From fd7754a7b61b5b4a77ccc34eba24a2bb51e53c43 Mon Sep 17 00:00:00 2001
From: Ben Visness <bvisness@gmail.com>
Date: Wed, 8 Sep 2021 19:43:24 -0500
Subject: [PATCH] Add redirect for old wiki URLs

---
 src/hmnurl/urls.go         |  2 ++
 src/website/forums.go      | 36 ++++++++++++++++++++++++++++++++++++
 src/website/post_helper.go | 13 ++++++++++++-
 src/website/routes.go      |  1 +
 4 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/src/hmnurl/urls.go b/src/hmnurl/urls.go
index d677fc2e..f2be182a 100644
--- a/src/hmnurl/urls.go
+++ b/src/hmnurl/urls.go
@@ -433,6 +433,8 @@ func BuildForumPostReply(projectSlug string, subforums []string, threadId int, p
 	return ProjectUrl(builder.String(), nil, projectSlug)
 }
 
+var RegexWikiArticle = regexp.MustCompile(`^/wiki/(?P<threadid>\d+)(-([^/]+))?$`)
+
 /*
 * Blog
  */
diff --git a/src/website/forums.go b/src/website/forums.go
index 15dbca81..9751ff57 100644
--- a/src/website/forums.go
+++ b/src/website/forums.go
@@ -2,6 +2,7 @@ package website
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"net/http"
 	"strconv"
@@ -851,6 +852,41 @@ func ForumPostDeleteSubmit(c *RequestContext) ResponseData {
 	}
 }
 
+func WikiArticleRedirect(c *RequestContext) ResponseData {
+	threadIdStr := c.PathParams["threadid"]
+	threadId, err := strconv.Atoi(threadIdStr)
+	if err != nil {
+		panic(err)
+	}
+
+	ithread, err := db.QueryOne(c.Context(), c.Conn, models.Thread{},
+		`
+		SELECT $columns
+		FROM handmade_thread
+		WHERE
+			id = $1
+			AND project_id = $2
+			AND NOT deleted
+		`,
+		threadId,
+		c.CurrentProject.ID,
+	)
+	if errors.Is(err, db.ErrNoMatchingRows) {
+		return FourOhFour(c)
+	} else if err != nil {
+		return c.ErrorResponse(http.StatusInternalServerError, oops.New(err, "failed to look up wiki thread"))
+	}
+	thread := ithread.(*models.Thread)
+
+	c.Perf.StartBlock("SQL", "Fetch subforum tree")
+	subforumTree := models.GetFullSubforumTree(c.Context(), c.Conn)
+	lineageBuilder := models.MakeSubforumLineageBuilder(subforumTree)
+	c.Perf.EndBlock()
+
+	dest := UrlForGenericThread(thread, lineageBuilder, c.CurrentProject.Slug)
+	return c.Redirect(dest, http.StatusFound)
+}
+
 type commonForumData struct {
 	c *RequestContext
 
diff --git a/src/website/post_helper.go b/src/website/post_helper.go
index 767c9f82..8c8fb764 100644
--- a/src/website/post_helper.go
+++ b/src/website/post_helper.go
@@ -6,7 +6,18 @@ import (
 	"git.handmade.network/hmn/hmn/src/templates"
 )
 
-// NOTE(asaf): Please don't use this if you already know the kind of the post beforehand. Just call the appropriate build function.
+// NOTE(asaf): Please don't use these if you already know the kind of the thread beforehand. Just call the appropriate build function.
+func UrlForGenericThread(thread *models.Thread, lineageBuilder *models.SubforumLineageBuilder, projectSlug string) string {
+	switch thread.Type {
+	case models.ThreadTypeProjectBlogPost:
+		return hmnurl.BuildBlogThread(projectSlug, thread.ID, thread.Title)
+	case models.ThreadTypeForumPost:
+		return hmnurl.BuildForumThread(projectSlug, lineageBuilder.GetSubforumLineageSlugs(*thread.SubforumID), thread.ID, thread.Title, 1)
+	}
+
+	return hmnurl.BuildProjectHomepage(projectSlug)
+}
+
 func UrlForGenericPost(thread *models.Thread, post *models.Post, lineageBuilder *models.SubforumLineageBuilder, projectSlug string) string {
 	switch post.ThreadType {
 	case models.ThreadTypeProjectBlogPost:
diff --git a/src/website/routes.go b/src/website/routes.go
index ee74dbb1..0aeef1f4 100644
--- a/src/website/routes.go
+++ b/src/website/routes.go
@@ -211,6 +211,7 @@ func NewWebsiteRoutes(longRequestContext context.Context, conn *pgxpool.Pool, pe
 	mainRoutes.POST(hmnurl.RegexForumPostEdit, authMiddleware(csrfMiddleware(ForumPostEditSubmit)))
 	mainRoutes.GET(hmnurl.RegexForumPostDelete, authMiddleware(ForumPostDelete))
 	mainRoutes.POST(hmnurl.RegexForumPostDelete, authMiddleware(csrfMiddleware(ForumPostDeleteSubmit)))
+	mainRoutes.GET(hmnurl.RegexWikiArticle, WikiArticleRedirect)
 
 	mainRoutes.GET(hmnurl.RegexBlog, BlogIndex)
 	mainRoutes.GET(hmnurl.RegexBlogNewThread, authMiddleware(BlogNewThread))