# Copyright 2017-2018 Spirent Communications.
#
# 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.

"""
Wrapper file to create and manage Stressor-VM as loadgen
"""

import logging
import os
from tools import tasks
from tools.load_gen.load_gen import ILoadGenerator
from conf import settings as S


class QemuVM(tasks.Process):
    """
    Class for controling an instance of QEMU
    """
    def __init__(self, index):
        self._running = False
        self._logger = logging.getLogger(__name__)
        self._number = index
        pnumber = int(S.getValue('NN_BASE_VNC_PORT')) + self._number
        cpumask = ",".join(S.getValue('NN_CORE_BINDING')[self._number])
        self._monitor = '%s/vm%dmonitor' % ('/tmp', pnumber)
        self._logfile = (os.path.join(S.getValue('LOG_DIR'),
                                      S.getValue('NN_LOG_FILE')) +
                         str(self._number))
        self._log_prefix = 'vnf_%d_cmd : ' % pnumber
        name = 'NN%d' % index
        vnc = ':%d' % pnumber
        self._shared_dir = '%s/qemu%d_share' % ('/tmp', pnumber)
        if not os.path.exists(self._shared_dir):
            try:
                os.makedirs(self._shared_dir)
            except OSError as exp:
                raise OSError("Failed to create shared directory %s: %s" %
                              self._shared_dir, exp)

        self.nics_nr = S.getValue('NN_NICS_NR')[self._number]
        self.image = S.getValue('NN_IMAGE')[self._number]
        self._cmd = ['sudo', '-E', 'taskset', '-c', cpumask,
                     S.getValue('TOOLS')['qemu-system'],
                     '-m', S.getValue('NN_MEMORY')[self._number],
                     '-smp', S.getValue('NN_SMP')[self._number],
                     '-cpu', 'host,migratable=off',
                     '-drive', 'if={},file='.format(
                         S.getValue('NN_BOOT_DRIVE_TYPE')[self._number]) +
                     self.image, '-boot',
                     'c', '--enable-kvm',
                     '-monitor', 'unix:%s,server,nowait' % self._monitor,
                     '-nographic', '-vnc', str(vnc), '-name', name,
                     '-snapshot', '-net none', '-no-reboot',
                     '-drive',
                     'if=%s,format=raw,file=fat:rw:%s,snapshot=off' %
                     (S.getValue('NN_SHARED_DRIVE_TYPE')[self._number],
                      self._shared_dir)
                    ]

    def start(self):
        """
        Start QEMU instance
        """
        super(QemuVM, self).start()
        self._running = True

    def stop(self, sig, slp):
        """
        Stops VNF instance.
        """
        if self._running:
            self._logger.info('Killing VNF...')
            # force termination of VNF and wait to terminate; It will avoid
            # sporadic reboot of host.
            super(QemuVM, self).kill(signal=sig, sleep=slp)
        # remove shared dir if it exists to avoid issues with file consistency
        if os.path.exists(self._shared_dir):
            tasks.run_task(['rm', '-f', '-r', self._shared_dir], self._logger,
                           'Removing content of shared directory...', True)
        self._running = False


# pylint: disable=super-init-not-called
class StressorVM(ILoadGenerator):
    """
    Wrapper Class for Load-Generation through stressor-vm
    """
    def __init__(self, _config):
        self.qvm_list = []
        for vmindex in range(int(S.getValue('NN_COUNT'))):
            qvm = QemuVM(vmindex)
            self.qvm_list.append(qvm)

    def start(self):
        """Start stressor VMs
        """
        for nvm in self.qvm_list:
            nvm.start()

    def kill(self, signal='-9', sleep=2):
        """
        Stop Stressor VMs
        """
        for nvm in self.qvm_list:
            nvm.stop(signal, sleep)