// 事件总线类型定义
type EventCallback = (...args: any[]) => void

// 事件总线实现
class EventBus {
  private events: Record<string, EventCallback[]> = {}

  // 订阅事件
  on(event: string, callback: EventCallback): void {
    if (!this.events[event]) {
      this.events[event] = []
    }
    this.events[event].push(callback)
  }

  // 取消订阅
  off(event: string, callback?: EventCallback): void {
    if (!this.events[event]) return

    if (!callback) {
      delete this.events[event]
    } else {
      this.events[event] = this.events[event].filter((cb) => cb !== callback)
    }
  }

  // 触发事件
  emit(event: string, ...args: any[]): void {
    if (!this.events[event]) return

    this.events[event].forEach((callback) => {
      callback(...args)
    })
  }

  // 只订阅一次
  once(event: string, callback: EventCallback): void {
    const onceCallback = (...args: any[]) => {
      callback(...args)
      this.off(event, onceCallback)
    }

    this.on(event, onceCallback)
  }
}

// 创建全局事件总线实例
export const eventBus = new EventBus()

// 预定义事件类型
export const EVENT_TYPES = {
  API_ERROR: "api:error",
  NOTIFICATION: "notification",
  AUTH_EXPIRED: "auth:expired",
}

// 通知类型
export interface Notification {
  title: string
  message: string
  type: "success" | "error" | "warning" | "info"
  duration?: number
}

// 辅助函数：发送通知
export function notify(notification: Notification): void {
  eventBus.emit(EVENT_TYPES.NOTIFICATION, notification)
}

// 辅助函数：发送API错误通知
export function notifyApiError(title: string, message: string): void {
  notify({
    title,
    message,
    type: "error",
    duration: 5000,
  })
}