From c1286661090731729e76e48d5e47988ad0175a20 Mon Sep 17 00:00:00 2001
From: Tulir Asokan <tulir@maunium.net>
Date: Sun, 25 Mar 2018 12:35:50 +0300
Subject: Refactor things and add proper wheel scroll support

---
 ui/widget/message-view.go | 39 +++++++++++++++++----------------------
 1 file changed, 17 insertions(+), 22 deletions(-)

(limited to 'ui/widget/message-view.go')

diff --git a/ui/widget/message-view.go b/ui/widget/message-view.go
index a3a7942..50de405 100644
--- a/ui/widget/message-view.go
+++ b/ui/widget/message-view.go
@@ -211,46 +211,41 @@ func (view *MessageView) recalculateBuffers() {
 
 const PaddingAtTop = 5
 
-func (view *MessageView) MoveUp(page bool) {
+func (view *MessageView) AddScrollOffset(diff int) {
 	_, _, _, height := view.GetInnerRect()
 
 	totalHeight := len(view.textBuffer)
-	if view.ScrollOffset >= totalHeight-height {
+	if diff >= 0 && view.ScrollOffset >= totalHeight-height {
 		// If the user is at the top and presses page up again, add a bit of blank space.
-		if page {
+		if view.ScrollOffset+diff >= totalHeight-height+PaddingAtTop {
 			view.ScrollOffset = totalHeight - height + PaddingAtTop
-		} else if view.ScrollOffset < totalHeight-height+PaddingAtTop {
-			view.ScrollOffset++
+		} else {
+			view.ScrollOffset += diff
 		}
 		return
 	}
 
-	if page {
-		view.ScrollOffset += height / 2
-	} else {
-		view.ScrollOffset++
-	}
+	view.ScrollOffset += diff
 	if view.ScrollOffset > totalHeight-height {
 		view.ScrollOffset = totalHeight - height
+	} else if view.ScrollOffset < 0 {
+		view.ScrollOffset = 0
 	}
 }
 
-func (view *MessageView) IsAtTop() bool {
+func (view *MessageView) Height() int {
 	_, _, _, height := view.GetInnerRect()
-	totalHeight := len(view.textBuffer)
-	return view.ScrollOffset >= totalHeight-height+PaddingAtTop
+	return height
+}
+
+func (view *MessageView) TotalHeight() int {
+	return len(view.textBuffer)
 }
 
-func (view *MessageView) MoveDown(page bool) {
+func (view *MessageView) IsAtTop() bool {
 	_, _, _, height := view.GetInnerRect()
-	if page {
-		view.ScrollOffset -= height / 2
-	} else {
-		view.ScrollOffset--
-	}
-	if view.ScrollOffset < 0 {
-		view.ScrollOffset = 0
-	}
+	totalHeight := len(view.textBuffer)
+	return view.ScrollOffset >= totalHeight-height+PaddingAtTop
 }
 
 func (view *MessageView) writeLine(screen tcell.Screen, line string, x, y int, color tcell.Color) {
-- 
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