backend/internal/handler/vote_handler.go

package handler

import (
	"errors"
	"net/http"

	"github.com/gin-gonic/gin"

	"with_you/internal/dto"
	"with_you/internal/pkg/response"
	"with_you/internal/service"
)

// VoteHandler 投票处理器
type VoteHandler struct {
	voteService service.VoteService
	postService service.PostService
}

// NewVoteHandler 创建投票处理器
func NewVoteHandler(voteService service.VoteService, postService service.PostService) *VoteHandler {
	return &VoteHandler{
		voteService: voteService,
		postService: postService,
	}
}

// CreateVotePost 创建投票帖子
// POST /api/v1/posts/vote
func (h *VoteHandler) CreateVotePost(c *gin.Context) {
	userID := c.GetString("user_id")
	if userID == "" {
		response.Unauthorized(c, "请先登录")
		return
	}

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

	post, err := h.voteService.CreateVotePost(c.Request.Context(), userID, &req)
	if err != nil {
		var moderationErr *service.PostModerationRejectedError
		if errors.As(err, &moderationErr) {
			response.BadRequest(c, moderationErr.UserMessage())
			return
		}
		// 幂等命中"进行中"占位：提示客户端稍候，避免重复提交
		if errors.Is(err, service.ErrDuplicatePostRequest) {
			response.ErrorWithStatusCode(c, http.StatusTooManyRequests, 429, err.Error())
			return
		}
		response.Error(c, http.StatusBadRequest, err.Error())
		return
	}

	response.Success(c, post)
}

// GetVoteResult 获取投票结果
// GET /api/v1/posts/:id/vote
func (h *VoteHandler) GetVoteResult(c *gin.Context) {
	postID := c.Param("id")
	if postID == "" {
		response.BadRequest(c, "帖子ID不能为空")
		return
	}

	// 验证帖子存在
	_, err := h.postService.GetByID(c.Request.Context(), postID)
	if err != nil {
		response.NotFound(c, "帖子不存在")
		return
	}

	// 获取当前用户ID（可选登录）
	userID := c.GetString("user_id")

	// 如果用户未登录，返回不带has_voted的结果
	if userID == "" {
		options, err := h.voteService.GetVoteOptions(postID)
		if err != nil {
			response.InternalServerError(c, "获取投票选项失败")
			return
		}

		// 计算总票数
		totalVotes := 0
		for _, option := range options {
			totalVotes += option.VotesCount
		}

		result := &dto.VoteResultDTO{
			Options:    options,
			TotalVotes: totalVotes,
			HasVoted:   false,
		}

		response.Success(c, result)
		return
	}

	// 用户已登录，获取完整的投票结果
	result, err := h.voteService.GetVoteResult(postID, userID)
	if err != nil {
		response.InternalServerError(c, "获取投票结果失败")
		return
	}

	response.Success(c, result)
}

// Vote 投票
// POST /api/v1/posts/:id/vote
func (h *VoteHandler) Vote(c *gin.Context) {
	userID := c.GetString("user_id")
	if userID == "" {
		response.Unauthorized(c, "请先登录")
		return
	}

	postID := c.Param("id")
	if postID == "" {
		response.BadRequest(c, "帖子ID不能为空")
		return
	}

	// 验证帖子存在
	_, err := h.postService.GetByID(c.Request.Context(), postID)
	if err != nil {
		response.NotFound(c, "帖子不存在")
		return
	}

	// 解析请求体
	var req struct {
		OptionID string `json:"option_id" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, err.Error())
		return
	}

	if err := h.voteService.Vote(c.Request.Context(), postID, userID, req.OptionID); err != nil {
		response.Error(c, http.StatusBadRequest, err.Error())
		return
	}

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

// Unvote 取消投票
// DELETE /api/v1/posts/:id/vote
func (h *VoteHandler) Unvote(c *gin.Context) {
	userID := c.GetString("user_id")
	if userID == "" {
		response.Unauthorized(c, "请先登录")
		return
	}

	postID := c.Param("id")
	if postID == "" {
		response.BadRequest(c, "帖子ID不能为空")
		return
	}

	// 验证帖子存在
	_, err := h.postService.GetByID(c.Request.Context(), postID)
	if err != nil {
		response.NotFound(c, "帖子不存在")
		return
	}

	if err := h.voteService.Unvote(c.Request.Context(), postID, userID); err != nil {
		response.Error(c, http.StatusBadRequest, err.Error())
		return
	}

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

// UpdateVoteOption 更新投票选项（仅作者）
// PUT /api/v1/vote-options/:id
func (h *VoteHandler) UpdateVoteOption(c *gin.Context) {
	userID := c.GetString("user_id")
	if userID == "" {
		response.Unauthorized(c, "请先登录")
		return
	}

	optionID := c.Param("id")
	if optionID == "" {
		response.BadRequest(c, "选项ID不能为空")
		return
	}

	// 解析请求体
	var req struct {
		Content string `json:"content" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, err.Error())
		return
	}

	// 获取帖子ID（从查询参数或请求体中获取）
	postID := c.Query("post_id")
	if postID == "" {
		response.BadRequest(c, "帖子ID不能为空")
		return
	}

	if err := h.voteService.UpdateVoteOption(c.Request.Context(), postID, optionID, userID, req.Content); err != nil {
		response.Error(c, http.StatusForbidden, err.Error())
		return
	}

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