backend/internal/handler/comment_handler.go

package handler

import (
	"encoding/json"
	"errors"
	"strconv"

	"github.com/gin-gonic/gin"

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

// CommentHandler 评论处理器
type CommentHandler struct {
	commentService *service.CommentService
}

// NewCommentHandler 创建评论处理器
func NewCommentHandler(commentService *service.CommentService) *CommentHandler {
	return &CommentHandler{
		commentService: commentService,
	}
}

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

	type CreateRequest struct {
		PostID   string   `json:"post_id" binding:"required"`
		Content  string   `json:"content"` // 内容可选，允许只发图片
		ParentID *string  `json:"parent_id"`
		Images   []string `json:"images"` // 图片URL列表
	}

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

	// 验证：评论必须有内容或图片
	if req.Content == "" && len(req.Images) == 0 {
		response.BadRequest(c, "评论内容或图片不能同时为空")
		return
	}

	// 将图片列表转换为JSON字符串
	var imagesJSON string
	if len(req.Images) > 0 {
		imagesBytes, _ := json.Marshal(req.Images)
		imagesJSON = string(imagesBytes)
	}

	comment, err := h.commentService.Create(c.Request.Context(), req.PostID, userID, req.Content, req.ParentID, imagesJSON, req.Images)
	if err != nil {
		var moderationErr *service.CommentModerationRejectedError
		if errors.As(err, &moderationErr) {
			response.BadRequest(c, moderationErr.UserMessage())
			return
		}
		response.InternalServerError(c, "failed to create comment")
		return
	}

	response.Success(c, dto.ConvertCommentToResponse(comment, false))
}

// GetByID 获取单条评论详情
func (h *CommentHandler) GetByID(c *gin.Context) {
	userID := c.GetString("user_id")
	id := c.Param("id")

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

	resp := dto.ConvertCommentToResponse(comment, h.commentService.IsLiked(c.Request.Context(), id, userID))
	response.Success(c, resp)
}

// GetByPostID 获取帖子评论
func (h *CommentHandler) GetByPostID(c *gin.Context) {
	userID := c.GetString("user_id")
	postID := c.Param("id")
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))

	comments, total, err := h.commentService.GetByPostID(c.Request.Context(), postID, page, pageSize)
	if err != nil {
		response.InternalServerError(c, "failed to get comments")
		return
	}

	// 转换为响应结构，检查每个评论的点赞状态
	commentResponses := dto.ConvertCommentsToResponseWithUser(comments, userID, h.commentService)

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

// GetReplies 获取回复
func (h *CommentHandler) GetReplies(c *gin.Context) {
	userID := c.GetString("user_id")
	parentID := c.Param("id")

	comments, err := h.commentService.GetReplies(c.Request.Context(), parentID)
	if err != nil {
		response.InternalServerError(c, "failed to get replies")
		return
	}

	// 转换为响应结构，检查每个回复的点赞状态
	commentResponses := dto.ConvertCommentsToResponseWithUser(comments, userID, h.commentService)

	response.Success(c, commentResponses)
}

// GetRepliesByRootID 根据根评论ID分页获取回复（扁平化）
func (h *CommentHandler) GetRepliesByRootID(c *gin.Context) {
	userID := c.GetString("user_id")
	rootID := c.Param("id")
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "10"))

	replies, total, err := h.commentService.GetRepliesByRootID(c.Request.Context(), rootID, page, pageSize)
	if err != nil {
		response.InternalServerError(c, "failed to get replies")
		return
	}

	// 转换为响应结构，检查每个回复的点赞状态
	replyResponses := dto.ConvertCommentsToResponseWithUser(replies, userID, h.commentService)

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

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

	id := c.Param("id")

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

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

	type UpdateRequest struct {
		Content string `json:"content" binding:"required"`
	}

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

	comment.Content = req.Content

	err = h.commentService.Update(c.Request.Context(), comment)
	if err != nil {
		response.InternalServerError(c, "failed to update comment")
		return
	}

	response.Success(c, dto.ConvertCommentToResponse(comment, false))
}

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

	id := c.Param("id")

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

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

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

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

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

	id := c.Param("id")

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

	response.SuccessWithMessage(c, "liked", nil)
}

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

	id := c.Param("id")

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

	response.SuccessWithMessage(c, "unliked", nil)
}

// GetByPostIDByCursor 游标分页获取帖子评论
func (h *CommentHandler) GetByPostIDByCursor(c *gin.Context) {
	userID := c.GetString("user_id")
	postID := c.Param("id")

	// 解析游标分页请求
	req := h.parseCursorRequest(c)

	// 调用游标分页服务
	result, err := h.commentService.GetCommentsByCursor(c.Request.Context(), postID, req)
	if err != nil {
		response.InternalServerError(c, "failed to get comments")
		return
	}

	// 转换为响应结构，检查每个评论的点赞状态
	commentResponses := dto.ConvertCommentsToResponseWithUser(result.Items, userID, h.commentService)

	// 构建游标分页响应
	cursorResp := &dto.CommentCursorPageResponse{
		Items:      commentResponses,
		NextCursor: result.NextCursor,
		PrevCursor: result.PrevCursor,
		HasMore:    result.HasMore,
	}

	response.Success(c, cursorResp)
}

// GetRepliesByRootIDByCursor 游标分页获取根评论的回复
func (h *CommentHandler) GetRepliesByRootIDByCursor(c *gin.Context) {
	userID := c.GetString("user_id")
	rootID := c.Param("id")

	// 解析游标分页请求
	req := h.parseCursorRequest(c)

	// 调用游标分页服务
	result, err := h.commentService.GetRepliesByCursor(c.Request.Context(), rootID, req)
	if err != nil {
		response.InternalServerError(c, "failed to get replies")
		return
	}

	// 转换为响应结构，检查每个回复的点赞状态
	replyResponses := dto.ConvertCommentsToResponseWithUser(result.Items, userID, h.commentService)

	// 构建游标分页响应
	cursorResp := &dto.CommentCursorPageResponse{
		Items:      replyResponses,
		NextCursor: result.NextCursor,
		PrevCursor: result.PrevCursor,
		HasMore:    result.HasMore,
	}

	response.Success(c, cursorResp)
}

// parseCursorRequest 解析游标分页请求参数
func (h *CommentHandler) parseCursorRequest(c *gin.Context) *cursor.PageRequest {
	cursorStr := c.Query("cursor")
	direction := cursor.Direction(c.DefaultQuery("direction", "forward"))
	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))

	return cursor.NewPageRequest(cursorStr, direction, pageSize)
}