# 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 logging
from typing import Dict, List, Optional  # NOQA

from clcommon import mysql_lib
from clcommon.cpapi import cpusers, db_access, dblogin_cplogin_pairs
from clcommon.utils import run_command

log = logging.getLogger('ustate')


class MySQLOperationalError(Exception):
    pass


def _parse_lveps_output(lveps_output):
    """
    parse /usr/sbin/lveps -c 1 -p -d -n -x result
    example returned data:
    {504:
        {'CPU': '26%', 'IO': '0', 'MEM': '1', 'EP': '0', 'IOPS': 'N/A', 'PNO': '3', 'TNO': '3', 'TID':
            {4400:
                {'CPU': '26%', 'IO': 'N/A', 'MEM': '1', 'CMD': 'md5sum', 'IOPS': 'N/A'},
            4381:
                {'CPU': '0%', 'IO': 'N/A', 'MEM': '1', 'CMD': 'su', 'IOPS': 'N/A'},
            4382:
                {'CPU': '0%', 'IO': 'N/A', 'MEM': '1', 'CMD': 'bash', 'IOPS': 'N/A'}}},
    500:
        {'CPU': '13%', 'IO': '0', 'MEM': '1', 'EP': '0', 'IOPS': 'N/A', 'PNO': '3', 'TNO': '3', 'TID':
            {4266:
                {'CPU': '0%', 'IO': 'N/A', 'MEM': '1', 'CMD': 'su', 'IOPS': 'N/A'},
            4299:
                {'CPU': '13%', 'IO': 'N/A', 'MEM': '1', 'CMD': 'cat', 'IOPS': 'N/A'},
            4267:
                {'CPU': '0%', 'IO': 'N/A', 'MEM': '1', 'CMD': 'bash', 'IOPS': 'N/A'}}}}

    example of data manipulation:
    getting a list of user id
    >>> lveps_data = _parse_lveps_output()
    >>> user_id_list = lveps_data.keys()
    a list of processes tid particular user id 504
    >>> user_tid_list = lveps_data[504]['TID'].keys()
    getting CPU load user
    >>> user_cpu = lveps_data[504]['CPU']
    getting CPU load specific process
    >>> lveps_data[504]['TID'][4400]
    """
    lveps_lines = lveps_output.split('\n')
    header_line = lveps_lines.pop(0)

    columns_name = header_line.split()
    # replace columns name to standart
    replace_col = {'SPEED': 'CPU', 'COM': 'CMD'}
    columns_name = [replace_col.get(col_name, col_name) for col_name in columns_name]

    lveps_data = {}
    user_id = 0
    for lveps_line_index, lveps_line in enumerate(lveps_lines):
        if not lveps_line:
            continue
        lveps_line_splited = lveps_line.split(None, len(columns_name) - 1)
        # if the first one is number - use it as lve_id
        has_id = (len(lveps_line_splited) == len(columns_name)) and lveps_line_splited[0].isdigit()
        if not has_id:
            lveps_line_splited = lveps_line.split(None, len(columns_name) - 2)
            lveps_line_splited.insert(0, '')
        if len(lveps_line_splited) != len(columns_name):
            log.error(
                "lveps output was incorrect: %s",
                lveps_line,
                extra={"data": {"lveps_lines": lveps_lines[max(0, lveps_line_index - 5):lveps_line_index + 15]}},
            )
            break
        lveps_dict_line = dict(zip(columns_name, lveps_line_splited))
        if has_id:
            # FIXME: need to add a filter to a minimum uid
            user_id = int(lveps_dict_line.pop('ID'))
            try:
                del lveps_dict_line['CMD']
            except KeyError:
                pass
            lveps_data[user_id] = lveps_dict_line
            lveps_data[user_id]['TID'] = {}
            lveps_data[user_id].pop('PID', None)
        else:
            lveps_dict_line.pop('EP', None)
            lveps_dict_line.pop('PNO', None)
            lveps_dict_line.pop('TNO', None)
            lveps_dict_line.pop('ID', None)

            try:
                lveps_data[user_id]['TID'][int(lveps_dict_line.pop('TID'))] = lveps_dict_line
            except (ValueError, KeyError) as e:
                log.error("Can't parse lveps output: %s", str(e))
    return lveps_data


