#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
# @Version     : Python 3.11.4
# @Software    : Sublime Text 4
# @Author      : StudentCWZ
# @Email       : StudentCWZ@outlook.com
# @Date        : 2023/11/20 09:57
# @File        : log.py
# @Description :
"""

from datetime import datetime
from typing import Generator

from loguru import logger
from sqlalchemy import text

from application.libs.helper import MySQLHelper
from application.models import Log
from application.utils import ElasticsearchUtil, ParseUtil
from application.extensions.init_sqlalchemy import db

created_partitions = set()  # Now it's a global variable


class LogDao:
    """
    Data Access Object for logs.
    This class includes methods to get data from Elasticsearch, process it and save it to MySQL.
    """

    @classmethod
    def get_data_from_es(cls, index=None, dsl=None, sid=None) -> dict:
        """
        Get data from Elasticsearch by either scroll searching or direct searching.

        Args:
            index (str): The name of the Elasticsearch index.
            dsl (dict): The DSL query for Elasticsearch.
            sid (str): The scroll id for Elasticsearch scroll search.

        Returns:
            dict: The data returned from Elasticsearch.

        Raises:
            SystemError: If none of the required parameters are provided.
        """
        if sid is not None:
            return ElasticsearchUtil.scroll_search(sid)
        elif index is not None and dsl is not None:
            return ElasticsearchUtil.search(index, dsl)
        else:
            raise SystemError('Could not get data from Elasticsearch')

    @classmethod
    def get_mdata(cls, data: dict) -> list:
        """
        Get metadata from the data returned by Elasticsearch.

        Args:
            data (dict): The data returned from Elasticsearch.

        Returns:
            list: The metadata extracted from the data.

        Raises:
            SystemError: If the metadata is empty.
        """
        mdata = data.get('hits').get('hits')
        if not mdata:
            logger.error('the mdata is an empty list ...')
            raise SystemError('the mdata is an empty list ...')
        return mdata

    @classmethod
    def get_intent_from_mysql(cls, sql: str, cfg: dict) -> list:
        """
        Get the intent mapping from MySQL using the provided SQL.

        Args:
            sql (str): The SQL query to execute.
            cfg (dict): The configuration for MySQL.

        Returns:
            list: The intent mapping list.
        """
        with MySQLHelper(**cfg) as helper:
            result = helper.execute(sql)
        mapping_list = [item[0] for item in result]
        return mapping_list

    @classmethod
    def batch_save(cls, objects: Generator) -> None:
        global created_partitions  # Reference the global variable
        for obj in objects:
            log = Log(**obj)
            # Convert string to datetime object
            date_time_obj = datetime.strptime(log.date_time, '%Y-%m-%d %H:%M:%S')
            partition_date = date_time_obj.strftime('%Y_%m')
            partition_name = f'{log.__tablename__}_{partition_date}'

            if partition_name not in created_partitions:
                db.session.execute(text(f"""
                CREATE TABLE IF NOT EXISTS {partition_name} PARTITION OF {log.__tablename__}
                FOR VALUES FROM ('{date_time_obj.strftime('%Y-%m-01')}') TO 
                ('{date_time_obj.strftime('%Y-%m-01')}'::date + interval '1 month');
                """))
                created_partitions.add(partition_name)  # Remember that this partition has been created

            db.session.add(log)
        db.session.commit()

    @classmethod
    def process_and_save_data(cls, lst: list, mapping_list: list) -> None:
        """
        Process the given list using the mapping list and save the result to the database.

        Args:
            lst (list): The list to process.
            mapping_list (list): The mapping list to use for processing.
        """
        if not lst:
            return
        result_generator = ParseUtil(mapping_list=mapping_list).filter(lst)
        # 批量保存数据
        cls.batch_save(result_generator)

    @classmethod
    def parse(cls, start: str, end: str, index: str, sql: str, options: dict) -> int:
        """
        Parse logs from Elasticsearch and save them to MySQL.

        Args:
            start (str): The start date for the logs.
            end (str): The end date for the logs.
            index (str): The Elasticsearch index to get logs from.
            sql (str): The SQL query to get the intent mapping from MySQL.
            options (dict): The configuration for MySQL.

        Returns:
            int: The total number of logs parsed.

        Raises:
            SystemError: If there is an error during the process.
        """

        # Get the DSL for the given start and end dates.
        dsl = ElasticsearchUtil.dsl(start, end)

        # Get data from Elasticsearch.
        data = cls.get_data_from_es(index=index, dsl=dsl)

        # Extract metadata from the data.
        mdata = cls.get_mdata(data)

        # Get the total number of logs.
        total = data.get('hits').get('total').get('value')
        logger.debug(f'The numbers of data by searching data from ES: {total}')

        # Log the start of the searching and saving process.
        logger.debug('The data is inserting ...')

        # Get the intent mapping from MySQL.
        mapping_list = cls.get_intent_from_mysql(sql, options)

        # Process and save the metadata.
        cls.process_and_save_data(mdata, mapping_list)

        # Get the scroll id for scroll searching in Elasticsearch.
        scroll_id = data.get('_scroll_id')

        try:
            for _ in range(0, int(total / dsl.get('size', 5000) + 1)):
                # Get more data from Elasticsearch using scroll searching.
                res = cls.get_data_from_es(sid=scroll_id)
                lst = res.get('hits').get('hits')

                if not lst:
                    continue

                # Process and save the data.
                cls.process_and_save_data(lst, mapping_list)
        except Exception as e:
            # Log the error and raise a SystemError.
            logger.error(f'The error: {e}')
            raise SystemError()
        else:
            # Log the success of the process.
            logger.debug('The process of inserting data succeed!')
        finally:
            # Log the end of the process.
            logger.debug('The inserting of the data finished!')

        return total