import type { EventHandler, Unsubscribe } from "./events";

export type Awaitable<T> = T | Promise<T>;
export type ExtensionConfig = Record<string, unknown>;

export interface ExtensionSetupContext {
  add<T>(name: string, value: T): void;
  on<T>(event: string, handler: EventHandler<T>): Unsubscribe;
}

export interface ExtensionRuntimeContext {
  get<T>(name: string): T;
  all<T>(name: string): T[];
  on<T>(event: string, handler: EventHandler<T>): Unsubscribe;
  emit<T>(event: string, payload: T): Promise<unknown[]>;
}

export interface Extension {
  setup(context: ExtensionSetupContext): Awaitable<void>;
  start?(context: ExtensionRuntimeContext): Awaitable<void>;
  stop?(context: ExtensionRuntimeContext): Awaitable<void>;
}

export interface ExtensionFactory {
  id: string;
  (options?: ExtensionConfig): Extension;
}