backend/internal/handler/post_handler.go

package handler

import (
	"errors"
	"fmt"
	"strconv"

	"github.com/gin-gonic/gin"

	"carrot_bbs/internal/dto"
	"carrot_bbs/internal/model"
	"carrot_bbs/internal/pkg/response"
	"carrot_bbs/internal/service"
)

// PostHandler 帖子处理器
type PostHandler struct {
	postService *service.PostService
	userService *service.UserService
}

// NewPostHandler 创建帖子处理器
func NewPostHandler(postService *service.PostService, userService *service.UserService) *PostHandler {
	return &PostHandler{
		postService: postService,
		userService: userService,
	}
}

// Create 创建帖子
func (h *PostHandler) Create(c *gin.Context) {
	userID := c.GetString("user_id")
	if userID == "" {
		response.Unauthorized(c, "")
		return
	}

	type CreateRequest struct {
		Title   string   `json:"title" binding:"required"`
		Content string   `json:"content" binding:"required"`
		Images  []string `json:"images"`
	}

	var req CreateRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, err.Error())
		return
	}

	post, err := h.postService.Create(c.Request.Context(), userID, req.Title, req.Content, req.Images)
	if err != nil {
		var moderationErr *service.PostModerationRejectedError
		if errors.As(err, &moderationErr) {
			response.BadRequest(c, moderationErr.UserMessage())
			return
		}
		response.InternalServerError(c, "failed to create post")
		return
	}

	response.Success(c, dto.ConvertPostToResponse(post, false, false))
}

// GetByID 获取帖子（不增加浏览量）
func (h *PostHandler) GetByID(c *gin.Context) {
	id := c.Param("id")

	post, err := h.postService.GetByID(c.Request.Context(), id)
	if err != nil {
		response.NotFound(c, "post not found")
		return
	}

	// 非作者不可查看未发布内容
	currentUserID := c.GetString("user_id")
	if post.Status != model.PostStatusPublished && post.UserID != currentUserID {
		response.NotFound(c, "post not found")
		return
	}

	// 注意：不再自动增加浏览量，浏览量通过 RecordView 端点单独记录

	// 获取交互状态
	isLiked, isFavorited := h.postService.GetPostInteractionStatusSingle(c.Request.Context(), id, currentUserID)

	// 如果有当前用户，检查与帖子作者的相互关注状态
	var authorWithFollowStatus *dto.UserResponse
	if currentUserID != "" && post.User != nil {
		_, isFollowing, isFollowingMe, err := h.userService.GetUserByIDWithMutualFollowStatus(c.Request.Context(), post.UserID, currentUserID)
		if err == nil {
			authorWithFollowStatus = dto.ConvertUserToResponseWithMutualFollow(post.User, isFollowing, isFollowingMe)
		} else {
			// 如果出错，使用默认的author
			authorWithFollowStatus = dto.ConvertUserToResponse(post.User)
		}
	}

	// 构建响应
	responseData := &dto.PostResponse{
		ID:             post.ID,
		UserID:         post.UserID,
		Title:          post.Title,
		Content:        post.Content,
		Images:         dto.ConvertPostImagesToResponse(post.Images),
		Status:         string(post.Status),
		LikesCount:     post.LikesCount,
		CommentsCount:  post.CommentsCount,
		FavoritesCount: post.FavoritesCount,
		SharesCount:    post.SharesCount,
		ViewsCount:     post.ViewsCount,
		IsPinned:       post.IsPinned,
		IsLocked:       post.IsLocked,
		IsVote:         post.IsVote,
		CreatedAt:      dto.FormatTime(post.CreatedAt),
		UpdatedAt:      dto.FormatTime(post.UpdatedAt),
		Author:         authorWithFollowStatus,
		IsLiked:        isLiked,
		IsFavorited:    isFavorited,
	}

	response.Success(c, responseData)
}

// RecordView 记录帖子浏览（增加浏览量）
func (h *PostHandler) RecordView(c *gin.Context) {
	id := c.Param("id")
	userID := c.GetString("user_id")

	// 验证帖子存在
	_, err := h.postService.GetByID(c.Request.Context(), id)
	if err != nil {
		response.NotFound(c, "post not found")
		return
	}

	// 增加浏览量
	if err := h.postService.IncrementViews(c.Request.Context(), id, userID); err != nil {
		fmt.Printf("[ERROR] Failed to increment views for post %s: %v\n", id, err)
		response.InternalServerError(c, "failed to record view")
		return
	}

	response.Success(c, gin.H{"success": true})
}

// List 获取帖子列表
func (h *PostHandler) List(c *gin.Context) {
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))
	userID := c.Query("user_id")
	tab := c.Query("tab") // recommend, follow, hot, latest

