mirror of
https://gitee.com/wanwujie/sub2api
synced 2026-04-17 13:24:45 +08:00
393 lines
11 KiB
Go
393 lines
11 KiB
Go
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package service
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import (
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"context"
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"crypto/rand"
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"encoding/hex"
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"errors"
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"fmt"
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"strings"
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"sub2api/internal/model"
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"sub2api/internal/repository"
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"time"
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"github.com/redis/go-redis/v9"
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"gorm.io/gorm"
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)
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var (
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ErrRedeemCodeNotFound = errors.New("redeem code not found")
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ErrRedeemCodeUsed = errors.New("redeem code already used")
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ErrRedeemCodeInvalid = errors.New("invalid redeem code")
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ErrInsufficientBalance = errors.New("insufficient balance")
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ErrRedeemRateLimited = errors.New("too many failed attempts, please try again later")
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ErrRedeemCodeLocked = errors.New("redeem code is being processed, please try again")
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)
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const (
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redeemRateLimitKeyPrefix = "redeem:rate_limit:"
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redeemLockKeyPrefix = "redeem:lock:"
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redeemMaxErrorsPerHour = 20
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redeemRateLimitDuration = time.Hour
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redeemLockDuration = 10 * time.Second // 锁超时时间，防止死锁
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)
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// GenerateCodesRequest 生成兑换码请求
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type GenerateCodesRequest struct {
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Count int `json:"count"`
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Value float64 `json:"value"`
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Type string `json:"type"`
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}
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// RedeemCodeResponse 兑换码响应
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type RedeemCodeResponse struct {
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Code string `json:"code"`
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Value float64 `json:"value"`
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Status string `json:"status"`
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CreatedAt time.Time `json:"created_at"`
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}
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// RedeemService 兑换码服务
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type RedeemService struct {
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redeemRepo *repository.RedeemCodeRepository
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userRepo *repository.UserRepository
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subscriptionService *SubscriptionService
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rdb *redis.Client
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billingCacheService *BillingCacheService
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}
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// NewRedeemService 创建兑换码服务实例
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func NewRedeemService(redeemRepo *repository.RedeemCodeRepository, userRepo *repository.UserRepository, subscriptionService *SubscriptionService, rdb *redis.Client) *RedeemService {
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return &RedeemService{
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redeemRepo: redeemRepo,
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userRepo: userRepo,
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subscriptionService: subscriptionService,
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rdb: rdb,
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}
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}
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// SetBillingCacheService 设置计费缓存服务（用于缓存失效）
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func (s *RedeemService) SetBillingCacheService(billingCacheService *BillingCacheService) {
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s.billingCacheService = billingCacheService
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}
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// GenerateRandomCode 生成随机兑换码
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func (s *RedeemService) GenerateRandomCode() (string, error) {
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// 生成16字节随机数据
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bytes := make([]byte, 16)
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if _, err := rand.Read(bytes); err != nil {
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return "", fmt.Errorf("generate random bytes: %w", err)
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}
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// 转换为十六进制字符串
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code := hex.EncodeToString(bytes)
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// 格式化为 XXXX-XXXX-XXXX-XXXX 格式
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parts := []string{
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strings.ToUpper(code[0:8]),
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strings.ToUpper(code[8:16]),
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strings.ToUpper(code[16:24]),
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strings.ToUpper(code[24:32]),
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}
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return strings.Join(parts, "-"), nil
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}
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// GenerateCodes 批量生成兑换码
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func (s *RedeemService) GenerateCodes(ctx context.Context, req GenerateCodesRequest) ([]model.RedeemCode, error) {
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if req.Count <= 0 {
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return nil, errors.New("count must be greater than 0")
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}
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if req.Value <= 0 {
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return nil, errors.New("value must be greater than 0")
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}
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if req.Count > 1000 {
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return nil, errors.New("cannot generate more than 1000 codes at once")
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}
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codeType := req.Type
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if codeType == "" {
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codeType = model.RedeemTypeBalance
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}
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codes := make([]model.RedeemCode, 0, req.Count)
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for i := 0; i < req.Count; i++ {
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code, err := s.GenerateRandomCode()
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if err != nil {
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return nil, fmt.Errorf("generate code: %w", err)
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}
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codes = append(codes, model.RedeemCode{
