"""Optional image metadata and computer-vision hints for image observations."""

from __future__ import annotations

import io
from typing import Any


def image_metadata(data: bytes) -> dict[str, Any]:
    """Read safe image metadata without changing the original upload."""
    try:
        from PIL import Image, ImageOps
        with Image.open(io.BytesIO(data)) as image:
            normalized = ImageOps.exif_transpose(image)
            return {
                "width": int(normalized.width),
                "height": int(normalized.height),
                "format": str(image.format or "").lower(),
                "orientation": "landscape" if normalized.width >= normalized.height else "portrait",
                "has_alpha": "A" in normalized.getbands(),
            }
    except Exception as error:
        return {"error": f"image metadata unavailable: {type(error).__name__}"}


def cv_hints(data: bytes) -> dict[str, Any]:
    """Return conservative CV hints; OpenCV is intentionally optional."""
    try:
        import cv2  # type: ignore
        import numpy as np  # type: ignore
    except Exception:
        return {"available": False, "hints": []}
    try:
        image = cv2.imdecode(np.frombuffer(data, dtype=np.uint8), cv2.IMREAD_GRAYSCALE)
        if image is None:
            return {"available": True, "hints": [], "error": "image decode failed"}
        edges = cv2.Canny(image, 50, 150)
        lines = cv2.HoughLinesP(edges, 1, 3.141592653589793 / 180, threshold=50, minLineLength=30, maxLineGap=8)
        line_hints = []
        for line in (lines[:32] if lines is not None else []):
            x1, y1, x2, y2 = [int(value) for value in line[0]]
            line_hints.append({"type": "line", "start_px": [x1, y1], "end_px": [x2, y2]})
        return {"available": True, "hints": line_hints, "edge_pixels": int((edges > 0).sum())}
    except Exception as error:
        return {"available": True, "hints": [], "error": f"cv failed: {type(error).__name__}"}