# coding=utf-8
#
# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2020 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENSE.TXT

import logging
import pwd
import json
import time

from clcommon import clpwd
from clcommon.lib.jwt_token import jwt_token_check
from clcommon.lib.cmt_utils import is_cmt_disabled, is_client_enabled
from clcommon.clproc import ProcLve, LIMIT_LVP_ID
from clcommon.lib import MySQLGovernor, MySQLGovException, MySQLGovernorAbsent

from lvestat import LVEStat
from lvestats.core.plugin import LveStatsPlugin
from lvestats.lib.commons.sizeutil import mempages_to_bytes
from lvestats.lib.commons.func import get_domains
from lvestats.plugins.generic.analyzers import LVEUsage
from secureio import write_file_via_tempfile

GOVERNOR_ENABLED_MSG = (
    "There was detected MySQL Governor and information about limits will be collected starting from now"
)
GOVERNOR_BASIC_ERROR_MSG = 'Error while getting Mysql Governor limits: %s. '
GOVERNOR_ABSENT_ERROR_MSG = (
    GOVERNOR_BASIC_ERROR_MSG + "Since the governor doesn't seem to be well "
    "configured, the limits statistics won't be "
    "collected. This warning won't be repeated to "
    "prevent annoying spam in logs."
)
CM_DISABLED_MSG = (
    "Centralized Monitoring isn't enabled. "
    "CMCollector plugin won't collect data. It's expected "
    "behaviour for non CL+ clients"
)
CM_ENABLED_MSG = (
    "Centralized Monitoring has been detected! From now, "
    "CMCollector will gather limits statistics for it gently "
    "and affectionate."
)


class CMCollector(LveStatsPlugin):
    """
    Collector plugin for Cloudlinux+ Centralized Monitoring
    """

    class DomainsCache:
        """
        Sub-class for keeping username:domain pairs
        """

        def __init__(self, logger):
            self.log = logger
            self.cache = {}
            self.cache_creation_time = 0
            self.cache_expiration_interval = 60 * 60 * 24  # 1 day

        def get(self, username):
            if self._is_expired():
                self.log.info('Domains cache is expired, going to regenerate user-domains cache')
                self.cache = {}
            if username in self.cache:
                return self.cache[username]
            domain = self._get_real_value(username)
            if domain:
                self.set(username, domain)
            return domain

        def set(self, username, domain):
            if not self.cache:
                self.cache_creation_time = int(time.time())
                self.log.info('Cache creation timestamp: %s', str(self.cache_creation_time))
            self.cache[username] = domain

        def _is_expired(self):
            return int(time.time()) - self.cache_creation_time > self.cache_expiration_interval

        def _get_real_value(self, username):
            try:
                return get_domains(username, raise_exception=False)[0]
            except Exception:
                # skip unavailable user or domain
                # We ignore all exceptions to reduce failure risks on custom panels
                return None

    def __init__(self):
        self.log = logging.getLogger('CL+CM_Collector')
        self.now = 0  # This changes in MainLoop
        self.period = 60  # Run this plugin every minute
        self._filename_to_write = '/var/lve/cm_lve.json'
        self._is_write_error = False
        self._is_jwt_token_error = False
        self._is_governor_absent_error = False
        self._is_cm_enabled_error = False
        self.log.info("CM Collector plugin init")
        self.proc_lve = ProcLve()
        self.governor = MySQLGovernor()
        self.min_uid = clpwd.ClPwd().get_sys_min_uid()
        self.domains_cache = self.DomainsCache(self.log)

    def _prepare_dbgov_limits(self, username):
        """
        Gets Mysql Governor limits and returns ready-to-send
        dict with limits and zero-usage
        """
        try:
            cpu, io = self.governor.get_limits_by_user(username)
            if self._is_governor_absent_error:
                self.log.info(GOVERNOR_ENABLED_MSG)
                self._is_governor_absent_error = False
        # Catch specific governor absence error to prevent logs spam
        except MySQLGovernorAbsent as e:
            if not self._is_governor_absent_error:
                self.log.warning(GOVERNOR_ABSENT_ERROR_MSG, str(e))
                self._is_governor_absent_error = True
            return None
        except MySQLGovException as e:
            self.log.warning(GOVERNOR_BASIC_ERROR_MSG, str(e))
            return None
        return {
            'mysql_cpu': {'l': cpu},
            'mysql_io': {
                'l': io * 1024  # convert values (in KB) from governor to bytes
            },
        }

    def _parse_limits(self, procs, lvp_id=0):
        """
        Parse lve limits from /proc/lve via ProcLve instance
        """
        limits = {}
        for line in self.proc_lve.lines(lvp_id, without_limits=False):
            version = self.proc_lve.version()
            stat = LVEStat(line, version)
            if stat.id == 0 or stat.id == LIMIT_LVP_ID:
                continue
            limits[stat.id] = self._lveusage_to_dict(
                LVEUsage(version).init_limits_from_lvestat(stat, procs), only_limits=True
            )
        return limits

    def _get_lve_users(self, procs):
        """
        Returns dict with lve_id and it`s limits from /proc/lve
        """
        users = {}
        if self.proc_lve.resellers_supported():
            for lvp_id in self.proc_lve.lvp_id_list():
                users.update(self._parse_limits(procs, lvp_id=lvp_id))
        users.update(self._parse_limits(procs))
        return users

