# -*- coding: utf-8 -*-

import dbmongo
import dbmemory
import fslocal
import msglocal
import msgkafka
import tarfile
import yaml
import json
import logging
from random import choice as random_choice
from uuid import uuid4
from hashlib import sha256, md5
from dbbase import DbException
from fsbase import FsException
from msgbase import MsgException
from http import HTTPStatus
from time import time
from copy import deepcopy
from validation import validate_input, ValidationError

__author__ = "Alfonso Tierno <alfonso.tiernosepulveda@telefonica.com>"


class EngineException(Exception):

    def __init__(self, message, http_code=HTTPStatus.BAD_REQUEST):
        self.http_code = http_code
        Exception.__init__(self, message)


def _deep_update(dict_to_change, dict_reference):
    """
    Modifies one dictionary with the information of the other following https://tools.ietf.org/html/rfc7396
    :param dict_to_change:  Ends modified
    :param dict_reference: reference
    :return: none
    """

    for k in dict_reference:
        if dict_reference[k] is None:   # None->Anything
            if k in dict_to_change:
                del dict_to_change[k]
        elif not isinstance(dict_reference[k], dict):  #  NotDict->Anything
            dict_to_change[k] = dict_reference[k]
        elif k not in dict_to_change:  # Dict->Empty
            dict_to_change[k] = deepcopy(dict_reference[k])
            _deep_update(dict_to_change[k], dict_reference[k])
        elif isinstance(dict_to_change[k], dict):  # Dict->Dict
            _deep_update(dict_to_change[k], dict_reference[k])
        else:       # Dict->NotDict
            dict_to_change[k] = deepcopy(dict_reference[k])
            _deep_update(dict_to_change[k], dict_reference[k])

class Engine(object):

    def __init__(self):
        self.tokens = {}
        self.db = None
        self.fs = None
        self.msg = None
        self.config = None
        self.logger = logging.getLogger("nbi.engine")

    def start(self, config):
        """
        Connect to database, filesystem storage, and messaging
        :param config: two level dictionary with configuration. Top level should contain 'database', 'storage',
        :return: None
        """
        self.config = config
        try:
            if not self.db:
                if config["database"]["driver"] == "mongo":
                    self.db = dbmongo.DbMongo()
                    self.db.db_connect(config["database"])
                elif config["database"]["driver"] == "memory":
                    self.db = dbmemory.DbMemory()
                    self.db.db_connect(config["database"])
                else:
                    raise EngineException("Invalid configuration param '{}' at '[database]':'driver'".format(
                        config["database"]["driver"]))
            if not self.fs:
                if config["storage"]["driver"] == "local":
                    self.fs = fslocal.FsLocal()
                    self.fs.fs_connect(config["storage"])
                else:
                    raise EngineException("Invalid configuration param '{}' at '[storage]':'driver'".format(
                        config["storage"]["driver"]))
            if not self.msg:
                if config["message"]["driver"] == "local":
                    self.msg = msglocal.MsgLocal()
                    self.msg.connect(config["message"])
                elif config["message"]["driver"] == "kafka":
                    self.msg = msgkafka.MsgKafka()
                    self.msg.connect(config["message"])
                else:
                    raise EngineException("Invalid configuration param '{}' at '[message]':'driver'".format(
                        config["storage"]["driver"]))
        except (DbException, FsException, MsgException) as e:
            raise EngineException(str(e), http_code=e.http_code)

    def stop(self):
        try:
            if self.db:
                self.db.db_disconnect()
            if self.fs:
                self.fs.fs_disconnect()
            if self.fs:
                self.fs.fs_disconnect()
        except (DbException, FsException, MsgException) as e:
            raise EngineException(str(e), http_code=e.http_code)

    def authorize(self, token):
        try:
            if not token:
                raise EngineException("Needed a token or Authorization http header",
                                      http_code=HTTPStatus.UNAUTHORIZED)
            if token not in self.tokens:
                raise EngineException("Invalid token or Authorization http header",
                                      http_code=HTTPStatus.UNAUTHORIZED)
            session = self.tokens[token]
            now = time()
            if session["expires"] < now:
                del self.tokens[token]
                raise EngineException("Expired Token or Authorization http header",
                                      http_code=HTTPStatus.UNAUTHORIZED)
            return session
        except EngineException:
            if self.config["global"].get("test.user_not_authorized"):
                return {"id": "fake-token-id-for-test",
                        "project_id": self.config["global"].get("test.project_not_authorized", "admin"),
                        "username": self.config["global"]["test.user_not_authorized"]}
            else:
                raise

    def new_token(self, session, indata, remote):
        now = time()
        user_content = None