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Code: code,
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Type: codeType,
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Value: req.Value,
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Status: model.StatusUnused,
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})
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}
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// 批量插入
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if err := s.redeemRepo.CreateBatch(ctx, codes); err != nil {
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return nil, fmt.Errorf("create batch codes: %w", err)
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}
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return codes, nil
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}
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// checkRedeemRateLimit 检查用户兑换错误次数是否超限
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func (s *RedeemService) checkRedeemRateLimit(ctx context.Context, userID int64) error {
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if s.rdb == nil {
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return nil
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}
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key := fmt.Sprintf("%s%d", redeemRateLimitKeyPrefix, userID)
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count, err := s.rdb.Get(ctx, key).Int()
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if err != nil && !errors.Is(err, redis.Nil) {
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// Redis 出错时不阻止用户操作
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return nil
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}
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if count >= redeemMaxErrorsPerHour {
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return ErrRedeemRateLimited
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}
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return nil
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}
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// incrementRedeemErrorCount 增加用户兑换错误计数
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func (s *RedeemService) incrementRedeemErrorCount(ctx context.Context, userID int64) {
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if s.rdb == nil {
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return
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}
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key := fmt.Sprintf("%s%d", redeemRateLimitKeyPrefix, userID)
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pipe := s.rdb.Pipeline()
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pipe.Incr(ctx, key)
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pipe.Expire(ctx, key, redeemRateLimitDuration)
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_, _ = pipe.Exec(ctx)
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}
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// acquireRedeemLock 尝试获取兑换码的分布式锁
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// 返回 true 表示获取成功，false 表示锁已被占用
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func (s *RedeemService) acquireRedeemLock(ctx context.Context, code string) bool {
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if s.rdb == nil {
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return true // 无 Redis 时降级为不加锁
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}
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key := redeemLockKeyPrefix + code
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ok, err := s.rdb.SetNX(ctx, key, "1", redeemLockDuration).Result()
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if err != nil {
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// Redis 出错时不阻止操作，依赖数据库层面的状态检查
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return true
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}
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return ok
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}
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// releaseRedeemLock 释放兑换码的分布式锁
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func (s *RedeemService) releaseRedeemLock(ctx context.Context, code string) {
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if s.rdb == nil {
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return
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}
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key := redeemLockKeyPrefix + code
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s.rdb.Del(ctx, key)
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}
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// Redeem 使用兑换码
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func (s *RedeemService) Redeem(ctx context.Context, userID int64, code string) (*model.RedeemCode, error) {
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// 检查限流
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if err := s.checkRedeemRateLimit(ctx, userID); err != nil {
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return nil, err
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}
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// 获取分布式锁，防止同一兑换码并发使用
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if !s.acquireRedeemLock(ctx, code) {
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return nil, ErrRedeemCodeLocked
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}
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defer s.releaseRedeemLock(ctx, code)
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// 查找兑换码
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redeemCode, err := s.redeemRepo.GetByCode(ctx, code)
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if err != nil {
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if errors.Is(err, gorm.ErrRecordNotFound) {
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s.incrementRedeemErrorCount(ctx, userID)
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return nil, ErrRedeemCodeNotFound
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}
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return nil, fmt.Errorf("get redeem code: %w", err)
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}
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// 检查兑换码状态
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if !redeemCode.CanUse() {
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s.incrementRedeemErrorCount(ctx, userID)
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return nil, ErrRedeemCodeUsed
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}
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// 验证兑换码类型的前置条件
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if redeemCode.Type == model.RedeemTypeSubscription && redeemCode.GroupID == nil {
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return nil, errors.New("invalid subscription redeem code: missing group_id")
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}
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// 获取用户信息
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user, err := s.userRepo.GetByID(ctx, userID)
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if err != nil {
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if errors.Is(err, gorm.ErrRecordNotFound) {
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return nil, ErrUserNotFound
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}
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return nil, fmt.Errorf("get user: %w", err)
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}
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_ = user // 使用变量避免未使用错误
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// 【关键】先标记兑换码为已使用，确保并发安全
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// 利用数据库乐观锁（WHERE status = 'unused'）保证原子性
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if err := s.redeemRepo.Use(ctx, redeemCode.ID, userID); err != nil {
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if errors.Is(err, gorm.ErrRecordNotFound) {
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// 兑换码已被其他请求使用
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return nil, ErrRedeemCodeUsed
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}
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return nil, fmt.Errorf("mark code as used: %w", err)
