##
# Copyright 2019 Telefonica Investigacion y Desarrollo, S.A.U.
# This file is part of OSM
# 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.
#
# For those usages not covered by the Apache License, Version 2.0 please
# contact with: nfvlabs@tid.es
##


import abc
import asyncio
import os
import subprocess
import shlex
import time
from enum import Enum
from http import HTTPStatus
from n2vc.loggable import Loggable
from n2vc.exceptions import N2VCBadArgumentsException

from osm_common.dbmongo import DbException


class N2VCDeploymentStatus(Enum):
    PENDING = 'pending'
    RUNNING = 'running'
    COMPLETED = 'completed'
    FAILED = 'failed'
    UNKNOWN = 'unknown'


class N2VCConnector(abc.ABC, Loggable):
    """Generic N2VC connector

    Abstract class
    """

    """
    ##################################################################################################
    ########################################## P U B L I C ###########################################
    ##################################################################################################
    """

    def __init__(
            self,
            db: object,
            fs: object,
            log: object,
            loop: object,
            url: str,
            username: str,
            vca_config: dict,
            on_update_db = None
    ):
        """Initialize N2VC abstract connector. It defines de API for VCA connectors

        :param object db: Mongo object managing the MongoDB (repo common DbBase)
        :param object fs: FileSystem object managing the package artifacts (repo common FsBase)
        :param object log: the logging object to log to
        :param object loop: the loop to use for asyncio (default current thread loop)
        :param str url: a string that how to connect to the VCA (if needed, IP and port can be obtained from there)
        :param str username: the username to authenticate with VCA
        :param dict vca_config: Additional parameters for the specific VCA. For example, for juju it will contain:
            secret: The password to authenticate with
            public_key: The contents of the juju public SSH key
            ca_cert str: The CA certificate used to authenticate
        :param on_update_db: callback called when n2vc connector updates database. Received arguments:
            table: e.g. "nsrs"
            filter: e.g. {_id: <nsd-id> }
            path: e.g. "_admin.deployed.VCA.3."
            updated_data: e.g. , "{ _admin.deployed.VCA.3.status: 'xxx', etc }"
        """

        # parent class
        Loggable.__init__(self, log=log, log_to_console=True, prefix='\nN2VC')

        # check arguments
        if db is None:
            raise N2VCBadArgumentsException('Argument db is mandatory', ['db'])
        if fs is None:
            raise N2VCBadArgumentsException('Argument fs is mandatory', ['fs'])

        self.info('url={}, username={}, vca_config={}'.format(url, username, vca_config))

        # store arguments into self
        self.db = db
        self.fs = fs
        self.loop = loop or asyncio.get_event_loop()
        self.url = url
        self.username = username
        self.vca_config = vca_config
        self.on_update_db = on_update_db

        # generate private/public key-pair
        self.private_key_path = None
        self.public_key_path = None
        self.get_public_key()

    @abc.abstractmethod
    async def get_status(self, namespace: str):
        """Get namespace status

        :param namespace: we obtain ns from namespace
        """

    # TODO: review which public key
    def get_public_key(self) -> str:
        """Get the VCA ssh-public-key

        Returns the SSH public key from local mahine, to be injected into virtual machines to
        be managed by the VCA.
        First run, a ssh keypair will be created.
        The public key is injected into a VM so that we can provision the
        machine with Juju, after which Juju will communicate with the VM 
        directly via the juju agent.
        """

        public_key = ''

        # Find the path where we expect our key lives (~/.ssh)
        homedir = os.environ['HOME']
        sshdir = "{}/.ssh".format(homedir)
        if not os.path.exists(sshdir):
            os.mkdir(sshdir)

        self.private_key_path = "{}/id_n2vc_rsa".format(sshdir)
        self.public_key_path = "{}.pub".format(self.private_key_path)

        # If we don't have a key generated, then we have to generate it using ssh-keygen
        if not os.path.exists(self.private_key_path):
            cmd = "ssh-keygen -t {} -b {} -N '' -f {}".format(
                "rsa",
                "4096",
                self.private_key_path
            )
            # run command with arguments
            subprocess.check_output(shlex.split(cmd))

        # Read the public key. Only one public key (one line) in the file
        with open(self.public_key_path, "r") as file:
            public_key = file.readline()

        return public_key

    @abc.abstractmethod
    async def create_execution_environment(
        self,
        namespace: str,
        db_dict: dict,
        reuse_ee_id: str = None,
        progress_timeout: float = None,
        total_timeout: float = None
    ) -> (str, dict):
        """Create an Execution Environment. Returns when it is created or raises an exception on failing

