#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time    : 2023/6/22 21:55
# @Author  : old tom
# @File    : sql_executor.py
# @Project : futool-db-lite
# @Desc    : 获取游标,执行SQL
from sqlalchemy import text, CursorResult
from transaction.connect_transaction import Transaction


class SQLExecutorError(Exception):
    def __init__(self, msg):
        Exception.__init__(self, msg)


class SQLExecutor(object):
    def __init__(self, tx: Transaction):
        self._tx = tx
        self._conn = tx.get_connection()

    @staticmethod
    def _format_sql(sql):
        return text(sql)

    def query(self, sql) -> CursorResult:
        """
        关于auto begin官方文档给出的解释 https://docs.sqlalchemy.org/en/20/core/connections.html#commit-as-you-go
        auto begin会导致出现： can't call begin() here unless rollback() or commit() is called first.
        """
        try:
            return self._conn.execute(self._format_sql(sql))
        except Exception as e:
            raise SQLExecutorError(msg=f'{e}')
        finally:
            self._conn.commit()

    def query_by_stream(self, sql, stream_size) -> CursorResult:
        """
        流式查询
        :param sql: sql
        :param stream_size: 每次返回数据量
        :return:
        """
        try:
            return self._conn.execution_options(yield_per=stream_size).execute(self._format_sql(sql))
        except Exception as e:
            raise SQLExecutorError(msg=f'{e}')
        finally:
            self._conn.commit()

    def execute_update(self, sql) -> int:
        try:
            rt = self._conn.execute(self._format_sql(sql))
            return rt.rowcount
        except Exception as e:
            raise SQLExecutorError(msg=f'{e}')

    def execute_batch(self, sql_template, data, batch_size=1000) -> int:
        """
        批量执行
        conn.exec_driver_sql(
                 "INSERT INTO table (id, value) VALUES (:id, :value)",
                 [{"id":1, "value":"v1"}, {"id":2, "value":"v2"}]
             )
        :return:
        """
        return self._conn.exec_driver_sql(sql_template, data,
                                          execution_options={'insertmanyvalues_page_size': batch_size})

    def get_connection(self):
        return self._conn

    def get_transaction(self):
        return self._tx