from collections.abc import MutableMapping, MutableSequence, Sequence
from copy import copy
from typing import TypeVar

from . import events as e
from .common import HookedContainer, MutableNesting
from .sequence import HookedList

T = TypeVar("T")


class HookedMapping(HookedContainer[T], MutableMapping[T, MutableNesting[T]]):
    _data: MutableMapping[T, MutableNesting[T]]

    def __init__(
        self,
        hook,
        existing: MutableMapping[T, MutableNesting[T]],
        path: Sequence[int] | None = None,
    ):
        self.hook = hook
        self._data = existing
        self._path = list(path) if path is not None else []

    def __getitem__(self, key: T) -> MutableNesting[T]:
        value = self._data[key]
        new_path = copy(self._path)
        new_path.append(key)
        match value:
            case MutableMapping() as mapping:
                return HookedMapping(hook=self.hook, existing=mapping, path=new_path)
            case MutableSequence() as seq:
                return HookedList(hook=self.hook, existing=seq, path=new_path)
            case _ as item:
                return item

    def __setitem__(self, key: T, value: MutableNesting[T]) -> None:
        self._data[key] = value
        if self.hook:
            self.hook(e.SetItemEvent(index=key, item=value))

    def __delitem__(self, key: T) -> None:
        item = self._data[key]
        del self._data[key]
        if self.hook:
            self.hook(e.RemoveItemEvent(index=key, item=item, path=self._path))