// BossAi Service Worker - 离线访问支持
// 策略:API 请求 network-first,静态资源 cache-first
// 注意:开发环境(localhost:5173)不应注册 SW,index.html 已做端口判断
// 本文件仅在生产环境生效

const CACHE_VERSION = 'bossai-v2'
const STATIC_CACHE = `${CACHE_VERSION}-static`
const API_CACHE = `${CACHE_VERSION}-api`

// 预缓存静态资源
const PRECACHE_URLS = [
  '/',
  '/index.html',
  '/manifest.json',
]

// 安装:预缓存
self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(STATIC_CACHE).then((cache) => cache.addAll(PRECACHE_URLS))
      .then(() => self.skipWaiting())
  )
})

// 激活:清理旧缓存
self.addEventListener('activate', (event) => {
  event.waitUntil(
    caches.keys().then((keys) =>
      Promise.all(
        keys
          .filter((key) => !key.startsWith(CACHE_VERSION))
          .map((key) => caches.delete(key))
      )
    ).then(() => self.clients.claim())
  )
})

// 请求拦截
self.addEventListener('fetch', (event) => {
  const { request } = event
  const url = new URL(request.url)

  // 只处理同源请求
  if (url.origin !== self.location.origin) return

  // API 请求:network-first,失败时返回缓存
  if (url.pathname.startsWith('/api/')) {
    event.respondWith(
      fetch(request)
        .then((response) => {
          // 缓存成功的 GET 响应
          if (request.method === 'GET' && response.ok) {
            const clone = response.clone()
            caches.open(API_CACHE).then((cache) => cache.put(request, clone))
          }
          return response
        })
        .catch(() => {
          // 网络失败,尝试缓存
          if (request.method === 'GET') {
            return caches.match(request).then(
              (cached) => cached || new Response(
                JSON.stringify({ detail: '离线模式,数据不可用' }),
                { status: 503, headers: { 'Content-Type': 'application/json' } }
              )
            )
          }
          // 非 GET 请求离线时返回错误
          return new Response(
            JSON.stringify({ detail: '离线模式,操作不可用' }),
            { status: 503, headers: { 'Content-Type': 'application/json' } }
          )
        })
    )
    return
  }

  // 静态资源:cache-first,失败时网络
  event.respondWith(
    caches.match(request).then((cached) => {
      if (cached) return cached
      return fetch(request).then((response) => {
        // 缓存成功的响应
        if (response.ok && request.method === 'GET') {
          const clone = response.clone()
          caches.open(STATIC_CACHE).then((cache) => cache.put(request, clone))
        }
        return response
      })
    })
  )
})