from dataclasses import dataclass
from app.core.ds.datasource import DataSourceBase
from mysql import connector
from mysql.connector import Error
from sqlalchemy import create_engine
import pandas as pd
from configs import logger
from utils import flat_map


@dataclass
class MysqlDS(DataSourceBase):
    type = 'mysql'

    @property
    def jdbc_url(self):
        return f'jdbc:mysql://{self.host}:{self.port}/{self.database_name}'

    @property
    def jdbc_driver_class(self):
        return 'com.mysql.jdbc.Driver'

    @property
    def connection_str(self):
        return f'mysql+pymysql://{self.username}:{self.password}@{self.host}:{self.port}/{self.database_name}'

    def is_connect(self):
        # 判断mysql是否连接成功
        conn = None
        try:
            conn  = connector.connect(host=self.host,
                                    port=self.port,
                                    database=self.database_name,
                                    user=self.username,
                                    password=self.password)
            if conn.is_connected():
                logger.info('Connected to MySQL database')

        except Error as e:
            logger.error(e)

        finally:
            if conn is not None and conn.is_connected():
                conn.close()
                return True
            else:
                return False

    def _execute_sql(self, sqls):
        conn = None
        res = []
        try:
            conn  = connector.connect(host=self.host,
                                    port=self.port,
                                    database=self.database_name,
                                    user=self.username,
                                    password=self.password)
            cursor = conn.cursor()
            for sql in sqls:
                cursor.execute(sql)
                res.append(cursor.fetchall())
            logger.info(res)
        except Error as e:
            logger.error(e)

        finally:
            if conn is not None and conn.is_connected():
                conn.close()
        return res


    def get_preview_data(self, table_name, limit=100):
        sql1 = f'SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA="{self.database_name}"  AND TABLE_NAME="{table_name}"'
        sql2 = f"SELECT * FROM {table_name} LIMIT {limit}"
        res = self._execute_sql([sql1, sql2])
        logger.info(res)
        return {
            'header': flat_map(lambda x: x, res[0]),
            'content': res[1]
        }
        # db_connection = create_engine(self.connection_str)
        # df = pd.read_sql(sql, con=db_connection)
        # # print(df)
        # logger.info(df.head())
        # return df.to_numpy()


    def list_tables(self):
        sql = f'SELECT table_name FROM information_schema.tables WHERE table_type = "base table" AND table_schema="{self.database_name}"'
        res = self._execute_sql([sql])
        return flat_map(lambda x: x, res[0])

    def get_table_schema(self, table_name):
        sql = f'describe {self.database_name}.{table_name}'
        res = self._execute_sql([sql])
        if res:
            res = [[str(i) , *x]for i, x in enumerate(res[0])]
            logger.info(res)

            return flat_map(lambda x: [':'.join(x[:3])], res)
        else:
            raise Exception('table not found')