feat: 增强会话管理和 Agent 服务

- 优化 session_handler 会话处理逻辑
- 增强 agent_service Agent 服务功能
- 新增 chat_repository 仓储方法
- 更新 agent_handler 和 chat_group_handler
- 更新数据模型 agent 和 chat_session

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/internal/handler/session_handler.go

@@ -1,8 +1,10 @@
 package handler
 
 import (
+	"fmt"
 	"net/http"
 	"strconv"
+	"strings"
 
 	"x-agents/server/internal/model"
 	"x-agents/server/internal/repository"
@@ -94,11 +96,12 @@ func (h *ChatHandler) CreateAgent(c *gin.Context) {
 
 // SessionHandler 处理会话管理
 type SessionHandler struct {
-	chatRepo *repository.ChatRepository
+	chatRepo     *repository.ChatRepository
+	agentService *service.AgentService
 }
 
-func NewSessionHandler(chatRepo *repository.ChatRepository) *SessionHandler {
-	return &SessionHandler{chatRepo: chatRepo}
+func NewSessionHandler(chatRepo *repository.ChatRepository, agentService *service.AgentService) *SessionHandler {
+	return &SessionHandler{chatRepo: chatRepo, agentService: agentService}
 }
 
 // CreateSession 创建会话
@@ -226,6 +229,16 @@ func (h *SessionHandler) CreateMessage(c *gin.Context) {
 		return
 	}
 
+	// Debug: 打印请求内容
+	fmt.Printf("[CreateMessage] Request: session_id=%s, role=%s, content_len=%d\n",
+		req.SessionID, req.Role, len(req.Content))
+
+	// 验证 content 不为空
+	if req.Content == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Content cannot be empty"})
+		return
+	}
+
 	// 检查会话是否存在
 	_, err := h.chatRepo.GetSessionByID(req.SessionID)
 	if err != nil {
@@ -250,3 +263,65 @@ func (h *SessionHandler) CreateMessage(c *gin.Context) {
 
 	c.JSON(http.StatusOK, message)
 }
+
+// GenerateSessionTitleRequest 生成会话标题请求
+type GenerateSessionTitleRequest struct {
+	SessionID string `json:"session_id" binding:"required"`
+}
+
+// GenerateSessionTitle 生成会话标题
+func (h *SessionHandler) GenerateSessionTitle(c *gin.Context) {
+	var req GenerateSessionTitleRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	// 获取会话的所有消息
+	messages, _, err := h.chatRepo.GetMessagesBySessionID(req.SessionID, 100, 0)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to get messages"})
+		return
+	}
+
+	if len(messages) < 2 {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Not enough messages to generate title"})
+		return
+	}
+
+	// 获取会话信息
+	session, err := h.chatRepo.GetSessionByID(req.SessionID)
+	if err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "Session not found"})
+		return
+	}
+
+	// 简单方式：从用户的第一条消息中提取前15个字符作为标题
+	var title string
+	for _, msg := range messages {
+		if msg.Role == "user" {
+			// 清理内容，去除换行和多余空格
+			content := strings.ReplaceAll(msg.Content, "\n", " ")
+			content = strings.TrimSpace(content)
+			// 限制长度
+			if len(content) > 15 {
+				title = content[:15] + "..."
+			} else {
+				title = content
+			}
+			break
+		}
+	}
+
+	if title == "" {
+		title = "新会话"
+	}
+
+	fmt.Printf("[GenerateSessionTitle] Generated title: %s\n", title)
+
+	// 更新会话标题
+	session.Title = title
+	h.chatRepo.UpdateSession(session)
+
+	c.JSON(http.StatusOK, gin.H{"title": title})
+}