#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2019 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENSE.TXT

import contextlib
import os
import errno
import syslog
import time
import pwd
from typing import Optional  # NOQA

from clcommon.clfunc import uid_max
from clcommon.clproc import ProcLve
from clcommon import cpapi, ClPwd
from clcommon.cpapi.cpapiexceptions import NotSupported
try:
    import pylve
except ImportError:
    pylve = None

from clveconfig import ve_config


UID_MAX = uid_max()
# kernel devs say that lve_id type is uint32_t
# so max id should be 0xFFFF_FFFF, it in fact we have this:
MAX_LVE_ID = 0x7FFFFFFF - 1
LVP_XML_TAG_NAME = "reseller"
LVE_NO_UBC = 1 << 1
LVE_NO_MAXENTER = 1 << 2




class NameMapError(Exception):
    pass


class NameMapConfigError(NameMapError):
    pass


class NameMapNotInitialized(NameMapError):
    pass


class NameMap:
    """
    Container for backend storing resellers_name<=>resellers_id map
    As backend store use ve.cfg

    Usage:
    >>> name_map = NameMap()
    >>> name_map.link_xml_node()

    >>> name_map.id_list()
    [1001]
    """
    def __init__(self, xml_tag_name=LVP_XML_TAG_NAME):
        self._xml_tag_name = xml_tag_name
        self._xml_node = None
        # Reseller name to id map (list of corteges)
        self._reseller_id_name_map = None

    def get_id(self, name):
        for name_, id_ in self.load_from_node():
            if name_ == name:
                return id_

    def get_name(self, id_):
        for name_, _id in self.load_from_node():
            if id_ == _id:
                return name_

    def id_list(self):
        return [id_ for _, id_ in self.load_from_node()]

    def link_xml_node(self, xml_node=None, use_cache=True):
        """
        Initialize NameMap. If xml_node is none,
        config will be loaded automatically
        :param use_cache: Bool whether bypass ve.cfg xml cache
        :param xml_node: !! DEPRECATED PARAM !!
                         this param is left only for
                         compatibility with our old code
        """
        if xml_node is None:
            # New mode, Load reseller_id, reseller_name pairs from ve.cfg to dictionary
            self._xml_node = None
            self._load_resellers_map_from_ve_cfg(use_cache)
        else:
            # For compatibility with our old code
            self._xml_node = xml_node
            self._reseller_id_name_map = None

    def _load_resellers_map_from_ve_cfg(self, use_cache):
        """
        Fills self._reseller_id_name_map from ve.cfg file
        :return:
        """
        self._reseller_id_name_map = []
        ve_cfg, xml_node = self._try_get_xml_node(use_cache=use_cache)
        for el_ in xml_node:
            name = el_.getAttribute('user')
            id_ = int(el_.getAttribute('id'))
            if name and id_ and id_ not in self._reseller_id_name_map:
                self._reseller_id_name_map.append((id_, name))
        # Force delete XML object to avoid high memory load
        del xml_node
        del ve_cfg

    def _try_get_xml_node(self, use_cache=True):
        try:
            ve_cfg, xml_node = ve_config.get_xml_config(use_cache=use_cache)
        except ve_config.BadVeConfigException as e:
            self._reseller_id_name_map = None
            raise NameMapConfigError("Error happened while loading data from ve.cfg") from e
        return ve_cfg, xml_node.getElementsByTagName(self._xml_tag_name)

    def load_from_node(self):
        """
        Obtain data from xml node as (name, id_) list
        """
        if self._xml_node is None and self._reseller_id_name_map is None:
            raise NameMapNotInitialized('Name map is not initialized. '
                                        'Use obj.link_xml_node() to get data from config')
        if self._xml_node:
            # For compatibility with our old code
            for el_ in self._xml_node.getElementsByTagName(self._xml_tag_name):
                name = el_.getAttribute('user')
                id_ = int(el_.getAttribute('id'))
                if name and id_:
                    yield name, id_

        if self._reseller_id_name_map:
            # New mode, use resellers map
            for id_, name in self._reseller_id_name_map:
                yield name, id_


class LvpMap:
    """
    Container for storing information about lve:lvp mapping
    In which reseller container stored lve
    """
    def __init__(self):
        self.name_map = NameMap()
        self._id_name_map = {}
        self._name_id_map = {}
        self._reseller_id_map_panel = None
        self._pwd = ClPwd()

    def _add_map(self, name, id_):
        self._id_name_map[id_] = name
        self._name_id_map[name] = id_

    def pw_uid(self, name, default=None):
        try:
            return self._pwd.get_pw_by_name(name).pw_uid
        except ClPwd.NoSuchUserException:
            return default

