"""Utility functions for SpaceDebris Localizer."""

from __future__ import annotations

import logging
from typing import Any

from PIL import Image

logger = logging.getLogger(__name__)


def validate_image(image: Any) -> tuple[bool, str]:
    """Validate that an input is a usable PIL image.

    Returns:
        Tuple of (is_valid, error_message).
    """
    if image is None:
        return False, "No image provided. Please upload an image."
    if not isinstance(image, Image.Image):
        return False, "Invalid image format. Please upload a valid image file."
    if image.mode not in ("RGB", "RGBA", "L"):
        return False, f"Unsupported image mode: {image.mode}. Use RGB or grayscale."
    w, h = image.size
    if w < 32 or h < 32:
        return False, f"Image too small ({w}x{h}). Minimum 32x32 pixels."
    if w > 8192 or h > 8192:
        return False, f"Image too large ({w}x{h}). Maximum 8192x8192 pixels."
    return True, ""


def ensure_rgb(image: Image.Image) -> Image.Image:
    """Convert image to RGB if needed."""
    if image.mode == "RGBA":
        background = Image.new("RGB", image.size, (0, 0, 0))
        background.paste(image, mask=image.split()[3])
        return background
    if image.mode == "L":
        return image.convert("RGB")
    if image.mode != "RGB":
        return image.convert("RGB")
    return image


def format_metadata(parse_result: Any) -> str:
    """Format parse result metadata as human-readable text."""
    lines = [
        f"Detected objects: {parse_result.num_detections}",
        f"Raw output length: {len(parse_result.raw_output)} chars",
    ]
    if parse_result.parse_errors:
        lines.append(f"Parse warnings: {len(parse_result.parse_errors)}")
        for err in parse_result.parse_errors[:5]:
            lines.append(f"  - {err}")
    return "\n".join(lines)


def format_json_output(parse_result: Any) -> dict[str, Any]:
    """Return JSON-serializable dict from parse result."""
    return parse_result.to_dict()