advent22/api/advent22_api/core/helpers.py

import itertools
import random
import re
from io import BytesIO
from typing import Any, Self, Sequence, TypeVar

from fastapi.responses import StreamingResponse
from PIL import Image

from .config import get_config
from .webdav import WebDAV

T = TypeVar("T")


class Random(random.Random):
    @classmethod
    async def get(cls, bonus_salt: Any = "") -> Self:
        cfg = await get_config()
        return cls(f"{cfg.puzzle.solution}{cfg.puzzle.random_seed}{bonus_salt}")

    def shuffled(self, population: Sequence[T]) -> Sequence[T]:
        return self.sample(population, k=len(population))


def set_len(seq: Sequence[T], len: int) -> Sequence[T]:
    # `seq` unendlich wiederholen
    infinite = itertools.cycle(seq)

    # Die ersten `length` einträge nehmen
    return list(itertools.islice(infinite, len))


async def list_images_auto() -> list[str]:
    """
    Finde alle Bilddateien im "automatisch"-Verzeichnis
    """

    return await WebDAV.list_files(
        directory="/images_auto",
        regex=re.compile(r"\.(gif|jpe?g|tiff?|png|bmp)$", flags=re.IGNORECASE),
    )


async def load_image(file_name: str) -> Image.Image:
    """
    Versuche, Bild aus Datei zu laden
    """

    if not await WebDAV.file_exists(file_name):
        raise RuntimeError(f"DAV-File {file_name} does not exist!")

    return Image.open(BytesIO(await WebDAV.read_bytes(file_name)))


async def api_return_image(img: Image.Image) -> StreamingResponse:
    """
    Bild mit API zurückgeben
    """

    # JPEG-Daten in Puffer speichern
    img_buffer = BytesIO()
    img.save(img_buffer, format="JPEG", quality=85)
    img_buffer.seek(0)

    # zurückgeben
    return StreamingResponse(
        media_type="image/jpeg",
        content=img_buffer,
    )