Implement message selection-based scrolling with j/k keys

Co-authored-by: foglar <82380203+foglar@users.noreply.github.com>

internal/tui/chat.go

@@ -28,26 +28,40 @@ func updateChatView(v *gocui.View) {
 	clear := cleanimage.NewKittyImageCleaner()
 	fmt.Print(clear.DeleteByColumn(chatViewColumn, false))
 
-	// Reset scroll offset when switching contacts or if out of bounds
-	if chatScrollOffset < 0 {
-		chatScrollOffset = 0
-	}
-	if chatScrollOffset > len(chatData.Messages) {
-		chatScrollOffset = len(chatData.Messages)
-	}
-
-	// Set view origin based on scroll offset
-	ox, _ := v.Origin()
-	v.SetOrigin(ox, chatScrollOffset)
-
 	// Check if we have valid users
 	if len(users) == 0 || selectedUserIdx >= len(users) {
 		return
 	}
 
-	// Get view dimensions to check if images are visible
+	// Ensure selectedMessageIdx is within bounds
+	if len(chatData.Messages) == 0 {
+		return
+	}
+	if selectedMessageIdx < 0 {
+		selectedMessageIdx = 0
+	}
+	if selectedMessageIdx >= len(chatData.Messages) {
+		selectedMessageIdx = len(chatData.Messages) - 1
+	}
+
+	// Get view dimensions
 	_, viewHeight := v.Size()
 
+	// Calculate which messages should be visible
+	// We want to show the selected message in the middle of the view when possible
+	messagesPerView := viewHeight / messageRowIncrement
+	if messagesPerView <= 0 {
+		messagesPerView = 1
+	}
+
+	// Calculate start index - show newest messages at bottom
+	startIdx := max(0, min(selectedMessageIdx-(messagesPerView/2), len(chatData.Messages)-messagesPerView))
+
+	// Calculate scroll offset to position view correctly
+	scrollOffset := startIdx * messageRowIncrement
+	ox, _ := v.Origin()
+	v.SetOrigin(ox, scrollOffset)
+
 	// Get terminal cell size once for all messages
 	w, h, err := cell_size.GetTerminalCellSizePixels()
 	if err != nil {
@@ -62,7 +76,10 @@ func updateChatView(v *gocui.View) {
 		h = 0
 	}
 
-	for i, msg := range chatData.Messages {
+	// Render only visible messages
+	endIdx := min(startIdx+messagesPerView+1, len(chatData.Messages))
+	for i := startIdx; i < endIdx; i++ {
+		msg := chatData.Messages[i]
 		decoded, err := base64.StdEncoding.DecodeString(msg.Content)
 		if err != nil {
 			log.Printf("Error decoding message: %v", err)
@@ -90,12 +107,20 @@ func updateChatView(v *gocui.View) {
 			iconPath = fmt.Sprintf(contactIconPathFmt, strings.ToLower(msg.Sender))
 		}
 
-		// Print message text
+		// Highlight selected message
-		fmt.Fprintf(v, "%s", "\t\t\t\t\t"+senderLabel+"\n\t\t\t\t\t"+string(decoded)+"\n\n")
+		prefix := "\t\t\t\t\t"
+		if i == selectedMessageIdx {
+			prefix = "\x1b[7m\t\t\t\t\t"
+			senderLabel = senderLabel + "\x1b[0m\x1b[7m"
+			decoded = append([]byte("\x1b[0m\x1b[7m"), decoded...)
+			decoded = append(decoded, []byte("\x1b[0m")...)
+		}
 
-		// Calculate row position accounting for scroll offset
+		// Print message text
-		// Each message takes 3 lines (messageRowIncrement)
+		fmt.Fprintf(v, "%s", prefix+senderLabel+"\n"+prefix+string(decoded)+"\n\n")
-		rowPosition := i*messageRowIncrement + messageRowOffset - chatScrollOffset
+
+		// Calculate row position for image rendering
+		rowPosition := i*messageRowIncrement + messageRowOffset - scrollOffset
 
