import type {
  DataProviderKey,
  DataProviderKeyHost,
} from "../../utils/dataProviderKey";
import { bind } from "./bind";

/**
 * Read-only subscription to a publisher path via DataProviderKey<T>. No reflect.
 * The decorated property is typed as `T` (or optional / `| null` / `| undefined` for Lit / TS 5).
 * Supports dynamic paths: use placeholders like "users.${userIndex}" in the DataProviderKey.
 *
 * @example
 * const dataKey = new DataProviderKey<Data>("data");
 * @subscribe(dataKey.count)
 * @state()
 * count: number;
 *
 * // Dynamic path:
 * @subscribe(new DataProviderKey<User>("users.${userIndex}"))
 * user: User | null;
 */
export function subscribe<T, U = any>(
  key: DataProviderKey<T, U>,
): <K extends string>(
  target: DataProviderKeyHost<U> & { [P in K]?: T | null | undefined },
  propertyKey: K,
) => void {
  return bind(key) as <K extends string>(
    target: DataProviderKeyHost<U> & { [P in K]?: T | null | undefined },
    propertyKey: K,
  ) => void;
}