    def _get_panel_reseller_id(self, reseller):
        # type: (str) -> Optional[int]
        uid = self.pw_uid(reseller)
        if uid is not None:
            return uid
        # in case when we cannot find reseller in passwd file
        # let's ask control panel for reseller's id
        if self._reseller_id_map_panel is None:
            self._reseller_id_map_panel = cpapi.get_reseller_id_pairs()
        return self._reseller_id_map_panel.get(reseller)

    def get_reseller_id(self, name):
        # type: (str) -> Optional[int]
        """
        Convert reseller name to an LVE id.
        It supports resellers without a system account (for Plesk compatibility).
        """
        uid = self.name_map.get_id(name) or self._name_id_map.get(name)
        if uid is not None:
            return uid
        try:
            uid = self._get_panel_reseller_id(name)
        except NotSupported:
            uid = None
        if uid is not None:
            self._add_map(name, uid)
        return uid

    def get_reseller_name(self, id_):
        """
        Convert reseller id to reseller name
        It support resellers without system account (for Plesk compatibilyty)
        """
        # add attribute fo in memory cache support
        name = self.name_map.get_name(id_) or self._id_name_map.get(id_)
        if name is not None:
            return name
        try:
            name = pwd.getpwuid(id_).pw_name
            if cpapi.is_reseller(name):
                self._add_map(name, id_)
            else:
                name = None
        except KeyError:
            name = None
        return name

    def lve_lvp_pairs(self):
        """
        This method loops over all user:reseller pairs in control panel
        and returns appropriate lve_id:lvp_id pairs.
        THIS METHOD WON'T CHECK IF 'RESELLER LIMITS' IS ENABLED IN ve.cfg
        """
        resellers = set(cpapi.resellers())
        reseller_uids = {}
        for reseller in resellers:
            try:
                reseller_uids[reseller] = self.get_reseller_id(reseller)
            except NotSupported:
                syslog.syslog(
                    syslog.LOG_WARNING, f"Reseller {reseller} still exists in control panel, "
                                        "but absent in /etc/passwd file")
        for cplogin, reseller in cpapi.cpinfo(keyls=('cplogin', 'reseller')):
            lve_id = self.pw_uid(cplogin)
            # for some reasons (process of destroying user died
            # or admin called 'pure' userdel), user may still exist in control panel
            # but absent in /etc/passwd file; we can do nothing with that,
            # so just skip and write a warning to syslog
            if lve_id is None:
                syslog.syslog(
                    syslog.LOG_WARNING, f"user {cplogin} still exists in control panel, "
                                        "but absent in /etc/passwd file")
                continue
            lvp_id = reseller_uids.get(reseller, 0)
            yield lve_id, lvp_id

    @staticmethod
    def resellers():
        for reseller_name in cpapi.resellers():
            yield reseller_name

    @staticmethod
    def reseller_uids(name):
        """
        Obtain from control panel resellers uids
        """
        uids = []
        reseller_users = cpapi.reseller_users(name)
        for user in reseller_users:
            try:
                id_ = pwd.getpwnam(user).pw_uid
                uids.append(id_)
            except KeyError:
                syslog.syslog(
                    syslog.LOG_WARNING, f"user {user} still exists in control panel, "
                                        "but absent in /etc/passwd file")
        return uids

    def lvp_lve_id_list(self, lvp_id):
        reseller_name = self.get_reseller_name(lvp_id)
        return self.reseller_uids(reseller_name)


class PyLveError(Exception):
    pass


class PyLve:
    """
    Wrapper for generate traceback with pretty descriptions
    """
    @staticmethod
    def _code_is_error(code):
        return isinstance(code, int) and code != -errno.ENOSYS and code != 0

    def _arg_to_str(self, arg_var):
        if isinstance(arg_var, self._pylve.liblve_settings):  # for pretty print liblve_settings object
            liblve_settings_attr = ', '.join(
                [f"{attr}={getattr(arg_var, attr)}" for attr in dir(arg_var) if not attr.startswith('_')]
            )
            arg_var_str = f'<liblve_settings object {liblve_settings_attr}>'
        else:
            arg_var_str = str(arg_var)
        return arg_var_str

    def _wrapped_fun(self, call, *args, **kwargs):
        msg_template = kwargs.pop('err_msg', self.default_msg_template)
        ignore_error = kwargs.pop('ignore_error', self.ignore_error)
        code = call(*args, **kwargs)
        is_error = self._code_is_error(code)
        if is_error and self._retry:  # wait and try again run function
            time.sleep(self._retry_time)
            code = call(*args, **kwargs)
            is_error = self._code_is_error(code)

