import traceback
import paginate_sqlalchemy
from sqlalchemy import create_engine, desc
from app.conf.Setting import settings
from sqlalchemy.orm import sessionmaker
from sqlalchemy.sql import func
from sqlalchemy.sql.elements import BinaryExpression, BooleanClauseList
from app.lib.Log import logger

class OrmBase(object):
    # 初始化数据库连接
    engine = create_engine(settings.SQLALCHEMY_DATABASE_URI,connect_args={'check_same_thread': False}, pool_size=100)
    # 创建session工厂
    DBSession = sessionmaker(bind=engine, autoflush=False, autocommit=False, expire_on_commit=True)
    # 创建session对象
    session = DBSession()
    # 事务标识
    transFlag = False

    def __init__(self, entityType):
        super().__init__()
        # 对象类型
        self.entityType = entityType

    # 开始事务
    def beginTrans(self):
        self.session = self.DBSession()
        self.transFlag = True

    # 提交事务
    def commitTrans(self):
        try:
            self.transFlag = False
            self.session.commit()
        except Exception as e:
            logger.error(traceback.format_exc())
            self.session.rollback()
            raise e
        finally:
            self.session.close()

    # 新增数据
    def insert(self, entity):
        try:
            if (not self.transFlag):
                self.session = self.DBSession()
            self.session.add(entity)
            if (not self.transFlag):
                self.session.commit()
                return True
        except Exception as e:
            logger.error(traceback.format_exc())
            self.session.rollback()
            raise e
        finally:
            self.session.close()

    # 新增多行数据
    def insert_many(self, entity_list):
        try:
            if (not self.transFlag):
                self.session = self.DBSession()
            self.session.bulk_save_objects(entity_list)
            if (not self.transFlag):
                self.session.commit()
                return True
        except Exception as e:
            logger.error(traceback.format_exc())
            self.session.rollback()
            raise e
        finally:
            self.session.close()

    # 更新数据
    def update(self, entity):
        try:
            if (not self.transFlag):
                self.session = self.DBSession()
            self.session.merge(entity)
            if (not self.transFlag):
                self.session.commit()
        except Exception as e:
            logger.error(traceback.format_exc())
            self.session.rollback()
            raise e
        finally:
            self.session.close()

    # 删除操作
    def delete(self, where):
        try:
            if (not self.transFlag):
                self.session = self.DBSession()
            self.session.query(self.entityType).filter(where).delete()
            if (not self.transFlag):
                self.session.commit()
        except Exception as e:
            logger.error(traceback.format_exc())
            self.session.rollback()
            raise e
        finally:
            self.session.close()

    # 查询单个实体
    def findEntity(self, *where):
        try:
            self.session = self.DBSession()
            if (type(*where) is BinaryExpression or type(*where) is BooleanClauseList):
                return self.session.query(self.entityType).filter(*where).first()
            else:
                return self.session.query(self.entityType).get(where)
        except Exception as e:
            logger.error(traceback.format_exc())
            self.session.rollback()
            raise e
        finally:
            self.session.close()

    def findLastEntity(self, order_by_field, *where):
        try:
            self.session = self.DBSession()
            if (type(*where) is BinaryExpression or type(*where) is BooleanClauseList):
                return self.session.query(self.entityType).filter(*where).order_by(desc(order_by_field)).first()
            else:
                return self.session.query(self.entityType).order_by(desc(order_by_field)).get(where)
        except Exception as e:
            logger.error(traceback.format_exc())
            self.session.rollback()
            raise e
        finally:
            self.session.close()

    # 查询实体列表
    def findList(self, *where):
        try:
            self.session = self.DBSession()
            return self.session.query(self.entityType).filter(*where)
        except Exception as e:
            logger.error(traceback.format_exc())
            self.session.rollback()
            raise e
        finally:
            self.session.close()

    # 查询所有实体列表
    def findAllList(self):
        try:
            self.session = self.DBSession()
            return self.session.query(self.entityType).all()
        except Exception as e:
            logger.error(traceback.format_exc())
            self.session.rollback()
            raise e
        finally:
            self.session.close()

    # 查询分页
    def queryPage(self, orm_query, pageParam):
        try:
            page = paginate_sqlalchemy.SqlalchemyOrmPage(
                orm_query, page=pageParam.curPage, items_per_page=pageParam.pageRows, db_session=self.DBSession)
            pageParam.totalRecords = page.item_count
            return page.items
        except Exception as e:
            logger.error(traceback.format_exc())
            raise e

    # 查询数量
    def findCount(self, *where):
        try:
            self.session = self.DBSession()
            return self.session.query(func.count('*')).select_from(self.entityType).filter(*where).scalar()
        except Exception as e:
            logger.error(traceback.format_exc())
            self.session.rollback()
            raise e
        finally:
            self.session.close()

    # 查询最大数
    def findMax(self, prop, *where):
        try:
            self.session = self.DBSession()
            return self.session.query(func.max(prop)).select_from(self.entityType).filter(*where).scalar()
        except Exception as e:
            logger.error(traceback.format_exc())
            self.session.rollback()
            raise e
        finally:
            self.session.close()

    # 执行Sql语句
    def execute(self, sql, *agrs):
        try:
            self.session = self.DBSession()
            return self.session.execute(sql, *agrs)
        except Exception as e:
            logger.error(traceback.format_exc())
            self.session.rollback()
            raise e
        finally:
            self.session.close()

    # 执行Sql语句
    def executeNoParam(self, sql):
        try:
            self.session = self.DBSession()
            self.session.execute(sql)
            if (not self.transFlag):
                self.session.commit()
        except Exception as e:
            logger.error(traceback.format_exc())
            self.session.rollback()
            raise e
        finally:
            self.session.close()