446 lines
13 KiB
Go
446 lines
13 KiB
Go
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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"time"
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dbent "github.com/Wei-Shaw/sub2api/ent"
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infraerrors "github.com/Wei-Shaw/sub2api/internal/pkg/errors"
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"github.com/Wei-Shaw/sub2api/internal/pkg/pagination"
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)
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var (
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ErrRedeemCodeNotFound = infraerrors.NotFound("REDEEM_CODE_NOT_FOUND", "redeem code not found")
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ErrRedeemCodeUsed = infraerrors.Conflict("REDEEM_CODE_USED", "redeem code already used")
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ErrInsufficientBalance = infraerrors.BadRequest("INSUFFICIENT_BALANCE", "insufficient balance")
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ErrRedeemRateLimited = infraerrors.TooManyRequests("REDEEM_RATE_LIMITED", "too many failed attempts, please try again later")
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ErrRedeemCodeLocked = infraerrors.Conflict("REDEEM_CODE_LOCKED", "redeem code is being processed, please try again")
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)
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const (
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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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// RedeemCache defines cache operations for redeem service
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type RedeemCache interface {
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GetRedeemAttemptCount(ctx context.Context, userID int64) (int, error)
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IncrementRedeemAttemptCount(ctx context.Context, userID int64) error
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AcquireRedeemLock(ctx context.Context, code string, ttl time.Duration) (bool, error)
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ReleaseRedeemLock(ctx context.Context, code string) error
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}
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type RedeemCodeRepository interface {
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Create(ctx context.Context, code *RedeemCode) error
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CreateBatch(ctx context.Context, codes []RedeemCode) error
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GetByID(ctx context.Context, id int64) (*RedeemCode, error)
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GetByCode(ctx context.Context, code string) (*RedeemCode, error)
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Update(ctx context.Context, code *RedeemCode) error
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Delete(ctx context.Context, id int64) error
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Use(ctx context.Context, id, userID int64) error
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List(ctx context.Context, params pagination.PaginationParams) ([]RedeemCode, *pagination.PaginationResult, error)
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ListWithFilters(ctx context.Context, params pagination.PaginationParams, codeType, status, search string) ([]RedeemCode, *pagination.PaginationResult, error)
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ListByUser(ctx context.Context, userID int64, limit int) ([]RedeemCode, error)
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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 RedeemCodeRepository
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userRepo UserRepository
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subscriptionService *SubscriptionService
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cache RedeemCache
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billingCacheService *BillingCacheService
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entClient *dbent.Client
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authCacheInvalidator APIKeyAuthCacheInvalidator
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}
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// NewRedeemService 创建兑换码服务实例
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func NewRedeemService(
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redeemRepo RedeemCodeRepository,
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userRepo UserRepository,
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subscriptionService *SubscriptionService,
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cache RedeemCache,
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billingCacheService *BillingCacheService,
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entClient *dbent.Client,
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authCacheInvalidator APIKeyAuthCacheInvalidator,
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) *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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cache: cache,
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billingCacheService: billingCacheService,
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entClient: entClient,
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authCacheInvalidator: authCacheInvalidator,
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}
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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) ([]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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// 邀请码类型不需要数值，其他类型需要
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if req.Type != RedeemTypeInvitation && 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 = RedeemTypeBalance
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}
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// 邀请码类型的 value 设为 0
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value := req.Value
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if codeType == RedeemTypeInvitation {
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value = 0
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}
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codes := make([]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, RedeemCode{
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Code: code,
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Type: codeType,
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Value: value,
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Status: 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.cache == nil {
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return nil
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}
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count, err := s.cache.GetRedeemAttemptCount(ctx, userID)
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if err != 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.cache == nil {
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return
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}
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_ = s.cache.IncrementRedeemAttemptCount(ctx, userID)
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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.cache == nil {
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return true // 无 Redis 时降级为不加锁
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}
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ok, err := s.cache.AcquireRedeemLock(ctx, code, redeemLockDuration)
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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.cache == nil {
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return
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}
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_ = s.cache.ReleaseRedeemLock(ctx, code)
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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) (*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, ErrRedeemCodeNotFound) {
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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 == RedeemTypeSubscription && redeemCode.GroupID == nil {
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return nil, infraerrors.BadRequest("REDEEM_CODE_INVALID", "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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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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// 使用数据库事务保证兑换码标记与权益发放的原子性