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}
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// 执行兑换逻辑（兑换码已被锁定，此时可安全操作）
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switch redeemCode.Type {
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case model.RedeemTypeBalance:
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// 增加用户余额
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if err := s.userRepo.UpdateBalance(ctx, userID, redeemCode.Value); err != nil {
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return nil, fmt.Errorf("update user balance: %w", err)
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}
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// 失效余额缓存
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if s.billingCacheService != nil {
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go func() {
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cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
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defer cancel()
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s.billingCacheService.InvalidateUserBalance(cacheCtx, userID)
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}()
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}
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case model.RedeemTypeConcurrency:
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// 增加用户并发数
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if err := s.userRepo.UpdateConcurrency(ctx, userID, int(redeemCode.Value)); err != nil {
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return nil, fmt.Errorf("update user concurrency: %w", err)
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}
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case model.RedeemTypeSubscription:
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validityDays := redeemCode.ValidityDays
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if validityDays <= 0 {
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validityDays = 30
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}
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_, _, err := s.subscriptionService.AssignOrExtendSubscription(ctx, &AssignSubscriptionInput{
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UserID: userID,
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GroupID: *redeemCode.GroupID,
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ValidityDays: validityDays,
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AssignedBy: 0, // 系统分配
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Notes: fmt.Sprintf("通过兑换码 %s 兑换", redeemCode.Code),
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})
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if err != nil {
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return nil, fmt.Errorf("assign or extend subscription: %w", err)
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}
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// 失效订阅缓存
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if s.billingCacheService != nil {
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groupID := *redeemCode.GroupID
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go func() {
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cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
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defer cancel()
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s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID)
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}()
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}
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default:
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return nil, fmt.Errorf("unsupported redeem type: %s", redeemCode.Type)
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}
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// 重新获取更新后的兑换码
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redeemCode, err = s.redeemRepo.GetByID(ctx, redeemCode.ID)
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if err != nil {
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return nil, fmt.Errorf("get updated redeem code: %w", err)
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}
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return redeemCode, nil
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}
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// GetByID 根据ID获取兑换码
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func (s *RedeemService) GetByID(ctx context.Context, id int64) (*model.RedeemCode, error) {
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code, err := s.redeemRepo.GetByID(ctx, id)
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if err != nil {
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if errors.Is(err, gorm.ErrRecordNotFound) {
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return nil, ErrRedeemCodeNotFound
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}
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return nil, fmt.Errorf("get redeem code: %w", err)
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}
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return code, nil
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}
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// GetByCode 根据Code获取兑换码
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func (s *RedeemService) GetByCode(ctx context.Context, code string) (*model.RedeemCode, error) {
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redeemCode, err := s.redeemRepo.GetByCode(ctx, code)
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if err != nil {
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if errors.Is(err, gorm.ErrRecordNotFound) {
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return nil, ErrRedeemCodeNotFound
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}
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return nil, fmt.Errorf("get redeem code: %w", err)
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}
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return redeemCode, nil
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}
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// List 获取兑换码列表（管理员功能）
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func (s *RedeemService) List(ctx context.Context, params repository.PaginationParams) ([]model.RedeemCode, *repository.PaginationResult, error) {
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codes, pagination, err := s.redeemRepo.List(ctx, params)
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if err != nil {
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|
|
return nil, nil, fmt.Errorf("list redeem codes: %w", err)
|
|||
|
|
}
|
|||
|
|
return codes, pagination, nil
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// Delete 删除兑换码（管理员功能）
|
|||
|
|
func (s *RedeemService) Delete(ctx context.Context, id int64) error {
|
|||
|
|
// 检查兑换码是否存在
|
|||
|
|
code, err := s.redeemRepo.GetByID(ctx, id)
|
|||
|
|
if err != nil {
|
|||
|
|
if errors.Is(err, gorm.ErrRecordNotFound) {
|
|||
|
|
return ErrRedeemCodeNotFound
|
|||
|
|
}
|
|||
|
|
return fmt.Errorf("get redeem code: %w", err)
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// 不允许删除已使用的兑换码
|
|||
|
|
if code.IsUsed() {
|
|||
|
|
return errors.New("cannot delete used redeem code")
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
if err := s.redeemRepo.Delete(ctx, id); err != nil {
|
|||
|
|
return fmt.Errorf("delete redeem code: %w", err)
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
return nil
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// GetStats 获取兑换码统计信息
|
|||
|
|
func (s *RedeemService) GetStats(ctx context.Context) (map[string]interface{}, error) {
|
|||
|
|
// TODO: 实现统计逻辑
|
|||
|
|
// 统计未使用、已使用的兑换码数量
|
|||
|
|
// 统计总面值等
|
|||
|
|
|
|||
|
|
stats := map[string]interface{}{
|
|||
|
|
"total_codes": 0,
|
|||
|
|
"unused_codes": 0,
|
|||
|
|
"used_codes": 0,
|
|||
|
|
"total_value": 0.0,
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
return stats, nil
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// GetUserHistory 获取用户的兑换历史
|
|||
|
|
func (s *RedeemService) GetUserHistory(ctx context.Context, userID int64, limit int) ([]model.RedeemCode, error) {
|
|||
|
|
codes, err := s.redeemRepo.ListByUser(ctx, userID, limit)
|
|||
|
|
if err != nil {
|
|||
|
|
return nil, fmt.Errorf("get user redeem history: %w", err)
|
|||
|
|
}
|
|||
|
|
return codes, nil
|
|||
|
|
}
|