"""
Definition of an asyncio compatible WebDAV file.

Caches files using `timed_alru_cache`.
"""

from dataclasses import dataclass
from io import BytesIO
from logging import getLogger
from typing import Any

from webdav3.client import Resource

from .async_helpers import get_ttl_hash, run_in_executor, timed_alru_cache
from .dav_common import webdav_resource
from .settings import SETTINGS

_logger = getLogger(__name__)


@timed_alru_cache(maxsize=SETTINGS.cache_size)
async def _get_buffer(
    remote_path: Any,
) -> BytesIO:
    """
    Download file contents into a new `BytesIO` object.
    """

    @run_in_executor
    def _inner() -> BytesIO:
        _logger.info(f"downloading {remote_path!r} ...")

        resource = webdav_resource(remote_path)
        buffer = BytesIO()
        resource.write_to(buffer)
        return buffer

    return await _inner()


@dataclass(frozen=True)
class DavFile:
    """
    Object representation of a WebDAV file.
    """

    remote_path: str

    @property
    def resource(self) -> Resource:
        """
        WebDAV file handle.
        """

        return webdav_resource(self.remote_path)

    @property
    async def __buffer(self) -> BytesIO:
        """
        File contents as binary stream.
        """

        return await _get_buffer(
            ttl_hash=get_ttl_hash(),
            remote_path=self.remote_path,
        )

    @property
    async def bytes(self) -> bytes:
        """
        File contents as binary data.
        """

        buffer = await self.__buffer

        buffer.seek(0)
        return buffer.read()

    @property
    async def string(self) -> str:
        """
        File contents as string.
        """

        bytes = await self.bytes
        return bytes.decode(encoding="utf-8")

    async def write(self, content: bytes) -> None:
        """
        Write bytes into file.
        """

        @run_in_executor
        def _inner() -> None:
            buffer = BytesIO(content)
            self.resource.read_from(buffer)

        await _inner()