package web

import (
	"fmt"
	"html"
	"net/http"
	"net/url"
	"strconv"
	"strings"

	"git.iioio.com/freefire/jiang13-forum/models"
	"git.iioio.com/freefire/jiang13-forum/modules/webctx"
	"git.iioio.com/freefire/jiang13-forum/services"
	"github.com/gin-gonic/gin"
)

// PostPageData 帖详情
type PostPageData struct {
	PageChrome
	PostID         uint
	PostPath       string
	PostTitle      string
	AuthorName     string
	AuthorID       uint
	BoardID        uint
	BoardName      string
	Pinned         bool // 展示用：全局或版内置顶
	GlobalPinned   bool
	BoardPinned    bool
	Featured       bool
	EditLocked     bool
	PostTypeLabel  string
	CreatedLabel   string
	ViewCount      int
	LikeCount      int
	Liked          bool
	Favorited      bool
	BodyHTML       string
	CommentCount   int
	Comments       []CommentView
	CommentsLocked bool
	CanEdit          bool
	CanViewRevisions bool
	CanReportPost    bool
	IsAdmin          bool
	Status           string
	StatusLabel      string
	ShowModerationBanner bool
	IsQuestion           bool
	QuestionResolved     bool
	CanToggleQuestion    bool
	Poll                 *postPollView
}

type postPollOptionView struct {
	ID        uint
	Text      string
	VoteCount int
	Percent   int
	Selected  bool
}

type postPollView struct {
	Multi        bool
	MaxChoices   int
	Closed       bool
	EndsLabel    string
	TotalVotes   int
	ShowResults  bool
	HasVoted     bool
	CanVote      bool
	CanClose     bool
	Options      []postPollOptionView
}

// CommentView 评论
type CommentView struct {
	ID             uint
	Floor          int
	AuthorName     string
	AuthorID       uint
	CreatedLabel   string
	Content        string
	ContentHidden  bool
	ReplyToID      uint
	ReplyToFloor   int
	ReplyToAuthor  string
	LikeCount      int
	Liked          bool
	IsPrivate      bool
	CanReport      bool
	CanEdit        bool
	CanDelete      bool
	Status         string
	StatusLabel    string
}

// PostView GET /post/:id
func (d Deps) PostView(c *gin.Context) {
	ctx := d.ctx(c)
	idStr := stripIDParam(c.Param("id"), d.Settings.Permalink().Ext)
	id, err := strconv.ParseUint(idStr, 10, 64)
	if err != nil || id == 0 {
		d.render404(ctx)
		return
	}
	post, err := d.Post.FindByID(uint(id))
	if err != nil || !services.CanViewPost(post, ctx.UserID(), ctx.IsAdmin()) {
		d.render404(ctx)
		return
	}
	if post.Status == models.ContentStatusPublished {
		d.Post.RecordView(uint(id))
	}

	hasReplied := ctx.UserID() > 0 && d.Comment.HasUserReplied(uint(id), ctx.UserID())
	body := services.ApplyPostContentGates(post.Content, post, ctx.UserID(), ctx.IsAdmin(), hasReplied)