        # Try using username/password
        if indata.get("username"):
            user_rows = self.db.get_list("users", {"username": indata.get("username")})
            user_content = None
            if user_rows:
                user_content = user_rows[0]
                salt = user_content["_admin"]["salt"]
                shadow_password = sha256(indata.get("password", "").encode('utf-8') + salt.encode('utf-8')).hexdigest()
                if shadow_password != user_content["password"]:
                    user_content = None
            if not user_content:
                raise EngineException("Invalid username/password", http_code=HTTPStatus.UNAUTHORIZED)
        elif session:
            user_rows = self.db.get_list("users", {"username": session["username"]})
            if user_rows:
                user_content = user_rows[0]
            else:
                raise EngineException("Invalid token", http_code=HTTPStatus.UNAUTHORIZED)
        else:
            raise EngineException("Provide credentials: username/password or Authorization Bearer token",
                                  http_code=HTTPStatus.UNAUTHORIZED)

        token_id = ''.join(random_choice('abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789')
                           for _ in range(0, 32))
        if indata.get("project_id"):
            project_id = indata.get("project_id")
            if project_id not in user_content["projects"]:
                raise EngineException("project {} not allowed for this user".format(project_id),
                                      http_code=HTTPStatus.UNAUTHORIZED)
        else:
            project_id = user_content["projects"][0]
        if project_id == "admin":
            session_admin = True
        else:
            project = self.db.get_one("projects", {"_id": project_id})
            session_admin = project.get("admin", False)
        new_session = {"issued_at": now, "expires": now+3600,
                       "_id": token_id, "id": token_id, "project_id": project_id, "username": user_content["username"],
                       "remote_port": remote.port, "admin": session_admin}
        if remote.name:
            new_session["remote_host"] = remote.name
        elif remote.ip:
            new_session["remote_host"] = remote.ip

        self.tokens[token_id] = new_session
        return deepcopy(new_session)

    def get_token_list(self, session):
        token_list = []
        for token_id, token_value in self.tokens.items():
            if token_value["username"] == session["username"]:
                token_list.append(deepcopy(token_value))
        return token_list

    def get_token(self, session, token_id):
        token_value = self.tokens.get(token_id)
        if not token_value:
            raise EngineException("token not found", http_code=HTTPStatus.NOT_FOUND)
        if token_value["username"] != session["username"] and not session["admin"]:
            raise EngineException("needed admin privileges", http_code=HTTPStatus.UNAUTHORIZED)
        return token_value

    def del_token(self, token_id):
        try:
            del self.tokens[token_id]
            return "token '{}' deleted".format(token_id)
        except KeyError:
            raise EngineException("Token '{}' not found".format(token_id), http_code=HTTPStatus.NOT_FOUND)

    @staticmethod
    def _remove_envelop(item, indata=None):
        """
        Obtain the useful data removing the envelop. It goes throw the vnfd or nsd catalog and returns the
        vnfd or nsd content
        :param item: can be vnfds, nsds, users, projects, userDefinedData (initial content of a vnfds, nsds
        :param indata: Content to be inspected
        :return: the useful part of indata
        """
        clean_indata = indata
        if not indata:
            return {}
        if item == "vnfds":
            if clean_indata.get('vnfd:vnfd-catalog'):
                clean_indata = clean_indata['vnfd:vnfd-catalog']
            elif clean_indata.get('vnfd-catalog'):
                clean_indata = clean_indata['vnfd-catalog']
            if clean_indata.get('vnfd'):
                if not isinstance(clean_indata['vnfd'], list) or len(clean_indata['vnfd']) != 1:
                    raise EngineException("'vnfd' must be a list only one element")
                clean_indata = clean_indata['vnfd'][0]
        elif item == "nsds":
            if clean_indata.get('nsd:nsd-catalog'):
                clean_indata = clean_indata['nsd:nsd-catalog']
            elif clean_indata.get('nsd-catalog'):
                clean_indata = clean_indata['nsd-catalog']
            if clean_indata.get('nsd'):
                if not isinstance(clean_indata['nsd'], list) or len(clean_indata['nsd']) != 1:
                    raise EngineException("'nsd' must be a list only one element")
                clean_indata = clean_indata['nsd'][0]
        elif item == "userDefinedData":
            if "userDefinedData" in indata:
                clean_indata = clean_indata['userDefinedData']
        return clean_indata

