feat(chat): 新增会话管理支持多轮对话

- 引入 KeyboardAiChatSession 实体及对应 Mapper、Service
- 为 KeyboardAiChatMessage 增加 session_id 字段
- ChatServiceImpl 保存消息时绑定会话，支持按用户+角色获取或创建活跃会话
- 保证同一用户同一角色的连续对话归属同一会话，实现多轮上下文管理

src/main/java/com/yolo/keyborad/mapper/KeyboardAiChatSessionMapper.java

@@ -0,0 +1,12 @@
+package com.yolo.keyborad.mapper;
+
+import com.baomidou.mybatisplus.core.mapper.BaseMapper;
+import com.yolo.keyborad.model.entity.KeyboardAiChatSession;
+
+/*
+* @author: ziin
+* @date: 2026/1/28 16:20
+*/
+    
+public interface KeyboardAiChatSessionMapper extends BaseMapper<KeyboardAiChatSession> {
+}

src/main/java/com/yolo/keyborad/model/entity/KeyboardAiChatMessage.java

@@ -75,4 +75,8 @@ public class KeyboardAiChatMessage {
     @TableField(value = "created_at")
     @Schema(description="消息创建时间")
     private Date createdAt;
+
+    @TableField(value = "session_id")
+    @Schema(description = "会话Id")
+    private Long sessionId;
 }

src/main/java/com/yolo/keyborad/model/entity/KeyboardAiChatSession.java

@@ -0,0 +1,71 @@
+package com.yolo.keyborad.model.entity;
+
+import com.baomidou.mybatisplus.annotation.IdType;
+import com.baomidou.mybatisplus.annotation.TableField;
+import com.baomidou.mybatisplus.annotation.TableId;
+import com.baomidou.mybatisplus.annotation.TableName;
+import io.swagger.v3.oas.annotations.media.Schema;
+import java.util.Date;
+import lombok.Data;
+
+/*
+* @author: ziin
+* @date: 2026/1/28 16:20
+*/
+    
+/**
+ * 用户与AI陪伴角色的聊天会话表，用于支持聊天重置与关系重启
+ */
+@Schema(description="用户与AI陪伴角色的聊天会话表，用于支持聊天重置与关系重启")
+@Data
+@TableName(value = "keyboard_ai_chat_session")
+public class KeyboardAiChatSession {
+    /**
+     * 聊天会话唯一ID
+     */
+    @TableId(value = "id", type = IdType.AUTO)
+    @Schema(description="聊天会话唯一ID")
+    private Long id;
+
+    /**
+     * 用户ID
+     */
+    @TableField(value = "user_id")
+    @Schema(description="用户ID")
+    private Long userId;
+
+    /**
+     * 陪伴角色ID
+     */
+    @TableField(value = "companion_id")
+    @Schema(description="陪伴角色ID")
+    private Long companionId;
+
+    /**
+     * 会话重置版本号，用于标识第几次重新开始陪伴关系
+     */
+    @TableField(value = "reset_version")
+    @Schema(description="会话重置版本号，用于标识第几次重新开始陪伴关系")
+    private Integer resetVersion;
+
+    /**
+     * 是否为当前活跃会话（true=当前使用中）
+     */
+    @TableField(value = "is_active")
+    @Schema(description="是否为当前活跃会话（true=当前使用中）")
+    private Boolean isActive;
+
+    /**
+     * 会话创建时间
+     */
+    @TableField(value = "created_at")
+    @Schema(description="会话创建时间")
+    private Date createdAt;
+
+    /**
+     * 会话结束时间（用户重置或系统关闭会话时记录）
+     */
+    @TableField(value = "ended_at")
+    @Schema(description="会话结束时间（用户重置或系统关闭会话时记录）")
+    private Date endedAt;
+}

src/main/java/com/yolo/keyborad/service/KeyboardAiChatSessionService.java

@@ -0,0 +1,29 @@
+package com.yolo.keyborad.service;
+
+import com.yolo.keyborad.model.entity.KeyboardAiChatSession;
+import com.baomidou.mybatisplus.extension.service.IService;
+
+/*
+ * @author: ziin
+ * @date: 2026/1/28 16:20
+ */
+public interface KeyboardAiChatSessionService extends IService<KeyboardAiChatSession> {
+
+    /**
+     * 获取用户与AI角色的活跃会话，如果不存在则创建新会话
+     *
+     * @param userId      用户ID
+     * @param companionId AI角色ID
+     * @return 活跃会话
+     */
+    KeyboardAiChatSession getOrCreateActiveSession(Long userId, Long companionId);
+
+    /**
+     * 获取用户与AI角色的活跃会话ID，如果不存在则创建新会话
+     *
+     * @param userId      用户ID
+     * @param companionId AI角色ID
+     * @return 活跃会话ID
+     */
+    Long getOrCreateActiveSessionId(Long userId, Long companionId);
+}

src/main/java/com/yolo/keyborad/service/impl/ChatServiceImpl.java

@@ -89,6 +89,9 @@ public class ChatServiceImpl implements ChatService {
     @Resource
     private KeyboardAiChatMessageService aiChatMessageService;
 
+    @Resource
+    private KeyboardAiChatSessionService aiChatSessionService;
+
     @Resource
     private ElevenLabsService elevenLabsService;
 
