feat(posts): add post reference/internal linking functionality

Add support for referencing other posts within messages through a new post_ref segment type. Includes new PostReference model to track relationships, PostRefService for processing references, and new endpoints for post suggestions, related posts, and reference click tracking.

internal/handler/post_handler.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"log"
 	"strconv"
 
 	"github.com/gin-gonic/gin"
@@ -19,14 +20,16 @@ import (
 // PostHandler 帖子处理器
 type PostHandler struct {
 	postService    service.PostService
+	postRefService service.PostRefService
 	userService    service.UserService
 	channelService service.ChannelService
 }
 
 // NewPostHandler 创建帖子处理器
-func NewPostHandler(postService service.PostService, userService service.UserService, channelService service.ChannelService) *PostHandler {
+func NewPostHandler(postService service.PostService, postRefService service.PostRefService, userService service.UserService, channelService service.ChannelService) *PostHandler {
 	return &PostHandler{
 		postService:    postService,
+		postRefService: postRefService,
 		userService:    userService,
 		channelService: channelService,
 	}
@@ -113,6 +116,15 @@ func (h *PostHandler) Create(c *gin.Context) {
 		return
 	}
 
+	if h.postRefService != nil && len(segments) > 0 {
+		go func() {
+			bgCtx := context.Background()
+			if err := h.postRefService.ProcessPostReferences(bgCtx, post.ID, segments); err != nil {
+				log.Printf("[WARN] process post references failed for post %s: %v", post.ID, err)
+			}
+		}()
+	}
+
 	chMap := h.channelMapForPosts([]*model.Post{post})
 	response.Success(c, dto.ConvertPostToResponse(post, chMap, false, false))
 }
@@ -136,6 +148,14 @@ func (h *PostHandler) GetByID(c *gin.Context) {
 
 	// 注意：不再自动增加浏览量，浏览量通过 RecordView 端点单独记录
 
+	// 增强 post_ref segments
+	enrichedSegments := dto.SegmentsOrDefault(post.Segments, post.Content)
+	if h.postRefService != nil && len(enrichedSegments) > 0 {
+		if enriched, err := h.postRefService.EnrichPostRefSegments(c.Request.Context(), enrichedSegments, currentUserID); err == nil {
+			enrichedSegments = enriched
+		}
+	}
+
 	// 获取交互状态
 	isLiked, isFavorited := h.postService.GetPostInteractionStatusSingle(c.Request.Context(), id, currentUserID)
 
@@ -160,7 +180,7 @@ func (h *PostHandler) GetByID(c *gin.Context) {
 		ChannelID:       post.ChannelID,
 		Title:           post.Title,
 		Content:         post.Content,
-		Segments:        dto.SegmentsOrDefault(post.Segments, post.Content),
+		Segments:        enrichedSegments,
 		Images:          dto.ConvertPostImagesToResponse(post.Images),
 		Status:          string(post.Status),
 		LikesCount:      post.LikesCount,
@@ -438,6 +458,15 @@ func (h *PostHandler) Update(c *gin.Context) {
 		return
 	}
 
+	if h.postRefService != nil && len(req.Segments) > 0 {
+		go func() {
+			bgCtx := context.Background()
+			if err := h.postRefService.ProcessPostReferences(bgCtx, post.ID, post.Segments); err != nil {
+				log.Printf("[WARN] process post references failed for post %s: %v", post.ID, err)
+			}
+		}()
+	}
+
 	post, err = h.postService.GetByID(c.Request.Context(), post.ID)
 	if err != nil {
 		response.InternalServerError(c, "failed to get updated post")
@@ -479,6 +508,15 @@ func (h *PostHandler) Delete(c *gin.Context) {
 		return
 	}
 
+	if h.postRefService != nil {
+		go func() {
+			bgCtx := context.Background()
+			if err := h.postRefService.HandlePostDeleted(bgCtx, id); err != nil {
+				log.Printf("[WARN] mark dead post references failed for post %s: %v", id, err)
+			}
+		}()
+	}
+
 	response.SuccessWithMessage(c, "post deleted", nil)
 }
 
