Tighten WeChat payment resume flow

frontend/src/views/user/paymentWechatResume.ts

@@ -0,0 +1,77 @@
+import type { LocationQuery, LocationQueryRaw } from 'vue-router'
+import type { SubscriptionPlan } from '@/types/payment'
+import { normalizeVisibleMethod } from '@/components/payment/paymentFlow'
+
+export interface ParsedWechatResumeRoute {
+  orderAmount: number
+  orderType: 'balance' | 'subscription'
+  paymentType: string
+  planId?: number
+  openid?: string
+  wechatResumeToken?: string
+}
+
+function readQueryString(query: LocationQuery, key: string): string {
+  const value = query[key]
+  if (Array.isArray(value)) {
+    return typeof value[0] === 'string' ? value[0] : ''
+  }
+  return typeof value === 'string' ? value : ''
+}
+
+export function parseWechatResumeRoute(
+  query: LocationQuery,
+  plans: SubscriptionPlan[],
+  fallbackBalanceAmount: number,
+): ParsedWechatResumeRoute | null {
+  if (readQueryString(query, 'wechat_resume') !== '1') {
+    return null
+  }
+
+  const wechatResumeToken = readQueryString(query, 'wechat_resume_token')
+  if (wechatResumeToken) {
+    return {
+      wechatResumeToken,
+      paymentType: 'wxpay',
+      orderType: 'balance',
+      orderAmount: 0,
+    }
+  }
+
+  const openid = readQueryString(query, 'openid')
+  if (!openid) {
+    return null
+  }
+
+  const paymentType = normalizeVisibleMethod(readQueryString(query, 'payment_type')) || 'wxpay'
+  const orderType = readQueryString(query, 'order_type') === 'subscription' ? 'subscription' : 'balance'
+  const planId = Number.parseInt(readQueryString(query, 'plan_id'), 10)
+  const rawAmount = Number.parseFloat(readQueryString(query, 'amount'))
+  const orderAmount = Number.isFinite(rawAmount) && rawAmount > 0
+    ? rawAmount
+    : (orderType === 'subscription'
+      ? (plans.find(plan => plan.id === planId)?.price ?? 0)
+      : fallbackBalanceAmount)
+
+  return {
+    openid,
+    paymentType,
+    orderType,
+    orderAmount,
+    planId: Number.isFinite(planId) && planId > 0 ? planId : undefined,
+  }
+}
+
+export function stripWechatResumeQuery(query: LocationQuery): LocationQueryRaw {
+  const nextQuery: LocationQueryRaw = { ...query }
+  delete nextQuery.wechat_resume
+  delete nextQuery.wechat_resume_token
+  delete nextQuery.openid
+  delete nextQuery.state
+  delete nextQuery.scope
+  delete nextQuery.payment_type
+  delete nextQuery.amount
+  delete nextQuery.order_type
+  delete nextQuery.plan_id
+  return nextQuery
+}