	comments, _ := d.Comment.ListByPost(uint(id), ctx.UserID(), ctx.IsAdmin(), post.UserID, nil)
	cv := make([]CommentView, 0, len(comments))
	for _, cm := range comments {
		an := strings.TrimSpace(cm.User.Nickname)
		if an == "" {
			an = cm.User.Username
		}
		view := CommentView{
			ID: cm.ID, Floor: cm.Floor, AuthorName: an, AuthorID: cm.UserID,
			CreatedLabel: formatTime(cm.CreatedAt),
			Content: cm.Content, ContentHidden: cm.ContentHidden,
			LikeCount: cm.LikeCount, Liked: cm.Liked, IsPrivate: cm.IsPrivate,
			CanReport: ctx.IsSigned() && (cm.UserID == 0 || cm.UserID != ctx.UserID()),
			CanEdit:   !cm.ContentHidden && d.Comment.CanUserEditComment(&cm, ctx.UserID(), ctx.IsAdmin()),
			CanDelete: !cm.ContentHidden && d.Comment.CanUserDeleteComment(&cm, ctx.UserID(), ctx.IsAdmin()),
			Status:    cm.Status,
		}
		if cm.Status == models.ContentStatusPending || cm.Status == models.ContentStatusRejected {
			if ctx.IsAdmin() || (cm.UserID > 0 && cm.UserID == ctx.UserID()) {
				view.StatusLabel = contentStatusLabel(cm.Status)
			}
		}
		if cm.ReplyTarget != nil {
			view.ReplyToID = cm.ReplyTarget.ID
			view.ReplyToFloor = cm.ReplyTarget.Floor
			rn := strings.TrimSpace(cm.ReplyTarget.User.Nickname)
			if rn == "" {
				rn = cm.ReplyTarget.User.Username
			}
			if rn == "" {
				rn = cm.ReplyTarget.GuestNick
			}
			view.ReplyToAuthor = rn
		} else if cm.ReplyTo != nil {
			view.ReplyToID = *cm.ReplyTo
		}
		cv = append(cv, view)
	}

	author := strings.TrimSpace(post.User.Nickname)
	if author == "" {
		author = post.User.Username
	}
	boardName := ""
	if post.Board.ID > 0 {
		boardName = post.Board.Name
	}

	chrome := d.chrome(ctx, post.Title+" · "+d.Settings.SiteBranding().Name, "", "post/body")
	chrome.ActiveBoard = post.BoardID

	statusLabel := ""
	showBanner := false
	if post.Status == models.ContentStatusPending || post.Status == models.ContentStatusRejected {
		if ctx.IsAdmin() || post.UserID == ctx.UserID() {
			statusLabel = contentStatusLabel(post.Status)
			showBanner = true
		}
	}

	var pollView *postPollView
	if post.PostType == models.PostTypePoll {
		if pv, err := services.GetPollView(post.ID, ctx.UserID()); err == nil && pv != nil {
			pollView = mapPollView(pv, ctx.IsSigned(), ctx.IsAdmin() || post.UserID == ctx.UserID())
		}
	}

	ctx.HTML(http.StatusOK, "post", PostPageData{
		PageChrome: chrome, PostID: post.ID,
		PostPath: url.QueryEscape(fmt.Sprintf("/post/%d", post.ID)),
		PostTitle: post.Title, AuthorName: author, AuthorID: post.UserID,
		BoardID: post.BoardID, BoardName: boardName,
		Pinned: post.Pinned || post.BoardPinned, GlobalPinned: post.Pinned, BoardPinned: post.BoardPinned,
		Featured: post.Featured, EditLocked: post.EditLocked,
		PostTypeLabel: postTypeLabel(post.PostType), CreatedLabel: formatTime(post.CreatedAt),
		ViewCount: post.ViewCount, LikeCount: post.LikeCount,
		Liked: d.Post.IsLiked(ctx.UserID(), post.ID), Favorited: d.Post.IsFavorited(ctx.UserID(), post.ID),
		BodyHTML: body, CommentCount: len(cv), Comments: cv,
		CommentsLocked: post.CommentsLocked,
		CanEdit:          d.Post.CanUserEdit(post, ctx.UserID(), ctx.IsAdmin()),
		CanViewRevisions: canViewPostRevisions(post, ctx.UserID(), ctx.IsAdmin()),
		CanReportPost:    ctx.IsSigned() && post.UserID != ctx.UserID(),
		IsAdmin:          ctx.IsAdmin(),
		Status:           post.Status,
		StatusLabel:      statusLabel,
		ShowModerationBanner: showBanner,
		IsQuestion:           post.PostType == models.PostTypeQuestion,
		QuestionResolved:     post.QuestionResolved,
		CanToggleQuestion:    post.PostType == models.PostTypeQuestion && (ctx.IsAdmin() || post.UserID == ctx.UserID()),
		Poll:                 pollView,
	})
}

