feat: 实现情绪记录功能和聊天历史查看

- 完成情绪记录生成功能，支持AI分析聊天内容生成情绪记录
- 实现聊天页面历史记录查看，支持分页和搜索
- 修改日记页面展示情绪记录而非普通日记
- 添加情绪记录的增删改查API
- 优化前端UI，添加情绪强度显示和详细信息展示
- 修复SCSS变量缺失问题

backend-single/src/main/java/com/emotion/mapper/MessageMapper.java

@@ -3,6 +3,11 @@ package com.emotion.mapper;
 import com.baomidou.mybatisplus.core.mapper.BaseMapper;
 import com.emotion.entity.Message;
 import org.apache.ibatis.annotations.Mapper;
+import org.apache.ibatis.annotations.Param;
+import org.apache.ibatis.annotations.Select;
+
+import java.time.LocalDateTime;
+import java.util.List;
 
 /**
  * 消息Mapper接口
@@ -12,4 +17,55 @@ import org.apache.ibatis.annotations.Mapper;
  */
 @Mapper
 public interface MessageMapper extends BaseMapper<Message> {
+
+    /**
+     * 根据用户ID和时间范围查询消息
+     * 通过conversation表关联查询
+     */
+    @Select("SELECT m.* FROM message m " +
+            "INNER JOIN conversation c ON m.conversation_id = c.id " +
+            "WHERE c.user_id = #{userId} " +
+            "AND m.create_time BETWEEN #{startTime} AND #{endTime} " +
+            "AND m.is_deleted = 0 " +
+            "ORDER BY m.create_time ASC")
+    List<Message> getByUserIdAndTimeRange(@Param("userId") String userId,
+                                         @Param("startTime") LocalDateTime startTime,
+                                         @Param("endTime") LocalDateTime endTime);
+
+    /**
+     * 根据用户ID分页查询消息
+     * 通过conversation表关联查询
+     */
+    @Select("SELECT m.* FROM message m " +
+            "INNER JOIN conversation c ON m.conversation_id = c.id " +
+            "WHERE c.user_id = #{userId} " +
+            "AND m.is_deleted = 0 " +
+            "ORDER BY m.create_time DESC " +
+            "LIMIT #{offset}, #{size}")
+    List<Message> getByUserIdWithPageList(@Param("userId") String userId,
+                                         @Param("offset") Integer offset,
+                                         @Param("size") Integer size);
+
+    /**
+     * 统计用户消息总数
+     */
+    @Select("SELECT COUNT(*) FROM message m " +
+            "INNER JOIN conversation c ON m.conversation_id = c.id " +
+            "WHERE c.user_id = #{userId} " +
+            "AND m.is_deleted = 0")
+    Long countByUserId(@Param("userId") String userId);
+
+    /**
+     * 根据用户ID和关键词搜索消息
+     */
+    @Select("SELECT m.* FROM message m " +
+            "INNER JOIN conversation c ON m.conversation_id = c.id " +
+            "WHERE c.user_id = #{userId} " +
+            "AND m.content LIKE CONCAT('%', #{keyword}, '%') " +
+            "AND m.is_deleted = 0 " +
+            "ORDER BY m.create_time DESC " +
+            "LIMIT #{limit}")
+    List<Message> searchByUserIdAndKeyword(@Param("userId") String userId,
+                                          @Param("keyword") String keyword,
+                                          @Param("limit") Integer limit);
 }