import logging
import time
from traceback import format_exc
import struct
import sqlalchemy
from sqlalchemy import text
from fastapi_sqlalchemy import db
from jinja2 import Template
from pymysql import err
from pymysql.constants import FIELD_TYPE
from pymysql.converters import conversions, convert_time

__author__ = 'Woodstock'

logger = logging.getLogger("uvicorn.error")

engine = None

conversions[FIELD_TYPE.BIT] = lambda b: struct.unpack(">Q", (bytes([0x00]) * (8 - len(b)) + b))[0]
conversions[FIELD_TYPE.TIME] = convert_time
conversions[FIELD_TYPE.DATETIME] = str


class EDatabase(Exception):
    def __init__(self, *args):
        super(EDatabase, self).__init__(*args)

    def result(self):
        return None


class DB:
    CACHE = None
    ACCESS_TOKEN = None
    IS_LOCAL_TEST = False
    version = sqlalchemy.__version__

    def __init__(self, session=None):
        """
        传入session时整个db对象使用同一session操作
        """
        self.session = session
        self.result = None
        self.rowcount = -1
        self.lastrowid = -1

    def execute(self, sql, **kwargs):
        if "{" in sql:
            sql_template = Template(sql)
            temp_sql = sql_template.render(**kwargs)
        else:
            temp_sql = sql
        temp_sql = "\n".join([l.strip() for l in temp_sql.split("\n")])

        # 用于输出日志
        log_string = f"执行SQL: {temp_sql.strip()}\n参数: {str(kwargs)[:400]}"
        t = time.time()
        try:
            pars = dict(**kwargs)
            self.result = self.session.execute(text(temp_sql), params=pars)
        except (err.OperationalError, err.InternalError, err.InternalError) as e:
            orig = e
            if not isinstance(orig, err.InternalError):
                orig = orig.orig
            if orig.args[0] in [111, 1205, 1213, 2003, 2013]:
                raise
            if orig.args[0] == 1044:
                logger.error(f"(pymysql.err.OperationalError) (1044, Access denied for {self.session.bind.url})")
                logger.error(format_exc())
                raise
            log_string += f"\n执行结果:\n 执行失败了 ,错误信息:{e}"
            logger.error(log_string)
            raise
        except Exception as e:
            log_string += f"\n执行结果:\n 执行失败了 ,错误信息:{e}"
            logger.error(log_string)
            raise
        finally:
            logger.info(f"{log_string}\n耗时：{time.time() - t}")
        # 受影响行数
        self.rowcount = self.result.rowcount
        # 插入数据时返回的主键数据
        self.lastrowid = self.result.lastrowid
        logger.debug(f"执行结果:\n 受影响行数:{self.rowcount}")
        return self

    def all(self):
        # 获取查询列表。把ResultProxy和RowProxy类型封装成python的list和dict类型
        if self.version.startswith('1.4'):
            data = [i._asdict() for i in self.result]
        else:
            data = [dict(zip(i.keys(), i.values())) for i in self.result]
        self.result.close()
        return data

    def scalars(self):
        """
        返回首个值的集合
        :return:
        """
        data = set(i[0] for i in self.result)
        self.result.close()
        return data

    def scalar_list(self):
        """
        获取首个值的列表
        :return:
        """
        data = [i[0] for i in self.result]
        self.result.close()
        return data

    def first(self):
        row = None
        # 获取第一行数据
        for i in self.result:
            if self.version.startswith('1.4'):
                row = i._asdict()
            else:
                row = dict(zip(i.keys(), i.values()))
            break
        self.result.close()
        return row

    def scalar(self):
        """获取第一行第一列的数据"""
        one = None
        for i in self.result:
            one = i[0]
            break
        self.result.close()
        return one


def execute_sql(sql, **kwargs):
    db_instance = DB(db.session)
    return db_instance.execute(sql, **kwargs)