    def _validate_new_data(self, session, item, indata, id=None):
        if item == "users":
            if not indata.get("username"):
                raise EngineException("missing 'username'", HTTPStatus.UNPROCESSABLE_ENTITY)
            if not indata.get("password"):
                raise EngineException("missing 'password'", HTTPStatus.UNPROCESSABLE_ENTITY)
            if not indata.get("projects"):
                raise EngineException("missing 'projects'", HTTPStatus.UNPROCESSABLE_ENTITY)
            # check username not exist
            if self.db.get_one(item, {"username": indata.get("username")}, fail_on_empty=False, fail_on_more=False):
                raise EngineException("username '{}' exist".format(indata["username"]), HTTPStatus.CONFLICT)
        elif item == "projects":
            if not indata.get("name"):
                raise EngineException("missing 'name'")
            # check name not exist
            if self.db.get_one(item, {"name": indata.get("name")}, fail_on_empty=False, fail_on_more=False):
                raise EngineException("name '{}' exist".format(indata["name"]), HTTPStatus.CONFLICT)
        elif item in ("vnfds", "nsds"):
            filter = {"id": indata["id"]}
            if id:
                filter["_id.neq"] = id
            # TODO add admin to filter, validate rights
            self._add_read_filter(session, item, filter)
            if self.db.get_one(item, filter, fail_on_empty=False):
                raise EngineException("{} with id '{}' already exist for this tenant".format(item[:-1], indata["id"]),
                                      HTTPStatus.CONFLICT)

            # TODO validate with pyangbind
        elif item == "userDefinedData":
            # TODO validate userDefinedData is a keypair values
            pass

        elif item == "nsrs":
            pass
        elif item == "vims" or item == "sdns":
            if self.db.get_one(item, {"name": indata.get("name")}, fail_on_empty=False, fail_on_more=False):
                raise EngineException("name '{}' already exist for {}".format(indata["name"], item),
                                      HTTPStatus.CONFLICT)


    def _format_new_data(self, session, item, indata, admin=None):
        now = time()
        if not "_admin" in indata:
            indata["_admin"] = {}
        indata["_admin"]["created"] = now
        indata["_admin"]["modified"] = now
        if item == "users":
            _id = indata["username"]
            salt = uuid4().hex
            indata["_admin"]["salt"] = salt
            indata["password"] = sha256(indata["password"].encode('utf-8') + salt.encode('utf-8')).hexdigest()
        elif item == "projects":
            _id = indata["name"]
        else:
            _id = None
            storage = None
            if admin:
                _id = admin.get("_id")
                storage = admin.get("storage")
            if not _id:
                _id = str(uuid4())
            if item in ("vnfds", "nsds"):
                if not indata["_admin"].get("projects_read"):
                    indata["_admin"]["projects_read"] = [session["project_id"]]
                if not indata["_admin"].get("projects_write"):
                    indata["_admin"]["projects_write"] = [session["project_id"]]
                indata["_admin"]["onboardingState"] = "CREATED"
                indata["_admin"]["operationalState"] = "DISABLED"
                indata["_admin"]["usageSate"] = "NOT_IN_USE"
            elif item in ("vims", "sdns"):
                indata["_admin"]["operationalState"] = "PROCESSING"

            if storage:
                indata["_admin"]["storage"] = storage
        indata["_id"] = _id

