from db import MongoClientHelper

class MongoDao:
    _instance = None
    
    def __new__(cls, collection_name):
        if not cls._instance:
            cls._instance = super(MongoDao, cls).__new__(cls)
            cls._instance._initialized = False
        return cls._instance
    
    def __init__(self, collection_name):
        if not self._initialized:
            self.db_client = MongoClientHelper()
            self._initialized = True
        self.collection_name = collection_name
            
    def get_one_record_by_query(self, query):
        res = self.db_client.find_one(self.collection_name, query)
        return res
    
    def get_records_by_query(self, query):
        collections = self.db_client.find_many(self.collection_name, query)
        records = [collection for collection in collections]
        return records
    
    def get_one_field_data(self, field):
        fields = [field]
        """获取指定key的所有数据，返回列表"""
        field_records = self.db_client.find_fields(self.collection_name, fields)
        return [record[field] for record in field_records]
    
    def get_fields_data(self, fields):
        records = self.db_client.find_fields(self.collection_name, fields)
        return [record for record in records]
    
    def get_all_records(self):
        records = self.db_client.find_all(self.collection_name)
        return [record for record in records]

        

if __name__ == '__main__':
    collection_name = "obrand-ec"
    dao = MongoDao(collection_name)
    field = "nick"
    res = dao.get_all_records()
    print(len(res))