def parse_selection(inp, max_index):
    if inp.strip().lower() == "all":
        return list(range(max_index))

    result = set()
    for part in inp.split(","):
        part = part.strip()
        if "-" in part:
            a, b = part.split("-")
            result.update(range(int(a) - 1, int(b)))
        else:
            result.add(int(part) - 1)

    return sorted(i for i in result if 0 <= i < max_index)