        format_args = {
            'code': code,
            'fun_name': call.__name__,
            'module': call.__module__,
            'args_': ', '.join(
                list(map(self._arg_to_str, args)) +
                [f"{k}={self._arg_to_str(v)}" for k, v in kwargs.items()]
            )
        }
        format_args = {
            'code': code,
            'fun_name': call.__name__,
            'module': call.__module__,
            'args_': ', '.join(list(map(self._arg_to_str, args)) +
                               [f"{k}={self._arg_to_str(v)}" for k, v in kwargs.items()])
        }
        if self.debug >= 1:
            print(self.debug_msg_template.format(**format_args))
        if self.debug >= 2:
            self.traceback.print_stack()
        if not ignore_error and is_error:
            msg = msg_template.format(**format_args)
            raise PyLveError(msg)
        return code

    def _wrap_code(self, call):
        def fun(*args, **kwargs):
            return self._wrapped_fun(call, *args, **kwargs)
        return fun

    def __init__(self, pylve=pylve, retry=True, retry_tyme=0.1, debug=0):
        self.debug = debug
        if self.debug >= 2:
            self.traceback = __import__('traceback')
        self.default_msg_template = 'Error code {code}; {module}.{fun_name}({args_})'
        self.debug_msg_template = "DEBUG [lvectl]: call {module}.{fun_name}({args_}) with code {code}"
        self.ignore_error = False
        self._pylve = pylve
        self._retry = retry
        self._proc = ProcLve()
        self._retry_time = retry_tyme
        self.api_version = self._pylve.lve_get_api_version()

        self.initialize = self._pylve.initialize
        self.lve_start = self._wrap_code(self._pylve.lve_start)
        self.liblve_settings = self._pylve.liblve_settings
        self.lve_create = self._wrap_code(self._pylve.lve_create)
        self.lve_destroy = self._wrap_code(self._pylve.lve_destroy)
        self.lve_info = self._pylve.lve_info
        self.lve_set_default = self._wrap_code(self._pylve.lve_set_default)
        self.lve_setup = self._wrap_code(self._pylve.lve_setup)
        self.lve_enter_pid = self._wrap_code(self._pylve.lve_enter_pid)
        self.lve_enter_pid_flags = self._wrap_code(self._pylve.lve_enter_pid_flags)
        self.lve_leave_pid = self._wrap_code(self._pylve.lve_leave_pid)
        if hasattr(pylve, 'lve_lvp_create'):
            self.lve_lvp_create = self._wrap_code(self._pylve.lve_lvp_create)
            self.lve_lvp_destroy = self._wrap_code(self._pylve.lve_lvp_destroy)
            self.lve_lvp_map = self._wrap_code(self._pylve.lve_lvp_map)
            self.lve_lvp_move = self._wrap_code(self._pylve.lve_lvp_move)

            # mocked functions. Not implement in pylve
            self.lve_lvp_setup = self._wrap_code(self.lve_lvp_setup)

    def resellers_supported(self):
        """
        Check in pylve binding reseller limits supported
        """
        return hasattr(self._pylve, 'lve_lvp_create')

    def lve_exists(self, lve_id):
        """
        Check if lve exists in kernel
        :rtype: bool
        """
        try:
            self.lve_info(lve_id)
            return True
        except OSError:
            return False

    # TODO: remove this wrapper when kernel logic is ready
    # upd: kernel logic is still not ready yet (KMODLVE-79)
    def lve_lvp_setup(self, lvp_id, settings):  # pylint: disable=method-hidden
        """
        Wrapper for lve_lvp_setup.
        When reseller's limits changed,
        we should iterate over his user's limits
        and set them again;

        This behaviour is needed cause kernel
        does not update users limits after
        changing reseller's one

        Adjust parameters for top level container.
        :param int lvp_id: top level container ID, 0 by default;
        :param settings: liblve_settings instance.
        :return: 0 or errno value
        """
        # is it real situation when lvp_id is 0?
        if lvp_id == 0:
            return self._pylve.lve_lvp_setup(lvp_id, settings)
        # reduce lve limits
        real_lve_settings = {}  # type: dict[int, pylve.liblve_settings]
        for lve_id in self._proc.lve_id_list(lvp_id):
            # save real settings to restore them later
            try:
                real_settings = self.lve_info(lve_id)
                real_lve_settings[lve_id] = real_settings

                if real_settings.ls_cpu > settings.ls_cpu:
                    # get current settings and reduce cpu
                    temp_settings = self.lve_info(lve_id)
                    temp_settings.ls_cpu = min(temp_settings.ls_cpu, settings.ls_cpu)

                    self.lve_setup(lve_id, temp_settings)
            except OSError:
                # lve was destroyed, ignore that
                pass

