"use strict";

class TarinaiEventBus {
  constructor({ historyLimit = 180 } = {}) {
    this.handlers = new Map();
    this.history = [];
    this.historyLimit = historyLimit;
  }

  on(type, handler) {
    if (!type || typeof handler !== "function") return () => {};
    let list = this.handlers.get(type);
    if (!list) {
      list = new Set();
      this.handlers.set(type, list);
    }
    list.add(handler);
    return () => this.off(type, handler);
  }

  off(type, handler) {
    const list = this.handlers.get(type);
    if (!list) return;
    list.delete(handler);
    if (!list.size) this.handlers.delete(type);
  }

  emit(type, detail = {}) {
    if (!type) return null;
    const event = { type, detail: detail || {}, at: performance?.now?.() ?? Date.now() };
    this.history.unshift(event);
    if (this.history.length > this.historyLimit) this.history.length = this.historyLimit;
    const direct = this.handlers.get(type);
    if (direct) for (const handler of [...direct]) this.safeCall(handler, event);
    const wildcard = this.handlers.get("*");
    if (wildcard) for (const handler of [...wildcard]) this.safeCall(handler, event);
    return event;
  }

  safeCall(handler, event) {
    try { handler(event); }
    catch (err) { console.error("event handler failed", event.type, err); }
  }

  recent(filter = null, limit = 40) {
    const list = filter ? this.history.filter(ev => ev.type === filter) : this.history;
    return list.slice(0, limit);
  }
}

window.TarinaiEventBus = TarinaiEventBus;
window.TarinaiEvents = window.TarinaiEvents || new TarinaiEventBus();