@@ -828,6 +866,114 @@ func (h *PostHandler) SearchByCursor(c *gin.Context) {
 	response.Success(c, cursorResp)
 }
 
+// RecordRefClick 记录内链点击
+func (h *PostHandler) RecordRefClick(c *gin.Context) {
+	id := c.Param("id")
+
+	type RefClickRequest struct {
+		TargetPostID string `json:"target_post_id" binding:"required"`
+	}
+	var req RefClickRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		response.BadRequest(c, "target_post_id is required")
+		return
+	}
+
+	if h.postRefService != nil {
+		if err := h.postRefService.RecordClick(c.Request.Context(), id, req.TargetPostID); err != nil {
+			log.Printf("[WARN] record ref click failed: %v", err)
+		}
+	}
+
+	response.Success(c, gin.H{"success": true})
+}
+
+// GetRelatedPosts 获取引用当前帖子的相关帖子
+func (h *PostHandler) GetRelatedPosts(c *gin.Context) {
+	id := c.Param("id")
+
+	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
+	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))
+	page, pageSize = normalizePagination(page, pageSize)
+
+	if h.postRefService == nil {
+		response.Paginated(c, []*dto.PostResponse{}, 0, page, pageSize)
+		return
+	}
+
+	posts, total, err := h.postRefService.GetRelatedPosts(c.Request.Context(), id, page, pageSize)
+	if err != nil {
+		response.InternalServerError(c, "failed to get related posts")
+		return
+	}
+
+	currentUserID := c.GetString("user_id")
+	posts = h.filterBlockedPosts(c.Request.Context(), posts, currentUserID)
+
+	postIDs := make([]string, len(posts))
+	for i, p := range posts {
+		postIDs[i] = p.ID
+	}
+	isLikedMap, isFavoritedMap, _ := h.postService.GetPostInteractionStatus(c.Request.Context(), postIDs, currentUserID)
+
+	chMap := h.channelMapForPosts(posts)
+	postResponses := dto.BuildPostsWithInteractionResponse(posts, chMap, isLikedMap, isFavoritedMap)
+
+	response.Paginated(c, postResponses, total, page, pageSize)
+}
+
+// GetReferencedPosts 获取当前帖子引用的目标帖子
+func (h *PostHandler) GetReferencedPosts(c *gin.Context) {
+	id := c.Param("id")
+
+	if h.postRefService == nil {
+		response.Success(c, []*dto.PostResponse{})
+		return
+	}
+
+	posts, err := h.postRefService.GetReferencedPosts(c.Request.Context(), id)
+	if err != nil {
+		response.InternalServerError(c, "failed to get referenced posts")
+		return
+	}
+
+	currentUserID := c.GetString("user_id")
+	posts = h.filterBlockedPosts(c.Request.Context(), posts, currentUserID)
+
+	postIDs := make([]string, len(posts))
+	for i, p := range posts {
+		postIDs[i] = p.ID
+	}
+	isLikedMap, isFavoritedMap, _ := h.postService.GetPostInteractionStatus(c.Request.Context(), postIDs, currentUserID)
+
+	chMap := h.channelMapForPosts(posts)
+	postResponses := dto.BuildPostsWithInteractionResponse(posts, chMap, isLikedMap, isFavoritedMap)
+
+	response.Success(c, postResponses)
+}
+
+// Suggest 帖子搜索联想
+func (h *PostHandler) Suggest(c *gin.Context) {
+	q := c.Query("q")
+	if q == "" {
+		response.Success(c, []dto.PostRefBrief{})
+		return
+	}
+
+	limit, _ := strconv.Atoi(c.DefaultQuery("limit", "10"))
+	if limit <= 0 || limit > 50 {
+		limit = 10
+	}
+
+	briefs, err := h.postRefService.SuggestPosts(c.Request.Context(), q, limit)
+	if err != nil {
+		response.InternalServerError(c, "failed to search posts")
+		return
+	}
+
+	response.Success(c, briefs)
+}
+
 // parseCursorRequest 解析游标分页请求参数
 func (h *PostHandler) parseCursorRequest(c *gin.Context) *cursor.PageRequest {
 	cursorStr := c.Query("cursor")