User Forums: Sort options and pagination

* The Explore tab can now sort forums by their:
  * Most recently updated thread
  * Topics, Posts or Users (counts)
* Show owner information in forum cards
* Passive pagination support for the "My List" on forum home page.
  * Only visible when there are >20 favorited Forums.

pkg/config/page_sizes.go

@@ -24,6 +24,7 @@ var (
 	PageSizeInboxThread            = 10 // conversation view
 	PageSizeBrowseForums           = 20
 	PageSizeForums                 = 100 // TODO: for main category index view
+	PageSizeMyListForums           = 20  // "My List" pager on forum home (categories) page.
 	PageSizeThreadList             = 20  // 20 threads per board, 20 posts per thread
 	PageSizeForumAdmin             = 20
 	PageSizeDashboardNotifications = 50

pkg/controller/forum/browse.go

@@ -20,6 +20,13 @@ func Explore() http.HandlerFunc {
 		"created_at asc",
 		"title asc",
 		"title desc",
+
+		// Special sort handlers.
+		// See PaginateForums for expanded handlers for these.
+		"by_latest",
+		"by_threads",
+		"by_posts",
+		"by_users",
 	}
 
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {

pkg/controller/forum/forums.go

@@ -33,14 +33,13 @@ func Landing() http.HandlerFunc {
 
 		// Get all the categorized index forums.
 		// XXX: we get a large page size to get ALL official forums
-		var pager = &models.Pagination{
+		// This pager is hardcoded and doesn't parse from ?page= params.
+		var indexPager = &models.Pagination{
 			Page:    1,
 			PerPage: config.PageSizeForums,
 			Sort:    "title asc",
 		}
-		pager.ParsePage(r)
+		forums, err := models.PaginateForums(currentUser, config.ForumCategories, nil, false, indexPager)
-
-		forums, err := models.PaginateForums(currentUser, config.ForumCategories, nil, false, pager)
 		if err != nil {
 			session.FlashError(w, r, "Couldn't paginate forums: %s", err)
 			templates.Redirect(w, "/")
@@ -51,6 +50,12 @@ func Landing() http.HandlerFunc {
 		categorized := models.CategorizeForums(forums, config.ForumCategories)
 
 		// Inject the "My List" Category if the user subscribes to forums.
+		var pager = &models.Pagination{
+			Page:    1,
+			PerPage: config.PageSizeMyListForums,
+			Sort:    "by_latest",
+		}
+		pager.ParsePage(r)
 		if config.UserForumsEnabled {
 			myList, err := models.PaginateForums(currentUser, nil, nil, true, pager)
 			if err != nil {

pkg/models/forum.go

@@ -85,6 +85,13 @@ Parameters:
 - userID: of who is looking
 - categories: optional, filter within categories
 - pager
+
+The pager Sort accepts a couple of custom values for more advanced sorting:
+
+- by_latest: recently updated posts
+- by_threads: thread count
+- by_posts: post count
+- by_users: user count
 */
 func PaginateForums(user *User, categories []string, search *Search, subscribed bool, pager *Pagination) ([]*Forum, error) {
 	var (
@@ -159,6 +166,37 @@ func PaginateForums(user *User, categories []string, search *Search, subscribed
 		)
 	}
 
+	// Custom SORT parameters.
+	switch pager.Sort {
+	case "by_latest":
+		pager.Sort = `(
+			SELECT MAX(threads.updated_at)
+			FROM threads
+			WHERE threads.forum_id = forums.id
+		) DESC NULLS LAST`
+	case "by_threads":
+		pager.Sort = `(
+			SELECT count(threads.id)
+			FROM threads
+			WHERE threads.forum_id = forums.id
+		) DESC`
+	case "by_posts":
+		pager.Sort = `(
+			SELECT count(comments.id)
+			FROM threads
+			JOIN comments ON comments.table_name='threads' AND comments.table_id=threads.id
+			WHERE threads.forum_id = forums.id
+		) DESC`
+	case "by_users":
+		pager.Sort = `(
+			SELECT count(distinct(users.id))
+			FROM threads
+			JOIN comments ON comments.table_name='threads' AND comments.table_id=threads.id
+			JOIN users ON comments.user_id=users.id
+			WHERE threads.forum_id = forums.id
+		) DESC`
+	}
+
 	query = query.Order(pager.Sort)
 	query.Model(&Forum{}).Count(&pager.Total)
 	result := query.Offset(pager.GetOffset()).Limit(pager.PerPage).Find(&fs)

