First commit

2025-12-18 13:50:39 +08:00
parent 569f4882e5
commit 642842c29e
218 changed files with 86902 additions and 0 deletions
--- a/backend/internal/service/redeem_service.go
+++ b/backend/internal/service/redeem_service.go
@@ -0,0 +1,392 @@
+package service
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"strings"
+	"sub2api/internal/model"
+	"sub2api/internal/repository"
+	"time"
+
+	"github.com/redis/go-redis/v9"
+	"gorm.io/gorm"
+)
+
+var (
+	ErrRedeemCodeNotFound  = errors.New("redeem code not found")
+	ErrRedeemCodeUsed      = errors.New("redeem code already used")
+	ErrRedeemCodeInvalid   = errors.New("invalid redeem code")
+	ErrInsufficientBalance = errors.New("insufficient balance")
+	ErrRedeemRateLimited   = errors.New("too many failed attempts, please try again later")
+	ErrRedeemCodeLocked    = errors.New("redeem code is being processed, please try again")
+)
+
+const (
+	redeemRateLimitKeyPrefix = "redeem:rate_limit:"
+	redeemLockKeyPrefix      = "redeem:lock:"
+	redeemMaxErrorsPerHour   = 20
+	redeemRateLimitDuration  = time.Hour
+	redeemLockDuration       = 10 * time.Second // 锁超时时间，防止死锁
+)
+
+// GenerateCodesRequest 生成兑换码请求
+type GenerateCodesRequest struct {
+	Count int     `json:"count"`
+	Value float64 `json:"value"`
+	Type  string  `json:"type"`
+}
+
+// RedeemCodeResponse 兑换码响应
+type RedeemCodeResponse struct {
+	Code      string    `json:"code"`
+	Value     float64   `json:"value"`
+	Status    string    `json:"status"`
+	CreatedAt time.Time `json:"created_at"`
+}
+
+// RedeemService 兑换码服务
+type RedeemService struct {
+	redeemRepo          *repository.RedeemCodeRepository
+	userRepo            *repository.UserRepository
+	subscriptionService *SubscriptionService
+	rdb                 *redis.Client
+	billingCacheService *BillingCacheService
+}
+
+// NewRedeemService 创建兑换码服务实例
+func NewRedeemService(redeemRepo *repository.RedeemCodeRepository, userRepo *repository.UserRepository, subscriptionService *SubscriptionService, rdb *redis.Client) *RedeemService {
+	return &RedeemService{
+		redeemRepo:          redeemRepo,
+		userRepo:            userRepo,
+		subscriptionService: subscriptionService,
+		rdb:                 rdb,
+	}
+}
+
+// SetBillingCacheService 设置计费缓存服务（用于缓存失效）
+func (s *RedeemService) SetBillingCacheService(billingCacheService *BillingCacheService) {
+	s.billingCacheService = billingCacheService
+}
+
+// GenerateRandomCode 生成随机兑换码
+func (s *RedeemService) GenerateRandomCode() (string, error) {
+	// 生成16字节随机数据
+	bytes := make([]byte, 16)
+	if _, err := rand.Read(bytes); err != nil {
+		return "", fmt.Errorf("generate random bytes: %w", err)
+	}
+
+	// 转换为十六进制字符串
+	code := hex.EncodeToString(bytes)
+
+	// 格式化为 XXXX-XXXX-XXXX-XXXX 格式
+	parts := []string{
+		strings.ToUpper(code[0:8]),
+		strings.ToUpper(code[8:16]),
+		strings.ToUpper(code[16:24]),
+		strings.ToUpper(code[24:32]),
+	}
+
+	return strings.Join(parts, "-"), nil
+}
+
+// GenerateCodes 批量生成兑换码
+func (s *RedeemService) GenerateCodes(ctx context.Context, req GenerateCodesRequest) ([]model.RedeemCode, error) {
+	if req.Count <= 0 {
+		return nil, errors.New("count must be greater than 0")
+	}
+
+	if req.Value <= 0 {
