种子，促销
Change-Id: I0ce919ce4228dcefec26ef636bacd3298c0dc77a
diff --git a/src/main/java/com/example/myproject/mapper/PromotionMapper.java b/src/main/java/com/example/myproject/mapper/PromotionMapper.java
new file mode 100644
index 0000000..a478835
--- /dev/null
+++ b/src/main/java/com/example/myproject/mapper/PromotionMapper.java
@@ -0,0 +1,52 @@
+package com.example.myproject.mapper;
+
+import com.baomidou.mybatisplus.core.mapper.BaseMapper;
+import com.example.myproject.entity.Promotion;
+import org.apache.ibatis.annotations.Mapper;
+import org.apache.ibatis.annotations.Param;
+import org.apache.ibatis.annotations.Select;
+import org.apache.ibatis.annotations.Update;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+@Mapper
+public interface PromotionMapper extends BaseMapper<Promotion> {
+
+ @Select("SELECT * FROM promotion WHERE is_deleted = false " +
+ "AND start_time <= #{now} AND end_time >= #{now}")
+ List<Promotion> findActivePromotions(@Param("now") LocalDateTime now);
+
+ /**
+ * 查找某个torrentId是否在促销活动的applicable_torrent_ids字符串中
+ * 用MySQL的FIND_IN_SET判断
+ */
+ @Select("SELECT p.* FROM promotion p " +
+ "WHERE p.is_deleted = false " +
+ "AND p.start_time <= #{now} AND p.end_time >= #{now} " +
+ "AND FIND_IN_SET(#{torrentId}, p.applicable_torrent_ids) > 0")
+ List<Promotion> findActivePromotionsForTorrent(
+ @Param("torrentId") Long torrentId,
+ @Param("now") LocalDateTime now);
+
+ /**
+ * 校验种子id是否存在，返回计数，0代表不存在，>0代表存在
+ */
+ @Select("SELECT COUNT(*) FROM torrent WHERE id = #{torrentId}")
+ int checkTorrentExists(@Param("torrentId") Long torrentId);
+
+ /**
+ * 插入促销活动
+ */
+// int insert(Promotion promotion);
+
+ /**
+ * 根据ID更新促销活动（例如软删除）
+ */
+ int updateById(Promotion promotion);
+
+ /**
+ * 根据ID查询促销活动
+ */
+ Promotion selectById(@Param("id") Long id);
+}