threads: add .ThreadUnread to template data

When a thread is folded, it can be useful to know how many unseen
messages lie below the root. For example, one might want to show that
count in the message list:

column-folded = {{if .ThreadFolded \
	}}{{if ne .ThreadUnread 0 \
		}}{{.ThreadUnread | printf "%s/"}}{{ \
	end}}{{ .ThreadCount | printf "%s"}}{{end}}

Add `.ThreadUnread` to the template functions.

Changelog-added: `.ThreadUnread` is now available in templates.
Signed-off-by: inwit <[email protected]>
Acked-by: Robin Jarry <[email protected]>

app/msglist.go

@@ -403,6 +403,20 @@ func countThreads(thread *types.Thread) (ctr int) {
 	return
 }
 
+func unreadInThread(thread *types.Thread, store *lib.MessageStore) (ctr int) {
+	if thread == nil {
+		return
+	}
+	_ = thread.Walk(func(t *types.Thread, _ int, _ error) error {
+		msg := store.Messages[t.Uid]
+		if msg != nil && !msg.Flags.Has(models.SeenFlag) {
+			ctr++
+		}
+		return nil
+	})
+	return
+}
+
 func threadPrefix(t *types.Thread, reverse bool, point bool) string {
 	var arrow string
 	if t.Parent != nil {
@@ -476,7 +490,7 @@ func newThreadView(store *lib.MessageStore) *threadView {
 }
 
 func (t *threadView) Update(data state.DataSetter, uid uint32) {
-	prefix, same, count, folded, context := "", false, 0, false, false
+	prefix, same, count, unread, folded, context := "", false, 0, 0, false, false
 	thread, err := t.store.Thread(uid)
 	if thread != nil && err == nil {
 		prefix = threadPrefix(thread, t.reverse, true)
@@ -485,8 +499,9 @@ func (t *threadView) Update(data state.DataSetter, uid uint32) {
 		t.prev = thread
 		t.prevSubj = subject
 		count = countThreads(thread)
+		unread = unreadInThread(thread, t.store)
 		folded = thread.FirstChild != nil && thread.FirstChild.Hidden != 0
 		context = thread.Context
 	}
-	data.SetThreading(prefix, same, count, folded, context)
+	data.SetThreading(prefix, same, count, unread, folded, context)
 }

config/templates.go

@@ -77,6 +77,7 @@ func (d *dummyData) DateAutoFormat(time.Time) string { return "" }
 func (d *dummyData) Header(string) string            { return "" }
 func (d *dummyData) ThreadPrefix() string            { return "└─>" }
 func (d *dummyData) ThreadCount() int                { return 0 }
+func (d *dummyData) ThreadUnread() int               { return 0 }
 func (d *dummyData) ThreadFolded() bool              { return false }
 func (d *dummyData) ThreadContext() bool             { return true }
 func (d *dummyData) Subject() string                 { return "Re: [PATCH] hey" }

doc/aerc-templates.7.scd

@@ -102,7 +102,10 @@ available always.
 		hidden by *:fold*.
 
 	_ThreadCount_
-		The number of thread children.
+		The number of messages in the thread.
+
+	_ThreadUnread_
+		The number of unread messages in the thread.
 
 *Flags*
 	List of message flags, not available when composing, replying nor

lib/state/templates.go

@@ -21,7 +21,7 @@ type DataSetter interface {
 	Data() models.TemplateData
 	SetHeaders(*mail.Header, *models.OriginalMail)
 	SetInfo(*models.MessageInfo, int, bool)
-	SetThreading(string, bool, int, bool, bool)
+	SetThreading(string, bool, int, int, bool, bool)
 	SetComposer(Composer)
 	SetAccount(*config.AccountConfig)
 	SetFolder(*models.Directory)
@@ -34,6 +34,7 @@ type ThreadInfo struct {
 	SameSubject bool
 	Prefix      string
 	Count       int
+	Unread      int
 	Folded      bool
 	Context     bool
 }
@@ -88,11 +89,12 @@ func (d *templateData) SetInfo(info *models.MessageInfo, num int, marked bool,
 }
 
 func (d *templateData) SetThreading(prefix string, same bool, count int,
-	folded bool, context bool,
+	unread int, folded bool, context bool,
 ) {
 	d.threadInfo.Prefix = prefix
 	d.threadInfo.SameSubject = same
 	d.threadInfo.Count = count
+	d.threadInfo.Unread = unread
 	d.threadInfo.Folded = folded
 	d.threadInfo.Context = context
 }
@@ -301,6 +303,10 @@ func (d *templateData) ThreadCount() int {
 	return d.threadInfo.Count
 }
 
+func (d *templateData) ThreadUnread() int {
+	return d.threadInfo.Unread
+}
+
 func (d *templateData) ThreadFolded() bool {
 	return d.threadInfo.Folded
 }

models/templates.go

@@ -21,6 +21,7 @@ type TemplateData interface {
 	Header(name string) string
 	ThreadPrefix() string
 	ThreadCount() int
+	ThreadUnread() int
 	ThreadFolded() bool
 	ThreadContext() bool
 	Subject() string