import os
from backports.tempfile import TemporaryDirectory

from config_app.config_util.config.fileprovider import FileConfigProvider

class TransientDirectoryProvider(FileConfigProvider):
    """ Implementation of the config provider that reads and writes the data
        from/to the file system, only using temporary directories,
        deleting old dirs and creating new ones as requested.
    """
    def __init__(self, config_volume, yaml_filename, py_filename):
        # Create a temp directory that will be cleaned up when we change the config path
        # This should ensure we have no "pollution" of different configs:
        # no uploaded config should ever affect subsequent config modifications/creations
        temp_dir = TemporaryDirectory()
        self.temp_dir = temp_dir
        super(TransientDirectoryProvider, self).__init__(temp_dir.name, yaml_filename, py_filename)

    @property
    def provider_id(self):
        return 'transient'

    def new_config_dir(self):
        """
        Update the path with a new temporary directory, deleting the old one in the process
        """
        temp_dir = TemporaryDirectory()

        self.config_volume = temp_dir.name
        self.temp_dir = temp_dir
        self.yaml_path = os.path.join(temp_dir.name, self.yaml_filename)

    def get_config_dir_path(self):
        return self.config_volume