from io import BytesIO

from PIL import Image, ImageOps, UnidentifiedImageError
from fastapi import HTTPException, UploadFile


def compress_image(file: UploadFile) -> bytes:
    if not file.content_type or not file.content_type.startswith("image/"):
        raise HTTPException(status_code=400, detail="File must be an image")
    try:
        file.file.seek(0)
        original_bytes = file.file.read()
        image = Image.open(BytesIO(original_bytes))
        image = ImageOps.exif_transpose(image)
        max_size = 512
        image.thumbnail((max_size, max_size), Image.Resampling.LANCZOS)
        if image.mode not in ("RGB", "RGBA"):
            image = image.convert("RGBA")
        buffer = BytesIO()
        image.save(buffer, format="PNG", optimize=True, compress_level=9)
        return buffer.getvalue()
    except (UnidentifiedImageError, OSError):
        raise HTTPException(status_code=400, detail="Invalid image file")
    finally:
        try:
            file.file.close()
        except Exception:
            pass