from collections.abc import MutableSequence
from dataclasses import dataclass
from typing import Generic, TypeVar

T = TypeVar("T")


@dataclass(frozen=True)
class ChangeEvent(Generic[T]):
    index: int
    item: T
    path: MutableSequence[int] | None = None


@dataclass(frozen=True)
class AddItemEvent(ChangeEvent[T]):
    item: T


@dataclass(frozen=True)
class SetItemEvent(ChangeEvent[T]):
    item: T


@dataclass(frozen=True)
class RemoveItemEvent(ChangeEvent[T]):
    item: T