import Queue
import os
import sys
from time import gmtime, strftime, sleep
import threading
import datetime
import pymongo
import smtplib
from email.mime.text import MIMEText



DEBUG = False
BACKGROUND = True
PID_FILE = "/opt/logs/FridgeAlarm.pid"
LOG_FILE = "/opt/logs/FridgeAlarm.log"
MONGO_HOST = "127.0.0.1"
MONGO_DATABASE = "iot"
MONGO_COLLECTION = "iot"
INTERVAL = 30 * 60
PERIOD = 120
THRESHOLD = 0.0
EMAIL_SENDER = 'freezer@hottis.de'
EMAIL_RECP = 'familie@hottis.de'



class Logger(object):
    debugFlag = False

    @classmethod
    def log(cls, data):
        t = strftime("%d %b %Y %H:%M:%S", gmtime())
        with open(cls.logfile, 'a') as f:
            f.write("%s %s\n" % (t, data))
        if cls.debugFlag:
            print data
    
    @classmethod
    def debug(cls, data):
        if cls.debugFlag:
            cls.log(data)
    
    @classmethod
    def debugEnable(cls):
        cls.debugFlag = True

    @classmethod
    def debugDisable(cls):
        cls.debugFlag = False

    @classmethod
    def openlog(cls, logfile):
        cls.logfile = logfile



class TemperatureChecker(threading.Thread):
    def __init__(self, queue, dbhost, database, collection, period, interval, threshold):
        threading.Thread.__init__(self)
        self.queue = queue
        self.dbhost = dbhost
        self.database = database
        self.collection = collection
        self.mongoClient = pymongo.MongoClient(self.dbhost)
        self.db = self.mongoClient[self.database]
        self.coll = self.db[self.collection]
        self.period = period
        self.interval = interval
        self.threshold = threshold
        self.setDaemon(True)

    def run(self):
        while True:
            try:
                now1 = datetime.datetime.now()
                now = now1.replace(now1.year, now1.month, now1.day, now1.hour, now1.minute, now1.second, 0)
                midnight = now.replace(now.year, now.month, now.day, 0,0,0,0)
                seconds = (now - midnight).seconds
                intervalBegin = seconds - self.interval

                if intervalBegin > 0:
                    pipeline = [
                                {'$match': {'metadata.device': 'ModbusHub', 
                                            'metadata.day': midnight,
                                            'metadata.seconds': {'$gt': intervalBegin, '$lt': seconds}
                                            }},
                                {'$sort': {'seconds': 1}},
                                # {'$project': {'_id': 0, 'ts': '$metadata.timestamp', 't': '$data.t2'}}
                                {'$group': {'_id': 0,
                                            'avgTemp': {'$avg': '$data.t2'}}}
                                ]
                    cursor = self.coll.aggregate(pipeline)
                    result = cursor.next()
                    result2 = {'temperature': result['avgTemp'], 'timestamp': now1}
                    Logger.log(result2)
                    
                    if result2['temperature'] > self.threshold:
                        Logger.log("Queueing an alarm")
                        self.queue.put_nowait(result2)
                    
            except pymongo.errors.ServerSelectionTimeoutError, e:
                Logger.log("Exception %s in TemperatureChecker, run" % str(e))
            except TypeError, e:
                Logger.log("Exception %s in TemperatureChecker, run" % str(e))
            except Exception, e:
                Logger.log("Unexcepted exception %s in TemperatureChecker: %s" % (e.__class__.__name__, str(e)))
            finally:
                sleep(self.period)


class AlarmSender(threading.Thread):
    def __init__(self, queue):
        threading.Thread.__init__(self)
        self.queue = queue
        self.setDaemon(True)

    def run(self):
        while True:
            try:
                msg = self.queue.get()
                emailMsg = MIMEText("Temperature in freezer to high: %s %s" % (msg['timestamp'], msg['temperature']))
                emailMsg['Subject'] = 'Freezer Alarm'
                emailMsg['From'] = EMAIL_SENDER
                emailMsg['To'] = EMAIL_RECP
                s = smtplib.SMTP('localhost')
                s.sendmail(EMAIL_SENDER, [EMAIL_RECP], emailMsg.as_string())
                s.quit()

                Logger.debug("AlarmSender sends message for: %s" % msg)
            except TypeError, e:
                Logger.log("Exception %s in AlarmSender, run" % str(e))
            except Exception, e:
                Logger.log("Unexcepted exception %s in AlarmSender: %s" % (e.__class__.__name__, str(e)))




if BACKGROUND:
    pid = os.fork()
else:
    pid = 0

if pid:
    pidFile = file(PID_FILE , mode='w')
    pidFile.write("%i\n" % pid)
    pidFile.close()
    sys.exit(0)

Logger.openlog(LOG_FILE)

if DEBUG:
    Logger.debugEnable()

Logger.log("FridgeAlarm starting")



try:
    alarmQueue = Queue.Queue()
    Logger.log("alarm queue created ...")

    temperatureChecker = TemperatureChecker(alarmQueue, MONGO_HOST, MONGO_DATABASE, MONGO_COLLECTION,
                                            PERIOD, INTERVAL, THRESHOLD)
    temperatureChecker.start()
    Logger.log("TemperatureChecker started ...")

    alarmSender = AlarmSender(alarmQueue)
    alarmSender.start()
    Logger.log("AlarmSender started ...")
    
    
    Logger.log("FridgeAlarm running")
    
    while (True):
        sleep(10)
except Exception, e:
    Logger.log("FridgeAlarm dying from %s, %s" % (str(e), e.msg))
finally:
    Logger.log("FridgeAlarm terminating ...")