added topic traversal (Read New/Next Topic), untested

conference.go

@@ -100,6 +100,9 @@ func Topics(ctxt ui.AmContext) (string, any, error) {
 		return ui.ErrorPage(ctxt, err)
 	}
 
+	traverser := ui.NewTopicTraverser(topics)
+	ctxt.SetSession("topic.traverser", traverser)
+
 	tz := prefs.Location()
 	loc := prefs.Localizer()
 	fdate := make([]string, len(topics))
@@ -107,10 +110,17 @@ func Topics(ctxt ui.AmContext) (string, any, error) {
 		fdate[i] = loc.Strftime("%x %X", t.LastUpdate.In(tz))
 	}
 
+	// create the "read new" URL
+	urlStem := fmt.Sprintf("/comm/%s/conf/%s", comm.Alias, ctxt.URLParam("confid"))
+	firstTopic := traverser.FirstTopic()
+	if firstTopic >= 1 {
+		ctxt.VarMap().Set("urlReadNew", fmt.Sprintf("%s/r/%d", urlStem, firstTopic))
+	}
+
 	ctxt.VarMap().Set("canCreate", conf.TestPermission("Conference.Create", myLevel))
 	ctxt.VarMap().Set("conferenceName", conf.Name)
 	ctxt.VarMap().Set("urlBack", fmt.Sprintf("/comm/%s/conf", comm.Alias))
-	ctxt.VarMap().Set("urlStem", fmt.Sprintf("/comm/%s/conf/%s", comm.Alias, ctxt.URLParam("confid")))
+	ctxt.VarMap().Set("urlStem", urlStem)
 	ctxt.VarMap().Set("permalink", "TODO")
 	ctxt.VarMap().Set("view", view)
 	ctxt.VarMap().Set("sort", sort)
@@ -433,6 +443,12 @@ func templateOverrideLink(args jet.Arguments) reflect.Value {
  *     Standard Go error status.
  */
 func ReadPosts(ctxt ui.AmContext) (string, any, error) {
+	// Extract the traverser first, so we can unclear it in background tasks.
+	var traverser ui.TopicTraverser = nil
+	if ctxt.IsSession("topic.traverser") {
+		traverser = ctxt.GetSession("topic.traverser").(ui.TopicTraverser)
+	}
+
 	// If we need to reset a topic's last read count (as with "Next & Keep New"), spin the task off.
 	if ctxt.HasParameter("rst") {
 		rst := strings.Split(ctxt.Parameter("rst"), ",")
@@ -445,6 +461,9 @@ func ReadPosts(ctxt ui.AmContext) (string, any, error) {
 					topic, _ := database.AmGetTopic(ctx, int32(topicId))
 					if topic != nil {
 						topic.SetLastRead(ctx, user, int32(lastRead))
+						if traverser != nil && int32(lastRead) < topic.TopMessage {
+							traverser.UnclearTopic(topic.Number)
+						}
 					}
 				}
 			})
@@ -567,6 +586,18 @@ func ReadPosts(ctxt ui.AmContext) (string, any, error) {
 	}
 	ctxt.VarMap().Set("advancedControls", advancedControls)
 
+	// Adjust the traverser and get the "next" link.
+	urlStem := fmt.Sprintf("/comm/%s/conf/%s", comm.Alias, ctxt.GetScratch("currentAlias").(string))
+	if traverser != nil {
+		traverser.ClearTopic(topic.Number)
+		nextTopic := traverser.NextTopic(topic.Number)
+		if nextTopic >= 0 {
+			nextTopicURL := fmt.Sprintf("%s/r/%d", urlStem, nextTopic)
+			ctxt.VarMap().Set("urlNextTopic", nextTopicURL)
+			ctxt.VarMap().Set("urlNextKeepNew", fmt.Sprintf("%s?rst=%d,%d", nextTopicURL, topic.TopicId, lastRead))
+		}
+	}
+
 	// Render the output.
 	ctxt.VarMap().Set("amsterdam_pageTitle", fmt.Sprintf("%s: %s", topic.Name, summaryLine))
 	ctxt.VarMap().Set("topicName", topic.Name)
@@ -578,7 +609,7 @@ func ReadPosts(ctxt ui.AmContext) (string, any, error) {
 	ctxt.VarMap().SetFunc("post_getOverrideLink", templateOverrideLink)
 	ctxt.VarMap().SetFunc("post_getText", templatePostText)
 	ctxt.VarMap().SetFunc("post_getUserName", templateExtractUserName)
-	ctxt.VarMap().Set("post_stem", fmt.Sprintf("/comm/%s/conf/%s/r/%d", comm.Alias, ctxt.GetScratch("currentAlias").(string), topic.Number))
+	ctxt.VarMap().Set("post_stem", fmt.Sprintf("%s/r/%d", urlStem, topic.Number))
 	ctxt.VarMap().Set("post_max", topic.TopMessage)
 	ctxt.VarMap().Set("post_topicPermalink", fmt.Sprintf("/go/%s", topicPostRef))
 	ctxt.VarMap().Set("posts", posts)
@@ -586,7 +617,7 @@ func ReadPosts(ctxt ui.AmContext) (string, any, error) {
 	ctxt.VarMap().Set("pin", pin)
 	ctxt.VarMap().Set("rangeEnd", postRange[1])
 	ctxt.VarMap().Set("rangeStart", postRange[0])
-	ctxt.VarMap().Set("topicListLink", fmt.Sprintf("/comm/%s/conf/%s", comm.Alias, ctxt.GetScratch("currentAlias").(string)))
+	ctxt.VarMap().Set("topicListLink", urlStem)
 	ctxt.VarMap().Set("topicNum", topic.Number)
 	if resetLastRead {
 		user := ctxt.CurrentUser()

