delete: improve find next function

Improve the function to find the next valid message after the delete
operation. This ensures that messages at the end or when marked in the
visual mode are properly dealt with.

Signed-off-by: Koni Marti <koni.marti@gmail.com>
Tested-by: Tim Culverhouse <tim@timculverhouse.com>
Acked-by: Robin Jarry <robin@jarry.cc>

commands/msg/delete.go

@@ -89,16 +89,24 @@ func (Delete) Execute(aerc *widgets.Aerc, args []string) error {
 }
 
 func findNextNonDeleted(deleted []uint32, store *lib.MessageStore) *models.MessageInfo {
-	selected := store.Selected()
-	if !contains(deleted, selected.Uid) {
-		return selected
+	var next, previous *models.MessageInfo
+	stepper := []func(){store.Next, store.Prev}
+	for _, stepFn := range stepper {
+		for {
+			next = store.Selected()
+			if next != nil && !contains(deleted, next.Uid) {
+				return next
+			}
+			if next == nil || previous == next {
+				break
+			}
+			stepFn()
+			previous = next
+		}
 	}
 
-	store.Next()
-	next := store.Selected()
-	if next == selected || next == nil {
-		// the last message is in the deleted state or doesn't exist
-		return nil
+	if next != nil {
+		store.Select(next.Uid)
 	}
 	return next
 }