import { post } from './request.js'

const QUEUE_KEY = 'analytics_queue'
const ANON_KEY = 'analytics_anonymous_id'
const MAX_QUEUE = 100
const FLUSH_SIZE = 20
const FLUSH_INTERVAL = 10000

let queue = []
let sessionId = ''
let pageEnterAt = {}
let flushTimer = null
let initialized = false

const runtimeRoot = typeof globalThis !== 'undefined' ? globalThis : {}

const now = () => Date.now()

const uuid = (prefix) => `${prefix}_${now()}_${Math.random().toString(36).slice(2, 10)}`

export const getAnonymousId = () => {
  let id = uni.getStorageSync(ANON_KEY)
  if (!id) {
    id = uuid('anon')
    uni.setStorageSync(ANON_KEY, id)
  }
  return id
}

const loadQueue = () => {
  const saved = uni.getStorageSync(QUEUE_KEY)
  queue = Array.isArray(saved) ? saved.slice(-MAX_QUEUE) : []
}

const saveQueue = () => {
  uni.setStorageSync(QUEUE_KEY, queue.slice(-MAX_QUEUE))
}

const getDeviceInfo = () => {
  try {
    const system = uni.getSystemInfoSync()
    return {
      platform: system.platform,
      model: system.model,
      system: system.system,
      version: system.version,
      SDKVersion: system.SDKVersion
    }
  } catch (error) {
    return { platform: 'unknown' }
  }
}

const safeProperties = (properties = {}) => {
  const blocked = ['token', 'access_token', 'refresh_token', 'phone', 'smsCode', 'content', 'fullContent']
  return Object.keys(properties || {}).reduce((acc, key) => {
    if (!blocked.includes(key)) acc[key] = properties[key]
    return acc
  }, {})
}

export const initAnalytics = () => {
  if (initialized) return
  initialized = true
  runtimeRoot.__emotionAnalyticsTrack = (eventName, properties = {}, options = {}) => {
    track(eventName, properties, options)
  }
  sessionId = uuid('session')
  loadQueue()
  track('app_launch', {}, { eventType: 'app' })
  if (!flushTimer) {
    flushTimer = setInterval(() => flush(), FLUSH_INTERVAL)
  }
}

export const track = (eventName, properties = {}, options = {}) => {
  if (!eventName) return
  queue.push({
    eventName,
    eventType: options.eventType || eventName.split('_')[0] || 'custom',
    pagePath: options.pagePath || '',
    referrerPath: options.referrerPath || '',
    properties: safeProperties(properties),
    durationMs: options.durationMs,
    occurredAt: new Date().toISOString().slice(0, 19).replace('T', ' ')
  })
  queue = queue.slice(-MAX_QUEUE)
  saveQueue()
  if (queue.length >= FLUSH_SIZE) {
    flush()
  }
}

export const trackPageView = (pagePath, properties = {}) => {
  pageEnterAt[pagePath] = now()
  track('page_view', properties, { eventType: 'page', pagePath })
}

export const trackPageLeave = (pagePath, properties = {}) => {
  const durationMs = pageEnterAt[pagePath] ? now() - pageEnterAt[pagePath] : undefined
  delete pageEnterAt[pagePath]
  track('page_leave', properties, { eventType: 'page', pagePath, durationMs })
}

export const flush = async () => {
  if (!queue.length || !sessionId) return
  const sending = queue.slice(0, 50)
  try {
    await post('/analytics/events/batch', {
      anonymousId: getAnonymousId(),
      sessionId,
      deviceInfo: getDeviceInfo(),
      events: sending
    })
    queue = queue.slice(sending.length)
    saveQueue()
  } catch (error) {
    saveQueue()
  }
}

export default {
  initAnalytics,
  track,
  trackPageView,
  trackPageLeave,
  flush,
  getAnonymousId
}