import logging
import time
from dataclasses import dataclass
from io import BytesIO
from typing import Any, Optional

from async_lru import alru_cache
from webdav3.client import Resource

from . import run_in_executor, webdav_resource

_logger = logging.getLogger(__name__)


def _get_ttl_hash(seconds: int = 20) -> int:
    """
    Return the same value within `seconds` time period
    https://stackoverflow.com/a/55900800
    """
    return round(time.time() / seconds)


@alru_cache(maxsize=20)
async def _get_buffer(
    remote_path: Any,
    ttl_hash: Optional[int] = None,
) -> BytesIO:
    del ttl_hash

    @run_in_executor
    def buffer_inner(resource: Resource) -> BytesIO:
        _logger.info(f"updating {resource}")
        print(f"updating {resource}")
        buffer = BytesIO()
        resource.write_to(buffer)
        return buffer

    resource = webdav_resource(remote_path)
    return await buffer_inner(resource)


@dataclass(frozen=True)
class DavFile:
    remote_path: str

    @property
    async def __buffer(self) -> BytesIO:
        return await _get_buffer(
            remote_path=self.remote_path,
            ttl_hash=_get_ttl_hash(20),
        )

    @property
    async def bytes(self) -> bytes:
        buffer = await self.__buffer

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

    @property
    async def string(self) -> str:
        bytes = await self.bytes
        return bytes.decode(encoding="utf-8")