#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time    : 2023/6/22 19:54
# @Author  : old tom
# @File    : dbengine.py
# @Project : futool-db-lite
# @Desc    :
from urllib.parse import quote_plus as urlquote
from sqlalchemy import create_engine
from config.db_config import DbConfigLoader, DEFAULT_CONF_PATH
from session.session import SqlsessionFactory
from util.futool_lang import str_md5


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


class ObjContainer(object):
    # DatabaseEngine容器
    engines = {}
    # SqlsessionFactory容器
    factory = {}

    def has_obj(self, attr, k):
        return k in getattr(self, attr)

    def get_obj(self, attr, k):
        return getattr(self, attr)[k]

    def put_obj(self, attr, k, v):
        getattr(self, attr)[k] = v

    def remove_obj(self, attr, k):
        del getattr(self, attr)[k]

    def clean(self):
        self.engines = {}
        self.factory = {}


container = ObjContainer()


class DatabaseEngine(object):
    """
    数据库连接
    dialect+driver://username:password@host:port/database
    mysql: mysql+pymysql://scott:tiger@localhost/foo
    sqlserver: mssql+pymssql://scott:tiger@hostname:port/dbname
    """
    DB_URL = {
        'postgresql': 'postgresql+psycopg2://{0}:{1}@{2}:{3}/{4}',
        # 使用thin客户端,不需要oracle client
        'oracle': 'oracle+oracledb://{0}:{1}@{2}:{3}/?service_name={4}'
    }
    # 连接池容器名称,具体看ObjContainer对象
    attr = 'engines'

    def __init__(self, db_name, conf_path=DEFAULT_CONF_PATH):
        """
        pool_size:连接池大小
        pool_recycle:连接回收（秒）
        pool_pre_ping:测试连接，执行select 1
        参考 https://docs.sqlalchemy.org/en/20/core/pooling.html#connection-pool-configuration
        """
        loader = DbConfigLoader(db_name, conf_path)
        # 数据库配置
        conf = loader.db_conf
        if conf.dialect not in self.DB_URL:
            raise DatabaseEngineError(msg='不支持的数据库类型')
        # urlquote 处理密码中的特殊字符
        url = self.DB_URL[conf.dialect].format(conf.user, urlquote(conf.passwd), conf.host, conf.port, conf.database)
        # URL生成唯一ID
        self.engine_id = str_md5(url)
        # 根据数据源ID判断是否新建连接池
        if container.has_obj(self.attr, self.engine_id):
            self.engine = container.get_obj(self.attr, self.engine_id)
        else:
            engine = create_engine(url, pool_size=conf.pool_size, pool_recycle=conf.pool_recycle, pool_pre_ping=True,
                                   echo=conf.show_sql)
            container.put_obj(self.attr, self.engine_id, engine)
            self.engine = engine

    def create_session_factory(self):
        """
        创建session工厂
        相同数据库URL下全局只有一个SqlsessionFactory,除非有其他数据源
        根据engine_id判断是否新建对象
        :return:
        """
        attr = 'factory'
        if container.has_obj(attr, self.engine_id):
            return container.get_obj(attr, self.engine_id)
        else:
            factory = SqlsessionFactory(self.engine)
            container.put_obj(attr, self.engine_id, factory)
        return factory