healthapp/backend/healthapi/internal/logic/send_message_logic.go

package logic

import (
	"context"

	"healthapi/internal/model"
	"healthapi/internal/svc"
	"healthapi/internal/types"
	"healthapi/pkg/ai"
	"healthapi/pkg/errorx"

	"github.com/zeromicro/go-zero/core/logx"
	"gorm.io/gorm"
)

type SendMessageLogic struct {
	logx.Logger
	ctx    context.Context
	svcCtx *svc.ServiceContext
}

func NewSendMessageLogic(ctx context.Context, svcCtx *svc.ServiceContext) *SendMessageLogic {
	return &SendMessageLogic{
		Logger: logx.WithContext(ctx),
		ctx:    ctx,
		svcCtx: svcCtx,
	}
}

func (l *SendMessageLogic) SendMessage(req *types.SendMessageReq) (resp *types.MessageResp, err error) {
	userID, err := GetUserIDFromCtx(l.ctx)
	if err != nil {
		return nil, errorx.ErrUnauthorized
	}

	// 验证对话属于该用户
	var conversation model.Conversation
	if err := l.svcCtx.DB.Where("id = ? AND user_id = ?", req.Id, userID).First(&conversation).Error; err != nil {
		return nil, errorx.ErrNotFound
	}

	// 保存用户消息
	userMessage := model.Message{
		ConversationID: conversation.ID,
		Role:           model.RoleUser,
		Content:        req.Content,
	}
	if err := l.svcCtx.DB.Create(&userMessage).Error; err != nil {
		return nil, errorx.ErrServerError
	}

	// 获取历史消息构建上下文
	var historyMessages []model.Message
	l.svcCtx.DB.Where("conversation_id = ?", conversation.ID).
		Order("created_at DESC").
		Limit(l.svcCtx.Config.AI.MaxHistoryMessages).
		Find(&historyMessages)

	// 获取用户健康档案构建系统提示
	systemPrompt := buildSystemPrompt(l.svcCtx.DB, userID)

	// 构建 AI 消息
	aiMessages := []ai.Message{{Role: "system", Content: systemPrompt}}
	for i := len(historyMessages) - 1; i >= 0; i-- {
		aiMessages = append(aiMessages, ai.Message{
			Role:    historyMessages[i].Role,
			Content: historyMessages[i].Content,
		})
	}

	// 调用 AI 服务
	aiResponse, err := l.svcCtx.AIClient.Chat(l.ctx, aiMessages)
	if err != nil {
		l.Logger.Errorf("AI service error: %v", err)
		aiResponse = "抱歉，AI 服务暂时不可用，请稍后再试。"
	}

	// 保存 AI 回复
	assistantMessage := model.Message{
		ConversationID: conversation.ID,
		Role:           model.RoleAssistant,
		Content:        aiResponse,
	}
	if err := l.svcCtx.DB.Create(&assistantMessage).Error; err != nil {
		return nil, errorx.ErrServerError
	}

	// 更新对话标题
	if conversation.Title == "新对话" {
		title := req.Content
		if len(title) > 50 {
			title = title[:50] + "..."
		}
		l.svcCtx.DB.Model(&conversation).Update("title", title)
	}

	return &types.MessageResp{
		UserMessage: types.Message{
			ID:             uint(userMessage.ID),
			ConversationID: userMessage.ConversationID,
			Role:           userMessage.Role,
			Content:        userMessage.Content,
			CreatedAt:      userMessage.CreatedAt.Format("2006-01-02 15:04:05"),
		},
		AssistantMessage: types.Message{
			ID:             uint(assistantMessage.ID),
			ConversationID: assistantMessage.ConversationID,
			Role:           assistantMessage.Role,
			Content:        assistantMessage.Content,
			CreatedAt:      assistantMessage.CreatedAt.Format("2006-01-02 15:04:05"),
		},
	}, nil
}

// buildSystemPrompt 构建系统提示（包含用户健康档案）
func buildSystemPrompt(db *gorm.DB, userID uint) string {
	basePrompt := `你是一位专业的中医健康顾问，名叫"健康小助手"。你的职责是：
1. 根据用户的健康档案和体质特点，提供个性化的健康建议
2. 解答用户关于中医养生、体质调理的问题
3. 推荐适合用户体质的饮食、运动和生活方式
4. 在必要时提醒用户寻求专业医疗帮助

请注意：
- 你的建议仅供参考，不能替代专业医疗诊断
- 回答要简洁明了，通俗易懂
- 适当使用中医术语，但要给出解释
- 保持友好、专业的语气`

	// 获取用户体质信息
	var assessment model.ConstitutionAssessment
	if err := db.Where("user_id = ?", userID).Order("assessed_at DESC").First(&assessment).Error; err == nil {
		if assessment.PrimaryConstitution != "" {
			basePrompt += "\n\n用户体质类型: " + model.ConstitutionNames[assessment.PrimaryConstitution]
		}
	}

	return basePrompt
}