    def upload_content(self, session, item, _id, indata, kwargs, headers):
        """
        Used for receiving content by chunks (with a transaction_id header and/or gzip file. It will store and extract)
        :param session: session
        :param item: can be nsds or vnfds
        :param _id : the nsd,vnfd is already created, this is the id
        :param indata: http body request
        :param kwargs: user query string to override parameters. NOT USED
        :param headers:  http request headers
        :return: True package has is completely uploaded or False if partial content has been uplodaed.
            Raise exception on error
        """
        # Check that _id exist and it is valid
        current_desc = self.get_item(session, item, _id)

        content_range_text = headers.get("Content-Range")
        expected_md5 = headers.get("Content-File-MD5")
        compressed = None
        content_type = headers.get("Content-Type")
        if content_type and "application/gzip" in content_type or "application/x-gzip" in content_type or \
                "application/zip" in content_type:
            compressed = "gzip"
        filename = headers.get("Content-Filename")
        if not filename:
            filename = "package.tar.gz" if compressed else "package"
        # TODO change to Content-Disposition filename https://tools.ietf.org/html/rfc6266
        file_pkg = None
        error_text = ""
        try:
            if content_range_text:
                content_range = content_range_text.replace("-", " ").replace("/", " ").split()
                if content_range[0] != "bytes":  # TODO check x<y not negative < total....
                    raise IndexError()
                start = int(content_range[1])
                end = int(content_range[2]) + 1
                total = int(content_range[3])
            else:
                start = 0

            if start:
                if not self.fs.file_exists(_id, 'dir'):
                    raise EngineException("invalid Transaction-Id header", HTTPStatus.NOT_FOUND)
            else:
                self.fs.file_delete(_id, ignore_non_exist=True)
                self.fs.mkdir(_id)

            storage = self.fs.get_params()
            storage["folder"] = _id

            file_path = (_id, filename)
            if self.fs.file_exists(file_path, 'file'):
                file_size = self.fs.file_size(file_path)
            else:
                file_size = 0
            if file_size != start:
                raise EngineException("invalid Content-Range start sequence, expected '{}' but received '{}'".format(
                    file_size, start), HTTPStatus.REQUESTED_RANGE_NOT_SATISFIABLE)
            file_pkg = self.fs.file_open(file_path, 'a+b')
            if isinstance(indata, dict):
                indata_text = yaml.safe_dump(indata, indent=4, default_flow_style=False)
                file_pkg.write(indata_text.encode(encoding="utf-8"))
            else:
                indata_len = 0
                while True:
                    indata_text = indata.read(4096)
                    indata_len += len(indata_text)
                    if not indata_text:
                        break
                    file_pkg.write(indata_text)
            if content_range_text:
                if indata_len != end-start:
                    raise EngineException("Mismatch between Content-Range header {}-{} and body length of {}".format(
                        start, end-1, indata_len), HTTPStatus.REQUESTED_RANGE_NOT_SATISFIABLE)
                if end != total:
                    # TODO update to UPLOADING
                    return False

            # PACKAGE UPLOADED
            if expected_md5:
                file_pkg.seek(0, 0)
                file_md5 = md5()
                chunk_data = file_pkg.read(1024)
                while chunk_data:
                    file_md5.update(chunk_data)
                    chunk_data = file_pkg.read(1024)
                if expected_md5 != file_md5.hexdigest():
                    raise EngineException("Error, MD5 mismatch", HTTPStatus.CONFLICT)
            file_pkg.seek(0, 0)
            if compressed == "gzip":
                tar = tarfile.open(mode='r', fileobj=file_pkg)
                descriptor_file_name = None
                for tarinfo in tar:
                    tarname = tarinfo.name
                    tarname_path = tarname.split("/")
                    if not tarname_path[0] or ".." in tarname_path:  # if start with "/" means absolute path
                        raise EngineException("Absolute path or '..' are not allowed for package descriptor tar.gz")
                    if len(tarname_path) == 1 and not tarinfo.isdir():
                        raise EngineException("All files must be inside a dir for package descriptor tar.gz")
                    if tarname.endswith(".yaml") or tarname.endswith(".json") or tarname.endswith(".yml"):
                        storage["pkg-dir"] = tarname_path[0]
                        if len(tarname_path) == 2:
                            if descriptor_file_name:
                                raise EngineException("Found more than one descriptor file at package descriptor tar.gz")
                            descriptor_file_name = tarname
                if not descriptor_file_name:
                    raise EngineException("Not found any descriptor file at package descriptor tar.gz")
                storage["descriptor"] = descriptor_file_name
                storage["zipfile"] = filename
                self.fs.file_extract(tar, _id)
                with self.fs.file_open((_id, descriptor_file_name), "r") as descriptor_file:
                    content = descriptor_file.read()
            else:
                content = file_pkg.read()
                storage["descriptor"] = descriptor_file_name = filename

