/** 针对某种事件进行的代码注入 */
export interface PluginHookProvider {
  /** 事件发生前执行 */
  before?: (...args: any[]) => void | Promise<void>
  /** 事件发生后执行 */
  after?: (...args: any[]) => void | Promise<void>
}
const pluginHookMap = new Map<
  string,
  {
    providers: PluginHookProvider[]
  }
>()

/**
 * 向由 `key` 指定的目标注入代码
 * @param key 标识ID
 * @param provider 代码注入的配置对象
 */
export const addHook = (key: string, provider: PluginHookProvider) => {
  if (pluginHookMap.has(key)) {
    const { providers } = pluginHookMap.get(key)
    providers.push(provider)
  } else {
    pluginHookMap.set(key, {
      providers: [provider],
    })
  }
}

/**
 * 根据 `key` 获取已添加的代码注入
 * @param key 标识ID
 * @param fixedArgs 运行代码注入函数时, 传入的固定参数
 */
export const getHook = (key: string, ...fixedArgs: any[]) => {
  if (pluginHookMap.has(key)) {
    const item = pluginHookMap.get(key)
    const { providers } = item
    return {
      before: async (...args: any[]) =>
        Promise.all(providers.map(p => p.before?.(...fixedArgs.concat(args)))),
      after: async (...args: any[]) =>
        Promise.all(providers.map(p => p.after?.(...fixedArgs.concat(args)))),
    }
  }
  return {
    before: async () => Promise.all<void>([]),
    after: async () => Promise.all<void>([]),
  }
}