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/view-main.go           | 51 +++++++++++++++++++++++++++++++++++++----------
 ui/widget/message-view.go | 39 ++++++++++++++++--------------------
 2 files changed, 57 insertions(+), 33 deletions(-)

(limited to 'ui')

diff --git a/ui/view-main.go b/ui/view-main.go
index e5c6792..a5580b3 100644
--- a/ui/view-main.go
+++ b/ui/view-main.go
@@ -195,16 +195,26 @@ func (view *MainView) KeyEventHandler(roomView *widget.RoomView, key *tcell.Even
 		} else {
 			return key
 		}
-	} else if k == tcell.KeyPgUp || k == tcell.KeyPgDn || k == tcell.KeyUp || k == tcell.KeyDown {
+	} else if k == tcell.KeyPgUp || k == tcell.KeyPgDn || k == tcell.KeyUp || k == tcell.KeyDown || k == tcell.KeyEnd || k == tcell.KeyHome {
 		msgView := roomView.MessageView()
-		if k == tcell.KeyPgUp || k == tcell.KeyUp {
-			if msgView.IsAtTop() {
-				go view.LoadHistory(roomView.Room.ID, false)
-			} else {
-				msgView.MoveUp(k == tcell.KeyPgUp)
-			}
-		} else {
-			msgView.MoveDown(k == tcell.KeyPgDn)
+
+		if msgView.IsAtTop() && (k == tcell.KeyPgUp || k == tcell.KeyUp) {
+			go view.LoadHistory(roomView.Room.ID, false)
+		}
+
+		switch k {
+		case tcell.KeyPgUp:
+			msgView.AddScrollOffset(msgView.Height() / 2)
+		case tcell.KeyPgDn:
+			msgView.AddScrollOffset(-msgView.Height() / 2)
+		case tcell.KeyUp:
+			msgView.AddScrollOffset(1)
+		case tcell.KeyDown:
+			msgView.AddScrollOffset(-1)
+		case tcell.KeyHome:
+			msgView.AddScrollOffset(msgView.TotalHeight())
+		case tcell.KeyEnd:
+			msgView.AddScrollOffset(-msgView.TotalHeight())
 		}
 	} else {
 		return key
@@ -212,9 +222,28 @@ func (view *MainView) KeyEventHandler(roomView *widget.RoomView, key *tcell.Even
 	return nil
 }
 
+const WheelScrollOffsetDiff = 3
+
 func (view *MainView) MouseEventHandler(roomView *widget.RoomView, event *tcell.EventMouse) *tcell.EventMouse {
-	if event.Buttons() != tcell.ButtonNone {
-		view.BumpFocus()
+	if event.Buttons() == tcell.ButtonNone {
+		return event
+	}
+	view.BumpFocus()
+
+	msgView := roomView.MessageView()
+	x, y := event.Position()
+
+	switch event.Buttons() {
+	case tcell.WheelUp:
+		if msgView.IsAtTop() {
+			go view.LoadHistory(roomView.Room.ID, false)
+		} else {
+			msgView.AddScrollOffset(WheelScrollOffsetDiff)
+		}
+	case tcell.WheelDown:
+		msgView.AddScrollOffset(-WheelScrollOffsetDiff)
+	default:
+		debug.Print("Mouse event received:", event.Buttons(), event.Modifiers(), x, y)
 	}
 
 	return event
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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