            if descriptor_file_name.endswith(".json"):
                error_text = "Invalid json format "
                indata = json.load(content)
            else:
                error_text = "Invalid yaml format "
                indata = yaml.load(content)

            current_desc["_admin"]["storage"] = storage
            current_desc["_admin"]["onboardingState"] = "ONBOARDED"
            current_desc["_admin"]["operationalState"] = "ENABLED"

            self._edit_item(session, item, _id, current_desc, indata, kwargs)
            # TODO if descriptor has changed because kwargs update content and remove cached zip
            # TODO if zip is not present creates one
            return True

        except EngineException:
            raise
        except IndexError:
            raise EngineException("invalid Content-Range header format. Expected 'bytes start-end/total'",
                                  HTTPStatus.REQUESTED_RANGE_NOT_SATISFIABLE)
        except IOError as e:
            raise EngineException("invalid upload transaction sequence: '{}'".format(e), HTTPStatus.BAD_REQUEST)
        except (ValueError, yaml.YAMLError) as e:
            raise EngineException(error_text + str(e))
        finally:
            if file_pkg:
                file_pkg.close()

    def new_nsr(self, session, ns_request):
        """
        Creates a new nsr into database
        :param session: contains the used login username and working project
        :param ns_request: params to be used for the nsr
        :return: nsr descriptor to be stored at database and the _id
        """

        # look for nsr
        nsd = self.get_item(session, "nsds", ns_request["nsdId"])
        _id = str(uuid4())
        nsr_descriptor = {
            "name": ns_request["nsName"],
            "name-ref": ns_request["nsName"],
            "short-name": ns_request["nsName"],
            "admin-status": "ENABLED",
            "nsd": nsd,
            "datacenter": ns_request["vimAccountId"],
            "resource-orchestrator": "osmopenmano",
            "description": ns_request.get("nsDescription", ""),
            "constituent-vnfr-ref": ["TODO datacenter-id, vnfr-id"],

            "operational-status": "init",    #  typedef ns-operational-
            "config-status": "init",         #  typedef config-states
            "detailed-status": "scheduled",

            "orchestration-progress": {},  # {"networks": {"active": 0, "total": 0}, "vms": {"active": 0, "total": 0}},

            "crete-time": time(),
            "nsd-name-ref": nsd["name"],
            "operational-events": [],   # "id", "timestamp", "description", "event",
            "nsd-ref": nsd["id"],
            "ns-instance-config-ref": _id,
            "id": _id,

            # "input-parameter": xpath, value,
            "ssh-authorized-key": ns_request.get("key-pair-ref"),
        }
        ns_request["nsr_id"] = _id
        return nsr_descriptor, _id

    def new_item(self, session, item, indata={}, kwargs=None, headers={}):
        """
        Creates a new entry into database. For nsds and vnfds it creates an almost empty DISABLED  entry,
        that must be completed with a call to method upload_content
        :param session: contains the used login username and working project
        :param item: it can be: users, projects, vims, sdns, nsrs, nsds, vnfds
        :param indata: data to be inserted
        :param kwargs: used to override the indata descriptor
        :param headers: http request headers
        :return: _id, transaction_id: identity of the inserted data. or transaction_id if Content-Range is used
        """

        transaction = None

        item_envelop = item
        if item in ("nsds", "vnfds"):
            item_envelop = "userDefinedData"
        content = self._remove_envelop(item_envelop, indata)

