/**
 * Cloudflare Worker — 定时刷新 ds2api 代理健康状态
 *
 * 部署步骤:
 *   1. cd cf-worker && npm install
 *   2. 设置 secrets:
 *        wrangler secret put DS2API_BASE_URL
 *        wrangler secret put ADMIN_KEY
 *        wrangler secret put VERCEL_BYPASS_TOKEN   (如果开了 Vercel Deployment Protection)
 *   3. wrangler deploy
 *
 * Cron 每 5 小时触发一次 (与 wrangler.toml 中的 crons 对应)。
 * 也可以手动 GET/POST https://<worker>/check 触发。
 */

const LOGIN_PATH = "/admin/login"
const CHECK_ALL_PATH = "/admin/proxies/check-all"

function vercelHeaders(env) {
  const headers = {}
  const bypass = env.VERCEL_BYPASS_TOKEN
  if (bypass) {
    headers["x-vercel-protection-bypass"] = bypass
  }
  return headers
}

async function login(baseURL, adminKey, extraHeaders) {
  const res = await fetch(`${baseURL}${LOGIN_PATH}`, {
    method: "POST",
    headers: { "Content-Type": "application/json", ...extraHeaders },
    body: JSON.stringify({ admin_key: adminKey, expire_hours: 1 }),
  })
  if (!res.ok) {
    const text = await res.text()
    throw new Error(`login failed (${res.status}): ${text}`)
  }
  const data = await res.json()
  return data.token
}

async function checkAll(baseURL, token, extraHeaders) {
  const res = await fetch(`${baseURL}${CHECK_ALL_PATH}`, {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      Authorization: `Bearer ${token}`,
      ...extraHeaders,
    },
  })
  if (!res.ok) {
    const text = await res.text()
    throw new Error(`check-all failed (${res.status}): ${text}`)
  }
  return res.json()
}

async function runCheck(env) {
  const baseURL = (env.DS2API_BASE_URL || "").replace(/\/+$/, "")
  const adminKey = env.ADMIN_KEY || ""

  if (!baseURL || !adminKey) {
    throw new Error("DS2API_BASE_URL and ADMIN_KEY secrets must be set")
  }

  const extraHeaders = vercelHeaders(env)
  const token = await login(baseURL, adminKey, extraHeaders)
  const result = await checkAll(baseURL, token, extraHeaders)
  return result
}

export default {
  async scheduled(event, env, ctx) {
    ctx.waitUntil(
      runCheck(env)
        .then((result) => {
          const items = result.items || []
          const healthy = items.filter((i) => i.healthy && !i.disabled).length
          const banned = items.filter((i) => i.disabled).length
          console.log(
            `proxy health check done: ${healthy}/${items.length} healthy, ${banned} banned`
          )
        })
        .catch((err) => {
          console.error(`proxy health check failed: ${err.message}`)
        })
    )
  },

  async fetch(request, env) {
    const url = new URL(request.url)
    if (url.pathname !== "/check") {
      return new Response("not found", { status: 404 })
    }

    try {
      const result = await runCheck(env)
      return Response.json(result)
    } catch (err) {
      return Response.json({ error: err.message }, { status: 500 })
    }
  },
}