@@ -457,10 +460,14 @@ public class ChatServiceImpl implements ChatService {
     private void saveChatMessages(Long userId, Long companionId, String userContent, String aiResponse) {
         Date now = new Date();
 
+        // 获取或创建活跃会话
+        Long sessionId = aiChatSessionService.getOrCreateActiveSessionId(userId, companionId);
+
         // 保存用户消息 (sender=1)
         KeyboardAiChatMessage userMessage = new KeyboardAiChatMessage();
         userMessage.setUserId(userId);
         userMessage.setCompanionId(companionId);
+        userMessage.setSessionId(sessionId);
         userMessage.setSender((short) 1);
         userMessage.setContent(userContent);
         userMessage.setCreatedAt(now);
@@ -469,13 +476,14 @@ public class ChatServiceImpl implements ChatService {
         KeyboardAiChatMessage aiMessage = new KeyboardAiChatMessage();
         aiMessage.setUserId(userId);
         aiMessage.setCompanionId(companionId);
+        aiMessage.setSessionId(sessionId);
         aiMessage.setSender((short) 2);
         aiMessage.setContent(aiResponse);
         aiMessage.setCreatedAt(now);
 
         // 批量保存
         aiChatMessageService.saveBatch(List.of(userMessage, aiMessage));
-        log.info("聊天记录保存成功, userId: {}, companionId: {}", userId, companionId);
+        log.info("聊天记录保存成功, userId: {}, companionId: {}, sessionId: {}", userId, companionId, sessionId);
     }
 
     /**

src/main/java/com/yolo/keyborad/service/impl/KeyboardAiChatSessionServiceImpl.java

@@ -0,0 +1,58 @@
+package com.yolo.keyborad.service.impl;
+
+import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
+import org.springframework.stereotype.Service;
+import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
+import com.yolo.keyborad.mapper.KeyboardAiChatSessionMapper;
+import com.yolo.keyborad.model.entity.KeyboardAiChatSession;
+import com.yolo.keyborad.service.KeyboardAiChatSessionService;
+
+import java.util.Date;
+
+/*
+ * @author: ziin
+ * @date: 2026/1/28 16:20
+ */
+@Service
+public class KeyboardAiChatSessionServiceImpl extends ServiceImpl<KeyboardAiChatSessionMapper, KeyboardAiChatSession> implements KeyboardAiChatSessionService {
+
+    @Override
+    public KeyboardAiChatSession getOrCreateActiveSession(Long userId, Long companionId) {
+        // 查询当前活跃会话
+        LambdaQueryWrapper<KeyboardAiChatSession> queryWrapper = new LambdaQueryWrapper<>();
+        queryWrapper.eq(KeyboardAiChatSession::getUserId, userId)
+                .eq(KeyboardAiChatSession::getCompanionId, companionId)
+                .eq(KeyboardAiChatSession::getIsActive, true);
+        KeyboardAiChatSession activeSession = this.getOne(queryWrapper);
+
+        if (activeSession != null) {
+            return activeSession;
+        }
+
+        // 不存在活跃会话，创建新会话
+        // 先查询该用户与该角色的最大版本号
+        LambdaQueryWrapper<KeyboardAiChatSession> maxVersionWrapper = new LambdaQueryWrapper<>();
+        maxVersionWrapper.eq(KeyboardAiChatSession::getUserId, userId)
+                .eq(KeyboardAiChatSession::getCompanionId, companionId)
+                .orderByDesc(KeyboardAiChatSession::getResetVersion)
+                .last("LIMIT 1");
+        KeyboardAiChatSession lastSession = this.getOne(maxVersionWrapper);
+        int newVersion = lastSession != null ? lastSession.getResetVersion() + 1 : 1;
+
+        // 创建新会话
+        KeyboardAiChatSession newSession = new KeyboardAiChatSession();
+        newSession.setUserId(userId);
+        newSession.setCompanionId(companionId);
+        newSession.setResetVersion(newVersion);
+        newSession.setIsActive(true);
+        newSession.setCreatedAt(new Date());
+        this.save(newSession);
+
+        return newSession;
+    }
+
+    @Override
+    public Long getOrCreateActiveSessionId(Long userId, Long companionId) {
+        return getOrCreateActiveSession(userId, companionId).getId();
+    }
+}

src/main/resources/mapper/KeyboardAiChatSessionMapper.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
+<mapper namespace="com.yolo.keyborad.mapper.KeyboardAiChatSessionMapper">
+  <resultMap id="BaseResultMap" type="com.yolo.keyborad.model.entity.KeyboardAiChatSession">
+    <!--@mbg.generated-->
+    <!--@Table keyboard_ai_chat_session-->
+    <id column="id" jdbcType="BIGINT" property="id" />
+    <result column="user_id" jdbcType="BIGINT" property="userId" />
+    <result column="companion_id" jdbcType="BIGINT" property="companionId" />
+    <result column="reset_version" jdbcType="INTEGER" property="resetVersion" />
+    <result column="is_active" jdbcType="BOOLEAN" property="isActive" />
+    <result column="created_at" jdbcType="TIMESTAMP" property="createdAt" />
+    <result column="ended_at" jdbcType="TIMESTAMP" property="endedAt" />
+  </resultMap>
+  <sql id="Base_Column_List">
+    <!--@mbg.generated-->
+    id, user_id, companion_id, reset_version, is_active, created_at, ended_at
+  </sql>
+</mapper>