        # Override descriptor with query string kwargs
        if kwargs:
            try:
                for k, v in kwargs.items():
                    update_content = content
                    kitem_old = None
                    klist = k.split(".")
                    for kitem in klist:
                        if kitem_old is not None:
                            update_content = update_content[kitem_old]
                        if isinstance(update_content, dict):
                            kitem_old = kitem
                        elif isinstance(update_content, list):
                            kitem_old = int(kitem)
                        else:
                            raise EngineException(
                                "Invalid query string '{}'. Descriptor is not a list nor dict at '{}'".format(k, kitem))
                    update_content[kitem_old] = v
            except KeyError:
                raise EngineException(
                    "Invalid query string '{}'. Descriptor does not contain '{}'".format(k, kitem_old))
            except ValueError:
                raise EngineException("Invalid query string '{}'. Expected integer index list instead of '{}'".format(
                    k, kitem))
            except IndexError:
                raise EngineException(
                    "Invalid query string '{}'. Index '{}' out of  range".format(k, kitem_old))
        try:
            validate_input(content, item, new=True)
        except ValidationError as e:
            raise EngineException(e, HTTPStatus.UNPROCESSABLE_ENTITY)

        if not indata and item not in ("nsds", "vnfds"):
            raise EngineException("Empty payload")

        if item == "nsrs":
            # in this case the imput descriptor is not the data to be stored
            ns_request = content
            content, _id = self.new_nsr(session, ns_request)
            transaction = {"_id": _id}

        self._validate_new_data(session, item_envelop, content)
        if item in ("nsds", "vnfds"):
            content = {"_admin": {"userDefinedData": content}}
        self._format_new_data(session, item, content, transaction)
        _id = self.db.create(item, content)
        if item == "nsrs":
            self.msg.write("ns", "create", _id)
        elif item == "vims":
            msg_data = self.db.get_one(item, {"_id": _id})
            msg_data.pop("_admin", None)
            self.msg.write("vim_account", "create", msg_data)
        elif item == "sdns":
            msg_data = self.db.get_one(item, {"_id": _id})
            msg_data.pop("_admin", None)
            self.msg.write("sdn", "create", msg_data)
        return _id

    def _add_read_filter(self, session, item, filter):
        if session["project_id"] == "admin":  # allows all
            return filter
        if item == "users":
            filter["username"] = session["username"]
        elif item == "vnfds" or item == "nsds":
            filter["_admin.projects_read.cont"] = ["ANY", session["project_id"]]

    def _add_delete_filter(self, session, item, filter):
        if session["project_id"] != "admin" and item in ("users", "projects"):
            raise EngineException("Only admin users can perform this task", http_code=HTTPStatus.FORBIDDEN)
        if item == "users":
            if filter.get("_id") == session["username"] or filter.get("username") == session["username"]:
                raise EngineException("You cannot delete your own user", http_code=HTTPStatus.CONFLICT)
        elif item == "project":
            if filter.get("_id") == session["project_id"]:
                raise EngineException("You cannot delete your own project", http_code=HTTPStatus.CONFLICT)
        elif item in ("vnfds", "nsds") and session["project_id"] != "admin":
            filter["_admin.projects_write.cont"] = ["ANY", session["project_id"]]

    def get_file(self, session, item, _id, path=None, accept_header=None):
        """
        Return the file content of a vnfd or nsd
        :param session: contains the used login username and working project
        :param item: it can be vnfds or nsds
        :param _id: Identity of the vnfd, ndsd
        :param path: artifact path or "$DESCRIPTOR" or None
        :param accept_header: Content of Accept header. Must contain applition/zip or/and text/plain
        :return: opened file or raises an exception
        """
        accept_text = accept_zip = False
        if accept_header:
            if 'text/plain' in accept_header or '*/*' in accept_header:
                accept_text = True
            if 'application/zip' in accept_header or '*/*' in accept_header:
                accept_zip = True
        if not accept_text and not accept_zip:
            raise EngineException("provide request header 'Accept' with 'application/zip' or 'text/plain'",
                                  http_code=HTTPStatus.NOT_ACCEPTABLE)