+		return nil, errors.New("value must be greater than 0")
+	}
+
+	if req.Count > 1000 {
+		return nil, errors.New("cannot generate more than 1000 codes at once")
+	}
+
+	codeType := req.Type
+	if codeType == "" {
+		codeType = model.RedeemTypeBalance
+	}
+
+	codes := make([]model.RedeemCode, 0, req.Count)
+	for i := 0; i < req.Count; i++ {
+		code, err := s.GenerateRandomCode()
+		if err != nil {
+			return nil, fmt.Errorf("generate code: %w", err)
+		}
+
+		codes = append(codes, model.RedeemCode{
+			Code:   code,
+			Type:   codeType,
+			Value:  req.Value,
+			Status: model.StatusUnused,
+		})
+	}
+
+	// 批量插入
+	if err := s.redeemRepo.CreateBatch(ctx, codes); err != nil {
+		return nil, fmt.Errorf("create batch codes: %w", err)
+	}
+
+	return codes, nil
+}
+
+// checkRedeemRateLimit 检查用户兑换错误次数是否超限
+func (s *RedeemService) checkRedeemRateLimit(ctx context.Context, userID int64) error {
+	if s.rdb == nil {
+		return nil
+	}
+
+	key := fmt.Sprintf("%s%d", redeemRateLimitKeyPrefix, userID)
+
+	count, err := s.rdb.Get(ctx, key).Int()
+	if err != nil && !errors.Is(err, redis.Nil) {
+		// Redis 出错时不阻止用户操作
+		return nil
+	}
+
+	if count >= redeemMaxErrorsPerHour {
+		return ErrRedeemRateLimited
+	}
+
+	return nil
+}
+
+// incrementRedeemErrorCount 增加用户兑换错误计数
+func (s *RedeemService) incrementRedeemErrorCount(ctx context.Context, userID int64) {
+	if s.rdb == nil {
+		return
+	}
+
+	key := fmt.Sprintf("%s%d", redeemRateLimitKeyPrefix, userID)
+
+	pipe := s.rdb.Pipeline()
+	pipe.Incr(ctx, key)
+	pipe.Expire(ctx, key, redeemRateLimitDuration)
+	_, _ = pipe.Exec(ctx)
+}
+
+// acquireRedeemLock 尝试获取兑换码的分布式锁
+// 返回 true 表示获取成功，false 表示锁已被占用
+func (s *RedeemService) acquireRedeemLock(ctx context.Context, code string) bool {
+	if s.rdb == nil {
+		return true // 无 Redis 时降级为不加锁
+	}
+
+	key := redeemLockKeyPrefix + code
+	ok, err := s.rdb.SetNX(ctx, key, "1", redeemLockDuration).Result()
+	if err != nil {
+		// Redis 出错时不阻止操作，依赖数据库层面的状态检查
+		return true
+	}
+	return ok
+}
+
+// releaseRedeemLock 释放兑换码的分布式锁
+func (s *RedeemService) releaseRedeemLock(ctx context.Context, code string) {
+	if s.rdb == nil {
+		return
+	}
+
+	key := redeemLockKeyPrefix + code
+	s.rdb.Del(ctx, key)
+}
+
+// Redeem 使用兑换码
+func (s *RedeemService) Redeem(ctx context.Context, userID int64, code string) (*model.RedeemCode, error) {
+	// 检查限流
+	if err := s.checkRedeemRateLimit(ctx, userID); err != nil {
+		return nil, err
+	}
+
+	// 获取分布式锁，防止同一兑换码并发使用
+	if !s.acquireRedeemLock(ctx, code) {
+		return nil, ErrRedeemCodeLocked
+	}
+	defer s.releaseRedeemLock(ctx, code)
+
+	// 查找兑换码
+	redeemCode, err := s.redeemRepo.GetByCode(ctx, code)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			s.incrementRedeemErrorCount(ctx, userID)
+			return nil, ErrRedeemCodeNotFound
+		}
+		return nil, fmt.Errorf("get redeem code: %w", err)
+	}
+
+	// 检查兑换码状态
+	if !redeemCode.CanUse() {
+		s.incrementRedeemErrorCount(ctx, userID)
+		return nil, ErrRedeemCodeUsed
+	}
+
+	// 验证兑换码类型的前置条件
+	if redeemCode.Type == model.RedeemTypeSubscription && redeemCode.GroupID == nil {
+		return nil, errors.New("invalid subscription redeem code: missing group_id")
+	}
+
+	// 获取用户信息
+	user, err := s.userRepo.GetByID(ctx, userID)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrUserNotFound
