from __future__ import print_function
from __future__ import unicode_literals

from twisted.internet.defer import inlineCallbacks
from twisted.logger import Logger

from autobahn.twisted.util import sleep
from autobahn.twisted.wamp import ApplicationSession

import time
import json

#generator that yields values from file
def ekg_gen(f):
    row = f.readline()
    while row:
        yield row
        row = f.readline()
        if len(row) == 0:
            f.seek(0,0)
            row = f.readline()

class AppSession(ApplicationSession):

    log = Logger()

    @inlineCallbacks
    def onJoin(self, details):
        self.log.info("ECG node up")
        with open("../ECG_data.txt", "r") as f: #simulated sample of an ECG-curve
            value = ekg_gen(f)
            while True:
                yield self.publish('com.testlab.ecg_update', json.dumps(next(value)))
                yield sleep(0.02)