        content = self.get_item(session, item, _id)
        if content["_admin"]["onboardingState"] != "ONBOARDED":
            raise EngineException("Cannot get content because this resource is not at 'ONBOARDED' state. "
                "onboardingState is {}".format(content["_admin"]["onboardingState"]),
                                  http_code=HTTPStatus.CONFLICT)
        storage = content["_admin"]["storage"]
        if path is not None and path != "$DESCRIPTOR":   # artifacts
            if not storage.get('pkg-dir'):
                raise EngineException("Packages does not contains artifacts", http_code=HTTPStatus.BAD_REQUEST)
            if self.fs.file_exists((storage['folder'], storage['pkg-dir'], *path), 'dir'):
                folder_content = self.fs.dir_ls((storage['folder'], storage['pkg-dir'], *path))
                return folder_content, "text/plain"
                # TODO manage folders in http
            else:
                return self.fs.file_open((storage['folder'], storage['pkg-dir'], *path), "rb"), \
                       "application/octet-stream"

        # pkgtype   accept  ZIP  TEXT    -> result
        # manyfiles         yes  X       -> zip
        #                   no   yes     -> error
        # onefile           yes  no      -> zip
        #                   X    yes     -> text

        if accept_text and (not storage.get('pkg-dir') or path == "$DESCRIPTOR"):
            return self.fs.file_open((storage['folder'], storage['descriptor']), "r"), "text/plain"
        elif storage.get('pkg-dir') and not accept_zip:
            raise EngineException("Packages that contains several files need to be retrieved with 'application/zip'"
                                      "Accept header", http_code=HTTPStatus.NOT_ACCEPTABLE)
        else:
            if not storage.get('zipfile'):
                # TODO generate zipfile if not present
                raise EngineException("Only allowed 'text/plain' Accept header for this descriptor. To be solved in future versions"
                                      "", http_code=HTTPStatus.NOT_ACCEPTABLE)
            return self.fs.file_open((storage['folder'], storage['zipfile']), "rb"), "application/zip"

    def get_item_list(self, session, item, filter={}):
        """
        Get a list of items
        :param session: contains the used login username and working project
        :param item: it can be: users, projects, vnfds, nsds, ...
        :param filter: filter of data to be applied
        :return: The list, it can be empty if no one match the filter.
        """
        # TODO add admin to filter, validate rights
        # TODO transform data for SOL005 URL requests. Transform filtering
        # TODO implement "field-type" query string SOL005

        self._add_read_filter(session, item, filter)
        return self.db.get_list(item, filter)

    def get_item(self, session, item, _id):
        """
        Get complete information on an items
        :param session: contains the used login username and working project
        :param item: it can be: users, projects, vnfds, nsds,
        :param _id: server id of the item
        :return: dictionary, raise exception if not found.
        """
        database_item = item
        filter = {"_id": _id}
        # TODO add admin to filter, validate rights
        # TODO transform data for SOL005 URL requests
        self._add_read_filter(session, item, filter)
        return self.db.get_one(item, filter)

    def del_item_list(self, session, item, filter={}):
        """
        Delete a list of items
        :param session: contains the used login username and working project
        :param item: it can be: users, projects, vnfds, nsds, ...
        :param filter: filter of data to be applied
        :return: The deleted list, it can be empty if no one match the filter.
        """
        # TODO add admin to filter, validate rights
        self._add_read_filter(session, item, filter)
        return self.db.del_list(item, filter)

    def del_item(self, session, item, _id):
        """
        Get complete information on an items
        :param session: contains the used login username and working project
        :param item: it can be: users, projects, vnfds, nsds, ...
        :param _id: server id of the item
        :return: dictionary, raise exception if not found.
        """
        # TODO add admin to filter, validate rights
        # data = self.get_item(item, _id)
        filter = {"_id": _id}
        self._add_delete_filter(session, item, filter)

        if item in ("nsrs", "vims", "sdns"):
            desc = self.db.get_one(item, filter)
            desc["_admin"]["to_delete"] = True
            self.db.replace(item, _id, desc)   # TODO change to set_one
            if item == "nsrs":
                self.msg.write("ns", "delete", _id)
            elif item == "vims":
                self.msg.write("vim_account", "delete", {"_id": _id})
            elif item == "sdns":
                self.msg.write("sdn", "delete", {"_id": _id})
            return {"deleted": 1}  # TODO indicate an offline operation to return 202 ACCEPTED

        v = self.db.del_one(item, filter)
        self.fs.file_delete(_id, ignore_non_exist=True)
        return v

