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

# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2021 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENSE.TXT

"""
This module contains SSA classes for sending e-mails with report
and sending reports to ClickHouse
"""
__package__ = 'ssa.modules'

import json
import logging
import subprocess
from email.message import EmailMessage
from functools import partial
from typing import Optional, Any
from socket import gethostname

from clcommon.cpapi import get_admin_email
from requests import Session, Response
from requests.adapters import HTTPAdapter
from requests.exceptions import RequestException
from requests.packages.urllib3.util.retry import Retry

from .common import Common
from .decision_maker import DecisionMaker
from ..internal.constants import stat_server
from ..internal.exceptions import SSAError
from ..internal.mailer import Mailer, render_report_table
from ..internal.utils import read_sys_id, sentry_init, duration_cast, \
    format_date


class StatisticsSender(Common):
    """
    Send report to ClickHouse and over e-mails
    """

    def __init__(self, ch_endpoint: str = f'https://{stat_server}/api/clos-ssa'):
        super().__init__()
        self.logger = logging.getLogger('stat_sender')
        self.logger.info('StatisticsSender enabled: %s', __package__)
        self.sys_id = read_sys_id()
        self.ch_endpoint = ch_endpoint
        self.mail_sender = Mailer()

        retry_conf = Retry(total=3,
                           allowed_methods=frozenset(['POST']),
                           status_forcelist=frozenset([502, 503, 504]),
                           backoff_factor=3)  # sleeps 0s, 6s, 18s
        adapter = HTTPAdapter(max_retries=retry_conf)
        self.session = Session()
        self.session.mount('https://', adapter)
        self.session.request = partial(self.session.request, timeout=10)

    def send(self, report: dict = None) -> None:
        """
        Send given report over e-mail
        If no report given, get it from DecisionMaker API
        """
        if report is None:
            report = DecisionMaker().get_json_report()

        if self.summary_notification_enabled:
            self.email_report(report)
        self.clickhouse_report(report)

    def email_report(self, report_view: dict) -> Optional[EmailMessage]:
        """
        Create and send e-mail with report
        """
        mail_to = self.get_mail_recipient()

        if mail_to and report_view.get('domains'):
            report_table, mail = render_report_table(report_view)
            msg = self.mail_sender._message(
                recipient=mail_to,
                template='ssa_report',
                date=format_date(report_view['date']),
                hostname=gethostname(),
                html=mail
            )
            msg.add_attachment(json.dumps(report_view),
                               subtype='json',
                               filename=f"report_{report_view['date']}.json")
            msg.add_attachment(report_table,
                               subtype='html',
                               filename=f"report_{report_view['date']}.html")

            self.mail_sender._send(msg)

            return msg

    def get_mail_recipient(self) -> Optional[str]:
        """
        Retrieve a recipient's e-mail:
        1. get address from a wmt-api utility
        2. if command failed or address is empty, get address of server admin
        """
        try:
            # get_admin_email could return '', None, or throw unexpected errors
            return self.wmt_api_report_email() or get_admin_email()
        except Exception as e:
            self.logger.error('get_admin_email failed with: %s', str(e))

    def wmt_api_report_email(self) -> Optional[str]:
        """
        Retrieve a recipient's e-mail address from WMT API
        """
        _util = 'wmt-api'
        try:
            api_response = subprocess.run(
                [f'/usr/share/web-monitoring-tool/wmtbin/{_util}',
                 '--config-get'],
                check=True, text=True,
                capture_output=True).stdout.strip()
        except (subprocess.CalledProcessError, AttributeError, OSError,
                ValueError) as e:
            self.logger.error('wmt-api utility failed: %s', str(e))
            return

        try:
            return json.loads(api_response).get('config').get('report_email')
        except json.JSONDecodeError as e:
            self.logger.error('wmt-api returned invalid json: %s',
                              str(e))
        except AttributeError:
            self.logger.error('wmt-api returned unexpected response: %s',
                              api_response)

    def clickhouse_report(self, report_view: dict) -> bool:
        """
        Send report to ClickHouse
        """
        if report_view.get('domains'):
            self.logger.info('Sending POST request to %s',
                             self.ch_endpoint)
            try:
                resp = self.session.post(self.ch_endpoint, json=self._ch_pack(
                    self.clickhouse_format(report_view)))
            except RequestException as e:
                self.logger.error('POST failed with %s', e,
                                  extra={'endpoint': self.ch_endpoint})
                raise SSAError(
                    f'Failed to POST data to SSA API server: {str(e)}') from e
            return self._process_response(resp)
        else:
            self.logger.info('Report is empty, not sending to ClickHouse')
            return False

    @staticmethod
    def _ch_pack(value: Any) -> dict:
        """
        Pack given value into data field of a dict
        """
        return dict(data=value)

    def clickhouse_format(self, original_report: dict) -> list:
        """
        Format local report for sending to ClickHouse
        (required structures differ)
        """
        ch_report = list()
        for domain in original_report.get('domains'):
            ch_report.append({
                'system_id': self.sys_id,
                'domain': domain.get('name'),
                'count_slow_urls': domain.get('slow_urls'),
                'count_slow_requests': domain.get('slow_reqs'),
                'total_requests': domain.get('total_reqs'),
                'details': [
                    {
                        "url": u.get('name'),
                        "count_requests": u.get('reqs_num'),
                        "avg_duration": duration_cast(
                            u.get('average_duration')),
                        "correlation": float(u.get('correlation', 0))
                    } for u in domain.get('urls')
                ]
            })
        return ch_report

    def _process_response(self, response: Response) -> bool:
        """
        Check received response
        :param response: a requests.Response object
        :return: True in case of success, False otherwise
        """
        if not response.ok:
            self.logger.error('Unable to connect to server with %s:%s',
                              response.status_code, response.reason,
                              extra={'resp_text': response.text})
            return False
        else:
            self.logger.info('[%s:%s] Response received %s',
                             response.status_code, response.reason,
                             response.url)

        result = response.json()
        if result['status'] != 'ok':
            self.logger.error('Received response with status %s',
                              result['status'], extra={'response': result})
            return False

        self.logger.info('Sent to ClickHouse successfully')
        return True


if __name__ == "__main__":
    sentry_init()
    logging.basicConfig(filename='stat_sender_standalone.log',
                        level=logging.INFO)
    try:
        StatisticsSender().send()
    except SSAError as exc:
        print(exc)
        raise SystemExit(1)