# -*- coding: utf-8 -*-

import sys
import logging


class InvalidSaveConfigsError(Exception):
    def __init__(self, message, errors):
        # Call the base class constructor with the parameters it needs
        super(InvalidSaveConfigsError, self).__init__(message)


class Saver(object):
    """
    get task from item queue, then save item to local storage
    """

    def __init__(self, save_configs=None):
        self._save_configs = save_configs

        if save_configs['type'] == 'file':
            write_path = self._save_configs['path']
            self._file_obj = open(write_path, 'w')
        elif save_configs['type'] == 'db':
            self._conn_pool = None

        return

    async def save(self, url, item):
        """
        try to save result according to save configs
        """
        try:
            configs = self._save_configs
            if configs['type'] == 'file':
                await self.save_to_file(url, item, self._file_obj)
            elif configs['type'] == 'db':
                await self.save_to_db()
            else:
                raise InvalidSaveConfigsError
        except InvalidSaveConfigsError:
            logging.error("invalid save configs, update 'save' field in the config.json")
        return


    async def save_to_file(self, url, item, file_obj):
        """
        save the item to a file, must "try, except" and don't change the parameters and return
        :return status:
        """
        logging.debug("%r start: url=%r", self.__class__.__name__, url)
        status = 0

        try:
            write_path = self._save_configs['path']
            item_str = ", ".join(str(x) for x in item)
            line = url + ": " + item_str + '\n'
            file_obj.write(line)

        # TODO: substitute to more specific exception
        except Exception as e:
            status = -1
            logging.error("%r error: %r, url=%r",
                          self.__class__.__name__, e, url)

        logging.debug("%r end: status=%r, url=%r",
                      self.__class__.__name__, status, url)
        return status


    async def save_to_db(self):
        """
        save the item to a database
        """
        raise NotImplementedError