'''
Created on 09.06.2015

@author: wn
'''

import threading
import Queue
from logger import Logger
import paho.mqtt.client as mqtt
import json
import datetime

_queue = None

def on_message(client, userdata, msg):
    try:
        j = json.loads(msg.payload)
        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
        j['metadata']['timestamp'] = now
        j['metadata']['seconds'] = seconds
        j['metadata']['day'] = midnight

        Logger.debug("MqttReceiver queues: %s" % j)
    
        _queue.put_nowait(j)
    except Queue.Full:
        Logger.log("Message %s dropped" % (j))
    except ValueError, e:
        Logger.log("Exception %s in MqttReceiver, on_message" % (str(e)))


class MqttReceiver(threading.Thread):
    singleton = None
    
    @classmethod
    def create(cls, queue, broker, topics):
        global _queue
        if cls.singleton is None:
            cls.singleton = MqttReceiver(queue, broker, topics)
            _queue = queue
        return cls.singleton
            
    def __init__(self, queue, broker, topics):
        threading.Thread.__init__(self)
        self.queue = queue
        self.broker = broker
        self.topics = topics
        self.setDaemon(True)

    def run(self):
        client = mqtt.Client()
        client.on_message = on_message
        client.connect(self.broker, 1883, 60)
        for topic in self.topics:
            Logger.log("Subscribing on %s" % str(topic))
            client.subscribe(topic)
        
        client.loop_forever()