import socket
from django.utils import timezone
from django_q.conf import Conf, logger, redis_client
import signing


class Status(object):
    """Cluster status base class."""

    def __init__(self, pid):
        self.workers = []
        self.tob = None
        self.reincarnations = 0
        self.cluster_id = pid
        self.sentinel = 0
        self.status = Conf.STOPPED
        self.done_q_size = 0
        self.host = socket.gethostname()
        self.monitor = 0
        self.task_q_size = 0
        self.pusher = 0
        self.timestamp = timezone.now()


class Stat(Status):
    """Status object for Cluster monitoring."""

    def __init__(self, sentinel):
        super(Stat, self).__init__(sentinel.parent_pid or sentinel.pid)
        self.r = sentinel.r
        self.tob = sentinel.tob
        self.reincarnations = sentinel.reincarnations
        self.sentinel = sentinel.pid
        self.status = sentinel.status()
        self.done_q_size = 0
        self.task_q_size = 0
        if Conf.QSIZE:
            self.done_q_size = sentinel.result_queue.qsize()
            self.task_q_size = sentinel.task_queue.qsize()
        if sentinel.monitor:
            self.monitor = sentinel.monitor.pid
        if sentinel.pusher:
            self.pusher = sentinel.pusher.pid
        self.workers = [w.pid for w in sentinel.pool]

    def uptime(self):
        return (timezone.now() - self.tob).total_seconds()

    @property
    def key(self):
        """
        :return: redis key for this cluster statistic
        """
        return self.get_key(self.cluster_id)

    @staticmethod
    def get_key(cluster_id):
        """
        :param cluster_id: cluster ID
        :return: redis key for the cluster statistic
        """
        return '{}:{}'.format(Conf.Q_STAT, cluster_id)

    def save(self):
        try:
            self.r.set(self.key, signing.SignedPackage.dumps(self, True), 3)
        except Exception as e:
            logger.error(e)

    def empty_queues(self):
        return self.done_q_size + self.task_q_size == 0

    @staticmethod
    def get(cluster_id, r=redis_client):
        """
        gets the current status for the cluster
        :param cluster_id: id of the cluster
        :return: Stat or Status
        """
        key = Stat.get_key(cluster_id)
        if r.exists(key):
            pack = r.get(key)
            try:
                return signing.SignedPackage.loads(pack)
            except signing.BadSignature:
                return None
        return Status(cluster_id)

    @staticmethod
    def get_all(r=redis_client):
        """
        Get the status for all currently running clusters with the same prefix
        and secret key.
        :return: list of type Stat
        """
        stats = []
        keys = r.keys(pattern='{}:*'.format(Conf.Q_STAT))
        if keys:
            packs = r.mget(keys)
            for pack in packs:
                try:
                    stats.append(signing.SignedPackage.loads(pack))
                except signing.BadSignature:
                    continue
        return stats

    def __getstate__(self):
        # Don't pickle the redis connection
        state = dict(self.__dict__)
        del state['r']
        return state


def ping_redis(r):
    try:
        r.ping()
    except Exception as e:
        logger.error('Can not connect to Redis server.')
        raise e