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tx, err := s.entClient.Tx(ctx)
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if err != nil {
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return nil, fmt.Errorf("begin transaction: %w", err)
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}
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defer func() { _ = tx.Rollback() }()
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// 将事务放入 context，使 repository 方法能够使用同一事务
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txCtx := dbent.NewTxContext(ctx, tx)
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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(txCtx, redeemCode.ID, userID); err != nil {
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if errors.Is(err, ErrRedeemCodeNotFound) || errors.Is(err, ErrRedeemCodeUsed) {
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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 RedeemTypeBalance:
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// 增加用户余额
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if err := s.userRepo.UpdateBalance(txCtx, 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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case RedeemTypeConcurrency:
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// 增加用户并发数
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if err := s.userRepo.UpdateConcurrency(txCtx, 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 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(txCtx, &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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default:
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return nil, fmt.Errorf("unsupported redeem type: %s", redeemCode.Type)
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}
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// 提交事务
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if err := tx.Commit(); err != nil {
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return nil, fmt.Errorf("commit transaction: %w", err)
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}
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// 事务提交成功后失效缓存
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s.invalidateRedeemCaches(ctx, userID, redeemCode)
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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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// invalidateRedeemCaches 失效兑换相关的缓存
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func (s *RedeemService) invalidateRedeemCaches(ctx context.Context, userID int64, redeemCode *RedeemCode) {
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switch redeemCode.Type {
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case RedeemTypeBalance:
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if s.authCacheInvalidator != nil {
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s.authCacheInvalidator.InvalidateAuthCacheByUserID(ctx, userID)
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}
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if s.billingCacheService == nil {
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return
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}
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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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case RedeemTypeConcurrency:
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if s.authCacheInvalidator != nil {
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s.authCacheInvalidator.InvalidateAuthCacheByUserID(ctx, userID)
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}
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if s.billingCacheService == nil {
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return
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}
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case RedeemTypeSubscription:
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if s.authCacheInvalidator != nil {
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s.authCacheInvalidator.InvalidateAuthCacheByUserID(ctx, userID)
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}
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if s.billingCacheService == nil {
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return
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}
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if redeemCode.GroupID != 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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}
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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) (*RedeemCode, error) {
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code, err := s.redeemRepo.GetByID(ctx, id)
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if err != nil {
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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) (*RedeemCode, error) {
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redeemCode, err := s.redeemRepo.GetByCode(ctx, code)
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if err != nil {
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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 pagination.PaginationParams) ([]RedeemCode, *pagination.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)
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}
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return codes, pagination, nil
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}
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// Delete 删除兑换码（管理员功能）
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func (s *RedeemService) Delete(ctx context.Context, id int64) error {
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// 检查兑换码是否存在
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code, err := s.redeemRepo.GetByID(ctx, id)
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if err != nil {
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return fmt.Errorf("get redeem code: %w", err)
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}
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// 不允许删除已使用的兑换码
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if code.IsUsed() {
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return infraerrors.Conflict("REDEEM_CODE_DELETE_USED", "cannot delete used redeem code")
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}
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if err := s.redeemRepo.Delete(ctx, id); err != nil {
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return fmt.Errorf("delete redeem code: %w", err)
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}
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return nil
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}
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// GetStats 获取兑换码统计信息
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func (s *RedeemService) GetStats(ctx context.Context) (map[string]any, error) {
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// TODO: 实现统计逻辑
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// 统计未使用、已使用的兑换码数量
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// 统计总面值等
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stats := map[string]any{
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"total_codes": 0,
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"unused_codes": 0,
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"used_codes": 0,
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"total_value": 0.0,
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}
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return stats, nil
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}
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// GetUserHistory 获取用户的兑换历史
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func (s *RedeemService) GetUserHistory(ctx context.Context, userID int64, limit int) ([]RedeemCode, error) {
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codes, err := s.redeemRepo.ListByUser(ctx, userID, limit)
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if err != nil {
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return nil, fmt.Errorf("get user redeem history: %w", err)
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}
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return codes, nil
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}
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