"""Shared helpers for portable YOLO datasets."""

from __future__ import annotations

from pathlib import Path

import yaml


IMAGE_SUFFIXES = {".jpg", ".jpeg", ".png", ".bmp", ".webp"}


def load_dataset(data_path: Path) -> tuple[dict, Path, dict[int, str]]:
    data_path = data_path.expanduser().resolve()
    data = yaml.safe_load(data_path.read_text(encoding="utf-8"))
    root_value = data.get("path")
    root = Path(root_value).expanduser() if root_value else data_path.parent
    if not root.is_absolute():
        root = (data_path.parent / root).resolve()
    raw_names = data["names"]
    names = (
        {i: str(name) for i, name in enumerate(raw_names)}
        if isinstance(raw_names, list)
        else {int(key): str(value) for key, value in raw_names.items()}
    )
    return data, root, names


def split_images(data_path: Path, split: str) -> tuple[list[Path], Path, dict[int, str]]:
    data, root, names = load_dataset(data_path)
    value = Path(str(data[split]))
    image_root = value if value.is_absolute() else root / value
    images = sorted(path for path in image_root.rglob("*") if path.suffix.lower() in IMAGE_SUFFIXES)
    return images, root, names


def label_for_image(image: Path, root: Path, split: str) -> Path:
    return root / "labels" / split / f"{image.stem}.txt"