	// 获取当前用户ID
	currentUserID := c.GetString("user_id")

	var posts []*model.Post
	var total int64
	var err error

	// 根据 tab 参数选择不同的获取方式
	switch tab {
	case "follow":
		// 获取关注用户的帖子，需要登录
		if currentUserID == "" {
			response.Unauthorized(c, "请先登录")
			return
		}
		posts, total, err = h.postService.GetFollowingPosts(c.Request.Context(), currentUserID, page, pageSize)
	case "hot":
		// 获取热门帖子
		posts, total, err = h.postService.GetHotPosts(c.Request.Context(), page, pageSize)
	case "recommend":
		// 推荐帖子（从Gorse获取个性化推荐）
		posts, total, err = h.postService.GetRecommendedPosts(c.Request.Context(), currentUserID, page, pageSize)
	case "latest":
		// 最新帖子
		if userID != "" && userID == currentUserID {
			posts, total, err = h.postService.GetLatestPostsForOwner(c.Request.Context(), page, pageSize, userID)
		} else {
			posts, total, err = h.postService.GetLatestPosts(c.Request.Context(), page, pageSize, userID)
		}
	default:
		// 默认获取最新帖子
		if userID != "" && userID == currentUserID {
			posts, total, err = h.postService.GetLatestPostsForOwner(c.Request.Context(), page, pageSize, userID)
		} else {
			posts, total, err = h.postService.GetLatestPosts(c.Request.Context(), page, pageSize, userID)
		}
	}

	if err != nil {
		response.InternalServerError(c, "failed to get posts")
		return
	}

	// 批量获取交互状态
	postIDs := make([]string, len(posts))
	for i, post := range posts {
		postIDs[i] = post.ID
	}
	isLikedMap, isFavoritedMap, _ := h.postService.GetPostInteractionStatus(c.Request.Context(), postIDs, currentUserID)

	// 转换为响应结构
	postResponses := dto.BuildPostsWithInteractionResponse(posts, isLikedMap, isFavoritedMap)

	response.Paginated(c, postResponses, total, page, pageSize)
}

// Update 更新帖子
func (h *PostHandler) Update(c *gin.Context) {
	userID := c.GetString("user_id")
	if userID == "" {
		response.Unauthorized(c, "")
		return
	}

	id := c.Param("id")

	post, err := h.postService.GetByID(c.Request.Context(), id)
	if err != nil {
		response.NotFound(c, "post not found")
		return
	}

	if post.UserID != userID {
		response.Forbidden(c, "cannot update others' post")
		return
	}

	type UpdateRequest struct {
		Title   string    `json:"title"`
		Content string    `json:"content"`
		Images  *[]string `json:"images"`
	}

	var req UpdateRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, err.Error())
		return
	}

	if req.Title != "" {
		post.Title = req.Title
	}
	if req.Content != "" {
		post.Content = req.Content
	}

	err = h.postService.UpdateWithImages(c.Request.Context(), post, req.Images)
	if err != nil {
		response.InternalServerError(c, "failed to update post")
		return
	}

	post, err = h.postService.GetByID(c.Request.Context(), post.ID)
	if err != nil {
		response.InternalServerError(c, "failed to get updated post")
		return
	}

	// 获取交互状态
	currentUserID := c.GetString("user_id")
	isLiked, isFavorited := h.postService.GetPostInteractionStatusSingle(c.Request.Context(), post.ID, currentUserID)

	response.Success(c, dto.BuildPostResponse(post, isLiked, isFavorited))
}

// Delete 删除帖子
func (h *PostHandler) Delete(c *gin.Context) {
	userID := c.GetString("user_id")
	if userID == "" {
		response.Unauthorized(c, "")
		return
	}

	id := c.Param("id")

	post, err := h.postService.GetByID(c.Request.Context(), id)
	if err != nil {
		response.NotFound(c, "post not found")
		return
	}

	if post.UserID != userID {
		response.Forbidden(c, "cannot delete others' post")
		return
	}

	err = h.postService.Delete(c.Request.Context(), id)
	if err != nil {
		response.InternalServerError(c, "failed to delete post")
		return
	}

	response.SuccessWithMessage(c, "post deleted", nil)
}

// Like 点赞帖子
func (h *PostHandler) Like(c *gin.Context) {
	userID := c.GetString("user_id")
	if userID == "" {
		response.Unauthorized(c, "")
		return
	}

	id := c.Param("id")

	err := h.postService.Like(c.Request.Context(), id, userID)
	if err != nil {
		response.InternalServerError(c, "failed to like post")
		return
	}

	// 获取更新后的帖子状态
	post, err := h.postService.GetByID(c.Request.Context(), id)
	if err != nil {
		response.InternalServerError(c, "failed to get post")
		return
	}

	// 获取交互状态
	isLiked, isFavorited := h.postService.GetPostInteractionStatusSingle(c.Request.Context(), id, userID)

	response.Success(c, dto.BuildPostResponse(post, isLiked, isFavorited))
}

// Unlike 取消点赞
func (h *PostHandler) Unlike(c *gin.Context) {
	userID := c.GetString("user_id")
	if userID == "" {
		response.Unauthorized(c, "")
		return
	}

	id := c.Param("id")

	err := h.postService.Unlike(c.Request.Context(), id, userID)
	if err != nil {
		response.InternalServerError(c, "failed to unlike post")
		return
	}

