1// Copyright 2025 Google LLC
 2//
 3// Licensed under the Apache License, Version 2.0 (the "License");
 4// you may not use this file except in compliance with the License.
 5// You may obtain a copy of the License at
 6//
 7//     https://www.apache.org/licenses/LICENSE-2.0
 8//
 9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15type TCallable = (...args: any[]) => any
16
17let locked = false
18const lock: () => void = () => (locked = true)
19
20const store: Map<string, any> = new Map()
21const override: (typeof store)['set'] = store.set.bind(store)
22function wrap<T extends object>(name: string, api: T): T {
23  if (locked) throw new Error('bus is locked')
24  override(name, api)
25  return new Proxy<T>(api, {
26    get(_, key) {
27      return store.get(name)[key] || store.get(name)?.default?.[key]
28    },
29    apply(_, self, args) {
30      return (store.get(name) as TCallable).apply(self, args)
31    },
32  })
33}
34
35/**
36 * @internal
37 * @private
38 * @protected
39 */
40export const bus = {
41  override,
42  wrap,
43  lock,
44}