# Copyright 2016 Cisco Systems, Inc.  All rights reserved.
#
#    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.

import os
import subprocess
import yaml

from log import LOG


class TrafficServerException(Exception):
    pass

class TrafficServer(object):
    """Base class for traffic servers."""

class TRexTrafficServer(TrafficServer):
    """Creates configuration file for TRex and runs server."""

    def __init__(self, trex_base_dir='/opt/trex'):
        contents = os.listdir(trex_base_dir)
        # only one version of TRex should be supported in container
        assert len(contents) == 1
        self.trex_dir = os.path.join(trex_base_dir, contents[0])

    def run_server(self, generator_config, filename='/etc/trex_cfg.yaml'):
        """
        Runs TRex server for specified traffic profile.

        :param traffic_profile: traffic profile object based on config file
        :param filename: path where to save TRex config file
        """
        cfg = self.__save_config(generator_config, filename)
        cores = generator_config.cores
        sw_mode = "--software" if generator_config.software_mode else ""
        vlan_opt = "--vlan" if generator_config.vlan_tagging else ""
        subprocess.Popen(['nohup', '/bin/bash', '-c',
                          './t-rex-64 -i -c {} --iom 0 --no-scapy-server --close-at-end {} '
                          '{} --cfg {} &> /tmp/trex.log & disown'.format(cores, sw_mode,
                                                                         vlan_opt, cfg)],
                         cwd=self.trex_dir)
        LOG.info('TRex server is running...')

    def __save_config(self, generator_config, filename):
        ifs = ",".join([repr(pci) for pci in generator_config.pcis])

        result = """# Config generated by NFVbench
        - port_limit : 2
          version    : 2
          interfaces : [{ifs}]""".format(ifs=ifs)

        yaml.safe_load(result)
        if os.path.exists(filename):
            os.remove(filename)
        with open(filename, 'w') as f:
            f.write(result)

        return filename