# Copyright (c) 2016-2019 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.

import abc

import logging
import six

from yardstick.network_services.helpers.samplevnf_helper import PortPairs


LOG = logging.getLogger(__name__)


class QueueFileWrapper(object):
    """ Class providing file-like API for talking with SSH connection """

    def __init__(self, q_in, q_out, prompt):
        self.q_in = q_in
        self.q_out = q_out
        self.closed = False
        self.buf = []
        self.bufsize = 20
        self.prompt = prompt

    def read(self, size):
        """ read chunk from input queue """
        if self.q_in.qsize() > 0 and size:
            in_data = self.q_in.get()
            return in_data

    def write(self, chunk):
        """ write chunk to output queue """
        self.buf.append(chunk)
        # flush on prompt or if we exceed bufsize

        size = sum(len(c) for c in self.buf)
        if self.prompt in chunk or size > self.bufsize:
            out = ''.join(self.buf)
            self.buf = []
            self.q_out.put(out)

    def close(self):
        """ close multiprocessing queue """
        pass

    def clear(self):
        """ clear queue """
        while self.q_out.qsize() > 0:
            self.q_out.get()


class VnfdHelper(dict):

    def __init__(self, *args, **kwargs):
        super(VnfdHelper, self).__init__(*args, **kwargs)
        self.port_pairs = PortPairs(self['vdu'][0]['external-interface'])
        # port num is not present until binding so we have to memoize
        self._port_num_map = {}

    @property
    def mgmt_interface(self):
        return self["mgmt-interface"]

    @property
    def vdu(self):
        return self['vdu']

    @property
    def vdu0(self):
        return self.vdu[0]

    @property
    def interfaces(self):
        return self.vdu0['external-interface']

    @property
    def kpi(self):
        return self['benchmark']['kpi']

    def find_virtual_interface(self, **kwargs):
        key, value = next(iter(kwargs.items()))
        for interface in self.interfaces:
            virtual_intf = interface["virtual-interface"]
            if virtual_intf[key] == value:
                return interface
        raise KeyError()

    def find_interface(self, **kwargs):
        key, value = next(iter(kwargs.items()))
        for interface in self.interfaces:
            if interface[key] == value:
                return interface
        raise KeyError()

    # hide dpdk_port_num key so we can abstract
    def find_interface_by_port(self, port):
        for interface in self.interfaces:
            virtual_intf = interface["virtual-interface"]
            # we have to convert to int to compare
            if int(virtual_intf['dpdk_port_num']) == port:
                return interface
        raise KeyError()

    def port_num(self, port):
        # we need interface name -> DPDK port num (PMD ID) -> LINK ID
        # LINK ID -> PMD ID is governed by the port mask
        """

        :rtype: int
        :type port: str
        """
        if isinstance(port, dict):
            intf = port
        else:
            intf = self.find_interface(name=port)
        return self._port_num_map.setdefault(intf["name"],
                                             int(intf["virtual-interface"]["dpdk_port_num"]))

    def port_nums(self, intfs):
        return [self.port_num(i) for i in intfs]

    def ports_iter(self):
        for port_name in self.port_pairs.all_ports:
            port_num = self.port_num(port_name)
            yield port_name, port_num


@six.add_metaclass(abc.ABCMeta)
class GenericVNF(object):
    """Class providing file-like API for generic VNF implementation

    Currently the only class implementing this interface is
    yardstick/network_services/vnf_generic/vnf/sample_vnf:SampleVNF.
    """

    # centralize network naming convention
    UPLINK = PortPairs.UPLINK
    DOWNLINK = PortPairs.DOWNLINK

    def __init__(self, name, vnfd):
        self.name = name
        self.vnfd_helper = VnfdHelper(vnfd)
        # List of statistics we can obtain from this VNF
        # - ETSI MANO 6.3.1.1 monitoring_parameter
        self.kpi = self.vnfd_helper.kpi
        # Standard dictionary containing params like thread no, buffer size etc
        self.config = {}
        self.runs_traffic = False

    @abc.abstractmethod
    def instantiate(self, scenario_cfg, context_cfg):
        """Prepare VNF for operation and start the VNF process/VM

        :param scenario_cfg: Scenario config
        :param context_cfg: Context config
        :return: True/False
        """

    @abc.abstractmethod
    def wait_for_instantiate(self):
        """Wait for VNF to start

        :return: True/False
        """

    @abc.abstractmethod
    def terminate(self):
        """Kill all VNF processes"""

    @abc.abstractmethod
    def scale(self, flavor=""):
        """rest

        :param flavor: Name of the flavor.
        :return:
        """

    @abc.abstractmethod
    def collect_kpi(self):
        """Return a dict containing the selected KPI at a given point of time

        :return: {"kpi": value, "kpi2": value}
        """

    @abc.abstractmethod
    def start_collect(self):
        """Start KPI collection
        :return: None
        """

    @abc.abstractmethod
    def stop_collect(self):
        """Stop KPI collection
        :return: None
        """


@six.add_metaclass(abc.ABCMeta)
class GenericTrafficGen(GenericVNF):
    """Class providing file-like API for generic traffic generator"""

    def __init__(self, name, vnfd):
        super(GenericTrafficGen, self).__init__(name, vnfd)
        self.runs_traffic = True
        self.traffic_finished = False

    @abc.abstractmethod
    def run_traffic(self, traffic_profile):
        """Generate traffic on the wire according to the given params.

        This method is non-blocking, returns immediately when traffic process
        is running. Mandatory.

        :param traffic_profile:
        :return: True/False
        """

    @abc.abstractmethod
    def terminate(self):
        """After this method finishes, all traffic processes should stop.

        Mandatory.

        :return: True/False
        """

    def listen_traffic(self, traffic_profile):
        """Listen to traffic with the given parameters.

        Method is non-blocking, returns immediately when traffic process
        is running. Optional.

        :param traffic_profile:
        :return: True/False
        """
        pass

    def verify_traffic(self, traffic_profile):
        """Verify captured traffic after it has ended.

        Optional.

        :param traffic_profile:
        :return: dict
        """
        pass

    def wait_for_instantiate(self):
        """Wait for an instance to load.

        Optional.

        :return: True/False
        """
        pass

    def start_collect(self):
        """Start KPI collection.

        Traffic measurements are always collected during injection.

        Optional.

        :return: True/False
        """
        pass

    def stop_collect(self):
        """Stop KPI collection.

        Optional.

        :return: True/False
        """
        pass