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"""This module contains SFTP sensor."""
from typing import TYPE_CHECKING, Optional, Sequence

from paramiko.sftp import SFTP_NO_SUCH_FILE

from airflow.providers.sftp.hooks.sftp import SFTPHook
from airflow.sensors.base import BaseSensorOperator

if TYPE_CHECKING:
    from airflow.utils.context import Context


class SFTPSensor(BaseSensorOperator):
    """
    Waits for a file or directory to be present on SFTP.

    :param path: Remote file or directory path
    :param sftp_conn_id: The connection to run the sensor against
    """

    template_fields: Sequence[str] = ('path',)

    def __init__(self, *, path: str, sftp_conn_id: str = 'sftp_default', **kwargs) -> None:
        super().__init__(**kwargs)
        self.path = path
        self.hook: Optional[SFTPHook] = None
        self.sftp_conn_id = sftp_conn_id

    def poke(self, context: 'Context') -> bool:
        self.hook = SFTPHook(self.sftp_conn_id)
        self.log.info('Poking for %s', self.path)
        try:
            mod_time = self.hook.get_mod_time(self.path)
            self.log.info('Found File %s last modified: %s', str(self.path), str(mod_time))
        except OSError as e:
            if e.errno != SFTP_NO_SUCH_FILE:
                raise e
            return False
        self.hook.close_conn()
        return True
