#
# Copyright 2019 the original author or authors.
#
# 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 binascii
import structlog
import time
import subprocess
import grpc
from scapy.layers.l2 import Ether, Dot1Q
from transitions import Machine
from twisted.internet import reactor

from voltha.registry import registry
from voltha.protos.device_pb2 import Port
from voltha.adapters.openolt.protos import openolt_pb2, openolt_pb2_grpc
from voltha.adapters.openolt.openolt_utils import OpenoltUtils
from voltha.adapters.openolt.openolt_indications import OpenoltIndications
from voltha.adapters.openolt.openolt_packet import OpenoltPacket
from voltha.adapters.openolt.openolt_kafka_admin import KAdmin


class OpenoltDevice(object):
    """
    OpenoltDevice state machine:

        null ----> init ------> connected -----> up -----> down
                   ^ ^             |             ^         | |
                   | |             |             |         | |
                   | +-------------+             +---------+ |
                   |                                         |
                   +-----------------------------------------+
    """
    # pylint: disable=too-many-instance-attributes
    # pylint: disable=R0904
    states = [
        'state_null',
        'state_init',
        'state_connected',
        'state_up',
        'state_down']

    transitions = [
        {'trigger': 'go_state_init',
         'source': ['state_null', 'state_connected', 'state_down'],
         'dest': 'state_init',
         'before': 'do_state_init',
         'after': 'post_init'},
        {'trigger': 'go_state_connected',
         'source': 'state_init',
         'dest': 'state_connected',
         'before': 'do_state_connected',
         'after': 'post_connected'},
        {'trigger': 'go_state_up',
         'source': ['state_connected', 'state_down'],
         'dest': 'state_up',
         'before': 'do_state_up'},
        {'trigger': 'go_state_down',
         'source': ['state_up'],
         'dest': 'state_down',
         'before': 'do_state_down',
         'after': 'post_down'}]

    def __init__(self, **kwargs):
        super(OpenoltDevice, self).__init__()

        self.admin_state = "up"

        adapter_agent = kwargs['adapter_agent']
        self.device_id = kwargs['device_id']

        self.data_model_class = kwargs['support_classes']['data_model']
        self.platform_class = kwargs['support_classes']['platform']
        self.platform = self.platform_class()
        self.resource_mgr_class = kwargs['support_classes']['resource_mgr']
        self.flow_mgr_class = kwargs['support_classes']['flow_mgr']
        self.alarm_mgr_class = kwargs['support_classes']['alarm_mgr']
        self.stats_mgr_class = kwargs['support_classes']['stats_mgr']

        is_reconciliation = kwargs.get('reconciliation', False)
        self.host_and_port = kwargs['host_and_port']
        self.extra_args = kwargs['extra_args']
        self.log = structlog.get_logger(ip=self.host_and_port)

        self.log.info('openolt-device-init')

        self.data_model = self.data_model_class(self.device_id, adapter_agent,
                                                self.platform)
        if is_reconciliation:
            self.log.info('reconcile data model')
            self.data_model.reconcile()

        # Initialize the OLT state machine
        self.machine = Machine(model=self, states=OpenoltDevice.states,
                               transitions=OpenoltDevice.transitions,
                               send_event=True, initial='state_null')

        self.device_info = None

        self._kadmin = KAdmin()
        self._kadmin.delete_topics([
            'openolt.ind-{}'.format(self.host_and_port.split(':')[0])])

        self.broker = registry('openolt_kafka_proxy').kafka_endpoint
        channel = grpc.insecure_channel(self.host_and_port)
        self.stub = openolt_pb2_grpc.OpenoltStub(channel)

        self._grpc = None
        self.go_state_init()

    def do_state_init(self, event):
        self.log.debug('init')
        self._indications = OpenoltIndications(self)
        self._indications.start()

    def post_init(self, event):
        self.log.debug('post_init')

        # FIXME
        time.sleep(10)

        reactor.callInThread(self.get_device_info)

    def do_state_connected(self, event):
        self.log.debug("do_state_connected")

        # Check that device_info was successfully retrieved
        assert(self.device_info is not None
               and self.device_info.device_serial_number is not None
               and self.device_info.device_serial_number != '')

        self.data_model.olt_create(self.device_info)