func mapPollView(pv *services.PollView, loggedIn, canClose bool) *postPollView {
	hasVoted := len(pv.MyOptionIDs) > 0
	selected := make(map[uint]bool, len(pv.MyOptionIDs))
	for _, id := range pv.MyOptionIDs {
		selected[id] = true
	}
	showResults := pv.Closed || hasVoted
	opts := make([]postPollOptionView, 0, len(pv.Options))
	for _, o := range pv.Options {
		opts = append(opts, postPollOptionView{
			ID: o.ID, Text: o.Text, VoteCount: o.VoteCount, Percent: o.Percent, Selected: selected[o.ID],
		})
	}
	ends := ""
	if pv.EndsAt != nil {
		ends = formatTime(*pv.EndsAt)
	}
	return &postPollView{
		Multi: pv.Multi, MaxChoices: pv.MaxChoices, Closed: pv.Closed,
		EndsLabel: ends, TotalVotes: pv.TotalVotes,
		ShowResults: showResults, HasVoted: hasVoted,
		CanVote: loggedIn && !pv.Closed && !hasVoted,
		CanClose: canClose && !pv.Closed,
		Options: opts,
	}
}

func contentStatusLabel(status string) string {
	switch status {
	case models.ContentStatusPending:
		return "审核中"
	case models.ContentStatusRejected:
		return "已拒绝"
	default:
		return ""
	}
}

func postTypeLabel(t string) string {
	switch t {
	case models.PostTypeQuestion:
		return "问答"
	case models.PostTypePoll:
		return "投票"
	case models.PostTypeBounty:
		return "悬赏"
	case models.PostTypeLottery:
		return "抽奖"
	default:
		return ""
	}
}

// PostComment POST 评论
func (d Deps) PostComment(c *gin.Context) {
	ctx := d.ctx(c)
	if !ctx.CheckCSRF() {
		ctx.SetFlash("无效请求，请重试")
		ctx.Redirect("/")
		return
	}
	id, err := parsePostID(c, d)
	if err != nil {
		d.render404(ctx)
		return
	}
	content := strings.TrimSpace(c.PostForm("content"))
	if content == "" {
		ctx.SetFlash("评论不能为空")
		ctx.Redirect(fmt.Sprintf("/post/%d#comments", id))
		return
	}
	var replyTo *uint
	if raw := strings.TrimSpace(c.PostForm("reply_to")); raw != "" {
		rid, err := strconv.ParseUint(raw, 10, 64)
		if err == nil && rid > 0 {
			v := uint(rid)
			replyTo = &v
		}
	}
	isPrivate := c.PostForm("is_private") == "1" || c.PostForm("is_private") == "on"
	safe := "<p>" + html.EscapeString(content) + "</p>"
	cm, err := d.Comment.Create(services.CommentCreateInput{
		PostID: id, UserID: ctx.UserID(), Content: safe,
		ReplyTo: replyTo, IsPrivate: isPrivate,
	})
	if err != nil {
		ctx.SetFlash(err.Error())
		ctx.Redirect(fmt.Sprintf("/post/%d#comments", id))
		return
	}
	if d.Notify != nil && cm != nil {
		switch cm.Status {
		case models.ContentStatusPublished:
			d.Notify.AsyncNotifyCommentPublished(cm)
			d.Notify.AsyncNotifyCommentMentions(cm)
		case models.ContentStatusPending:
			ctx.SetFlash("评论已提交，审核通过后公开显示")
			d.Notify.AsyncNotifyPendingComment(cm)
		}
	}
	anchor := "#comments"
	if cm != nil && cm.Floor > 0 {
		anchor = fmt.Sprintf("#floor-%d", cm.Floor)
	}
	ctx.Redirect(fmt.Sprintf("/post/%d%s", id, anchor))
}