    def prune(self):
        """
        Prune database not needed content
        :return: None
        """
        return self.db.del_list("nsrs", {"_admin.to_delete": True})

    def create_admin(self):
        """
        Creates a new user admin/admin into database if database is empty. Useful for initialization
        :return: _id identity of the inserted data, or None
        """
        users = self.db.get_one("users", fail_on_empty=False, fail_on_more=False)
        if users:
            return None
            # raise EngineException("Unauthorized. Database users is not empty", HTTPStatus.UNAUTHORIZED)
        indata = {"username": "admin", "password": "admin", "projects": ["admin"]}
        fake_session = {"project_id": "admin", "username": "admin"}
        self._format_new_data(fake_session, "users", indata)
        _id = self.db.create("users", indata)
        return _id

    def init_db(self, target_version='1.0'):
        """
        Init database if empty. If not empty it checks that database version is ok.
        If empty, it creates a new user admin/admin at 'users' and a new entry at 'version'
        :return: None if ok, exception if error or if the version is different.
        """
        version = self.db.get_one("version", fail_on_empty=False, fail_on_more=False)
        if not version:
            # create user admin
            self.create_admin()
            # create database version
            version_data = {
                "_id": '1.0',                     # version text
                "version": 1000,                  # version number
                "date": "2018-04-12",             # version date
                "description": "initial design",  # changes in this version
                'status': 'ENABLED'               # ENABLED, DISABLED (migration in process), ERROR,
            }
            self.db.create("version", version_data)
        elif version["_id"] != target_version:
            # TODO implement migration process
            raise EngineException("Wrong database version '{}'. Expected '{}'".format(
                version["_id"], target_version), HTTPStatus.INTERNAL_SERVER_ERROR)
        elif version["status"] != 'ENABLED':
            raise EngineException("Wrong database status '{}'".format(
                version["status"]), HTTPStatus.INTERNAL_SERVER_ERROR)
        return

    def _edit_item(self, session, item, id, content, indata={}, kwargs=None):
        if indata:
            indata = self._remove_envelop(item, indata)

        # Override descriptor with query string kwargs
        if kwargs:
            try:
                for k, v in kwargs.items():
                    update_content = indata
                    kitem_old = None
                    klist = k.split(".")
                    for kitem in klist:
                        if kitem_old is not None:
                            update_content = update_content[kitem_old]
                        if isinstance(update_content, dict):
                            kitem_old = kitem
                        elif isinstance(update_content, list):
                            kitem_old = int(kitem)
                        else:
                            raise EngineException(
                                "Invalid query string '{}'. Descriptor is not a list nor dict at '{}'".format(k, kitem))
                    update_content[kitem_old] = v
            except KeyError:
                raise EngineException(
                    "Invalid query string '{}'. Descriptor does not contain '{}'".format(k, kitem_old))
            except ValueError:
                raise EngineException("Invalid query string '{}'. Expected integer index list instead of '{}'".format(
                    k, kitem))
            except IndexError:
                raise EngineException(
                    "Invalid query string '{}'. Index '{}' out of  range".format(k, kitem_old))
        try:
            validate_input(content, item, new=False)
        except ValidationError as e:
            raise EngineException(e, HTTPStatus.UNPROCESSABLE_ENTITY)

        _deep_update(content, indata)
        self._validate_new_data(session, item, content, id)
        # self._format_new_data(session, item, content)
        self.db.replace(item, id, content)
        if item in ("vims", "sdns"):
            indata.pop("_admin", None)
            indata["_id"] = id
            if item == "vims":
                self.msg.write("vim_account", "edit", indata)
            elif item == "sdns":
                self.msg.write("sdn", "edit", indata)
        return id

    def edit_item(self, session, item, _id, indata={}, kwargs=None):
        """
        Update an existing entry at database
        :param session: contains the used login username and working project
        :param item: it can be: users, projects, vnfds, nsds, ...
        :param _id: identifier to be updated
        :param indata: data to be inserted
        :param kwargs: used to override the indata descriptor
        :return: dictionary, raise exception if not found.
        """

        content = self.get_item(session, item, _id)
        return self._edit_item(session, item, _id, content, indata, kwargs)