import os
import stat
import time

MESSAGE_NAMES = [ 'ADT', 'ORM' ]

INACTIVITY_TIME = 30
WARNING_FREQUENCY = 60

# create global list variables for message timestamps:
#        Timestamp contains the last time a message of this type was seen
#        WarningTime contains the last time a warning was sent for
#                    messages of this type
try:
    Timestamp
except NameError:
       # the following statements are needed to define the dictionaries
       Timestamp = {'ADT':0}
       MessageCount = {'ADT':0}
       WarningTime = {'ADT':0}
       # now that the dictionaries are defined, they can be initialized
       for MessageName in MESSAGE_NAMES:
           Timestamp[MessageName] = time.time()
           MessageCount[MessageName] = 0
           WarningTime[MessageName] = 0

# update the timestamp for this message and increment message counter
def touchMessage(MessageName):
    Timestamp[MessageName] = time.time()
    MessageCount[MessageName] += 1

def checkForInactivity():
    CurrentTime = time.time()
    for MessageName in MESSAGE_NAMES:
        # check whether messages of this type have arrived recently
        LastTime = Timestamp[MessageName]
        Delta = int(CurrentTime - LastTime)
        if Delta > INACTIVITY_TIME:
           # check whether a warning message has been sent recently
           LastWarningTime = WarningTime[MessageName]
           WarningDelta = int(CurrentTime - LastWarningTime)
           if WarningDelta > WARNING_FREQUENCY:
              # send the warning message
              print "CHANNEL INACTIVITY WARNING:"
              if MessageCount[MessageName] > 0:
                 LastString = time.strftime( '%Y-%m-%d %H:%M', time.localtime(LastTime))
                 print "No %s messages since %s" % (MessageName, LastString)
              else:
                   print "No %s messages ever" % MessageName
              # update the timestamp for warning messages
              WarningTime[MessageName] = CurrentTime