// PostCommentLike 评论点赞切换（PRG）
func (d Deps) PostCommentLike(c *gin.Context) {
	ctx := d.ctx(c)
	if !ctx.CheckCSRF() {
		ctx.SetFlash("无效请求")
		ctx.Redirect("/")
		return
	}
	postID, err := parsePostID(c, d)
	if err != nil {
		d.render404(ctx)
		return
	}
	cid, err := strconv.ParseUint(c.Param("cid"), 10, 64)
	if err != nil || cid == 0 {
		d.render404(ctx)
		return
	}
	cm, err := d.Comment.GetByID(uint(cid))
	if err != nil || cm.PostID != postID {
		d.render404(ctx)
		return
	}
	_, _, _ = d.Comment.ToggleLike(ctx.UserID(), uint(cid))
	ctx.Redirect(fmt.Sprintf("/post/%d#floor-%d", postID, cm.Floor))
}

// PostUnlock POST /post/:id/unlock — 积分解锁（JSON，供详情页渐进增强）
func (d Deps) PostUnlock(c *gin.Context) {
	ctx := d.ctx(c)
	if !ctx.CheckCSRF() {
		c.JSON(http.StatusBadRequest, gin.H{"error": "无效请求，请重试"})
		return
	}
	id, err := parsePostID(c, d)
	if err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "帖子不存在"})
		return
	}
	var req struct {
		BlockKey string `json:"block_key" form:"block_key"`
	}
	_ = c.ShouldBindJSON(&req)
	if req.BlockKey == "" {
		req.BlockKey = strings.TrimSpace(c.PostForm("block_key"))
	}
	if req.BlockKey == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "缺少 block_key"})
		return
	}
	res, err := services.UnlockPointsBlock(ctx.UserID(), id, req.BlockKey)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"message": "解锁成功",
		"unlock":  res,
	})
}

// PostLike 赞
func (d Deps) PostLike(c *gin.Context) {
	ctx := d.ctx(c)
	if !ctx.CheckCSRF() {
		ctx.SetFlash("无效请求")
		ctx.Redirect("/")
		return
	}
	id, err := parsePostID(c, d)
	if err != nil {
		d.render404(ctx)
		return
	}
	_, _ = d.Post.ToggleLike(ctx.UserID(), id)
	ctx.Redirect(fmt.Sprintf("/post/%d", id))
}

// PostFavorite 收藏
func (d Deps) PostFavorite(c *gin.Context) {
	ctx := d.ctx(c)
	if !ctx.CheckCSRF() {
		ctx.SetFlash("无效请求")
		ctx.Redirect("/")
		return
	}
	id, err := parsePostID(c, d)
	if err != nil {
		d.render404(ctx)
		return
	}
	_, _ = d.Post.ToggleFavorite(ctx.UserID(), id)
	ctx.Redirect(fmt.Sprintf("/post/%d", id))
}

// PostPollVote 投票提交
func (d Deps) PostPollVote(c *gin.Context) {
	ctx := d.ctx(c)
	id, err := parsePostID(c, d)
	if err != nil || id == 0 {
		d.render404(ctx)
		return
	}
	if !ctx.CheckCSRF() {
		ctx.SetFlash("无效请求，请重试")
		ctx.Redirect(fmt.Sprintf("/post/%d", id))
		return
	}
	raw := c.PostFormArray("option_ids")
	if len(raw) == 0 {
		if one := strings.TrimSpace(c.PostForm("option_id")); one != "" {
			raw = []string{one}
		}
	}
	oids := make([]uint, 0, len(raw))
	for _, s := range raw {
		v, err := strconv.ParseUint(strings.TrimSpace(s), 10, 64)
		if err == nil && v > 0 {
			oids = append(oids, uint(v))
		}
	}
	if err := services.VotePoll(id, ctx.UserID(), oids); err != nil {
		ctx.SetFlash(err.Error())
		ctx.Redirect(fmt.Sprintf("/post/%d", id))
		return
	}
	ctx.SetFlash("投票成功")
	ctx.Redirect(fmt.Sprintf("/post/%d", id))
}

