From a953e4dbe914def4275a6ddfc16e3046804fe03e Mon Sep 17 00:00:00 2001
From: Tim Culverhouse <tim@timculverhouse.com>
Date: Tue, 5 Jul 2022 14:48:41 -0500
Subject: [PATCH] threading: refactor reselect logic

This patch refactors reselection of a message during certain operations
(searching, filtering, clearing, deleting, moving, new message arrival).
The addition of server-side filtering for threaded views broke the
existing reselection logic.

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Acked-by: Robin Jarry <robin@jarry.cc>
---
 commands/account/clear.go      |  3 +--
 commands/msg/toggle-threads.go |  2 +-
 lib/msgstore.go                | 28 ++++++++++++++++++++++++----
 widgets/msglist.go             | 22 +---------------------
 4 files changed, 27 insertions(+), 28 deletions(-)

diff --git a/commands/account/clear.go b/commands/account/clear.go
index 69fac2d..5bab710 100644
--- a/commands/account/clear.go
+++ b/commands/account/clear.go
@@ -52,9 +52,8 @@ func (Clear) Execute(aerc *widgets.Aerc, args []string) error {
 	if clearSelected {
 		defer store.Select(0)
 	} else {
-		defer store.Reselect(store.Selected())
+		store.SetReselect(store.Selected())
 	}
-
 	store.ApplyClear()
 	acct.SetStatus(statusline.SearchFilterClear())
 
diff --git a/commands/msg/toggle-threads.go b/commands/msg/toggle-threads.go
index aa0e655..05c2c5e 100644
--- a/commands/msg/toggle-threads.go
+++ b/commands/msg/toggle-threads.go
@@ -34,7 +34,7 @@ func (ToggleThreads) Execute(aerc *widgets.Aerc, args []string) error {
 	if err != nil {
 		return err
 	}
-	defer store.Reselect(store.Selected())
+	store.SetReselect(store.Selected())
 	store.SetThreadedView(!store.ThreadedView())
 	acct.SetStatus(statusline.Threading(store.ThreadedView()))
 	acct.Messages().Invalidate()
diff --git a/lib/msgstore.go b/lib/msgstore.go
index 2e77369..a54b20b 100644
--- a/lib/msgstore.go
+++ b/lib/msgstore.go
@@ -21,6 +21,7 @@ type MessageStore struct {
 	Threads []*types.Thread
 
 	selected        int
+	reselect        *models.MessageInfo
 	bodyCallbacks   map[uint32][]func(*types.FullMessage)
 	headerCallbacks map[uint32][]func(*types.MessageInfo)
 
@@ -196,6 +197,9 @@ func merge(to *models.MessageInfo, from *models.MessageInfo) {
 func (store *MessageStore) Update(msg types.WorkerMessage) {
 	update := false
 	directoryChange := false
+	if store.reselect == nil {
+		store.SetReselect(store.Selected())
+	}
 	switch msg := msg.(type) {
 	case *types.DirectoryInfo:
 		store.DirInfo = *msg.Info
@@ -363,6 +367,7 @@ func (store *MessageStore) SetThreadedView(thread bool) {
 		if store.threadedView {
 			store.runThreadBuilder()
 		}
+		store.Reselect()
 		return
 	}
 	store.Sort(store.sortCriteria, nil)
@@ -508,11 +513,11 @@ func (store *MessageStore) Select(index int) {
 	store.updateVisual()
 }
 
-func (store *MessageStore) Reselect(info *models.MessageInfo) {
-	if info == nil {
+func (store *MessageStore) Reselect() {
+	if store.reselect == nil {
 		return
 	}
-	uid := info.Uid
+	uid := store.reselect.Uid
 	newIdx := 0
 	for idx, uidStore := range store.Uids() {
 		if uidStore == uid {
@@ -520,9 +525,14 @@ func (store *MessageStore) Reselect(info *models.MessageInfo) {
 			break
 		}
 	}
+	store.reselect = nil
 	store.Select(newIdx)
 }
 
+func (store *MessageStore) SetReselect(info *models.MessageInfo) {
+	store.reselect = info
+}
+
 // Mark sets the marked state on a MessageInfo
 func (store *MessageStore) Mark(uid uint32) {
 	if store.visualMarkMode {
@@ -718,11 +728,21 @@ func (store *MessageStore) SetFilter(args []string) {
 }
 
 func (store *MessageStore) ApplyClear() {
+	if store.reselect == nil {
+		store.SetReselect(store.Selected())
+	}
 	store.filter = []string{"filter"}
+	store.results = nil
 	if store.onFilterChange != nil {
 		store.onFilterChange(store)
 	}
-	store.Sort(nil, nil)
+	cb := func(msg types.WorkerMessage) {
+		switch msg.(type) {
+		case *types.Done:
+			store.Reselect()
+		}
+	}
+	store.Sort(nil, cb)
 }
 
 func (store *MessageStore) nextPrevResult(delta int) {
diff --git a/widgets/msglist.go b/widgets/msglist.go
index 9e68f21..e9603ca 100644
--- a/widgets/msglist.go
+++ b/widgets/msglist.go
@@ -345,27 +345,7 @@ func (ml *MessageList) storeUpdate(store *lib.MessageStore) {
 	if ml.Store() != store {
 		return
 	}
-	uids := store.Uids()
-
-	if len(uids) > 0 {
-		// When new messages come in, advance the cursor accordingly
-		// Note that this assumes new messages are appended to the top, which
-		// isn't necessarily true once we implement SORT... ideally we'd look
-		// for the previously selected UID.
-		if len(uids) > ml.nmsgs && ml.nmsgs != 0 {
-			for i := 0; i < len(uids)-ml.nmsgs; i++ {
-				ml.Store().Next()
-			}
-		}
-		if len(uids) < ml.nmsgs && ml.nmsgs != 0 {
-			for i := 0; i < ml.nmsgs-len(uids); i++ {
-				ml.Store().Prev()
-			}
-		}
-		ml.nmsgs = len(uids)
-	}
-
-	ml.Invalidate()
+	store.Reselect()
 }
 
 func (ml *MessageList) SetStore(store *lib.MessageStore) {