	// 获取更新后的帖子状态
	post, err := h.postService.GetByID(c.Request.Context(), id)
	if err != nil {
		response.InternalServerError(c, "failed to get post")
		return
	}

	// 获取交互状态
	isLiked, isFavorited := h.postService.GetPostInteractionStatusSingle(c.Request.Context(), id, userID)

	response.Success(c, dto.BuildPostResponse(post, isLiked, isFavorited))
}

// Favorite 收藏帖子
func (h *PostHandler) Favorite(c *gin.Context) {
	userID := c.GetString("user_id")
	if userID == "" {
		response.Unauthorized(c, "")
		return
	}

	id := c.Param("id")

	err := h.postService.Favorite(c.Request.Context(), id, userID)
	if err != nil {
		response.InternalServerError(c, "failed to favorite post")
		return
	}

	// 获取更新后的帖子状态
	post, err := h.postService.GetByID(c.Request.Context(), id)
	if err != nil {
		response.InternalServerError(c, "failed to get post")
		return
	}

	// 获取交互状态
	isLiked, isFavorited := h.postService.GetPostInteractionStatusSingle(c.Request.Context(), id, userID)

	response.Success(c, dto.BuildPostResponse(post, isLiked, isFavorited))
}

// Unfavorite 取消收藏
func (h *PostHandler) Unfavorite(c *gin.Context) {
	userID := c.GetString("user_id")
	if userID == "" {
		response.Unauthorized(c, "")
		return
	}

	id := c.Param("id")

	err := h.postService.Unfavorite(c.Request.Context(), id, userID)
	if err != nil {
		response.InternalServerError(c, "failed to unfavorite post")
		return
	}

	// 获取更新后的帖子状态
	post, err := h.postService.GetByID(c.Request.Context(), id)
	if err != nil {
		response.InternalServerError(c, "failed to get post")
		return
	}

	// 获取交互状态
	isLiked, isFavorited := h.postService.GetPostInteractionStatusSingle(c.Request.Context(), id, userID)

	response.Success(c, dto.BuildPostResponse(post, isLiked, isFavorited))
}

// GetUserPosts 获取用户帖子列表
func (h *PostHandler) GetUserPosts(c *gin.Context) {
	userID := c.Param("id")
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))

	currentUserID := c.GetString("user_id")
	includePending := currentUserID != "" && currentUserID == userID
	posts, total, err := h.postService.GetUserPosts(c.Request.Context(), userID, page, pageSize, includePending)
	if err != nil {
		response.InternalServerError(c, "failed to get user posts")
		return
	}

	// 批量获取交互状态
	postIDs := make([]string, len(posts))
	for i, post := range posts {
		postIDs[i] = post.ID
	}
	isLikedMap, isFavoritedMap, _ := h.postService.GetPostInteractionStatus(c.Request.Context(), postIDs, currentUserID)

	// 转换为响应结构
	postResponses := dto.BuildPostsWithInteractionResponse(posts, isLikedMap, isFavoritedMap)

	response.Paginated(c, postResponses, total, page, pageSize)
}

// GetFavorites 获取收藏列表
func (h *PostHandler) GetFavorites(c *gin.Context) {
	userID := c.Param("id")
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))

	posts, total, err := h.postService.GetFavorites(c.Request.Context(), userID, page, pageSize)
	if err != nil {
		response.InternalServerError(c, "failed to get favorites")
		return
	}

	// 批量获取交互状态
	currentUserID := c.GetString("user_id")
	postIDs := make([]string, len(posts))
	for i, post := range posts {
		postIDs[i] = post.ID
	}
	isLikedMap, isFavoritedMap, _ := h.postService.GetPostInteractionStatus(c.Request.Context(), postIDs, currentUserID)

	// 转换为响应结构
	postResponses := dto.BuildPostsWithInteractionResponse(posts, isLikedMap, isFavoritedMap)

	response.Paginated(c, postResponses, total, page, pageSize)
}

// Search 搜索帖子
func (h *PostHandler) Search(c *gin.Context) {
	keyword := c.Query("keyword")
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))

	posts, total, err := h.postService.Search(c.Request.Context(), keyword, page, pageSize)
	if err != nil {
		response.InternalServerError(c, "failed to search posts")
		return
	}

	// 批量获取交互状态
	currentUserID := c.GetString("user_id")
	postIDs := make([]string, len(posts))
	for i, post := range posts {
		postIDs[i] = post.ID
	}
	isLikedMap, isFavoritedMap, _ := h.postService.GetPostInteractionStatus(c.Request.Context(), postIDs, currentUserID)

	// 转换为响应结构
	postResponses := dto.BuildPostsWithInteractionResponse(posts, isLikedMap, isFavoritedMap)

	response.Paginated(c, postResponses, total, page, pageSize)
}