// PostPollClose 结束投票
func (d Deps) PostPollClose(c *gin.Context) {
	ctx := d.ctx(c)
	id, err := parsePostID(c, d)
	if err != nil || id == 0 {
		d.render404(ctx)
		return
	}
	if !ctx.CheckCSRF() {
		ctx.SetFlash("无效请求，请重试")
		ctx.Redirect(fmt.Sprintf("/post/%d", id))
		return
	}
	post, err := d.Post.FindByID(id)
	if err != nil {
		d.render404(ctx)
		return
	}
	if err := services.ClosePoll(id, ctx.UserID(), ctx.IsAdmin(), post.UserID); err != nil {
		ctx.SetFlash(err.Error())
		ctx.Redirect(fmt.Sprintf("/post/%d", id))
		return
	}
	ctx.SetFlash("投票已结束")
	ctx.Redirect(fmt.Sprintf("/post/%d", id))
}

// PostQuestionResolvePost 标记问答帖已解决 / 未解决
func (d Deps) PostQuestionResolvePost(c *gin.Context) {
	ctx := d.ctx(c)
	id, err := parsePostID(c, d)
	if err != nil || id == 0 {
		d.render404(ctx)
		return
	}
	if !ctx.CheckCSRF() {
		ctx.SetFlash("无效请求，请重试")
		ctx.Redirect(fmt.Sprintf("/post/%d", id))
		return
	}
	resolved := c.PostForm("resolved") == "1" || c.PostForm("resolved") == "on"
	if err := d.Post.SetQuestionResolved(ctx.UserID(), id, ctx.IsAdmin(), resolved); err != nil {
		ctx.SetFlash(err.Error())
		ctx.Redirect(fmt.Sprintf("/post/%d", id))
		return
	}
	if resolved {
		ctx.SetFlash("已标为已解决")
	} else {
		ctx.SetFlash("已标为未解决")
	}
	ctx.Redirect(fmt.Sprintf("/post/%d", id))
}

type commentEditData struct {
	PageChrome
	PostID   uint
	CommentID uint
	Floor    int
	Content  string
}

// CommentEditGet 编辑评论页
func (d Deps) CommentEditGet(c *gin.Context) {
	ctx := d.ctx(c)
	postID, cm, errMsg := d.loadEditableComment(ctx, c)
	if errMsg != "" {
		ctx.SetFlash(errMsg)
		if postID > 0 {
			ctx.Redirect(fmt.Sprintf("/post/%d#comments", postID))
			return
		}
		ctx.Redirect("/")
		return
	}
	chrome := d.chrome(ctx, "编辑评论 · "+d.Settings.SiteBranding().Name, "", "")
	ctx.HTML(http.StatusOK, "post/comment_edit", commentEditData{
		PageChrome: chrome,
		PostID:     postID,
		CommentID:  cm.ID,
		Floor:      cm.Floor,
		Content:    commentHTMLToPlain(cm.Content),
	})
}

// CommentEditPost 保存评论编辑
func (d Deps) CommentEditPost(c *gin.Context) {
	ctx := d.ctx(c)
	postID, cm, errMsg := d.loadEditableComment(ctx, c)
	if errMsg != "" {
		ctx.SetFlash(errMsg)
		if postID > 0 {
			ctx.Redirect(fmt.Sprintf("/post/%d#comments", postID))
			return
		}
		ctx.Redirect("/")
		return
	}
	if !ctx.CheckCSRF() {
		d.renderCommentEdit(ctx, "无效请求，请重试", postID, cm, c.PostForm("content"))
		return
	}
	plain := strings.TrimSpace(c.PostForm("content"))
	if plain == "" {
		d.renderCommentEdit(ctx, "评论不能为空", postID, cm, plain)
		return
	}
	safe := "<p>" + html.EscapeString(plain) + "</p>"
	_, enteredPending, err := d.Comment.Update(ctx.UserID(), cm.ID, ctx.IsAdmin(), ctx.SkipsModeration(), safe)
	if err != nil {
		d.renderCommentEdit(ctx, err.Error(), postID, cm, plain)
		return
	}
	if enteredPending {
		ctx.SetFlash("评论已更新，审核通过后公开显示")
	} else {
		ctx.SetFlash("评论已更新")
	}
	ctx.Redirect(fmt.Sprintf("/post/%d#floor-%d", postID, cm.Floor))
}

