Ship signup sheet, subscribe reminders, cover crop, and theme updates.

Wire real WeChat app config, prefer activity cover over posters, and add admin cover cropping for the home banner.

Co-authored-by: Cursor <cursoragent@cursor.com>

server/lib/wechat.js

@@ -1,10 +1,14 @@
 const crypto = require('crypto')
 const { HttpError } = require('./http')
 
+let tokenCache = null
+
+function wxConfigured() {
+  return !!(process.env.WX_APPID && process.env.WX_SECRET)
+}
+
 async function code2session(code, deviceId) {
-  const appid = process.env.WX_APPID
-  const secret = process.env.WX_SECRET
-  if (!appid || !secret) {
+  if (!wxConfigured()) {
     const seed = deviceId || 'guest'
     return {
       openid: `demo_${crypto.createHash('sha1').update(seed).digest('hex').slice(0, 16)}`,
@@ -14,8 +18,8 @@ async function code2session(code, deviceId) {
 
   const url = new URL('https://api.weixin.qq.com/sns/jscode2session')
   url.search = new URLSearchParams({
-    appid,
-    secret,
+    appid: process.env.WX_APPID,
+    secret: process.env.WX_SECRET,
     js_code: code,
     grant_type: 'authorization_code'
   }).toString()
@@ -31,4 +35,66 @@ async function code2session(code, deviceId) {
   return { openid: session.openid, demo: false }
 }
 
-module.exports = { code2session }
+async function getAccessToken() {
+  if (!wxConfigured()) throw new HttpError(400, '未配置 WX_APPID / WX_SECRET，无法发送订阅消息')
+  if (tokenCache && tokenCache.expiresAt > Date.now() + 60_000) return tokenCache.token
+
+  const url = new URL('https://api.weixin.qq.com/cgi-bin/token')
+  url.search = new URLSearchParams({
+    grant_type: 'client_credential',
+    appid: process.env.WX_APPID,
+    secret: process.env.WX_SECRET
+  }).toString()
+
+  const res = await fetch(url, { signal: AbortSignal.timeout(8000) })
+  const body = await res.json()
+  if (!body.access_token) throw new HttpError(502, body.errmsg || '获取微信 access_token 失败')
+  tokenCache = {
+    token: body.access_token,
+    expiresAt: Date.now() + (Number(body.expires_in) || 7200) * 1000
+  }
+  return tokenCache.token
+}
+
+function clip(value, max) {
+  const text = value == null ? '' : String(value)
+  return text.length > max ? text.slice(0, max) : text
+}
+
+// Default field mapping for a typical “活动提醒” template (thing / time / thing).
+function buildRemindData(activity) {
+  return {
+    thing1: { value: clip(activity.title || '卓米会活动', 20) },
+    time2: { value: clip(activity.startAt || '待定', 20) },
+    thing3: { value: clip(activity.address || '详见活动页', 20) }
+  }
+}
+
+async function sendSubscribeMessage({ openid, templateId, page, data }) {
+  const token = await getAccessToken()
+  const res = await fetch(
+    `https://api.weixin.qq.com/cgi-bin/message/subscribe/send?access_token=${encodeURIComponent(token)}`,
+    {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({
+        touser: openid,
+        template_id: templateId,
+        page: page || '',
+        data,
+        miniprogram_state: process.env.WX_MINI_STATE || 'formal'
+      }),
+      signal: AbortSignal.timeout(8000)
+    }
+  )
+  const body = await res.json()
+  return { ok: body.errcode === 0, errcode: body.errcode, errmsg: body.errmsg || '' }
+}
+
+module.exports = {
+  wxConfigured,
+  code2session,
+  getAccessToken,
+  buildRemindData,
+  sendSubscribeMessage
+}