web/templates/forum/index.html

@@ -87,9 +87,17 @@
                             <label class="label" for="sort">Sort by:</label>
                             <div class="select is-fullwidth">
                                 <select id="sort" name="sort">
+                                    <optgroup label="Forum">
                                         <option value="title asc"{{if eq .Sort "title asc"}} selected{{end}}>Title (A-Z)</option>
                                         <option value="title desc"{{if eq .Sort "title desc"}} selected{{end}}>Title (Z-A)</option>
                                         <option value="created_at desc"{{if eq .Sort "created_at desc"}} selected{{end}}>Recently created</option>
+                                    </optgroup>
+                                    <optgroup label="Contents">
+                                        <option value="by_latest"{{if eq .Sort "by_latest"}} selected{{end}}>Latest post</option>
+                                        <option value="by_threads"{{if eq .Sort "by_threads"}} selected{{end}}>Topic count</option>
+                                        <option value="by_posts"{{if eq .Sort "by_posts"}} selected{{end}}>Post count</option>
+                                        <option value="by_users"{{if eq .Sort "by_users"}} selected{{end}}>User count</option>
+                                    </optgroup>
                                 </select>
                             </div>
                         </div>
@@ -121,16 +129,22 @@
 {{end}}
 
 {{range .Categories}}
+    {{$IsMyList := eq .Category "My List"}}
     <div class="block p-4">
         {{if .Category}}
         <h1 class="title">
             {{.Category}}
-            {{if eq .Category "My List"}}
+            {{if $IsMyList}}
                 <i class="fa fa-book-bookmark ml-2"></i>
             {{end}}
         </h1>
         {{end}}
 
+        <!-- My List: show pagers if needed -->
+        {{if and $IsMyList (gt $Root.Pager.Pages 1)}}
+            {{SimplePager $Root.Pager}}
+        {{end}}
+
         {{if eq (len .Forums) 0}}
             <em>
                 There are no forums under this category.
@@ -159,7 +173,7 @@
                                 {{end}}
                             </div>
 
-                            <div>
+                            <div class="mb-3">
                                 {{if .Explicit}}
                                 <span class="tag is-danger is-light">
                                     <span class="icon"><i class="fa fa-fire"></i></span>
@@ -189,6 +203,25 @@
                                 {{end}}
                             </div>
 
+                            <!-- Owner line -->
+                            {{if .Category}}
+                            <div class="mt-2 has-text-grey" style="font-size: smaller">
+                                by <a href="/f/{{.Fragment}}">{{PrettyTitle}}</a>
+                            </div>
+                            {{else}}
+                            <div class="mt-2 has-text-grey" style="font-size: smaller">
+                                by
+                                {{template "avatar-16x16" .Owner}}
+                                {{if .Owner.Username}}
+                                    <a href="/u/{{.Owner.Username}}" class="has-text-grey">
+                                        <strong>{{or .Owner.Username "[unavailable]"}}</strong>
+                                    </a>
+                                {{else}}
+                                    [unavailable]
+                                {{end}}
+                            </div>
+                            {{end}}
+
                         </div>
                         <div class="column py-1">
                             <div class="box has-background-success-light has-text-dark">
@@ -251,6 +284,12 @@
             </div>
             {{end}}
         {{end}}
+
+        <!-- My List: show pagers -->
+        {{if and $IsMyList (gt $Root.Pager.Pages 1)}}
+            {{SimplePager $Root.Pager}}
+            <hr class="mb-0">
+        {{end}}
     </div>
 {{end}}<!-- range .Categories -->