// CommentDeletePost 软删评论
func (d Deps) CommentDeletePost(c *gin.Context) {
	ctx := d.ctx(c)
	postID, err := parsePostID(c, d)
	if err != nil || postID == 0 {
		d.render404(ctx)
		return
	}
	cid, err := strconv.ParseUint(c.Param("cid"), 10, 64)
	if err != nil || cid == 0 {
		d.render404(ctx)
		return
	}
	if !ctx.CheckCSRF() {
		ctx.SetFlash("无效请求，请重试")
		ctx.Redirect(fmt.Sprintf("/post/%d#comments", postID))
		return
	}
	cm, err := d.Comment.GetByID(uint(cid))
	if err != nil || cm.PostID != postID {
		d.render404(ctx)
		return
	}
	if !d.Comment.CanUserDeleteComment(cm, ctx.UserID(), ctx.IsAdmin()) {
		ctx.SetFlash(services.ErrPermissionDenied.Error())
		ctx.Redirect(fmt.Sprintf("/post/%d#comments", postID))
		return
	}
	if err := d.Comment.Delete(ctx.UserID(), cm.ID, ctx.IsAdmin()); err != nil {
		ctx.SetFlash(err.Error())
		ctx.Redirect(fmt.Sprintf("/post/%d#floor-%d", postID, cm.Floor))
		return
	}
	ctx.SetFlash("评论已删除")
	ctx.Redirect(fmt.Sprintf("/post/%d#comments", postID))
}

func (d Deps) loadEditableComment(ctx *webctx.Context, c *gin.Context) (postID uint, cm *models.Comment, errMsg string) {
	pid, err := parsePostID(c, d)
	if err != nil || pid == 0 {
		return 0, nil, "帖子不存在"
	}
	cid, err := strconv.ParseUint(c.Param("cid"), 10, 64)
	if err != nil || cid == 0 {
		return pid, nil, "评论不存在"
	}
	cm, err = d.Comment.GetByID(uint(cid))
	if err != nil || cm.PostID != pid {
		return pid, nil, "评论不存在"
	}
	if !d.Comment.CanUserEditComment(cm, ctx.UserID(), ctx.IsAdmin()) {
		return pid, cm, "无权编辑该评论或已超过可编辑时限"
	}
	return pid, cm, ""
}

func (d Deps) renderCommentEdit(ctx *webctx.Context, errMsg string, postID uint, cm *models.Comment, content string) {
	chrome := d.chrome(ctx, "编辑评论 · "+d.Settings.SiteBranding().Name, "", "")
	chrome.Error = errMsg
	ctx.HTML(http.StatusOK, "post/comment_edit", commentEditData{
		PageChrome: chrome,
		PostID:     postID,
		CommentID:  cm.ID,
		Floor:      cm.Floor,
		Content:    content,
	})
}

// commentHTMLToPlain 发评存的是转义后的 <p>…</p>，编辑时还原为纯文本
func commentHTMLToPlain(s string) string {
	s = strings.TrimSpace(s)
	s = strings.TrimPrefix(s, "<p>")
	s = strings.TrimSuffix(s, "</p>")
	return html.UnescapeString(s)
}

type postRevisionRow struct {
	ID         uint
	EditorName string
	Title      string
	CreatedLabel string
}

type postRevisionsData struct {
	PageChrome
	PostID    uint
	PostTitle string
	Revisions []postRevisionRow
}

type postRevisionDetailData struct {
	PageChrome
	PostID       uint
	PostTitle    string
	RevID        uint
	EditorName   string
	CreatedLabel string
	Title        string
	Tags         string
	BodyHTML     string
}

