from ucloud.common.host import HostPool
from ucloud.common.request import RequestPool
from ucloud.common.vm import VmPool
from ucloud.common.storage_handlers import FileSystemBasedImageStorageHandler, CEPHBasedImageStorageHandler

# Replacing decouple inline
import configparser
import os
import os.path

import logging
log = logging.getLogger("ucloud.config")

conf_name = "ucloud.conf"

try:
    conf_dir = os.environ["UCLOUD_CONF_DIR"]
except KeyError:
    conf_dir = "/etc/ucloud"

config_file = os.path.join(conf_dir, conf_name)

config = configparser.ConfigParser()

try:
    config.read(config_file)
except FileNotFoundError:
    log.warn("Configuration file not found - using defaults")


################################################################################
# ETCD3 support
import etcd3
import json
import queue
import copy
from collections import namedtuple

PseudoEtcdMeta = namedtuple("PseudoEtcdMeta", ["key"])

class EtcdEntry:
    # key: str
    # value: str

    def __init__(self, meta, value, value_in_json=False):
        self.key = meta.key.decode("utf-8")
        self.value = value.decode("utf-8")

        if value_in_json:
            self.value = json.loads(self.value)

class Etcd3Wrapper:
    def __init__(self, *args, **kwargs):
        self.client = etcd3.client(*args, **kwargs)

    def get(self, *args, value_in_json=False, **kwargs):
        _value, _key = self.client.get(*args, **kwargs)
        if _key is None or _value is None:
            return None
        return EtcdEntry(_key, _value, value_in_json=value_in_json)

    def put(self, *args, value_in_json=False, **kwargs):
        _key, _value = args
        if value_in_json:
            _value = json.dumps(_value)

        if not isinstance(_key, str):
            _key = _key.decode("utf-8")

        return self.client.put(_key, _value, **kwargs)

    def get_prefix(self, *args, value_in_json=False, **kwargs):
        r = self.client.get_prefix(*args, **kwargs)
        for entry in r:
            e = EtcdEntry(*entry[::-1], value_in_json=value_in_json)
            if e.value:
                yield e

    def watch_prefix(self, key, timeout=0, value_in_json=False):
        timeout_event = EtcdEntry(PseudoEtcdMeta(key=b"TIMEOUT"),
                                  value=str.encode(json.dumps({"status": "TIMEOUT",
                                                               "type": "TIMEOUT"})),
                                  value_in_json=value_in_json)

        event_queue = queue.Queue()

        def add_event_to_queue(event):
            for e in event.events:
                if e.value:
                    event_queue.put(EtcdEntry(e, e.value, value_in_json=value_in_json))

        self.client.add_watch_prefix_callback(key, add_event_to_queue)

        while True:
            try:
                while True:
                    v = event_queue.get(timeout=timeout)
                    yield v
            except queue.Empty:
                event_queue.put(copy.deepcopy(timeout_event))


class PsuedoEtcdEntry(EtcdEntry):
    def __init__(self, key, value, value_in_json=False):
        super().__init__(PseudoEtcdMeta(key=key.encode("utf-8")), value, value_in_json=value_in_json)


etcd_wrapper_args = ()
etcd_wrapper_kwargs = {
    'host':      config['etcd']['ETCD_URL'],
    'port':      config['etcd']['ETCD_PORT'],
    'ca_cert':   config['etcd']['CA_CERT'],
    'cert_cert': config['etcd']['CERT_CERT'],
    'cert_key':  config['etcd']['CERT_KEY']
}

etcd_client = Etcd3Wrapper(*etcd_wrapper_args, **etcd_wrapper_kwargs)

host_pool = HostPool(etcd_client, config['etcd']['HOST_PREFIX'])
vm_pool = VmPool(etcd_client, config['etcd']['VM_PREFIX'])
request_pool = RequestPool(etcd_client, config['etcd']['REQUEST_PREFIX'])

running_vms = []

__storage_backend = config['storage']["STORAGE_BACKEND"]
if __storage_backend == "filesystem":
    image_storage_handler = FileSystemBasedImageStorageHandler(vm_base=config['storage']["VM_DIR"],
                                                               image_base=config['storage']["IMAGE_DIR"])
elif __storage_backend == "ceph":
    image_storage_handler = CEPHBasedImageStorageHandler(vm_base=config['storage']["CEPH_VM_POOL"],
                                                         image_base=config['storage']["CEPH_IMAGE_POOL"])
else:
    raise Exception("Unknown Image Storage Handler")