feat: unified gravity system - VIP members consume gravity instead of unlimited; add monthly gravity top-up cron

backend/src/modules/user/quota.service.ts

@@ -2,6 +2,7 @@ import { Injectable, HttpException, HttpStatus, Logger } from '@nestjs/common'
 import { InjectModel } from '@nestjs/mongoose'
 import { Model } from 'mongoose'
 import { User, UserDocument } from './user.schema'
+import { PricingService } from '../schemas/pricing.service'
 
 const FREE_OPTIMIZE_LIMIT = 3
 
@@ -11,119 +12,143 @@ export class QuotaService {
 
   constructor(
     @InjectModel(User.name) private userModel: Model<UserDocument>,
+    private pricingService: PricingService,
   ) {}
 
+  /** 检查并扣除面试引力值（所有计划统一走引力值） */
   async checkAndDeductInterview(userId: string) {
     const user = await this.userModel.findById(userId).exec()
     if (!user) throw new HttpException('用户不存在', HttpStatus.NOT_FOUND)
-    if (user.plan !== 'free') return
 
-    // Backward compat: migrate remaining → interviewCredits
-    if ((user.interviewCredits ?? 0) <= 0 && (user.remaining ?? 0) > 0) {
-      await this.userModel.findByIdAndUpdate(userId, {
-        $set: { interviewCredits: user.remaining, remaining: 0 },
-      }).exec()
+    // 迁移旧字段到 gravity
+    if ((user.gravity ?? 0) <= 0 && this.hasOldCredits(user)) {
+      await this.migrateOldCredits(userId)
     }
 
-    const result = await this.userModel.findOneAndUpdate(
-      { _id: userId, interviewCredits: { $gt: 0 } },
-      { $inc: { interviewCredits: -1, interviewCount: 1 } },
-      { new: true },
-    ).exec()
+    const rates = (await this.pricingService.getConfig()).gravityRates
+    const cost = rates.interviewPerUse
+
+    // 用 gravity 支付，后备 shareCredits
+    const result = await this.deductGravityOrFallback(userId, cost)
     if (result) return
 
-    // Fallback to share credits
-    const shareResult = await this.userModel.findOneAndUpdate(
-      { _id: userId, shareCredits: { $gt: 0 } },
-      { $inc: { shareCredits: -1, interviewCount: 1 } },
-    ).exec()
-    if (shareResult) return
-
-    throw new HttpException('面试次数已用完，请购买面试次数或开通会员', HttpStatus.FORBIDDEN)
+    throw new HttpException('引力值不足，请充值或分享获取', HttpStatus.FORBIDDEN)
   }
 
+  /** 检查并扣除优化引力值（所有计划统一走引力值） */
   async checkAndDeductOptimize(userId: string) {
     const user = await this.userModel.findById(userId).exec()
     if (!user) throw new HttpException('用户不存在', HttpStatus.NOT_FOUND)
-    if (user.plan !== 'free') return
 
-    // Try paid credits first
-    const paid = await this.userModel.findOneAndUpdate(
-      { _id: userId, resumeOptimizeCredits: { $gt: 0 } },
-      { $inc: { resumeOptimizeCredits: -1 } },
-    ).exec()
-    if (paid) return
+    // 迁移旧字段
+    if ((user.gravity ?? 0) <= 0 && this.hasOldCredits(user)) {
+      await this.migrateOldCredits(userId)
+    }
 
-    // Try old remaining credits (backward compat)
-    const oldRemaining = await this.userModel.findOneAndUpdate(
-      { _id: userId, remaining: { $gt: 0 } },
-      { $inc: { remaining: -1 } },
-    ).exec()
-    if (oldRemaining) return
-
-    // Then free limit
+    // 免费优化次数
     const freeResult = await this.userModel.findOneAndUpdate(
       { _id: userId, freeOptimizeUsed: { $lt: FREE_OPTIMIZE_LIMIT } },
       { $inc: { freeOptimizeUsed: 1 } },
     ).exec()
     if (freeResult) return
 
-    // Fallback to share credits
+    const rates = (await this.pricingService.getConfig()).gravityRates
+    const cost = rates.optimizePerUse
+
+    const result = await this.deductGravityOrFallback(userId, cost)
+    if (result) return
+
+    throw new HttpException('引力值不足，请充值或分享获取', HttpStatus.FORBIDDEN)
+  }
+
+  /** 检查并扣除下载引力值 */
+  async checkAndDeductDownload(userId: string, paidDownload: boolean): Promise<boolean> {
+    if (paidDownload) return true
+
+    const rates = (await this.pricingService.getConfig()).gravityRates
+    const cost = rates.downloadPerUse
+
+    const result = await this.deductGravityOrFallback(userId, cost)
+    if (result) return true
+
+    return false
+  }
+
+  /** 从 gravity 扣除，后备从 shareCredits 扣除（兼容旧数据） */
+  private async deductGravityOrFallback(userId: string, cost: number): Promise<boolean> {
+    // 主路径：gravity
+    const gravResult = await this.userModel.findOneAndUpdate(
+      { _id: userId, gravity: { $gte: cost } },
+      { $inc: { gravity: -cost } },
+    ).exec()
+    if (gravResult) return true
+
+    // 后备：旧 shareCredits
     const shareResult = await this.userModel.findOneAndUpdate(
       { _id: userId, shareCredits: { $gt: 0 } },
       { $inc: { shareCredits: -1 } },
     ).exec()
-    if (shareResult) return
+    if (shareResult) return true
 
