邹方成
45815bfb7d
refactor(utils): 修复密码哈希比较逻辑错误 feat(user): 新增按状态筛选优惠券接口 docs: 添加虚拟发货与任务中心相关文档 fix(wechat): 修正Code2Session上下文传递问题 test: 补充订单折扣与积分转换测试用例 build: 更新配置文件与构建脚本 style: 清理多余的空行与注释
95 lines
2.7 KiB
Go
95 lines
2.7 KiB
Go
package strategy
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import (
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"bindbox-game/internal/repository/mysql/dao"
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"context"
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"crypto/hmac"
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"crypto/rand"
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"crypto/sha256"
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"encoding/binary"
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"errors"
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"fmt"
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)
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type defaultStrategy struct {
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read *dao.Query
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write *dao.Query
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}
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func NewDefault(read *dao.Query, write *dao.Query) ActivityDrawStrategy {
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return &defaultStrategy{read: read, write: write}
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}
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func (s *defaultStrategy) PreChecks(ctx context.Context, activityID int64, issueID int64, userID int64) error {
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issue, err := s.read.ActivityIssues.WithContext(ctx).Where(s.read.ActivityIssues.ID.Eq(issueID), s.read.ActivityIssues.ActivityID.Eq(activityID)).First()
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if err != nil || issue == nil {
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return errors.New("issue not found")
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}
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return nil
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}
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func (s *defaultStrategy) SelectItem(ctx context.Context, activityID int64, issueID int64, userID int64) (int64, map[string]any, error) {
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rewards, err := s.read.ActivityRewardSettings.WithContext(ctx).ReadDB().Where(s.read.ActivityRewardSettings.IssueID.Eq(issueID)).Find()
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if err != nil || len(rewards) == 0 {
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return 0, nil, errors.New("no rewards")
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}
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var total int64
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for _, r := range rewards {
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if r.Quantity != 0 {
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total += int64(r.Weight)
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}
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}
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if total <= 0 {
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return 0, nil, errors.New("no weight")
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}
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// 使用 crypto/rand 生成加密安全的随机种子
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seed := make([]byte, 32)
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if _, err := rand.Read(seed); err != nil {
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return 0, nil, errors.New("crypto rand failed")
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}
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// 使用 HMAC-SHA256 生成加密安全的随机数
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mac := hmac.New(sha256.New, seed)
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mac.Write([]byte(fmt.Sprintf("draw:issue:%d|user:%d", issueID, userID)))
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sum := mac.Sum(nil)
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rnd := int64(binary.BigEndian.Uint64(sum[:8]) % uint64(total))
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var acc int64
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var picked int64
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for _, r := range rewards {
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if r.Quantity == 0 {
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continue
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}
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acc += int64(r.Weight)
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if rnd < acc {
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picked = r.ID
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break
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}
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}
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if picked == 0 {
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return 0, nil, errors.New("pick failed")
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}
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proof := map[string]any{"weights_total": total, "rand": rnd, "seed_hash": fmt.Sprintf("%x", sha256.Sum256(seed))}
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return picked, proof, nil
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}
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func (s *defaultStrategy) GrantReward(ctx context.Context, userID int64, rewardID int64) error {
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// 【使用乐观锁扣减库存】直接用 Quantity > 0 作为更新条件，避免并发超卖
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result, err := s.write.ActivityRewardSettings.WithContext(ctx).Where(
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s.write.ActivityRewardSettings.ID.Eq(rewardID),
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s.write.ActivityRewardSettings.Quantity.Gt(0), // 乐观锁：只有库存>0才能扣减
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).UpdateSimple(s.write.ActivityRewardSettings.Quantity.Add(-1))
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if err != nil {
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return err
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}
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if result.RowsAffected == 0 {
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return errors.New("sold out or reward not found")
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}
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return nil
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}
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func (s *defaultStrategy) PostEffects(ctx context.Context, userID int64, activityID int64, issueID int64, rewardID int64) error {
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return nil
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}
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