// PostRevisionsGet 帖子修订历史列表（作者或管理员）
func (d Deps) PostRevisionsGet(c *gin.Context) {
	ctx := d.ctx(c)
	post, ok := d.loadRevisionPost(ctx, c)
	if !ok {
		return
	}
	revs, err := d.Post.ListRevisions(post.ID)
	if err != nil {
		ctx.SetFlash(err.Error())
		ctx.Redirect(fmt.Sprintf("/post/%d", post.ID))
		return
	}
	rows := make([]postRevisionRow, 0, len(revs))
	for _, r := range revs {
		name := displayName(&r.Editor)
		if name == "" {
			name = fmt.Sprintf("用户 #%d", r.EditorID)
		}
		rows = append(rows, postRevisionRow{
			ID: r.ID, EditorName: name, Title: r.Title, CreatedLabel: formatTime(r.CreatedAt),
		})
	}
	chrome := d.chrome(ctx, "修订历史 · "+post.Title+" · "+d.Settings.SiteBranding().Name, "", "")
	ctx.HTML(http.StatusOK, "post/revisions", postRevisionsData{
		PageChrome: chrome, PostID: post.ID, PostTitle: post.Title, Revisions: rows,
	})
}

// PostRevisionDetailGet 单条修订快照
func (d Deps) PostRevisionDetailGet(c *gin.Context) {
	ctx := d.ctx(c)
	post, ok := d.loadRevisionPost(ctx, c)
	if !ok {
		return
	}
	rid, err := strconv.ParseUint(c.Param("rid"), 10, 64)
	if err != nil || rid == 0 {
		d.render404(ctx)
		return
	}
	rev, err := d.Post.GetRevision(post.ID, uint(rid))
	if err != nil {
		d.render404(ctx)
		return
	}
	name := displayName(&rev.Editor)
	if name == "" {
		name = fmt.Sprintf("用户 #%d", rev.EditorID)
	}
	chrome := d.chrome(ctx, "修订 #"+strconv.FormatUint(rid, 10)+" · "+post.Title+" · "+d.Settings.SiteBranding().Name, "", "")
	ctx.HTML(http.StatusOK, "post/revision_detail", postRevisionDetailData{
		PageChrome: chrome, PostID: post.ID, PostTitle: post.Title,
		RevID: rev.ID, EditorName: name, CreatedLabel: formatTime(rev.CreatedAt),
		Title: rev.Title, Tags: rev.Tags, BodyHTML: rev.Content,
	})
}

func (d Deps) loadRevisionPost(ctx *webctx.Context, c *gin.Context) (*models.Post, bool) {
	id, err := parsePostID(c, d)
	if err != nil || id == 0 {
		d.render404(ctx)
		return nil, false
	}
	post, err := d.Post.FindByID(id)
	if err != nil || !services.CanViewPost(post, ctx.UserID(), ctx.IsAdmin()) {
		d.render404(ctx)
		return nil, false
	}
	if !canViewPostRevisions(post, ctx.UserID(), ctx.IsAdmin()) {
		ctx.SetFlash("无权查看编辑历史")
		ctx.Redirect(fmt.Sprintf("/post/%d", post.ID))
		return nil, false
	}
	return post, true
}

func canViewPostRevisions(post *models.Post, userID uint, isAdmin bool) bool {
	if post == nil || userID == 0 {
		return false
	}
	return isAdmin || post.UserID == userID
}

func parsePostID(c *gin.Context, d Deps) (uint, error) {
	idStr := stripIDParam(c.Param("id"), d.Settings.Permalink().Ext)
	id, err := strconv.ParseUint(idStr, 10, 64)
	return uint(id), err
}