    @staticmethod
    def _lveusage_to_dict(usage: LVEUsage, only_limits: bool = False):
        """
        Return ready-to-send dict with metrics by passed lve usage
        """
        if only_limits:
            return {
                'cpu': {'l': usage.lcpu / 100},
                'ep': {'l': usage.lep},
                'pmem': {'l': mempages_to_bytes(usage.lmemphy)},
                'nproc': {'l': usage.lnproc},
                'io': {'l': usage.io},
                'iops': {'l': usage.liops},
            }
        return {
            'cpu': {
                'a': int(round(usage.cpu_usage)) / 100,
                'l': usage.lcpu / 100,
                'f': usage.cpu_fault,
            },
            'ep': {'a': usage.mep, 'l': usage.lep, 'f': usage.mep_fault},
            'pmem': {
                'a': mempages_to_bytes(int(round(usage.memphy))),
                'l': mempages_to_bytes(usage.lmemphy),
                'f': usage.memphy_fault,
            },
            'nproc': {
                'a': int(round(usage.nproc)),
                'l': usage.lnproc,
                'f': usage.nproc_fault,
            },
            'io': {
                'a': int(round(usage.io_usage)),
                'l': usage.io,
                'f': usage.io_fault,
            },
            'iops': {
                'a': int(round(usage.iops)),
                'l': usage.liops,
                'f': usage.iops_fault,
            },
        }

    def _prepare_metrics_to_send(self, lve_data):
        """
        Returns list with metrics (lve&mysql) by each lve_id
        In case there is some usage for lve_id -> it will be used
        otherwise -> zero-usage values with actual lve/mysql limits are used
        """
        lve_data_list = []
        dbgov_data_for_cm = lve_data.pop("dbgov_data_for_cm", {})
        users = self._get_lve_users(lve_data.get('procs', 1))
        lve_usage = lve_data.get('lve_usage', {})
        for lve_id, limits_data in users.items():
            try:
                username = pwd.getpwuid(lve_id).pw_name
            except Exception:
                # skip unavailable user
                continue
            domain = self.domains_cache.get(username)
            if not domain:
                continue
            lve_data_dict = {"lve_id": lve_id, "username": username, "domain": domain}
            if lve_id in lve_usage:
                v = lve_usage[lve_id]
                lve_data_dict.update(self._lveusage_to_dict(v))
            else:
                lve_data_dict.update(limits_data)
            # process MySQL governor data
            # dbgov_data_for_cm example
            # {1001: {'cpu_limit': 100, 'io_limit': 562036736, 'cpu_usage': 99.498342, 'io_usage': 2055473}}
            if lve_id in dbgov_data_for_cm:
                lve_data_dict["mysql_cpu"] = {
                    "a": dbgov_data_for_cm[lve_id]['cpu_usage'],
                    "l": dbgov_data_for_cm[lve_id]['cpu_limit'],
                }
                lve_data_dict["mysql_io"] = {
                    "a": dbgov_data_for_cm[lve_id]['io_usage'],
                    "l": dbgov_data_for_cm[lve_id]['io_limit'],
                }
            else:
                mysql_limits = self._prepare_dbgov_limits(username)
                # append mysql limits only if governor present
                if mysql_limits is not None:
                    lve_data_dict.update(mysql_limits)
            lve_data_list.append(lve_data_dict)
        return lve_data_list

    def execute(self, lve_data):
        """
        Main plugin entrypoint
        """
        # Check and read JWT token
        token_is_valid, token_error_msg, _ = jwt_token_check()
        if not token_is_valid:
            # Token absent or invalid
            if not self._is_jwt_token_error:
                self.log.info(
                    "JWT token error: '%s'. CM Collector plugin will not work, "
                    "it is expected behaviour for non CL+ clients",
                    token_error_msg,
                )
                self._is_jwt_token_error = True
            return
        # CMCollector should be executed only if CM for client is enabled
        if is_cmt_disabled() or not is_client_enabled():
            # CM isn't enabled
            if not self._is_cm_enabled_error:
                self.log.info(CM_DISABLED_MSG)
                self._is_cm_enabled_error = True
            return
        self._is_jwt_token_error = False
        if self._is_cm_enabled_error:
            # Welcome message after plugin start
            self.log.info(CM_ENABLED_MSG)
            self._is_cm_enabled_error = False
        json_result = json.dumps({'lve_stats': self._prepare_metrics_to_send(lve_data)})
        try:
            write_file_via_tempfile(json_result, self._filename_to_write, 0o600)
            self._is_write_error = False
        except (IOError, OSError) as e:
            if not self._is_write_error:
                self.log.error(str(e))
                self._is_write_error = True