from datetime import datetime, date


def db_page(entity_filter, order, data, number):
    """分页帮助方法.

        对db.session出来的实体进行分页

        Args:
            entity_filter: an entity that need pagination.
            order: Sort by.
            data: get pageNumber.
            number: Number of lists per page

        Returns:
            可供json转换的dict

        Raises:
            TYPEError: 类型转换出错
        """
    entityPaginate = entity_filter.order_by(order.desc()).paginate(
        int(data.get('pageNumber')), number,
        error_out=False)
    resultList = []
    for (i, result) in enumerate(entityPaginate.items):
        result_modified = dict(zip(result.keys(), result))
        for (j, child) in enumerate(result):
            if type(child) == date or type(child) == datetime:
                result_modified.__setitem__(result.keys()[j], str(child))
        resultList.append(result_modified)
    return resultList


def db_page_entity(entity, data, number):
    """分页帮助方法.

            对实体查询出来的实体集合进行分页

            Args:
                entity: an entity that need pagination.
                data: get pageNumber.
                number: Number of lists per page

            Returns:
                可供json转换的dict

            Raises:
                TYPEError: 类型转换出错
            """
    data_list = entity.paginate(int(data.get('pageNumber')), number, error_out=False)
    result_list = [dict(zip([attr for attr in dir(result) if '_' not in attr and
                             attr is not 'query' and
                             attr is not 'metadata'],
                            [str(getattr(result, attr)) if
                             type(getattr(result, attr)) == date or
                             type(getattr(result, attr)) == datetime else
                             getattr(result, attr) for attr in dir(result) if '_' not in attr and
                             attr is not 'query' and
                             attr is not 'metadata']))
                   for result in data_list.items]
    return result_list


def entityDictToStringDict(resultList):
    """
    没啥用的函数，以前用来转换json数据为string模式的，更新了之后可以支持所有类型的数据 以前是因为json.dumps()不支持decimal类型的数据
    用List2Json中的方法转换为float就解决了
    """
    jsonList = []
    for dic in resultList:
        dicItem = {}
        for key, value in dic.items():
            if value is None:
                value = ''
            dicItem[key] = str(value)
        jsonList.append(dicItem)
    return jsonList


def singleEntityToJson(singleEntity):
    """
    单条数据转json，不需要分页的
    """
    dictList = [dict(zip([attr for attr in dir(singleEntity) if '_' not in attr and
                     attr is not 'query' and
                     attr is not 'metadata'],
                     [getattr(singleEntity, attr) for attr in dir(singleEntity)
                      if '_' not in attr and
                      attr is not 'query' and
                      attr is not 'metadata']))]
    return dictList[0]