        # set new reseller settings
        _lve_lvp_setup = self._wrap_code(self._pylve.lve_lvp_setup)
        # ignore errors here and raise errors after operations
        result = _lve_lvp_setup(lvp_id, settings, ignore_error=True)

        # pass lve's limits again, so kernel will apply them
        for lve_id in self._proc.lve_id_list(lvp_id):
            if lve_id in real_lve_settings:
                self.lve_setup(lve_id, real_lve_settings[lve_id])
            else:
                # some lve was created during operations above
                # nothing bad, but we can do nothing with that
                # until we have no lock's for this method
                self.lve_setup(lve_id, self.lve_info(lve_id))

        return result

    def get_available_lve_id(self, start=UID_MAX, stop=MAX_LVE_ID):
        """
        Iter over lves and find available one.
        :param int start: value to start search from; UID_MAX by default
        :param int stop: max value when we will stop search
        :return int: lve_id
        """
        for lve_id in range(start + 1, stop):
            try:
                self.lve_info(lve_id)
            except OSError:
                return lve_id
        raise PyLveError(f"Unable to find free lve in range ({start}, {stop})")

    @contextlib.contextmanager
    def context_ignore_error(self, ignore_error):
        self.ignore_error, saved_ignore_error = ignore_error, self.ignore_error
        try:
            yield
        finally:
            self.ignore_error = saved_ignore_error


class Lve:
    def __init__(self, proc=None, py=None, map=None):
        self.proc = proc or ProcLve()
        self.py = py or PyLve()
        self.map = map or LvpMap()

    def lve_id_lvp_id_pairs(self):
        """
        Obtain {lve id}:{lvp id} pairs iterator based on ve.cfg config
        (detect enabled resellers containers)

        This method (unlike LvpMap.lve_lvp_pairs) will check
        if reseller is enabled in ve.cfg and return lvp_id=0
        for users of reseller with disabled reseller limits
        """
        enabled_lvp_id = set(self.map.name_map.id_list())
        for lve_id, lvp_id in self.map.lve_lvp_pairs():
            if lvp_id in enabled_lvp_id:  # load map for enabled resellers only
                yield lve_id, lvp_id
            else:
                yield lve_id, 0

    def lve2lvp(self, lve_id):
        """
        Obtain lvp id based on ve.cfg config (detect enabled resellers containers)
        """
        for lve_id_, lvp_id_ in self.lve_id_lvp_id_pairs():
            if lve_id == lve_id_:
                return lvp_id_
        return 0

    def lve_destroy(self, lve_id, *args, **kwargs):
        """
        safe destroy lve container with preserving lvp mapping
        """
        if os.path.exists(self.proc.proc_lve_map()):
            lvp_id = self.proc.map().get(lve_id, 0)
        else:
            lvp_id = 0
        self.py.lve_destroy(lve_id, *args, **kwargs)
        if lvp_id != 0:
            try:
                pwd.getpwuid(lve_id)
                self.py.lve_lvp_map(lvp_id, lve_id)
            except KeyError:
                pass

    def _sync_map(self):
        """
        Load lve_id:lvp_id map to kmod-lve
        """
        # laod mapping information from kernel (/proc/lve/map)
        proc_map_dict = self.proc.map()
        # loop over user_id:reseller_id pairs
        # lve_id_lvp_id_pairs includes all control panel users
        # and checks for enabled resellers in ve.cfg
        # so user of reseller without reseller limits
        # will be listed in response like 'tuple(user_id, 0)'
        for lve_id, lvp_id in self.lve_id_lvp_id_pairs():
            if proc_map_dict.get(lve_id, 0) != lvp_id:  # change map if needed only
                if not self.proc.exist_lvp(lvp_id=lvp_id):
                    self.py.lve_lvp_create(lvp_id)
                self.py.lve_lvp_move(lvp_id, lve_id)
                proc_map_dict[lve_id] = lvp_id

    def sync_map(self):
        """
        wrapped _sync_map function for prevent error if some cpapi not supported
        """
        try:
            self._sync_map()
        except NotSupported:
            pass

    def is_panel_supported(self):
        """
        Check if current panel supported for reseller's limits;
        :rtype: bool
        """
        try:
            return cpapi.is_reseller_limits_supported()
        except NotSupported:
            return False

    def reseller_limit_supported(self):
        """
        Check present all needed (kmod-lve, liblve, /proc/lve, panel) for manipulate resellers limits
        """
        return all((self.py.resellers_supported(),
                    self.proc.resellers_supported(),
                    self.is_panel_supported()))

    def is_lve10(self):
        """
        Check present all needed (kmod-lve, liblve, /proc/lve) for manipulate resellers limits
        """
        return all((self.py.resellers_supported(), self.proc.resellers_supported()))