 		// Only render images that are visible in the view
 		if rowPosition >= 0 && rowPosition < viewHeight {
@@ -126,36 +151,45 @@ func sendMessage(g *gocui.Gui, v *gocui.View) error {
 		return err
 	}
 
-	// Reset scroll to bottom when sending a new message
+	// Select newest message (at the end)
-	chatScrollOffset = 0
+	if len(chatData.Messages) > 0 {
+		selectedMessageIdx = len(chatData.Messages) - 1
+	}
 	updateChatView(chatView)
 	return nil
 }
 
 func scrollChatUp(g *gocui.Gui, v *gocui.View) error {
+	if len(chatData.Messages) == 0 {
+		return nil
+	}
+
 	chatView, err := g.View("chat")
 	if err != nil {
 		return err
 	}
 
-	// Scroll up by 1 line
+	// Move selection up (to older messages)
-	if chatScrollOffset > 0 {
+	if selectedMessageIdx > 0 {
-		chatScrollOffset--
+		selectedMessageIdx--
 		updateChatView(chatView)
 	}
 	return nil
 }
 
 func scrollChatDown(g *gocui.Gui, v *gocui.View) error {
+	if len(chatData.Messages) == 0 {
+		return nil
+	}
+
 	chatView, err := g.View("chat")
 	if err != nil {
 		return err
 	}
 
-	// Scroll down by 1 line
+	// Move selection down (to newer messages)
-	maxScroll := len(chatData.Messages) * messageRowIncrement
+	if selectedMessageIdx < len(chatData.Messages)-1 {
-	if chatScrollOffset < maxScroll {
+		selectedMessageIdx++
-		chatScrollOffset++
 		updateChatView(chatView)
 	}
 	return nil

internal/tui/sidebar.go

@@ -74,8 +74,15 @@ func nextContact(g *gocui.Gui, v *gocui.View) error {
 		selectedUserIdx = 0
 	}
 
-	// Reset scroll offset when changing contacts
+	// Load messages for new contact
-	chatScrollOffset = 0
+	LoadMessages(users[selectedUserIdx])
+
+	// Select newest message (scroll to bottom)
+	if len(chatData.Messages) > 0 {
+		selectedMessageIdx = len(chatData.Messages) - 1
+	} else {
+		selectedMessageIdx = 0
+	}
 
 	if err := updateContactsView(g); err != nil {
 		return err
@@ -99,8 +106,15 @@ func prevContact(g *gocui.Gui, v *gocui.View) error {
 		selectedUserIdx = len(users) - 1
 	}
 
-	// Reset scroll offset when changing contacts
+	// Load messages for new contact
-	chatScrollOffset = 0
+	LoadMessages(users[selectedUserIdx])
+
+	// Select newest message (scroll to bottom)
+	if len(chatData.Messages) > 0 {
+		selectedMessageIdx = len(chatData.Messages) - 1
+	} else {
+		selectedMessageIdx = 0
+	}
 
 	if err := updateContactsView(g); err != nil {
 		return err

internal/tui/tui.go

@@ -10,7 +10,7 @@ var users []string
 var prevWidth, prevHeight int
 var chatData ChatData
 var selectedUserIdx int = 0
-var chatScrollOffset int = 0
+var selectedMessageIdx int = 0
 
 func Run() {
 	LoadContacts(defaultServerPath)
@@ -18,6 +18,10 @@ func Run() {
 	// Load initial messages if there are any contacts
 	if len(users) > 0 && selectedUserIdx < len(users) {
 		LoadMessages(users[selectedUserIdx])
+		// Initialize to newest message (bottom)
+		if len(chatData.Messages) > 0 {
+			selectedMessageIdx = len(chatData.Messages) - 1
+		}
 	}
 
 	g, err := gocui.NewGui(gocui.OutputNormal)