# Copyright 2015-2016 Intel Corporation.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
""" VNF Controller interface
"""

import logging
import pexpect
from conf import settings
from vnfs.vnf.vnf import IVnf

class VnfController(object):
    """VNF controller class

    Used to set-up and control VNFs for specified scenario

    Attributes:
        _vnf_class: A class object representing the VNF to be used.
        _deployment: A string describing the scenario to set-up in the
            constructor.
        _vnfs: A list of vnfs controlled by the controller.
    """

    def __init__(self, deployment, vnf_class):
        """Sets up the VNF infrastructure based on deployment scenario

        :param vnf_class: The VNF class to be used.
        """
        # reset VNF ID counter for each testcase
        IVnf.reset_vnf_counter()

        # setup controller with requested number of VNFs
        self._logger = logging.getLogger(__name__)
        self._vnf_class = vnf_class
        self._deployment = deployment.lower()
        self._vnfs = []
        if self._deployment == 'pvp':
            vm_number = 1
        elif (self._deployment.startswith('pvvp') or
              self._deployment.startswith('pvpv')):
            if len(self._deployment) > 4:
                vm_number = int(self._deployment[4:])
            else:
                vm_number = 2
        else:
            raise RuntimeError('Deployment {} is not supported by '
                               'VnfController.'.format(self._deployment))

        if vm_number:
            self._logger.debug('Check configuration for %s guests.', vm_number)
            settings.check_vm_settings(vm_number)
            # enforce that GUEST_NIC_NR is 1 or even number of NICs
            updated = False
            nics_nr = settings.getValue('GUEST_NICS_NR')
            for index in range(len(nics_nr)):
                if nics_nr[index] > 1 and nics_nr[index] % 2:
                    updated = True
                    nics_nr[index] = int(nics_nr[index] / 2) * 2
            if updated:
                settings.setValue('GUEST_NICS_NR', nics_nr)
                self._logger.warning('Odd number of NICs was detected. Configuration '
                                     'was updated to GUEST_NICS_NR = %s',
                                     settings.getValue('GUEST_NICS_NR'))

            self._vnfs = [vnf_class() for _ in range(vm_number)]

        self._logger.debug('__init__ ' + str(len(self._vnfs)) +
                           ' VNF[s] with ' + ' '.join(map(str, self._vnfs)))

    def get_vnfs(self):
        """Returns a list of vnfs controlled by this controller.
        """
        self._logger.debug('get_vnfs ' + str(len(self._vnfs)) +
                           ' VNF[s] with ' + ' '.join(map(str, self._vnfs)))
        return self._vnfs

    def get_vnfs_number(self):
        """Returns a number of vnfs controlled by this controller.
        """
        self._logger.debug('get_vnfs_number ' + str(len(self._vnfs)) +
                           ' VNF[s]')
        return len(self._vnfs)

    def start(self):
        """Boots all VNFs set-up by __init__.

        This is a blocking function.
        """
        self._logger.debug('start ' + str(len(self._vnfs)) +
                           ' VNF[s] with ' + ' '.join(map(str, self._vnfs)))
        try:
            for vnf in self._vnfs:
                vnf.start()
        except pexpect.TIMEOUT:
            self.stop()
            raise

    def stop(self):
        """Stops all VNFs set-up by __init__.

        This is a blocking function.
        """
        self._logger.debug('stop ' + str(len(self._vnfs)) +
                           ' VNF[s] with ' + ' '.join(map(str, self._vnfs)))
        for vnf in self._vnfs:
            vnf.stop()

    def __enter__(self):
        self.start()

    def __exit__(self, type_, value, traceback):
        self.stop()