threads: reverse thread ordering

Add reverse-thread-order option to the ui config to enable reverse
display of the mesage threads. Default order is the the intial message
is on the top with all the replies being displayed below. The reverse
options will put the initial message at the bottom with the replies on
top.

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

CHANGELOG.md

@@ -12,6 +12,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   `:rmdir`, `:archive` and the `copy-to` option.
 - Display messages from bottom to top with `reverse-msglist-order=true` in
   `aerc.conf`.
+- Display threads from bottom to top with `reverse-thread-order=true` in
+  `aerc.conf`.
 
 ### Fixed
 

config/aerc.conf

@@ -194,6 +194,14 @@ completion-popovers=true
 # Default: false
 #reverse-msglist-order = false
 
+# Reverse display of the mesage threads. Default order is the the intial
+# message is on the top with all the replies being displayed below. The
+# reverse option will put the initial message at the bottom with the
+# replies on top.
+#
+# Default: false
+#reverse-thread-order=false
+
 #[ui:account=foo]
 #
 # Enable a threaded view of messages. If this is not supported by the backend

config/config.go

@@ -80,6 +80,7 @@ type UIConfig struct {
 	BorderCharHorizontal rune `ini:"-"`
 
 	ReverseOrder       bool `ini:"reverse-msglist-order"`
+	ReverseThreadOrder bool `ini:"reverse-thread-order"`
 }
 
 type ContextType int

doc/aerc-config.5.scd

@@ -335,6 +335,14 @@ These options are configured in the *[ui]* section of aerc.conf.
 
 	Default: false
 
+*reverse-thread-order*
+	Reverse display of the mesage threads. Default order is the the intial
+	message is on the top with all the replies being displayed below. The
+	reverse option will put the initial message at the bottom with the
+	replies on top.
+
+	Default: false
+
 *threading-enabled*
 	Enable a threaded view of messages. If this is not supported by the
 	backend (IMAP server or notmuch), threads will be built by the client.

lib/msgstore.go

@@ -40,6 +40,7 @@ type MessageStore struct {
 	sortCriteria []*types.SortCriterion
 
 	threadedView       bool
+	reverseThreadOrder bool
 	buildThreads       bool
 	builder            *ThreadBuilder
 
@@ -74,7 +75,7 @@ func NewMessageStore(worker *types.Worker,
 	dirInfo *models.DirectoryInfo,
 	defaultSortCriteria []*types.SortCriterion,
 	thread bool, clientThreads bool, clientThreadsDelay time.Duration,
-	reverseOrder bool,
+	reverseOrder bool, reverseThreadOrder bool,
 	triggerNewEmail func(*models.MessageInfo),
 	triggerDirectoryChange func(),
 ) *MessageStore {
@@ -93,6 +94,7 @@ func NewMessageStore(worker *types.Worker,
 
 		threadedView:       thread,
 		buildThreads:       clientThreads,
+		reverseThreadOrder: reverseThreadOrder,
 
 		filter:       []string{"filter"},
 		sortCriteria: defaultSortCriteria,
@@ -231,7 +233,7 @@ func (store *MessageStore) Update(msg types.WorkerMessage) {
 		newMap := make(map[uint32]*models.MessageInfo)
 
 		builder := NewThreadBuilder(store.iterFactory)
-		builder.RebuildUids(msg.Threads)
+		builder.RebuildUids(msg.Threads, store.reverseThreadOrder)
 		store.uids = builder.Uids()
 		store.threads = msg.Threads
 
@@ -364,6 +366,14 @@ func (store *MessageStore) update(threads bool) {
 	}
 }
 
+func (store *MessageStore) SetReverseThreadOrder(reverse bool) {
+	store.reverseThreadOrder = reverse
+}
+
+func (store *MessageStore) ReverseThreadOrder() bool {
+	return store.reverseThreadOrder
+}
+
 func (store *MessageStore) SetThreadedView(thread bool) {
 	store.threadedView = thread
 	if store.buildThreads {
@@ -424,7 +434,7 @@ func (store *MessageStore) runThreadBuilderNow() {
 		}
 	}
 	// build new threads
-	th := store.builder.Threads(store.uids)
+	th := store.builder.Threads(store.uids, store.reverseThreadOrder)
 
 	// save local threads to the message store variable and
 	// run callback if defined (callback should reposition cursor)

lib/threadbuilder.go

@@ -55,7 +55,7 @@ func (builder *ThreadBuilder) Update(msg *models.MessageInfo) {
 }
 
 // Threads returns a slice of threads for the given list of uids
-func (builder *ThreadBuilder) Threads(uids []uint32) []*types.Thread {
+func (builder *ThreadBuilder) Threads(uids []uint32, inverse bool) []*types.Thread {
 	builder.Lock()
 	defer builder.Unlock()
 
@@ -67,7 +67,7 @@ func (builder *ThreadBuilder) Threads(uids []uint32) []*types.Thread {
 	builder.sortThreads(threads, uids)
 
 	// rebuild uids from threads
-	builder.RebuildUids(threads)
+	builder.RebuildUids(threads, inverse)
 
 	elapsed := time.Since(start)
 	logging.Infof("%d threads created in %s", len(threads), elapsed)
@@ -155,15 +155,23 @@ func (builder *ThreadBuilder) sortThreads(threads []*types.Thread, orderedUids [
 }
 
 // RebuildUids rebuilds the uids from the given slice of threads
-func (builder *ThreadBuilder) RebuildUids(threads []*types.Thread) {
+func (builder *ThreadBuilder) RebuildUids(threads []*types.Thread, inverse bool) {
 	uids := make([]uint32, 0, len(threads))
 	iterT := builder.iterFactory.NewIterator(threads)
 	for iterT.Next() {
+		var threaduids []uint32
 		_ = iterT.Value().(*types.Thread).Walk(
 			func(t *types.Thread, level int, currentErr error) error {
-				uids = append(uids, t.Uid)
+				threaduids = append(threaduids, t.Uid)
 				return nil
 			})
+		if inverse {
+			for j := len(threaduids) - 1; j >= 0; j-- {
+				uids = append(uids, threaduids[j])
+			}
+		} else {
+			uids = append(uids, threaduids...)
+		}
 	}
 	result := make([]uint32, 0, len(uids))
 	iterU := builder.iterFactory.NewIterator(uids)

widgets/account.go

@@ -286,6 +286,7 @@ func (acct *AccountView) onMessage(msg types.WorkerMessage) {
 				acct.dirlist.UiConfig(name).ForceClientThreads,
 				acct.dirlist.UiConfig(name).ClientThreadsDelay,
 				acct.dirlist.UiConfig(name).ReverseOrder,
+				acct.dirlist.UiConfig(name).ReverseThreadOrder,
 				func(msg *models.MessageInfo) {
 					acct.conf.Triggers.ExecNewEmail(acct.acct,
 						acct.conf, msg)