From 9faa8b227fc13c741ea89751024765bd8a2437a1 Mon Sep 17 00:00:00 2001
From: Kujtim Hoxha <kujtimii.h@gmail.com>
Date: Mon, 26 Jan 2026 16:19:25 +0100
Subject: [PATCH] fix: enable left/right scrolling of diff (#1984)

* fix: enable left/rigth scrolling of diff

this also fixes an issue introduced in #1931 where the model info was
not showing in the landing page.

* chore: simplify model info
---
 internal/ui/dialog/permissions.go | 43 ++++++++++++++++++++++++++-----
 internal/ui/model/sidebar.go      |  3 +--
 2 files changed, 37 insertions(+), 9 deletions(-)

diff --git a/internal/ui/dialog/permissions.go b/internal/ui/dialog/permissions.go
index 143dbbd8baffa8e89b1654175039e8eb9d913bf0..d877d7085afbe8920c96898ce029e059dfa59e46 100644
--- a/internal/ui/dialog/permissions.go
+++ b/internal/ui/dialog/permissions.go
@@ -70,6 +70,7 @@ type Permissions struct {
 	// Diff view state.
 	diffSplitMode        *bool // nil means use default based on width
 	defaultDiffSplitMode bool  // default split mode based on width
+	diffXOffset          int   // horizontal scroll offset for diff view
 	unifiedDiffContent   string
 	splitDiffContent     string
 
@@ -259,12 +260,31 @@ func (p *Permissions) HandleMsg(msg tea.Msg) Action {
 		case key.Matches(msg, p.keyMap.ScrollUp):
 			p.viewport, _ = p.viewport.Update(msg)
 		case key.Matches(msg, p.keyMap.ScrollLeft):
-			p.viewport, _ = p.viewport.Update(msg)
+			if p.hasDiffView() {
+				p.scrollLeft()
+			} else {
+				p.viewport, _ = p.viewport.Update(msg)
+			}
 		case key.Matches(msg, p.keyMap.ScrollRight):
-			p.viewport, _ = p.viewport.Update(msg)
+			if p.hasDiffView() {
+				p.scrollRight()
+			} else {
+				p.viewport, _ = p.viewport.Update(msg)
+			}
 		}
 	case tea.MouseWheelMsg:
-		p.viewport, _ = p.viewport.Update(msg)
+		if p.hasDiffView() {
+			switch msg.Button {
+			case tea.MouseWheelLeft:
+				p.scrollLeft()
+			case tea.MouseWheelRight:
+				p.scrollRight()
+			default:
+				p.viewport, _ = p.viewport.Update(msg)
+			}
+		} else {
+			p.viewport, _ = p.viewport.Update(msg)
+		}
 	default:
 		// Pass unhandled keys to viewport for non-diff content scrolling.
 		if !p.hasDiffView() {
@@ -309,6 +329,18 @@ func (p *Permissions) isSplitMode() bool {
 	return p.defaultDiffSplitMode
 }
 
+const horizontalScrollStep = 5
+
+func (p *Permissions) scrollLeft() {
+	p.diffXOffset = max(0, p.diffXOffset-horizontalScrollStep)
+	p.viewportDirty = true
+}
+
+func (p *Permissions) scrollRight() {
+	p.diffXOffset += horizontalScrollStep
+	p.viewportDirty = true
+}
+
 // Draw implements [Dialog].
 func (p *Permissions) Draw(scr uv.Screen, area uv.Rectangle) *tea.Cursor {
 	t := p.com.Styles
@@ -558,10 +590,7 @@ func (p *Permissions) renderDiff(filePath, oldContent, newContent string, conten
 	formatter := common.DiffFormatter(p.com.Styles).
 		Before(fsext.PrettyPath(filePath), oldContent).
 		After(fsext.PrettyPath(filePath), newContent).
-		// TODO: Allow horizontal scrolling instead of cropping. However, the
-		// diffview currently would only background color the width of the
-		// content. If the viewport is wider than the content, the rest of the
-		// line would not be colored properly.
+		XOffset(p.diffXOffset).
 		Width(contentWidth)
 
 	var result string
diff --git a/internal/ui/model/sidebar.go b/internal/ui/model/sidebar.go
index a0623a1262863da749bbaebdfb2f42eccef7cf50..7e6a61864a42f37ba7bf1c955b6844f4c488b942 100644
--- a/internal/ui/model/sidebar.go
+++ b/internal/ui/model/sidebar.go
@@ -51,9 +51,8 @@ func (m *UI) modelInfo(width int) string {
 			Cost:         m.session.Cost,
 			ModelContext: model.CatwalkCfg.ContextWindow,
 		}
-		return common.ModelInfo(m.com.Styles, model.CatwalkCfg.Name, providerName, reasoningInfo, modelContext, width)
 	}
-	return ""
+	return common.ModelInfo(m.com.Styles, model.CatwalkCfg.Name, providerName, reasoningInfo, modelContext, width)
 }
 
 // getDynamicHeightLimits will give us the num of items to show in each section based on the hight