from abc import ABCMeta, abstractmethod
import os
from typing import Tuple, Optional, Any

import jinja2

from app import app


class BaseAutomation(metaclass=ABCMeta):
    short_name: str = "base"
    description: str = "Abstract base automation."
    frequency: int

    """
    The short name of the automation provider. This is used as an opaque token throughout
    the portal system.
    """

    @abstractmethod
    def automate(self, full: bool = False) -> Tuple[bool, str]:
        raise NotImplementedError()

    def working_directory(self, filename: Optional[str] = None) -> str:
        """
        Provides a filesystem path that can be used during the automation run.
        This is currently a persistent path, but this should not be relied upon
        as future versions may use disposable temporary paths instead. State that
        is needed in subsequent runs should be stored elsewhere.

        :param filename: the filename inside the working directory to create a path for
        :return: filesystem path for that filename
        """
        return os.path.join(
            app.config['TERRAFORM_DIRECTORY'],
            self.short_name or self.__class__.__name__.lower(),
            filename or ""
        )

    def tmpl_write(self, filename: str, template: str, **kwargs: Any) -> None:
        """
        Write a Jinja2 template to the working directory for use by an automation module.

        :param filename: filename to write to
        :param template: Jinja2 template
        :param kwargs: variables for use with the template
        :return: None
        """
        tmpl = jinja2.Template(template)
        with open(self.working_directory(filename), 'w', encoding="utf-8") as tf:
            tf.write(tmpl.render(**kwargs))