From 06dcf69cae808f47e61bd65fc05342dd485ed63e Mon Sep 17 00:00:00 2001
From: Noboru Saito <noborusai@gmail.com>
Date: Thu, 31 Oct 2024 14:16:50 +0900
Subject: [PATCH] Improve follow/followAll/followSection

Fix followAll for omission of doc.height update.
Reduce branching of follow* to make it clearer.
---
 oviewer/action.go      | 34 ++++++++++++++++++++++++----------
 oviewer/action_test.go |  2 +-
 oviewer/event.go       |  8 ++++++--
 3 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/oviewer/action.go b/oviewer/action.go
index c75c82c8..d716e0a1 100644
--- a/oviewer/action.go
+++ b/oviewer/action.go
@@ -744,22 +744,23 @@ func (root *Root) updateEndNum() {
 	root.Screen.Sync()
 }
 
-// follow updates the document in follow mode.
-func (root *Root) follow(ctx context.Context) {
-	if root.General.FollowAll {
-		root.followAll(ctx)
-	}
+// updateLatestNum updates the last line number in follow mode.
+func (root *Root) updateLatestNum() bool {
 	num := root.Doc.BufEndNum()
 	if root.Doc.latestNum == num {
-		return
+		return false
 	}
 	root.skipDraw = false
-	if root.Doc.FollowSection {
-		root.tailSection(ctx)
-	} else {
+	root.Doc.latestNum = num
+	return true
+}
+
+// follow monitors and switches the document update
+// in follow mode.
+func (root *Root) follow(ctx context.Context) {
+	if root.updateLatestNum() {
 		root.TailSync(ctx)
 	}
-	root.Doc.latestNum = num
 }
 
 // followAll monitors and switches all document updates
@@ -772,6 +773,8 @@ func (root *Root) followAll(ctx context.Context) {
 	current := root.CurrentDoc
 	root.mu.RLock()
 	for n, doc := range root.DocList {
+		doc.width = root.scr.vWidth - root.scr.startX
+		doc.height = doc.statusPos - doc.headerHeight
 		if doc.latestNum != doc.BufEndNum() {
 			current = n
 		}
@@ -781,6 +784,17 @@ func (root *Root) followAll(ctx context.Context) {
 	if root.CurrentDoc != current {
 		root.switchDocument(ctx, current)
 	}
+	if root.updateLatestNum() {
+		root.TailSync(ctx)
+	}
+}
+
+// followSection monitors and switches the document update
+// in follow section mode.
+func (root *Root) followSection(ctx context.Context) {
+	if root.updateLatestNum() {
+		root.tailSection(ctx)
+	}
 }
 
 // Cancel follow mode and follow all mode.
diff --git a/oviewer/action_test.go b/oviewer/action_test.go
index e903fd57..cf0e0c63 100644
--- a/oviewer/action_test.go
+++ b/oviewer/action_test.go
@@ -1378,7 +1378,7 @@ func TestRoot_followAll(t *testing.T) {
 			ctx := context.Background()
 			root.prepareScreen()
 			root.everyUpdate(ctx)
-			root.follow(ctx)
+			root.followAll(ctx)
 			if root.Doc.topLN != tt.want {
 				t.Errorf("follow() topLN = %v, want %v", root.Doc.topLN, tt.want)
 			}
diff --git a/oviewer/event.go b/oviewer/event.go
index 3dbc9c04..460eafb7 100644
--- a/oviewer/event.go
+++ b/oviewer/event.go
@@ -146,9 +146,13 @@ func (root *Root) everyUpdate(ctx context.Context) {
 
 	root.Doc.width = root.scr.vWidth - root.scr.startX
 	root.Doc.height = root.Doc.statusPos - root.Doc.headerHeight
-
-	if root.General.FollowAll || root.Doc.FollowMode || root.Doc.FollowSection {
+	switch {
+	case root.General.FollowAll:
+		root.followAll(ctx)
+	case root.Doc.FollowMode:
 		root.follow(ctx)
+	case root.Doc.FollowSection:
+		root.followSection(ctx)
 	}
 
 	if !root.skipDraw && root.Doc.height > 0 {