import binascii
import logging
import requests

from pyotp import TOTP

from uncloud.common.shared import shared
from uncloud.common.settings import settings

logger = logging.getLogger(__name__)


def check_otp(name, realm, token):
    try:
        data = {
            'auth_name': settings['otp']['auth_name'],
            'auth_token': TOTP(settings['otp']['auth_seed']).now(),
            'auth_realm': settings['otp']['auth_realm'],
            'name': name,
            'realm': realm,
            'token': token,
        }
    except binascii.Error:
        logger.error('Cannot compute OTP for seed: {}'.format(settings['otp']['auth_seed']))
        return 400
    else:
        response = requests.post(settings['otp']['verification_controller_url'], json=data)
        return response.status_code


def resolve_vm_name(name, owner):
    """Return UUID of Virtual Machine of name == name and owner == owner

    Input: name of vm, owner of vm.
    Output: uuid of vm if found otherwise None
    """
    result = next(
        filter(lambda vm: vm.value['owner'] == owner and vm.value['name'] == name, shared.vm_pool.vms),
        None
    )
    if result:
        return result.key.split('/')[-1]

    return None


def resolve_image_name(name):
    """Return image uuid given its name and its store

       * If the provided name is not in correct format
         i.e {store_name}:{image_name} return ValueError
       * If no such image found then return KeyError
    """

    seperator = ':'

    # Ensure, user/program passed valid name that is of type string
    try:
        store_name_and_image_name = name.split(seperator)

        """
        Examples, where it would work and where it would raise exception
        'images:alpine' --> ['images', 'alpine']

        'images' --> ['images'] it would raise Exception as non enough value to unpack

        'images:alpine:meow' --> ['images', 'alpine', 'meow'] it would raise Exception
                                                              as too many values to unpack
        """
        store_name, image_name = store_name_and_image_name
    except Exception:
        raise ValueError('Image name not in correct format i.e {store_name}:{image_name}')

    images = shared.etcd_client.get_prefix(settings['etcd']['image_prefix'], value_in_json=True)

    # Try to find image with name == image_name and store_name == store_name
    try:
        image = next(
            filter(
                lambda im: im.value['name'] == image_name
                and im.value['store_name'] == store_name,
                images,
            )
        )
    except StopIteration:
        raise KeyError('No image with name {} found.'.format(name))
    else:
        image_uuid = image.key.split('/')[-1]

    return image_uuid


def make_return_message(err, status_code=200):
    return {'message': str(err)}, status_code