##
# 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
from http import HTTPStatus
import os
import shlex
import subprocess
import time

from n2vc.exceptions import N2VCBadArgumentsException
from osm_common.dbmongo import DbException
import yaml

from n2vc.loggable import Loggable
from n2vc.utils import JujuStatusToOSM, N2VCDeploymentStatus


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,
        **kwargs,
    ):
        """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.log.info(
            "url={}, username={}, vca_config={}".format(
                url,
                username,
                {
                    k: v
                    for k, v in vca_config.items()
                    if k
                    not in ("host", "port", "user", "secret", "public_key", "ca_cert")
                },
            )
        )

        # 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

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

        :param namespace: we obtain ns from namespace
        :param yaml_format: returns a yaml string
        """

    # 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.
        """

        # Find the path where we expect our key lives (~/.ssh)
        homedir = os.environ.get("HOME")
        if not homedir:
            self.log.warning("No HOME environment variable, using /tmp")
            homedir = "/tmp"
        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 install_k8s_proxy_charm(
        self,
        charm_name: str,
        namespace: str,
        artifact_path: str,
        db_dict: dict,
        progress_timeout: float = None,
        total_timeout: float = None,
        config: dict = None,
    ) -> str:
        """
        Install a k8s proxy charm

        :param charm_name: Name of the charm being deployed
        :param namespace: collection of all the uuids related to the charm.
        :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:
        :param config: Dictionary with additional configuration

        :returns ee_id: execution environment id.
        """

    @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.log.debug("No db_dict => No database write")
            return

        # self.log.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.log.error(
                    "NOT_FOUND error: Exception writing status to database: {}".format(
                        e
                    )
                )
            else:
                self.log.info("Exception writing status to database: {}".format(e))

    def osm_status(self, entity_type: str, status: str) -> N2VCDeploymentStatus:
        if status not in JujuStatusToOSM[entity_type]:
            self.log.warning("Status {} not found in JujuStatusToOSM.".format(status))
            return N2VCDeploymentStatus.UNKNOWN
        return JujuStatusToOSM[entity_type][status]


def obj_to_yaml(obj: object) -> str:
    # dump to yaml
    dump_text = yaml.dump(obj, default_flow_style=False, indent=2)
    # split lines
    lines = dump_text.splitlines()
    # remove !!python/object tags
    yaml_text = ""
    for line in lines:
        index = line.find("!!python/object")
        if index >= 0:
            line = line[:index]
        yaml_text += line + "\n"
    return yaml_text


def obj_to_dict(obj: object) -> dict:
    # convert obj to yaml
    yaml_text = obj_to_yaml(obj)
    # parse to dict
    return yaml.load(yaml_text, Loader=yaml.Loader)