added chat scrolling

3 files changed, 30 insertions, 9 deletions

diff --git a/src/main.rs b/src/main.rs
index 9c3d631..23a44f8 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -70,7 +70,7 @@ async fn run(
     // neither blocks the other.
     loop {
         // Draw
-        terminal.draw(|f| ui::draw(f, &app))?;
+        terminal.draw(|f| ui::draw(f, &mut app))?;
 
         // Poll crossterm for keyboard input (non-blocking, 20ms timeout)
         if event::poll(Duration::from_millis(20))? {
@@ -96,6 +96,8 @@ async fn run(
                     (_, KeyCode::Backspace) => app.input_backspace(),
                     (_, KeyCode::Left) => app.cursor_left(),
                     (_, KeyCode::Right) => app.cursor_right(),
+                    (_, KeyCode::Up) => app.scroll_up(),
+                    (_, KeyCode::Down) => app.scroll_down(),
                     (_, KeyCode::Home) => app.cursor = 0,
                     (_, KeyCode::End) => app.cursor = app.input.len(),
                     _ => {}
diff --git a/src/tui/app.rs b/src/tui/app.rs
index 82342c0..7786858 100644
--- a/src/tui/app.rs
+++ b/src/tui/app.rs
@@ -23,6 +23,8 @@ pub struct AppState {
     pub input: String,
     /// Cursor position within `input` (byte index)
     pub cursor: usize,
+    /// Line scroll offset (byte index)
+    pub scroll_offset: usize,
     /// Status line text (connection state, errors, etc.)
     pub status: String,
     /// Whether we've fully registered
@@ -38,6 +40,7 @@ impl AppState {
             members: Vec::new(),
             input: String::new(),
             cursor: 0,
+            scroll_offset: 0,
             status: "Set nick with /nick to connect.".into(),
             connected: false,
         }
@@ -101,6 +104,16 @@ impl AppState {
         }
     }
 
+    /// Scroll up one line
+    pub fn scroll_up(&mut self) {
+        self.scroll_offset += 1;
+    }
+
+    /// Scroll down one line
+    pub fn scroll_down(&mut self) {
+        self.scroll_offset = self.scroll_offset.saturating_sub(1);
+    }
+
     /// Take the current input, clear the box, return the text
     pub fn take_input(&mut self) -> String {
         self.cursor = 0;
diff --git a/src/tui/ui.rs b/src/tui/ui.rs
index 0f552f2..ecdc477 100644
--- a/src/tui/ui.rs
+++ b/src/tui/ui.rs
@@ -12,7 +12,7 @@ use unicode_width::UnicodeWidthStr;
 // Dark terminal aesthetic: near-black background, cool grey chrome,
 // amber accent for our own nick, cyan for others, muted green for system.
 
-pub fn draw(f: &mut Frame, state: &AppState) {
+pub fn draw(f: &mut Frame, state: &mut AppState) {
     let area = f.area();
 
     // Fill background
@@ -54,7 +54,7 @@ fn draw_titlebar(f: &mut Frame, area: Rect, state: &AppState) {
     f.render_widget(Paragraph::new(title).style(Style::default()), area);
 }
 
-fn draw_body(f: &mut Frame, area: Rect, state: &AppState) {
+fn draw_body(f: &mut Frame, area: Rect, state: &mut AppState) {
     // Body:  [chat (fill)] | [members (18)]
     let cols = Layout::default()
         .direction(Direction::Horizontal)
@@ -68,7 +68,7 @@ fn draw_body(f: &mut Frame, area: Rect, state: &AppState) {
     draw_members_panel(f, cols[1], state);
 }
 
-fn draw_center(f: &mut Frame, area: Rect, state: &AppState) {
+fn draw_center(f: &mut Frame, area: Rect, state: &mut AppState) {
     // Centre column: chat log on top, input box on bottom
     let rows = Layout::default()
         .direction(Direction::Vertical)
@@ -82,38 +82,44 @@ fn draw_center(f: &mut Frame, area: Rect, state: &AppState) {
     draw_input(f, rows[1], state);
 }
 
-fn draw_chat_log(f: &mut Frame, area: Rect, state: &AppState) {
+fn draw_chat_log(f: &mut Frame, area: Rect, state: &mut AppState) {
     let lines: Vec<Line> = state
         .messages
         .iter()
         .map(|msg| render_chat_line(msg))
         .collect();
+
     let block = Block::default()
         .borders(Borders::ALL)
         .border_type(BorderType::Plain)
         .border_style(Style::default().fg(Color::Green))
         .style(Style::default());
+
     let inner_width = area.width.saturating_sub(2) as usize;
     let inner_height = area.height.saturating_sub(2) as usize;
     let total_wrapped = count_wrapped_lines(&lines, inner_width);
 
-    let (padded_lines, scroll) = if total_wrapped < inner_height {
-        // Pad the top with empty lines to push content to the bottom
+    let (padded_lines, base_scroll) = if total_wrapped < inner_height {
         let padding = inner_height - total_wrapped;
         let mut padded = vec![Line::raw(""); padding];
         padded.extend(lines);
         (padded, 0u16)
     } else {
-        // Content overflows — scroll to keep the latest lines visible
         let scroll = total_wrapped.saturating_sub(inner_height);
         (lines, scroll as u16)
     };
+    // Max scrollable lines upward from the natural bottom position
+    let max_offset = base_scroll as usize;
+
+    // Clamp the offset and write it back so app.rs stays in sync
+    state.scroll_offset = state.scroll_offset.clamp(0, max_offset);
+    let final_scroll = (base_scroll as i32 - state.scroll_offset as i32) as u16;
 
     f.render_widget(
         Paragraph::new(Text::from(padded_lines))
             .block(block)
             .wrap(Wrap { trim: false })
-            .scroll((scroll, 0)),
+            .scroll((final_scroll, 0)),
         area,
     );
 }