        # FIXME
        self._kadmin.delete_topics([
            'voltha.pktout-{}'.format(self.data_model.logical_device_id)])
        self._kadmin.delete_topics(['openolt.pktin-{}'.format(
            self.host_and_port.split(':')[0])])

        self._packet = OpenoltPacket(self)
        self._packet.start()

        self.resource_mgr = self.resource_mgr_class(self.device_id,
                                                    self.host_and_port,
                                                    self.extra_args,
                                                    self.device_info)
        self.flow_mgr = self.flow_mgr_class(self.log, self.stub,
                                            self.device_id,
                                            self.data_model.logical_device_id,
                                            self.platform, self.resource_mgr,
                                            self.data_model)

        self.alarm_mgr = self.alarm_mgr_class(self.log, self.platform,
                                              self.data_model)
        self.stats_mgr = self.stats_mgr_class(self, self.log, self.platform,
                                              self.data_model)

    def post_connected(self, event):
        # FIXME - better way that avoids absolute paths?
        self._grpc = subprocess.Popen(
            ['python',
             'openolt_grpc.py',
             self.broker,
             self.host_and_port],
            env={'PYTHONPATH': '/voltha:/voltha/voltha/protos/third_party'},
            cwd='/voltha/voltha/adapters/openolt/grpc',
        )

    def do_state_up(self, event):
        self.log.debug("do_state_up")
        self.data_model.olt_oper_up()

    def do_state_down(self, event):
        self.log.debug("do_state_down")
        self.data_model.olt_oper_down()

    def post_down(self, event):
        self.log.debug('post_down')
        self.flow_mgr.reset_flows()
        self.go_state_init()

    def olt_indication(self, olt_indication):
        if olt_indication.oper_state == "up":
            self.go_state_up()
        elif olt_indication.oper_state == "down":
            self.go_state_down()

    def intf_indication(self, intf_indication):
        self.log.debug("intf indication", intf_id=intf_indication.intf_id,
                       oper_state=intf_indication.oper_state)
        # NOTE - BAL only sends interface indications for PON ports,
        # not for NNI ports.
        self.data_model.olt_port_add_update(intf_indication.intf_id,
                                            "pon",
                                            intf_indication.oper_state)

    def intf_oper_indication(self, intf_oper_indication):
        self.log.debug("Received interface oper state change indication",
                       intf_id=intf_oper_indication.intf_id,
                       type=intf_oper_indication.type,
                       oper_state=intf_oper_indication.oper_state)
        self.data_model.olt_port_add_update(intf_oper_indication.intf_id,
                                            intf_oper_indication.type,
                                            intf_oper_indication.oper_state)

    def onu_discovery_indication(self, onu_disc_indication):
        intf_id = onu_disc_indication.intf_id
        serial_number = onu_disc_indication.serial_number
        serial_number_str = OpenoltUtils.stringify_serial_number(serial_number)

        self.log.debug("onu discovery indication", intf_id=intf_id,
                       serial_number=serial_number_str)

        try:
            onu_id = self.data_model.onu_id(serial_number=serial_number_str)
        except ValueError:
            # FIXME - resource_mgr.get_onu_id() should raise exception
            onu_id = self.resource_mgr.get_onu_id(intf_id)
            if onu_id is None:
                raise Exception("onu-id-unavailable")

        try:
            self.data_model.onu_create(intf_id, onu_id, serial_number_str)
        except ValueError:
            pass
        else:
            self.activate_onu(intf_id, onu_id, serial_number,
                              serial_number_str)

    def onu_indication(self, onu_indication):
        self.log.debug("onu indication", intf_id=onu_indication.intf_id,
                       onu_id=onu_indication.onu_id,
                       serial_number=onu_indication.serial_number,
                       oper_state=onu_indication.oper_state,
                       admin_state=onu_indication.admin_state)

        # Admin state
        if onu_indication.admin_state == 'down':
            if onu_indication.oper_state != 'down':
                self.log.error('ONU-admin-state-down-and-oper-status-not-down',
                               oper_state=onu_indication.oper_state)
                # Forcing the oper state change code to execute
                onu_indication.oper_state = 'down'

            # Port and logical port update is taken care of by oper state block

        self.log.debug('admin-state-dealt-with')

        # Operating state
        if onu_indication.oper_state == 'down':
            self.data_model.onu_oper_down(onu_indication.intf_id,
                                          onu_indication.onu_id)

        elif onu_indication.oper_state == 'up':
            self.data_model.onu_oper_up(onu_indication.intf_id,
                                        onu_indication.onu_id)

    def omci_indication(self, omci_indication):

        self.log.debug("omci indication", intf_id=omci_indication.intf_id,
                       onu_id=omci_indication.onu_id)

        self.data_model.onu_omci_rx(omci_indication.intf_id,
                                    omci_indication.onu_id,
                                    omci_indication.pkt)

    def send_proxied_message(self, proxy_address, msg):
        omci = openolt_pb2.OmciMsg(intf_id=proxy_address.channel_id,
                                   onu_id=proxy_address.onu_id, pkt=str(msg))
        reactor.callInThread(self.stub.OmciMsgOut, omci)

    def update_flow_table(self, flows):
        self.log.debug('No updates here now, all is done in logical flows '
                       'update')

    def update_logical_flows(self, flows_to_add, flows_to_remove,
                             device_rules_map):
        if not self.is_state_up():
            self.log.info('The OLT is not up, we cannot update flows',
                          flows_to_add=[f.id for f in flows_to_add],
                          flows_to_remove=[f.id for f in flows_to_remove])
            return

        self.flow_mgr.update_logical_flows(flows_to_add, flows_to_remove,
                                           device_rules_map)

    def disable(self):
        self.log.debug('sending-deactivate-olt-message')

        try:
            # Send grpc call
            self.stub.DisableOlt(openolt_pb2.Empty())
            self.admin_state = "down"
            self.log.info('openolt device disabled')
        except Exception as e:
            self.log.error('Failure to disable openolt device', error=e)

    def delete(self):
        self.log.info('deleting-olt')

