0:
					break


def track_time_change(eventBus, action, year='*', month='*', day='*', hour='*', minute='*', second='*', datetime=None, listen_once=False):
	year, month, day = ensure_list(year), ensure_list(month), ensure_list(day)
	hour, minute, second = ensure_list(hour), ensure_list(minute), ensure_list(second)

	def listener(event):
		assert isinstance(event, Event), "event needs to be of Event type"

		if  (datetime is not None and event.data['now'] > datetime) or \
			datetime is None and \
			matcher(event.data['now'].year, year) and \
			matcher(event.data['now'].month, month) and \
			matcher(event.data['now'].day, day) and \
			matcher(event.data['now'].hour, hour) and \
			matcher(event.data['now'].minute, minute) and \
			matcher(event.data['now'].second, second):

			# datetime are exact points in time so we always remove it after fire
			event.removeListener = listen_once or datetime is not None

			action(event.data['now'])

	eventBus.listen(EVENT_TIME_CHANGED, listener)