"""Celery tasks.
"""
from datetime import timedelta
from celery.task import PeriodicTask
import subprocess
import urllib2
from PIL import Image, ImageOps
from StringIO import StringIO
from django.conf import settings
import os

import sublab_monitor

class NetworkStatus(PeriodicTask):
    """Periodic task for getting sublab network status
    """
    hosts = {
            'taifun': '172.22.83.5',
            'trieste': '172.22.80.4',
            'nautilus': '172.22.80.7',
    }
    run_every = timedelta(minutes=2)
    ignore_result = True

    def __init__(self, *args, **kwargs):
        PeriodicTask.__init__(self, *args, **kwargs)


    @staticmethod
    def host_alive(host):
        rc = subprocess.call(['ping', '-c', '2', '-W', '1', host])

        if rc == 0:
            return True
        else:
            return False

    def run(self, **kwargs):
        """Ping all the hosts.
        """
        self.logger = self.get_logger(**kwargs)

        results = {}
        for host, target in self.hosts.items():
            results[host] = self.host_alive(target)

        storage = sublab_monitor.Storage('network_status')
        for host, status in results.items():
            storage.set(host, status)

        return repr(results)


class ImageFetcher(object):
    """
    A task mixin which downloads, processes and stores an Image
    """

    @property
    def fetch_url(self):
        """
        The location from which the image should be fetched
        """
        raise NotImplementedError

    @property
    def store_name(self):
        """
        The name under which the image should be stored
        """
        raise NotImplementedError

    def process_image(self, image):
        """
        This method may be overwritten to perform some
        processing on the image
        """
        raise NotImplementedError

    def run(self, **kwargs):
        upstream = urllib2.urlopen(self.fetch_url).read()
        image = Image.open(StringIO(upstream))

        try:
            image = self.process_image(image)
        except NotImplementedError:
            pass

        fn = os.path.join(settings.MEDIA_ROOT, self.store_name)
        fn_new = os.path.join(settings.MEDIA_ROOT, 'new-%s' % self.store_name)

        image.save(fn_new)
        os.rename(fn_new, fn)


class EnhancingImageFetcher(ImageFetcher):
    def process_image(self, image):
        rv = ImageOps.autocontrast(image)
        rv.im = ImageOps.unsharp_mask(rv, 10.0, 40, 7)

        return rv


class KarlHeineCamFetcher(EnhancingImageFetcher, PeriodicTask):
    run_every = timedelta(minutes=5)
    fetch_url = 'http://taifun.local.sublab.org/webcam.jpg'
    store_name = 'karlheine_cam.jpg'


class TempGraphFetcher(ImageFetcher, PeriodicTask):
    run_every = timedelta(minutes=5)
    fetch_url = 'http://taifun.local.sublab.org/temperature/temp-2hour.png'
    store_name = 'tempgraph.png'