        # Terminate the grpc subprocess
        self._grpc.terminate()

        # Clears up the data from the resource manager KV store
        # for the device
        del self.resource_mgr

        try:
            # Rebooting to reset the state
            self.reboot()
            self.data_model.olt_delete()
        except Exception as e:
            self.log.error('Failure to delete openolt device', error=e)
            raise e
        else:
            self.log.info('successfully-deleted-olt')

    def reenable(self):
        self.log.debug('reenabling-olt')

        try:
            self.stub.ReenableOlt(openolt_pb2.Empty())
        except Exception as e:
            self.log.error('Failure to reenable openolt device', error=e)
        else:
            self.log.info('openolt device reenabled')
            self.admin_state = "up"

    def activate_onu(self, intf_id, onu_id, serial_number,
                     serial_number_str):
        self.log.debug("activating-onu", intf_id=intf_id, onu_id=onu_id,
                       serial_number_str=serial_number_str,
                       serial_number=serial_number)
        onu = openolt_pb2.Onu(intf_id=intf_id, onu_id=onu_id,
                              serial_number=serial_number)

        self.log.info('activating onu', serial_number=serial_number_str)
        reactor.callInThread(self.stub.ActivateOnu, onu)

    # FIXME - instead of passing child_device around, delete_child_device
    # needs to change to use serial_number.
    def delete_child_device(self, child_device):
        self.log.debug('sending-deactivate-onu',
                       onu_device=child_device,
                       onu_serial_number=child_device.serial_number)

        self.data_model.onu_delete(child_device.serial_number)

        # TODO FIXME - For each uni.
        # TODO FIXME - Flows are not deleted
        uni_id = 0  # FIXME
        try:
            self.flow_mgr.delete_tech_profile_instance(
                        child_device.proxy_address.channel_id,
                        child_device.proxy_address.onu_id,
                        uni_id, None)
        except Exception as e:
            self.log.exception("error-removing-tp-instance")

        try:
            pon_intf_id_onu_id = (child_device.proxy_address.channel_id,
                                  child_device.proxy_address.onu_id,
                                  uni_id)
            # Free any PON resources that were reserved for the ONU
            self.resource_mgr.free_pon_resources_for_onu(pon_intf_id_onu_id)
        except Exception as e:
            self.log.exception("error-removing-pon-resources-for-onu")

        serial_number = OpenoltUtils.destringify_serial_number(
            child_device.serial_number)
        try:
            onu = openolt_pb2.Onu(
                intf_id=child_device.proxy_address.channel_id,
                onu_id=child_device.proxy_address.onu_id,
                serial_number=serial_number)
            self.stub.DeleteOnu(onu)
        except Exception as e:
            self.log.warn("error-deleting-the-onu-on-olt-device", error=e)

    def reboot(self):
        self.log.debug('rebooting openolt device')
        try:
            self.stub.Reboot(openolt_pb2.Empty())
        except Exception as e:
            self.log.error('something went wrong with the reboot', error=e)
        else:
            self.log.info('device rebooted')

    def trigger_statistics_collection(self):
        try:
            self.stub.CollectStatistics(openolt_pb2.Empty())
        except Exception as e:
            self.log.error('Error while triggering statistics collection',
                           error=e)
        else:
            self.log.info('statistics requested')

    def simulate_alarm(self, alarm):
        self.alarm_mgr.simulate_alarm(alarm)

    def get_device_info(self):
        self.log.debug('get_device_info')
        timeout = 60*60
        delay = 1
        exponential_back_off = False
        while True:
            try:
                self.device_info \
                    = self.stub.GetDeviceInfo(openolt_pb2.Empty())
                break
            except Exception as e:
                if delay > timeout:
                    self.log.error("openolt grpc timed out connecting to olt")
                    return
                else:
                    self.log.warn(
                        "openolt grpc retry connecting to olt in %ds: %s"
                        % (delay, repr(e)))
                    time.sleep(delay)
                    if exponential_back_off:
                        delay += delay
                    else:
                        delay += 1

        self.log.info('openolt grpc connected to olt',
                      device_info=self.device_info)

        self.go_state_connected()