OnPlayerDied: playerId:int, cause:string
OnScoreChanged: score:int, delta:int
OnLevelComplete: levelId:string, timeSeconds:float
OnItemCollected: itemId:string
OnEnemySpawned: enemyId:string, spawnPoint:vector3

export interface GameEventBusMap {
  OnPlayerDied: { playerId: number; cause: string };
  OnScoreChanged: { score: number; delta: number };
  OnLevelComplete: { levelId: string; timeSeconds: number };
  OnItemCollected: { itemId: string };
  OnEnemySpawned: { enemyId: string; spawnPoint: Vector3 };
}

type EventKey = keyof GameEventBusMap;
type Handler<K extends EventKey> = (payload: GameEventBusMap[K]) => void;

export class GameEventBus {
  private handlers = new Map<EventKey, Set<Handler<EventKey>>>();

  on<K extends EventKey>(event: K, handler: Handler<K>): () => void {
    let set = this.handlers.get(event);
    if (!set) { set = new Set(); this.handlers.set(event, set); }
    set.add(handler as Handler<EventKey>);
    return () => this.off(event, handler);
  }

  once<K extends EventKey>(event: K, handler: Handler<K>): () => void {
    const stop = this.on(event, (payload) => { stop(); handler(payload); });
    return stop;
  }

  off<K extends EventKey>(event: K, handler: Handler<K>): void {
    const set = this.handlers.get(event);
    if (!set) return;
    set.delete(handler as Handler<EventKey>);
    if (set.size === 0) this.handlers.delete(event);
  }

  emit<K extends EventKey>(event: K, payload: GameEventBusMap[K]): void {
    const set = this.handlers.get(event);
    if (!set) return;
    for (const handler of [...set]) (handler as Handler<K>)(payload);
  }

  clear(event?: EventKey): void {
    if (event) this.handlers.delete(event); else this.handlers.clear();
  }
}

export const gameEvents = new GameEventBus();

import { gameEvents } from "./GameEventBus";
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