from typing import Sequence

from .todo_item import Todo
from .todo_list_types import ToggleAllMode


def toggle_all_mode(todos: Sequence[Todo]) -> ToggleAllMode:
    """What toggle_all would do: complete while any todo is open, reopen once none is, none when empty."""
    if len(todos) == 0:
        return "none"
    return "complete" if any(not t.done for t in todos) else "reopen"