#!/usr/bin/env python

#
# Implementation for experiment session controller.
#

import time

from dm.common.objects.experiment import Experiment
from dm.common.objects.dmObjectManager import DmObjectManager
from dm.common.exceptions.invalidRequest import InvalidRequest
from dm.ds_web_service.api.dsRestApiFactory import DsRestApiFactory
from fileSystemObserver import FileSystemObserver

class ExperimentSessionControllerImpl(DmObjectManager):
    """ Experiment session controller implementation class. """

    def __init__(self):
        DmObjectManager.__init__(self)
        self.experimentDict = {}

    def startDaq(self, name, dataDirectory):
        FileSystemObserver.getInstance().startObservingPath(dataDirectory)
        startTime = time.time()
        experiment = Experiment({'name' : name, 'dataDirectory' : dataDirectory, 'daqStartTime' : startTime})
        self.experimentDict[name] = experiment
        return experiment

    def stopDaq(self, name):
        experiment = self.experimentDict.get(name)
        if experiment is None or experiment.get('daqEndTime') is not None:
            raise InvalidRequest('Experiment %s is not active.' % name)
        dataDirectory = experiment.get('dataDirectory')
        FileSystemObserver.getInstance().stopObservingPath(dataDirectory)
        experiment['daqEndTime'] = time.time()
        return experiment