feat(chat): 为AI陪聊增加历史消息上下文支持

- ChatServiceImpl#message 现在会读取最近20条聊天记录作为LLM上下文
- 新增 callLLMWithHistory 方法，使用 Spring AI Message 构造对话历史
- KeyboardAiChatMessageService 新增 getRecentMessages 接口及实现，按时间正序返回指定条数消息
- 保持原有分页查询接口不变，仅补充上下文所需方法

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

@@ -5,6 +5,8 @@ import com.yolo.keyborad.model.entity.KeyboardAiChatMessage;
 import com.baomidou.mybatisplus.extension.service.IService;
 import com.yolo.keyborad.model.vo.ChatMessageHistoryVO;
 
+import java.util.List;
+
 /*
  * @author: ziin
  * @date: 2026/1/26 17:00
@@ -21,4 +23,14 @@ public interface KeyboardAiChatMessageService extends IService<KeyboardAiChatMes
      * @return 分页结果
      */
     IPage<ChatMessageHistoryVO> pageHistory(Long userId, Long companionId, Integer pageNum, Integer pageSize);
+
+    /**
+     * 获取最近的聊天记录（按时间正序，用于LLM上下文）
+     *
+     * @param userId      用户ID
+     * @param companionId AI陪聊角色ID
+     * @param limit       获取条数
+     * @return 聊天记录列表（时间正序）
+     */
+    List<KeyboardAiChatMessage> getRecentMessages(Long userId, Long companionId, int limit);
 }

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

@@ -25,6 +25,9 @@ import lombok.extern.slf4j.Slf4j;
 import org.dromara.x.file.storage.core.FileInfo;
 import org.dromara.x.file.storage.core.FileStorageService;
 import org.springframework.ai.chat.client.ChatClient;
+import org.springframework.ai.chat.messages.AssistantMessage;
+import org.springframework.ai.chat.messages.Message;
+import org.springframework.ai.chat.messages.UserMessage;
 import org.springframework.ai.openai.OpenAiChatOptions;
 import org.springframework.data.redis.core.StringRedisTemplate;
 import org.springframework.http.codec.ServerSentEvent;
@@ -371,7 +374,12 @@ public class ChatServiceImpl implements ChatService {
         // 获取AI人设的系统提示词
         String systemPrompt = aiCompanionService.getSystemPromptById(companionId);
 
-        String response = callLLM(content, systemPrompt);
+        // 获取最近20条聊天记录作为上下文
+        List<KeyboardAiChatMessage> historyMessages = aiChatMessageService.getRecentMessages(
+                Long.parseLong(userId), companionId, 20);
+        log.info("获取历史消息, userId: {}, companionId: {}, 数量: {}", userId, companionId, historyMessages.size());
+
+        String response = callLLMWithHistory(content, systemPrompt, historyMessages);
 
         long llmDuration = System.currentTimeMillis() - startTime;
         log.info("LLM 完成, userId: {}, 耗时: {}ms, 响应长度: {}", userId, llmDuration, response.length());
@@ -423,13 +431,27 @@ public class ChatServiceImpl implements ChatService {
     }
 
     /**
-     * 调用 LLM 生成响应
+     * 调用 LLM 生成响应（带历史消息上下文）
      */
-    private String callLLM(String content, String systemPrompt) {
+    private String callLLMWithHistory(String content, String systemPrompt, List<KeyboardAiChatMessage> historyMessages) {
+        // 构建历史消息列表
+        List<Message> messages = new ArrayList<>();
+        for (KeyboardAiChatMessage msg : historyMessages) {
+            if (msg.getSender() == 1) {
+                // 用户消息
+                messages.add(new UserMessage(msg.getContent()));
+            } else {
+                // AI消息
+                messages.add(new AssistantMessage(msg.getContent()));
+            }
+        }
+        // 添加当前用户消息
+        messages.add(new UserMessage(content));
+
         return client
                 .prompt()
                 .system(systemPrompt)
-                .user(content)
+                .messages(messages)
                 .call()
                 .content();
     }

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

@@ -11,6 +11,9 @@ import com.yolo.keyborad.model.vo.ChatMessageHistoryVO;
 import com.yolo.keyborad.service.KeyboardAiChatMessageService;
 import org.springframework.stereotype.Service;
 
+import java.util.Collections;
+import java.util.List;
+
 /*
  * @author: ziin
  * @date: 2026/1/26 17:00
@@ -28,4 +31,17 @@ public class KeyboardAiChatMessageServiceImpl extends ServiceImpl<KeyboardAiChat
         IPage<KeyboardAiChatMessage> entityPage = this.page(page, queryWrapper);
         return entityPage.convert(entity -> BeanUtil.copyProperties(entity, ChatMessageHistoryVO.class));
     }
+
+    @Override
+    public List<KeyboardAiChatMessage> getRecentMessages(Long userId, Long companionId, int limit) {
+        LambdaQueryWrapper<KeyboardAiChatMessage> queryWrapper = new LambdaQueryWrapper<>();
+        queryWrapper.eq(KeyboardAiChatMessage::getUserId, userId)
+                .eq(KeyboardAiChatMessage::getCompanionId, companionId)
+                .orderByDesc(KeyboardAiChatMessage::getCreatedAt)
+                .last("LIMIT " + limit);
+        List<KeyboardAiChatMessage> messages = this.list(queryWrapper);
+        // 反转列表，使其按时间正序排列（旧消息在前）
+        Collections.reverse(messages);
+        return messages;
+    }
 }