-    throw new HttpException('简历优化次数已用完，请购买优化次数或开通会员', HttpStatus.FORBIDDEN)
+    return false
   }
 
-  async grantShareCredits(userId: string, amount = 1): Promise<boolean> {
-    const result = await this.userModel.findByIdAndUpdate(
-      userId,
-      { $inc: { shareCredits: amount } },
-    ).exec()
-    return !!result
-  }
-
-  async checkAndDeductDownload(userId: string, paidDownload: boolean): Promise<boolean> {
-    if (paidDownload) return true
-
-    const result = await this.userModel.findOneAndUpdate(
-      { _id: userId, resumeDownloadCredits: { $gt: 0 } },
-      { $inc: { resumeDownloadCredits: -1 } },
-    ).exec()
-    return !!result
-  }
-
-  async grantCredits(userId: string, type: 'interview' | 'optimize' | 'download', amount: number) {
+  /** 增加引力值 */
+  async grantGravity(userId: string, amount: number) {
     if (amount <= 0) throw new HttpException('无效数量', HttpStatus.BAD_REQUEST)
-
-    const fieldMap: Record<string, string> = {
-      interview: 'interviewCredits',
-      optimize: 'resumeOptimizeCredits',
-      download: 'resumeDownloadCredits',
-    }
-    const field = fieldMap[type]
-    if (!field) throw new HttpException('无效类型', HttpStatus.BAD_REQUEST)
-
     const result = await this.userModel.findByIdAndUpdate(
       userId,
-      { $inc: { [field]: amount } },
+      { $inc: { gravity: amount } },
     ).exec()
     if (!result) throw new HttpException('用户不存在', HttpStatus.NOT_FOUND)
   }
 
-  async setPlanQuota(userId: string, _plan: string, credits: { interview: number; resumeOptimize: number; resumeDownload: number }) {
+  /** 设置 VIP 套餐引力值额度 */
+  async setPlanQuota(userId: string, gravityAmount: number) {
     const result = await this.userModel.findByIdAndUpdate(userId, {
       $set: {
-        remaining: 999,
-        interviewCredits: credits.interview,
-        resumeOptimizeCredits: credits.resumeOptimize,
-        resumeDownloadCredits: credits.resumeDownload,
+        gravity: gravityAmount,
         freeOptimizeUsed: FREE_OPTIMIZE_LIMIT,
       },
     }).exec()
     if (!result) throw new HttpException('用户不存在', HttpStatus.NOT_FOUND)
   }
+
+  /** 是否为非会员用户授予初始引力值 */
+  async grantFreeGravity(userId: string) {
+    await this.userModel.findByIdAndUpdate(userId, {
+      $set: { interviewCredits: 1, gravity: 5 },
+    }).exec()
+  }
+
+  /** 判断是否有旧额度需要迁移 */
+  private hasOldCredits(user: UserDocument): boolean {
+    return (user.interviewCredits ?? 0) > 0
+      || (user.resumeOptimizeCredits ?? 0) > 0
+      || (user.resumeDownloadCredits ?? 0) > 0
+      || (user.remaining ?? 0) > 0
+  }
+
+  /** 迁移旧额度到 gravity */
+  private async migrateOldCredits(userId: string) {
+    const user = await this.userModel.findById(userId).exec()
+    if (!user) return
+    const interviewVal = (user.interviewCredits ?? 0) * 5
+    const optimizeVal = (user.resumeOptimizeCredits ?? 0) * 3
+    const downloadVal = (user.resumeDownloadCredits ?? 0) * 2
+    const oldRemainVal = (user.remaining ?? 0) * 5
+    const shareVal = (user.shareCredits ?? 0) * 1
+    const total = interviewVal + optimizeVal + downloadVal + oldRemainVal + shareVal
+    if (total <= 0) return
+    await this.userModel.findByIdAndUpdate(userId, {
+      $inc: { gravity: total },
+      $set: {
+        interviewCredits: 0,
+        resumeOptimizeCredits: 0,
+        resumeDownloadCredits: 0,
+        remaining: 0,
+        shareCredits: 0,
+      },
+    }).exec()
+  }
 }