ui/topic_traverser.go

@@ -0,0 +1,100 @@
+/*
+ * Amsterdam Web Communities System
+ * Copyright (c) 2025-2026 Erbosoft Metaverse Design Solutions, All Rights Reserved
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+// Package ui holds the support for the Amsterdam user interface, wrapping Echo and Jet templates.
+package ui
+
+import (
+	"sync"
+
+	"git.erbosoft.com/amy/amsterdam/database"
+	"github.com/bits-and-blooms/bitset"
+)
+
+// TopicTraverser is the data structure that allows us to navigate to "next" topics.
+type TopicTraverser interface {
+	FirstTopic() int16
+	NextTopic(int16) int16
+	ClearTopic(int16)
+	UnclearTopic(int16)
+}
+
+// topicTraverser is the internal data structure that implements TopicTraverser.
+type topicTraverser struct {
+	lock   sync.RWMutex
+	topics []int16
+	active *bitset.BitSet
+}
+
+// NewTopicTraverser creates the traverser data structure from the topic listing.
+func NewTopicTraverser(topics []*database.TopicSummary) TopicTraverser {
+	trav := topicTraverser{
+		topics: make([]int16, 0, len(topics)),
+		active: bitset.New(uint(len(topics))),
+	}
+	p := 0
+	for _, t := range topics {
+		if t.Unread > 0 {
+			trav.topics = append(trav.topics, t.Number)
+			trav.active.Set(uint(p))
+			p++
+		}
+	}
+	return &trav
+}
+
+// FirstTopic returns the first unread topic number in the traverser.
+func (trav *topicTraverser) FirstTopic() int16 {
+	trav.lock.RLock()
+	defer trav.lock.RUnlock()
+	i, b := trav.active.NextSet(0)
+	if b {
+		return trav.topics[i]
+	}
+	return -1
+}
+
+// NextTopic returns the unread topic number in the traverser after the specified one.
+func (trav *topicTraverser) NextTopic(cur int16) int16 {
+	trav.lock.RLock()
+	defer trav.lock.RUnlock()
+	seeking := false
+	for i, v := range trav.topics {
+		if v == cur {
+			seeking = true
+		} else if seeking && trav.active.Test(uint(i)) {
+			return v
+		}
+	}
+	return trav.FirstTopic() // look from the beginning
+}
+
+// ClearTopic clears the specified topic number from the traverser.
+func (trav *topicTraverser) ClearTopic(num int16) {
+	trav.lock.Lock()
+	defer trav.lock.Unlock()
+	for i, v := range trav.topics {
+		if v == num {
+			trav.active.Clear(uint(i))
+			return
+		}
+	}
+}
+
+// UnclearTopic restores the specified topic number to the traverser.
+func (trav *topicTraverser) UnclearTopic(num int16) {
+	trav.lock.Lock()
+	defer trav.lock.Unlock()
+	for i, v := range trav.topics {
+		if v == num {
+			trav.active.Set(uint(i))
+			return
+		}
+	}
+}

ui/views/posts.jet

@@ -24,13 +24,13 @@
                     class="bg-gray-600 hover:bg-gray-700 text-white px-4 py-2 rounded text-sm font-medium transition-colors">
                     {{ if isTopicHidden }}Show Topic{{ else }}Hide Topic{{ end }}
                 </a>
-                {{ if false }}{* TODO *}
+                {{ if isset(urlNextTopic) }}
-                    <a href="/TODO" 
+                    <a href="{{ urlNextTopic }}" 
                         class="bg-green-600 hover:bg-green-700 text-white px-4 py-2 rounded text-sm font-medium transition-colors">Next Topic</a>
-                    {{ if false }}{* TODO *}
+                {{ end }}
-                        <a href="/TODO" 
+                {{ if isset(urlNextKeepNew) }}
-                            class="bg-green-600 hover:bg-green-700 text-white px-4 py-2 rounded text-sm font-medium transition-colors">Next & Keep New</a>
+                    <a href="{{ urlNextKeepNew }}" 
-                    {{ end }}
+                        class="bg-green-600 hover:bg-green-700 text-white px-4 py-2 rounded text-sm font-medium transition-colors">Next & Keep New</a>
                 {{ end }}
                 <a href="/TODO" 
                     class="bg-blue-600 hover:bg-blue-700 text-white px-4 py-2 rounded text-sm font-medium transition-colors">Find</a>

ui/views/topiclist.jet

@@ -26,6 +26,12 @@
                     Add Topic
                 </a>
             {{ end }}
+            {{ if isset(urlReadNew) }}
+                <a href="{{ urlReadNew }}"
+                    class="bg-blue-600 hover:bg-blue-700 text-white px-4 py-2 rounded text-sm font-medium transition-colors">
+                    Read New
+                </a>
+            {{ end }}
             <a href="/TODO/find"
                 class="bg-blue-600 hover:bg-blue-700 text-white px-4 py-2 rounded text-sm font-medium transition-colors">
                 Find