/**
 * 前端埋点工具
 * 记录用户关键操作和错误信息
 */

import { request } from './request'

interface TrackEvent {
  event: string
  page?: string
  data?: Record<string, any>
}

/** 上报队列（批量上报，减少请求） */
let eventQueue: TrackEvent[] = []
let flushTimer: number | null = null
const FLUSH_INTERVAL = 500 // 500ms 攒批
const MAX_QUEUE_SIZE = 10   // 10 条立即发送

/** 获取当前页面路径 */
function getCurrentPage(): string {
  const pages = getCurrentPages()
  if (pages.length > 0) {
    return `/${pages[pages.length - 1].route}`
  }
  return '/unknown'
}

/** 批量上报事件 */
async function flushEvents() {
  if (eventQueue.length === 0) return

  const events = [...eventQueue]
  eventQueue = []

  try {
    await request({
      url: '/track',
      method: 'POST',
      data: { events }
    })
  } catch {
    // 上报失败不处理，避免影响用户体验
  }
}

/** 添加事件到队列 */
function addToQueue(event: TrackEvent) {
  eventQueue.push(event)

  // 队列满时立即上报
  if (eventQueue.length >= MAX_QUEUE_SIZE) {
    flushEvents()
    return
  }

  // 设置定时上报
  if (!flushTimer) {
    flushTimer = setTimeout(() => {
      flushTimer = null
      flushEvents()
    }, FLUSH_INTERVAL) as unknown as number
  }
}

/**
 * 追踪页面访问
 */
export function trackPageView(pagePath?: string) {
  addToQueue({
    event: 'page_view',
    page: pagePath || getCurrentPage()
  })
}

/**
 * 追踪用户操作
 * @param action 操作名称，如 'click_save', 'submit_form'
 * @param data 附加数据
 */
export function trackAction(action: string, data?: Record<string, any>) {
  addToQueue({
    event: 'action',
    page: getCurrentPage(),
    data: { action, ...data }
  })
}

/**
 * 追踪错误
 */
export function trackError(error: Error | string, extra?: Record<string, any>) {
  const errorInfo = typeof error === 'string'
    ? { message: error }
    : { message: error.message, stack: error.stack?.slice(0, 500) }

  addToQueue({
    event: 'error',
    page: getCurrentPage(),
    data: { ...errorInfo, ...extra }
  })
}

/**
 * 追踪 API 请求失败
 */
export function trackApiError(url: string, status: number, message: string) {
  addToQueue({
    event: 'api_error',
    page: getCurrentPage(),
    data: { url, status, message }
  })
}

/**
 * 设置全局错误监听
 */
export function setupErrorTracking() {
  // Vue 错误处理
  uni.onError((err: string) => {
    trackError(err, { type: 'global' })
  })

  // 未处理的 Promise rejection
  // #ifdef H5
  if (typeof window !== 'undefined') {
    window.addEventListener('unhandledrejection', (event) => {
      trackError(String(event.reason), { type: 'unhandledrejection' })
    })
  }
  // #endif
}

export default {
  trackPageView,
  trackAction,
  trackError,
  trackApiError,
  setupErrorTracking
}