+		}
+		return nil, fmt.Errorf("get user: %w", err)
+	}
+	_ = user // 使用变量避免未使用错误
+
+	// 【关键】先标记兑换码为已使用，确保并发安全
+	// 利用数据库乐观锁（WHERE status = 'unused'）保证原子性
+	if err := s.redeemRepo.Use(ctx, redeemCode.ID, userID); err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			// 兑换码已被其他请求使用
+			return nil, ErrRedeemCodeUsed
+		}
+		return nil, fmt.Errorf("mark code as used: %w", err)
+	}
+
+	// 执行兑换逻辑（兑换码已被锁定，此时可安全操作）
+	switch redeemCode.Type {
+	case model.RedeemTypeBalance:
+		// 增加用户余额
+		if err := s.userRepo.UpdateBalance(ctx, userID, redeemCode.Value); err != nil {
+			return nil, fmt.Errorf("update user balance: %w", err)
+		}
+		// 失效余额缓存
+		if s.billingCacheService != nil {
+			go func() {
+				cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+				defer cancel()
+				s.billingCacheService.InvalidateUserBalance(cacheCtx, userID)
+			}()
+		}
+
+	case model.RedeemTypeConcurrency:
+		// 增加用户并发数
+		if err := s.userRepo.UpdateConcurrency(ctx, userID, int(redeemCode.Value)); err != nil {
+			return nil, fmt.Errorf("update user concurrency: %w", err)
+		}
+
+	case model.RedeemTypeSubscription:
+		validityDays := redeemCode.ValidityDays
+		if validityDays <= 0 {
+			validityDays = 30
+		}
+		_, _, err := s.subscriptionService.AssignOrExtendSubscription(ctx, &AssignSubscriptionInput{
+			UserID:       userID,
+			GroupID:      *redeemCode.GroupID,
+			ValidityDays: validityDays,
+			AssignedBy:   0, // 系统分配
+			Notes:        fmt.Sprintf("通过兑换码 %s 兑换", redeemCode.Code),
+		})
+		if err != nil {
+			return nil, fmt.Errorf("assign or extend subscription: %w", err)
+		}
+		// 失效订阅缓存
+		if s.billingCacheService != nil {
+			groupID := *redeemCode.GroupID
+			go func() {
+				cacheCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+				defer cancel()
+				s.billingCacheService.InvalidateSubscription(cacheCtx, userID, groupID)
+			}()
+		}
+
+	default:
+		return nil, fmt.Errorf("unsupported redeem type: %s", redeemCode.Type)
+	}
+
+	// 重新获取更新后的兑换码
+	redeemCode, err = s.redeemRepo.GetByID(ctx, redeemCode.ID)
+	if err != nil {
+		return nil, fmt.Errorf("get updated redeem code: %w", err)
+	}
+
+	return redeemCode, nil
+}
+
+// GetByID 根据ID获取兑换码
+func (s *RedeemService) GetByID(ctx context.Context, id int64) (*model.RedeemCode, error) {
+	code, err := s.redeemRepo.GetByID(ctx, id)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrRedeemCodeNotFound
+		}
+		return nil, fmt.Errorf("get redeem code: %w", err)
+	}
+	return code, nil
+}
+
+// GetByCode 根据Code获取兑换码
+func (s *RedeemService) GetByCode(ctx context.Context, code string) (*model.RedeemCode, error) {
+	redeemCode, err := s.redeemRepo.GetByCode(ctx, code)
+	if err != nil {
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			return nil, ErrRedeemCodeNotFound
+		}
+		return nil, fmt.Errorf("get redeem code: %w", err)
+	}
+	return redeemCode, nil
+}
+
+// List 获取兑换码列表（管理员功能）
+func (s *RedeemService) List(ctx context.Context, params repository.PaginationParams) ([]model.RedeemCode, *repository.PaginationResult, error) {
+	codes, pagination, err := s.redeemRepo.List(ctx, params)
+	if err != nil {
+		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
+}