def get_lveps():
    lveps_output = _get_lveps_output()
    return _parse_lveps_output(lveps_output)


def _get_lveps_output():
    lveps_output = run_command(
        [
            '/usr/sbin/lveps',
            '-c',
            '1',
            '-p',
            '-d',
            '-n',
            '-o',
            '-x',  # tells lveps to put at least one space between columns for correct parsing
            'id:10,ep:10,pno:10,pid:15,tno:5,tid:15,cpu:7,mem:15,com:256',
        ],
        convert_to_str=False,
    )
    # ignore any non-utf8 symbols here
    # we use this information only to show user
    return lveps_output.decode('utf-8', 'replace')


class SQLSnapshot(object):
    def __init__(self):
        self._mysql_conn = None
        self._dblogin_cplogin_map = {}
        self._db_users = set()  # attribute to detect new database users

    def __enter__(self):
        self.connect()
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        self.close()

    def connect(self):
        """
        Obtain access data and connect to mysql database
        """
        access = db_access()
        mysql_login = access['login']
        mysql_pass = access['pass']
        mysql_host = access.get('host', 'localhost')
        connector = mysql_lib.MySQLConnector(
            host=mysql_host,
            user=mysql_login,
            passwd=mysql_pass,
            use_unicode=True,
            charset="utf8mb4",
        )
        try:
            self._mysql_conn = connector.connect()
        except mysql_lib.MySQLError as e:
            raise MySQLOperationalError(str(e)) from e

    def _refresh_map(self):
        """
        Refresh <database user>:<system user> map
        """
        self._dblogin_cplogin_map = dict(dblogin_cplogin_pairs())

    def close(self):
        """
        Close Mysql connection
        """
        self._mysql_conn.close()

    def _raw_processlist(self):
        result = tuple()
        try:
            cursor = self._mysql_conn.cursor()
            cursor.execute('SHOW FULL PROCESSLIST')
            result = cursor.fetchall()
        except (UnicodeDecodeError, mysql_lib.MySQLError) as e:
            log.warning('Error occurred during executing the `SHOW FULL PROCESSLIST` command', exc_info=e)
        return result

    def _get_sql_process_list(self):
        """
        Group processlist by database user name
        :rtype: dict
        """
        process_snapshot = {}
        for sql_tuple in self._raw_processlist():
            db_username = sql_tuple[1]
            sql_cmd = sql_tuple[4]  # (CMD) type/state of the request, in this case we are only interested 'Query'
            sql_time = sql_tuple[5]  # (Time) Time
            sql_query = sql_tuple[7] or ''  # (SQL-query) sql query, None if no sql query
            if sql_cmd == 'Sleep':  # filter 'Sleep' state
                continue
            snapshot_line = [sql_cmd, sql_time, sql_query]
            # group by database user name
            grouped_by_user = process_snapshot.get(db_username, [])
            grouped_by_user.append(snapshot_line)
            process_snapshot[db_username] = grouped_by_user
        return process_snapshot

    def get(self, cplogin_lst=None):
        # type: (Optional[List[str]]) -> Dict[str, List]
        """
        :param cplogin_lst: a list of users to retrieve data;
            None if the data is returned for all users registered in the control panel
        :return: sql queries for each user
        """
        process_snapshot = self._get_sql_process_list()

        # refresh map if new database users detect
        new_db_users = set(process_snapshot.keys()) - self._db_users
        if new_db_users:
            self._refresh_map()
            log.debug(
                'New database user(s) %s detected; database users map refreshed',
                str(list(new_db_users))[1:-1],
            )
            # refresh self._db_users to detect new users
            for new_db_user in new_db_users:
                self._db_users.add(new_db_user)

        # group and filter by control panel users
        sql_snapshot = {}
        cplogin_lst_ = cplogin_lst or cpusers() or []
        for db_username, sql_snap in list(process_snapshot.items()):
            cp_username = self._dblogin_cplogin_map.get(db_username)
            if cp_username is not None and cp_username in cplogin_lst_:
                # group sql snapshots by control panel user
                sql_snap_ = sql_snapshot.get(cp_username, [])
                sql_snap_.extend(sql_snap)
                sql_snapshot[cp_username] = sql_snap_
        return sql_snapshot