        :param str namespace: Contains a dot separate string.
                    LCM will use: [<nsi-id>].<ns-id>.<vnf-id>.<vdu-id>[-<count>]
        :param dict db_dict: where to write to database when the status changes.
            It contains a dictionary with {collection: str, filter: {},  path: str},
                e.g. {collection: "nsrs", filter: {_id: <nsd-id>, path: "_admin.deployed.VCA.3"}
        :param str reuse_ee_id: ee id from an older execution. It allows us to reuse an older environment
        :param float progress_timeout:
        :param float total_timeout:
        :returns str, dict: id of the new execution environment and credentials for it
                    (credentials can contains hostname, username, etc depending on underlying cloud)
        """

    @abc.abstractmethod
    async def register_execution_environment(
        self,
        namespace: str,
        credentials: dict,
        db_dict: dict,
        progress_timeout: float = None,
        total_timeout: float = None
    ) -> str:
        """
        Register an existing execution environment at the VCA

        :param str namespace: same as create_execution_environment method
        :param dict credentials: credentials to access the existing execution environment
                    (it can contains hostname, username, path to private key, etc depending on underlying cloud)
        :param dict db_dict: where to write to database when the status changes.
            It contains a dictionary with {collection: str, filter: {},  path: str},
                e.g. {collection: "nsrs", filter: {_id: <nsd-id>, path: "_admin.deployed.VCA.3"}
        :param float progress_timeout:
        :param float total_timeout:
        :returns str: id of the execution environment
        """

    @abc.abstractmethod
    async def install_configuration_sw(
        self,
        ee_id: str,
        artifact_path: str,
        db_dict: dict,
        progress_timeout: float = None,
        total_timeout: float = None
    ):
        """
        Install the software inside the execution environment identified by ee_id

        :param str ee_id: the id of the execution environment returned by create_execution_environment
                        or register_execution_environment
        :param str artifact_path: where to locate the artifacts (parent folder) using the self.fs
            the final artifact path will be a combination of this artifact_path and additional string from
            the config_dict (e.g. charm name)
        :param dict db_dict: where to write into database when the status changes.
                        It contains a dict with {collection: <str>, filter: {},  path: <str>},
                            e.g. {collection: "nsrs", filter: {_id: <nsd-id>, path: "_admin.deployed.VCA.3"}
        :param float progress_timeout:
        :param float total_timeout:
        """

    @abc.abstractmethod
    async def get_ee_ssh_public__key(
        self,
        ee_id: str,
        db_dict: dict,
        progress_timeout: float = None,
        total_timeout: float = None
    ) -> str:
        """
        Generate a priv/pub key pair in the execution environment and return the public key

        :param str ee_id: the id of the execution environment returned by create_execution_environment
                        or register_execution_environment
        :param dict db_dict: where to write into database when the status changes.
                        It contains a dict with {collection: <str>, filter: {},  path: <str>},
                            e.g. {collection: "nsrs", filter: {_id: <nsd-id>, path: "_admin.deployed.VCA.3"}
        :param float progress_timeout:
        :param float total_timeout:
        :returns: public key of the execution environment
                    For the case of juju proxy charm ssh-layered, it is the one returned by 'get-ssh-public-key'
                    primitive.
                    It raises a N2VC exception if fails
        """

    @abc.abstractmethod
    async def add_relation(
        self,
        ee_id_1: str,
        ee_id_2: str,
        endpoint_1: str,
        endpoint_2: str
    ):
        """
        Add a relation between two Execution Environments (using their associated endpoints).

        :param str ee_id_1: The id of the first execution environment
        :param str ee_id_2: The id of the second execution environment
        :param str endpoint_1: The endpoint in the first execution environment
        :param str endpoint_2: The endpoint in the second execution environment
        """

    # TODO
    @abc.abstractmethod
    async def remove_relation(
        self
    ):
        """
        """

    # TODO
    @abc.abstractmethod
    async def deregister_execution_environments(
        self
    ):
        """
        """

    @abc.abstractmethod
    async def delete_namespace(
        self,
        namespace: str,
        db_dict: dict = None,
        total_timeout: float = None
    ):
        """
        Remove a network scenario and its execution environments
        :param namespace: [<nsi-id>].<ns-id>
        :param dict db_dict: where to write into database when the status changes.
                        It contains a dict with {collection: <str>, filter: {},  path: <str>},
                            e.g. {collection: "nsrs", filter: {_id: <nsd-id>, path: "_admin.deployed.VCA.3"}
        :param float total_timeout:
        """

    @abc.abstractmethod
    async def delete_execution_environment(
        self,
        ee_id: str,
        db_dict: dict = None,
        total_timeout: float = None
    ):
        """
        Delete an execution environment
        :param str ee_id: id of the execution environment to delete
        :param dict db_dict: where to write into database when the status changes.
                        It contains a dict with {collection: <str>, filter: {},  path: <str>},
                            e.g. {collection: "nsrs", filter: {_id: <nsd-id>, path: "_admin.deployed.VCA.3"}
        :param float total_timeout:
        """

