feat: 支持聊天多版本答案切换

- 为管理端、公共聊天和用户中心补充回答变体查询与切换能力

- 支持基于指定轮次重新生成并同步前后端多版本状态

- 保留 application.yml 与本地截图文件为未提交状态

easyflow-api/easyflow-api-usercenter/src/main/java/tech/easyflow/usercenter/controller/ai/UcBotController.java

@@ -29,7 +29,9 @@ import tech.easyflow.common.satoken.util.SaTokenUtil;
 import tech.easyflow.common.web.controller.BaseCurdController;
 import tech.easyflow.common.web.exceptions.BusinessException;
 import tech.easyflow.common.web.jsonbody.JsonBody;
+import tech.easyflow.chatlog.service.ChatRoundOperateService;
 import tech.easyflow.core.runtime.ChatChannel;
+import tech.easyflow.core.runtime.ChatRuntimeExtKeys;
 import tech.easyflow.core.runtime.ChatRuntimeContext;
 import tech.easyflow.system.entity.vo.RoleCategoryAccessSnapshot;
 import tech.easyflow.system.service.CategoryPermissionService;
@@ -67,6 +69,8 @@ public class UcBotController extends BaseCurdController<BotService, Bot> {
     private Cache<String, Object> cache;
     @Resource
     private AudioServiceManager audioServiceManager;
+    @Resource
+    private ChatRoundOperateService chatRoundOperateService;
 
     public UcBotController(BotService service, ModelService modelService, BotWorkflowService botWorkflowService,
                            BotDocumentCollectionService botDocumentCollectionService) {
@@ -153,13 +157,17 @@ public class UcBotController extends BaseCurdController<BotService, Bot> {
             @JsonBody(value = "botId", required = true) BigInteger botId,
             @JsonBody(value = "conversationId", required = true) BigInteger conversationId,
             @JsonBody(value = "messages") List<Map<String, String>> messages,
-            @JsonBody(value = "attachments") List<String> attachments
+            @JsonBody(value = "attachments") List<String> attachments,
+            @JsonBody(value = "regenerateRoundId") BigInteger regenerateRoundId
 
     ) {
         BotServiceImpl.ChatCheckResult chatCheckResult = new BotServiceImpl.ChatCheckResult();
+        if (regenerateRoundId != null) {
+            chatRoundOperateService.requireRegeneratableRound(conversationId, regenerateRoundId);
+        }
 
         // 前置校验：失败则直接返回错误SseEmitter
-        SseEmitter errorEmitter = botService.checkChatBeforeStart(botId, prompt, conversationId.toString(), chatCheckResult);
+        SseEmitter errorEmitter = botService.checkChatBeforeStart(botId, prompt, conversationId.toString(), chatCheckResult, regenerateRoundId);
         if (errorEmitter != null) {
             return errorEmitter;
         }
@@ -171,7 +179,7 @@ public class UcBotController extends BaseCurdController<BotService, Bot> {
                 messages,
                 chatCheckResult,
                 attachments,
-                buildRuntimeContext(chatCheckResult.getAiBot(), conversationId, prompt, attachments)
+                buildRuntimeContext(chatCheckResult.getAiBot(), conversationId, prompt, attachments, regenerateRoundId)
         );
 
     }
@@ -287,7 +295,8 @@ public class UcBotController extends BaseCurdController<BotService, Bot> {
         return super.onSaveOrUpdateBefore(entity, isSave);
     }
 
-    private ChatRuntimeContext buildRuntimeContext(Bot bot, BigInteger conversationId, String prompt, List<String> attachments) {
+    private ChatRuntimeContext buildRuntimeContext(Bot bot, BigInteger conversationId, String prompt, List<String> attachments,
+                                                   BigInteger regenerateRoundId) {
         LoginAccount account = requireCurrentLoginAccount();
         ChatRuntimeContext context = new ChatRuntimeContext();
         context.setChannel(ChatChannel.USER_CENTER);
@@ -303,6 +312,9 @@ public class UcBotController extends BaseCurdController<BotService, Bot> {
         context.setSessionTitle(prompt.length() > 200 ? prompt.substring(0, 200) : prompt);
         context.setAnonymous(false);
         context.setAttachments(attachments);
+        if (regenerateRoundId != null) {
+            context.getExt().put(ChatRuntimeExtKeys.REGENERATE_ROUND_ID, regenerateRoundId);
+        }
         ChatTimeToolAvailabilityContext.bindLoggedInSnapshot(context, account, bot);
         return context;
     }

easyflow-api/easyflow-api-usercenter/src/main/java/tech/easyflow/usercenter/controller/ai/UcChatHistoryController.java

@@ -7,6 +7,7 @@ import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 import tech.easyflow.chatlog.domain.dto.ChatHistoryPage;
+import tech.easyflow.chatlog.domain.dto.ChatMessageRecord;
 import tech.easyflow.chatlog.domain.dto.ChatSessionPage;
 import tech.easyflow.chatlog.domain.dto.ChatSessionSummary;
 import tech.easyflow.chatlog.domain.query.ChatPageQuery;
@@ -17,6 +18,7 @@ import tech.easyflow.common.satoken.util.SaTokenUtil;
 import tech.easyflow.common.web.jsonbody.JsonBody;
 
 import java.math.BigInteger;
+import java.util.List;
 
 @RestController
 @RequestMapping("/userCenter/chatHistory")
@@ -61,4 +63,19 @@ public class UcChatHistoryController {
         chatHistoryManageService.deleteUserSession(account.getId(), sessionId, account.getId());
         return Result.ok();
     }
+
+    @GetMapping("/sessions/{sessionId}/rounds/{roundId}/variants")
+    public Result<List<ChatMessageRecord>> listRoundVariants(@PathVariable BigInteger sessionId,
+                                                             @PathVariable BigInteger roundId) {
+        LoginAccount account = SaTokenUtil.getLoginAccount();
+        return Result.ok(chatHistoryManageService.listUserRoundVariants(account.getId(), sessionId, roundId));
+    }
+
+    @PostMapping("/sessions/{sessionId}/rounds/{roundId}/selectVariant")
+    public Result<ChatMessageRecord> selectRoundVariant(@PathVariable BigInteger sessionId,
+                                                        @PathVariable BigInteger roundId,
+                                                        @JsonBody(value = "variantIndex", required = true) Integer variantIndex) {
+        LoginAccount account = SaTokenUtil.getLoginAccount();
+        return Result.ok(chatHistoryManageService.selectUserRoundVariant(account.getId(), sessionId, roundId, variantIndex, account.getId()));
+    }
 }