# Copyright 2022-2023 ETSI TeraFlowSDN - TFS OSG (https://tfs.etsi.org/)
#
# 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.

# Convert the path defined as explicit hops with ingress and egress endpoints per device into a set of connections and
# compute the dependencies among them.
#
# Example:
# o-- int DC1 eth1 -- 10/1 CS1 1/2 -- 1/2 R2 2/1 -- a7.. OLS 60.. -- 2/1 R3 1/1 -- 1/1 CS2 10/1 -- eth1 DC2 int --o
#         APP              PKT            PKT            CTRL            PKT           PKT              APP
#
# path_hops = [
#     {'device': 'DC1-GW', 'ingress_ep': 'int', 'egress_ep': 'eth1'},
#     {'device': 'CS1-GW1', 'ingress_ep': '10/1', 'egress_ep': '1/2'},
#     {'device': 'TN-R2', 'ingress_ep': '1/2', 'egress_ep': '2/1'},
#     {'device': 'TN-OLS', 'ingress_ep': 'a7a80b23a703', 'egress_ep': '60519106029e'},
#     {'device': 'TN-R3', 'ingress_ep': '2/1', 'egress_ep': '1/1'},
#     {'device': 'CS2-GW1', 'ingress_ep': '1/1', 'egress_ep': '10/1'},
#     {'device': 'DC2-GW', 'ingress_ep': 'eth1', 'egress_ep': 'int'}
# ]
#
# connections=[
#     (UUID('7548edf7-ee7c-4adf-ac0f-c7a0c0dfba8e'), ServiceTypeEnum.SERVICETYPE_TAPI_CONNECTIVITY_SERVICE, [
#             {'device': 'TN-OLS', 'ingress_ep': '833760219d0f', 'egress_ep': 'cf176771a4b9'}
#         ], []),
#     (UUID('c2e57966-5d82-4705-a5fe-44cf6487219e'), ServiceTypeEnum.SERVICETYPE_L2NM, [
#             {'device': 'CS1-GW1', 'ingress_ep': '10/1', 'egress_ep': '1/2'},
#             {'device': 'TN-R2', 'ingress_ep': '1/2', 'egress_ep': '2/1'},
#             {'device': 'TN-R3', 'ingress_ep': '2/1', 'egress_ep': '1/1'},
#             {'device': 'CS2-GW1', 'ingress_ep': '1/1', 'egress_ep': '10/1'}
#         ], [UUID('7548edf7-ee7c-4adf-ac0f-c7a0c0dfba8e')]),
#     (UUID('1e205c82-f6ea-4977-9e97-dc27ef1f4802'), ServiceTypeEnum.SERVICETYPE_L2NM, [
#             {'device': 'DC1-GW', 'ingress_ep': 'int', 'egress_ep': 'eth1'},
#             {'device': 'DC2-GW', 'ingress_ep': 'eth1', 'egress_ep': 'int'}
#         ], [UUID('c2e57966-5d82-4705-a5fe-44cf6487219e')])
# ]

import logging, queue, uuid
from typing import Dict, List, Optional, Tuple
from common.DeviceTypes import DeviceTypeEnum
from common.proto.context_pb2 import Device, ServiceTypeEnum
from .ResourceGroups import IGNORED_DEVICE_TYPES, get_resource_classification
from .ServiceTypes import get_service_type

LOGGER = logging.getLogger(__name__)

def convert_explicit_path_hops_to_connections(
    path_hops : List[Dict], device_dict : Dict[str, Tuple[Dict, Device]],
    main_service_uuid : str, main_service_type : ServiceTypeEnum
) -> List[Tuple[str, int, List[str], List[str]]]:

    LOGGER.debug('path_hops={:s}'.format(str(path_hops)))

    connection_stack = queue.LifoQueue()
    connections : List[Tuple[str, int, List[str], List[str]]] = list()
    prv_device_uuid = None
    prv_res_class : Tuple[Optional[int], Optional[DeviceTypeEnum], Optional[str]] = None, None, None

    for path_hop in path_hops:
        LOGGER.debug('path_hop={:s}'.format(str(path_hop)))
        device_uuid = path_hop['device']
        if prv_device_uuid == device_uuid: continue
        device_tuple = device_dict.get(device_uuid)
        if device_tuple is None: raise Exception('Device({:s}) not found'.format(str(device_uuid)))
        _,grpc_device = device_tuple

        res_class = get_resource_classification(grpc_device, device_dict)
        LOGGER.debug('  prv_res_class={:s}'.format(str(prv_res_class)))
        LOGGER.debug('  res_class={:s}'.format(str(res_class)))
        if res_class[1] in IGNORED_DEVICE_TYPES:
            LOGGER.debug('  ignored')
            continue

        if prv_res_class[0] is None:
            # path ingress
            LOGGER.debug('  path ingress')
            connection_stack.put((main_service_uuid, main_service_type, [path_hop], []))
        elif prv_res_class[0] > res_class[0]:
            # create underlying connection
            LOGGER.debug('  create underlying connection')
            connection_uuid = str(uuid.uuid4())
            prv_service_type = connection_stack.queue[-1][1]
            service_type = get_service_type(res_class[1], prv_service_type)
            connection_stack.put((connection_uuid, service_type, [path_hop], []))
        elif prv_res_class[0] == res_class[0]:
            # same resource group kind
            LOGGER.debug('  same resource group kind')
            if prv_res_class[1] == res_class[1] and prv_res_class[2] == res_class[2]:
                # same device type and device controller: connection continues
                LOGGER.debug('  connection continues')
                connection_stack.queue[-1][2].append(path_hop)
            else:
                # different device type or device controller: chain connections
                LOGGER.debug('  chain connections')
                connection = connection_stack.get()
                connections.append(connection)
                connection_stack.queue[-1][3].append(connection[0])

                connection_uuid = str(uuid.uuid4())
                prv_service_type = connection_stack.queue[-1][1]
                service_type = get_service_type(res_class[1], prv_service_type)
                connection_stack.put((connection_uuid, service_type, [path_hop], []))
        elif prv_res_class[0] < res_class[0]:
            # underlying connection ended
            LOGGER.debug('  underlying connection ended')
            connection = connection_stack.get()
            connections.append(connection)
            connection_stack.queue[-1][3].append(connection[0])
            connection_stack.queue[-1][2].append(path_hop)
        else:
            raise Exception('Uncontrolled condition')

        prv_device_uuid = device_uuid
        prv_res_class = res_class

    # path egress
    LOGGER.debug('  path egress')
    connections.append(connection_stack.get())
    LOGGER.debug('connections={:s}'.format(str(connections)))
    assert connection_stack.empty()
    return connections

def convert_explicit_path_hops_to_plain_connection(
    path_hops : List[Dict], main_service_uuid : str, main_service_type : ServiceTypeEnum
) -> List[Tuple[str, int, List[str], List[str]]]:

    connection : Tuple[str, int, List[str], List[str]] = \
        (main_service_uuid, main_service_type, [], [])

    prv_device_uuid = None
    for path_hop in path_hops:
        device_uuid = path_hop['device']
        if prv_device_uuid == device_uuid: continue
        connection[2].append(path_hop)
        prv_device_uuid = device_uuid

    return [connection]
