"""Authoritative image decoding and metadata removal for evidence uploads."""

from __future__ import annotations

import io

from PIL import Image, ImageOps


MAX_IMAGE_PIXELS = 12 * 1024 * 1024


def sanitize_image(content_type: str, content: bytes) -> bytes:
    """Apply orientation and return metadata-free bytes in the claimed format."""
    format_names = {
        "image/png": "PNG",
        "image/jpeg": "JPEG",
        "image/webp": "WEBP",
    }
    try:
        with Image.open(io.BytesIO(content)) as source:
            claimed_format = format_names[content_type]
            if source.format != claimed_format:
                raise ValueError("image content does not match the selected image type")
            if getattr(source, "n_frames", 1) != 1:
                raise ValueError("animated image evidence is not supported")
            if source.width * source.height > MAX_IMAGE_PIXELS:
                raise ValueError("attachment must not exceed 12 megapixels")
            image = ImageOps.exif_transpose(source)
            image.load()
            output = io.BytesIO()
            save_options = {"quality": 90} if claimed_format in {"JPEG", "WEBP"} else {}
            image.save(output, format=claimed_format, **save_options)
            return output.getvalue()
    except ValueError:
        raise
    except (KeyError, OSError) as exc:
        raise ValueError("attachment must be a valid static image") from exc