    @abc.abstractmethod
    async def exec_primitive(
        self,
        ee_id: str,
        primitive_name: str,
        params_dict: dict,
        db_dict: dict = None,
        progress_timeout: float = None,
        total_timeout: float = None
    ) -> str:
        """
        Execute a primitive in the execution environment

        :param str ee_id: the one returned by create_execution_environment or register_execution_environment
        :param str primitive_name: must be one defined in the software. There is one called 'config',
            where, for the proxy case, the 'credentials' of VM are provided
        :param dict params_dict: parameters of the action
        :param dict db_dict: where to write into database when the status changes.
                        It contains a dict with {collection: <str>, filter: {},  path: <str>},
                            e.g. {collection: "nsrs", filter: {_id: <nsd-id>, path: "_admin.deployed.VCA.3"}
        :param float progress_timeout:
        :param float total_timeout:
        :returns str: primitive result, if ok. It raises exceptions in case of fail
        """

    async def disconnect(self):
        """
        Disconnect from VCA
        """

    """
    ##################################################################################################
    ########################################## P R I V A T E #########################################
    ##################################################################################################
    """

    def _get_namespace_components(self, namespace: str) -> (str, str, str, str, str):
        """
        Split namespace components

        :param namespace: [<nsi-id>].<ns-id>.<vnf-id>.<vdu-id>[-<count>]
        :return: nsi_id, ns_id, vnf_id, vdu_id, vdu_count
        """

        # check parameters
        if namespace is None or len(namespace) == 0:
            raise N2VCBadArgumentsException('Argument namespace is mandatory', ['namespace'])

        # split namespace components
        parts = namespace.split('.')
        nsi_id = None
        ns_id = None
        vnf_id = None
        vdu_id = None
        vdu_count = None
        if len(parts) > 0 and len(parts[0]) > 0:
            nsi_id = parts[0]
        if len(parts) > 1 and len(parts[1]) > 0:
            ns_id = parts[1]
        if len(parts) > 2 and len(parts[2]) > 0:
            vnf_id = parts[2]
        if len(parts) > 3 and len(parts[3]) > 0:
            vdu_id = parts[3]
            vdu_parts = parts[3].split('-')
            if len(vdu_parts) > 1:
                vdu_id = vdu_parts[0]
                vdu_count = vdu_parts[1]

        return nsi_id, ns_id, vnf_id, vdu_id, vdu_count

    async def write_app_status_to_db(
            self,
            db_dict: dict,
            status: N2VCDeploymentStatus,
            detailed_status: str,
            vca_status: str,
            entity_type: str
    ):
        if not db_dict:
            self.debug('No db_dict => No database write')
            return

        self.debug('status={} / detailed-status={} / VCA-status={} / entity_type={}'
                   .format(str(status.value), detailed_status, vca_status, entity_type))

        try:

            the_table = db_dict['collection']
            the_filter = db_dict['filter']
            the_path = db_dict['path']
            if not the_path[-1] == '.':
                the_path = the_path + '.'
            update_dict = {
                the_path + 'status': str(status.value),
                the_path + 'detailed-status': detailed_status,
                the_path + 'VCA-status': vca_status,
                the_path + 'entity-type': entity_type,
                the_path + 'status-time': str(time.time()),
            }

            self.db.set_one(
                table=the_table,
                q_filter=the_filter,
                update_dict=update_dict,
                fail_on_empty=True
            )

            # database callback
            if self.on_update_db:
                if asyncio.iscoroutinefunction(self.on_update_db):
                    await self.on_update_db(the_table, the_filter, the_path, update_dict)
                else:
                    self.on_update_db(the_table, the_filter, the_path, update_dict)

        except DbException as e:
            if e.http_code == HTTPStatus.NOT_FOUND:
                self.error('NOT_FOUND error: Exception writing status to database: {}'.format(e))
            else:
                self.info('Exception writing status to database: {}'.format(e))


def juju_status_2_osm_status(type: str, status: str) -> N2VCDeploymentStatus:
    if type == 'application' or type == 'unit':
        if status in ['waiting', 'maintenance']:
            return N2VCDeploymentStatus.RUNNING
        elif status in ['active']:
            return N2VCDeploymentStatus.COMPLETED
        elif status in ['blocked']:
            return N2VCDeploymentStatus.RUNNING
        else:
            return N2VCDeploymentStatus.UNKNOWN
    elif type == 'action':
        if status in ['running']:
            return N2VCDeploymentStatus.RUNNING
        elif status in ['completed']:
            return N2VCDeploymentStatus.COMPLETED
        else:
            return N2VCDeploymentStatus.UNKNOWN
    elif type == 'machine':
        if status in ['pending']:
            return N2VCDeploymentStatus.PENDING
        elif status in ['started']:
            return N2VCDeploymentStatus.COMPLETED
        else:
            return N2VCDeploymentStatus.UNKNOWN

    return N2VCDeploymentStatus.FAILED