from __future__ import annotations

import io
from typing import Optional, Tuple
import requests
from PIL import Image

DEFAULT_MAX_BYTES = 50 * 1024 * 1024  # 50MB

class ImageLoadError(Exception):
    pass

def fetch_url_bytes(url: str, timeout: float = 10.0, max_bytes: int = DEFAULT_MAX_BYTES) -> bytes:
    try:
        with requests.get(url, stream=True, timeout=timeout) as r:
            r.raise_for_status()
            buf = io.BytesIO()
            total = 0
            for chunk in r.iter_content(chunk_size=1024 * 64):
                if not chunk:
                    continue
                total += len(chunk)
                if total > max_bytes:
                    raise ImageLoadError(f"Image exceeds max_bytes={max_bytes}")
                buf.write(chunk)
            return buf.getvalue()
    except Exception as e:
        raise ImageLoadError(f"Cannot fetch image url: {e}") from e

def bytes_to_pil(data: bytes) -> Image.Image:
    try:
        img = Image.open(io.BytesIO(data)).convert("RGB")
        return img
    except Exception as e:
        raise ImageLoadError(f"Cannot decode image: {e}") from e