"""Shared tiny registry for eval-layer plugins (mirrors data registry semantics)."""

import difflib
from typing import Callable, Dict, List


class EvalRegistry:
    """Dict registry: decorator registration, duplicate guard, suggestions."""

    def __init__(self, kind: str):
        self.kind = kind
        self._items: Dict[str, Callable] = {}

    def register(self, name: str, fn: Callable) -> Callable:
        if name in self._items:
            raise ValueError(f'{self.kind} {name!r} is already registered')
        self._items[name] = fn
        return fn

    def get(self, name: str) -> Callable:
        if name not in self._items:
            near = difflib.get_close_matches(name, self._items, n=3)
            hint = f" Did you mean: {', '.join(near)}?" if near else ''
            raise KeyError(f'unknown {self.kind} {name!r}.{hint}')
        return self._items[name]

    def names(self) -> List[str]:
        return sorted(self._items)

    def __contains__(self, name: str) -> bool:
        return name in self._items

    def __len__(self) -> int:
        return len(self._items)