import os
from pathlib import Path
from tempfile import TemporaryDirectory
from typing import TYPE_CHECKING

from cloudpathlib.exceptions import CloudPathIsADirectoryError

try:
    from azure.core.exceptions import ResourceNotFoundError
except ImportError:
    pass

from ..cloudpath import CloudPath, NoStatError, register_path_class


if TYPE_CHECKING:
    from .azblobclient import AzureBlobClient


@register_path_class("azure")
class AzureBlobPath(CloudPath):
    """Class for representing and operating on Azure Blob Storage URIs, in the style of the Python
    standard library's [`pathlib` module](https://docs.python.org/3/library/pathlib.html).
    Instances represent a path in Blob Storage with filesystem path semantics, and convenient
    methods allow for basic operations like joining, reading, writing, iterating over contents,
    etc. This class almost entirely mimics the [`pathlib.Path`](https://docs.python.org/3/library/pathlib.html#pathlib.Path)
    interface, so most familiar properties and methods should be available and behave in the
    expected way.

    The [`AzureBlobClient`](../azblobclient/) class handles authentication with Azure. If a
    client instance is not explicitly specified on `AzureBlobPath` instantiation, a default client
    is used. See `AzureBlobClient`'s documentation for more details.
    """

    cloud_prefix: str = "az://"
    client: "AzureBlobClient"

    @property
    def drive(self) -> str:
        return self.container

    def mkdir(self, parents=False, exist_ok=False):
        self.client._mkdir(self, parents=parents, exist_ok=exist_ok)

    def touch(self, exist_ok: bool = True):
        if self.exists():
            if not exist_ok:
                raise FileExistsError(f"File exists: {self}")
            self.client._move_file(self, self)
        else:
            tf = TemporaryDirectory()
            p = Path(tf.name) / "empty"
            p.touch()

            self.client._upload_file(p, self)

            tf.cleanup()

    def stat(self):
        try:
            meta = self.client._get_metadata(self)
        except ResourceNotFoundError:
            raise NoStatError(
                f"No stats available for {self}; it may be a directory or not exist."
            )

        return os.stat_result(
            (
                None,  # mode
                None,  # ino
                self.cloud_prefix,  # dev,
                None,  # nlink,
                None,  # uid,
                None,  # gid,
                meta.get("size", 0),  # size,
                None,  # atime,
                meta.get("last_modified", 0).timestamp(),  # mtime,
                None,  # ctime,
            )
        )

    def replace(self, target: "AzureBlobPath") -> "AzureBlobPath":
        try:
            return super().replace(target)

        # we can rename directories on ADLS Gen2
        except CloudPathIsADirectoryError:
            if self.client._check_hns(self):
                return self.client._move_file(self, target)
            else:
                raise

    @property
    def container(self) -> str:
        return self._no_prefix.split("/", 1)[0]

    @property
    def blob(self) -> str:
        key = self._no_prefix_no_drive

        # key should never have starting slash for
        if key.startswith("/"):
            key = key[1:]

        return key

    @property
    def etag(self):
        return self.client._get_metadata(self).get("etag", None)

    @property
    def md5(self) -> str:
        return self.client._get_metadata(self).get("content_settings", {}).get("content_md5", None)