import abc
import gzip
import logging
import os
from itertools import repeat
from operator import attrgetter
from typing import Iterable

from mini_queue.utils.file import path_to_compressed_storage_pdf_object_name, provide_directory
from mini_queue.utils.meta import NoAttemptsLeft, max_attempts


class StorageHandle:
    """Storage API base"""

    def __init__(self):
        self.default_container_name = None

    @abc.abstractmethod
    def __provide_container(self, container_name):
        pass

    @abc.abstractmethod
    def __add_file(self, path, filename, container_name=None):
        pass

    @max_attempts(n_attempts=10, max_timeout=60)
    def add_file(self, path: str, folder: str = None, container_name: str = None) -> None:
        """Adds a file to the store.

        Args:
            path: Path to file to add to store.
            folder: Folder to hold file.
            container_name: container to hold file.
        """
        storage_path = self.__storage_path(path, folder=folder)
        self.__add_file(path, storage_path, container_name)

    @max_attempts()
    def _list_files(self, object_name_attr="object_name", container_name=None) -> Iterable[str]:
        """List all files in a container.

        Args:
            container_name: container to list files from.

        Returns:
            Iterable of filenames.
        """
        if container_name is None:
            container_name = self.default_container_name
        return map(attrgetter(object_name_attr), self.get_objects(container_name))

    @abc.abstractmethod
    def list_files(self, container_name=None) -> Iterable[str]:
        pass

    @abc.abstractmethod
    def get_objects(self, container_name=None):
        pass

    @abc.abstractmethod
    def __list_containers(self):
        pass

    @max_attempts()
    def get_all_objects(self) -> Iterable:
        """Gets all objects in the store

        Returns:
            Iterable over all objects in the store.
        """
        for container in self.__list_containers():
            yield from zip(repeat(container), self.get_objects(container.name))

    @abc.abstractmethod
    def __purge(self) -> None:
        pass

    @max_attempts()
    def purge(self) -> None:
        self.__purge()

    def list_files_by_type(self, container_name=None, extension=".pdf.gz"):
        return filter(lambda p: p.endswith(extension), self.list_files(container_name))

    @abc.abstractmethod
    def __fget_object(self, *args, **kwargs):
        pass

    @staticmethod
    def __storage_path(path, folder: str = None):
        def path_to_filename(path):
            return os.path.basename(path)

        storage_path = path_to_filename(path)
        if folder is not None:
            storage_path = os.path.join(folder, storage_path)

        return storage_path

    @max_attempts()
    def list_folders_and_files(self, container_name: str = None) -> Iterable[str]:
        """Lists pairs of folder name (dossier-IDs) and file name (file-IDs) of items in a container.

        Args:
            container_name: container to list items for.

        Returns:
            Iterable of pairs folder name (dossier-ID) and file names (file-ID)
        """
        return map(lambda p: p.split("/"), self.list_files_by_type(container_name))

    @abc.abstractmethod
    def __remove_file(self, folder: str, filename: str, container_name: str = None) -> None:
        pass

    @max_attempts()
    def remove_file(self, folder: str, filename: str, container_name: str = None) -> None:
        self.__remove_file(folder, filename, container_name)

    def add_file_compressed(self, path, folder: str = None, container_name: str = None) -> None:
        """Adds a file as a .gz archive to the store.

        Args:
            path: Path to file to add to store.
            folder: Folder to hold file.
            container_name: container to hold file.
        """

        def compress(path_in: str, path_out: str):
            with open(path_in, "rb") as f_in, gzip.open(path_out, "wb") as f_out:
                f_out.writelines(f_in)

        path_gz = path_to_compressed_storage_pdf_object_name(path)
        compress(path, path_gz)

        self.add_file(path_gz, folder, container_name)
        os.unlink(path_gz)

    @max_attempts()
    def download_file(self, object_names: str, target_root_dir: str, container_name: str = None) -> str:
        """Downloads a file from the store.

        Args:
            object_names: Complete object name (folder and file).
            target_root_dir: Root directory to download file into (including its folder).
            container_name: container to load file from.

        Returns:
            str: Path to downloaded file.
        """

        @max_attempts(5, exceptions=(FileNotFoundError,))
        def download(object_name: str) -> str:

            path, basename = os.path.split(object_name)
            target_dir = os.path.join(target_root_dir, path)
            provide_directory(target_dir)
            target_path = os.path.join(target_dir, basename)

            logging.log(msg=f"Downloading {object_name}...", level=logging.DEBUG)
            try:
                self.__fget_object(container_name, object_name, target_path)
                logging.log(msg=f"Downloaded {object_name}.", level=logging.DEBUG)
            except Exception as err:
                logging.log(msg=f"Downloading {object_name} failed.", level=logging.ERROR)
                raise err
            return target_path

        if container_name is None:
            container_name = self.default_container_name

        try:
            target_path = download(object_names)
        except NoAttemptsLeft as err:
            logging.log(msg=f"{err}", level=logging.ERROR)
            raise err

        return target_path