Log panel

kiln-tui/src/main.rs

@@ -12,14 +12,44 @@ mod render;
 mod term;
 
 use kiln_core::game::GameState;
+use kiln_core::log::LogLine;
 use kiln_core::map_file;
 use ratatui::Frame;
-use ratatui::crossterm::event::{self, Event, KeyCode, KeyEventKind};
-use ratatui::widgets::Block;
-use render::BoardWidget;
+use ratatui::crossterm::event::{
+    self, DisableMouseCapture, EnableMouseCapture, Event, KeyCode, KeyEventKind, MouseEventKind,
+};
+use ratatui::crossterm::execute;
+use ratatui::layout::{Constraint, Layout, Spacing};
+use ratatui::style::{Color, Style};
+use ratatui::text::{Line, Span};
+use ratatui::widgets::{Block, Paragraph, Wrap};
+use render::{BoardWidget, logline_to_line};
+use std::io;
 use std::process::ExitCode;
+use ratatui::symbols::merge::MergeStrategy;
 use term::TerminalCaps;
 
+/// View-only UI state for the log panel. This is presentation state, so it lives
+/// in the front-end rather than on the engine's [`GameState`].
+struct Ui {
+    /// Whether the bottom log panel is open.
+    log_open: bool,
+    /// Height (in terminal rows, borders included) of the log panel when open.
+    log_height: u16,
+    /// Vertical scroll offset of the log panel, in lines from the top (newest).
+    scroll: u16,
+}
+
+impl Default for Ui {
+    fn default() -> Self {
+        Self {
+            log_open: false,
+            log_height: 10,
+            scroll: 0,
+        }
+    }
+}
+
 /// Entry point: parse the map path, load the board, then run the play loop with
 /// the terminal in raw/alternate-screen mode (restored on every exit path).
 fn main() -> ExitCode {
@@ -43,6 +73,10 @@ fn main() -> ExitCode {
     // `init` enters the alternate screen and raw mode; `restore` always undoes it.
     let mut terminal = ratatui::init();
 
+    // Capture mouse events so the log panel can be scrolled with the wheel and
+    // resized by dragging its divider. Disabled again before restoring.
+    let _ = execute!(io::stdout(), EnableMouseCapture);
+
     // Detect terminal capabilities (now that we're in raw mode) and enable the
     // Kitty keyboard protocol when it's available, so scripts can rely on the
     // richer bindings it provides. Disabled again before restoring the terminal.
@@ -51,11 +85,19 @@ fn main() -> ExitCode {
         let _ = term::push_kitty_flags();
     }
 
-    let result = run(&mut terminal, &mut game, &caps);
+    // Seed the log: the terminal-capabilities badge plus a couple of test
+    // messages (temporary, just to exercise the panel).
+    // Note these will appear in reverse order, latest on top
+    game.log(LogLine::raw("Press 'q' to exit."));
+    game.log(LogLine::raw("Welcome to kiln - ").append(caps.status_logline()));
+
+    let mut ui = Ui::default();
+    let result = run(&mut terminal, &mut game, &mut ui);
 
     if caps.keyboard_enhancement {
         let _ = term::pop_kitty_flags();
     }
+    let _ = execute!(io::stdout(), DisableMouseCapture);
     ratatui::restore();
 
     if let Err(e) = result {
@@ -69,44 +111,114 @@ fn main() -> ExitCode {
 fn run(
     terminal: &mut ratatui::DefaultTerminal,
     game: &mut GameState,
-    caps: &TerminalCaps,
+    ui: &mut Ui,
 ) -> std::io::Result<()> {
     loop {
-        // Redraw the board every iteration; ratatui diffs against the previous
-        // frame so only changed cells are actually written to the terminal.
-        terminal.draw(|frame| draw(frame, game, caps))?;
+        // Redraw every iteration; ratatui diffs against the previous frame so
+        // only changed cells are actually written to the terminal.
+        terminal.draw(|frame| draw(frame, game, ui))?;
 
-        // Block until the next input event.
-        if let Event::Key(key) = event::read()? {
-            // Act on Press and Repeat so holding a key moves the player
-            // continuously (the Kitty protocol emits Repeat events while a key is
-            // held). Ignore Release, which that protocol also emits and which
-            // would otherwise fire a second, spurious move per keypress.
-            if key.kind == KeyEventKind::Release {
-                continue;
+        match event::read()? {
+            Event::Key(key) => {
+                // Act on Press and Repeat so holding a key moves the player
+                // continuously (the Kitty protocol emits Repeat events while a
+                // key is held). Ignore Release, which that protocol also emits
+                // and which would otherwise fire a second, spurious move.
+                if key.kind == KeyEventKind::Release {
+                    continue;
+                }
+                match key.code {
+                    KeyCode::Char('q') | KeyCode::Esc => return Ok(()),
+                    KeyCode::Up => game.try_move(0, -1),
+                    KeyCode::Down => game.try_move(0, 1),
+                    KeyCode::Left => game.try_move(-1, 0),
+                    // Right arrow moves right; 'l' is reserved for the log panel.
+                    KeyCode::Right => game.try_move(1, 0),
+                    // 'l' toggles the log panel; reset the scroll to the newest.
+                    KeyCode::Char('l') => {
+                        ui.log_open = !ui.log_open;
+                        ui.scroll = 0;
+                    }
+                    // PageUp/PageDown scroll the log when it's open.
+                    KeyCode::PageUp if ui.log_open => scroll_log(ui, game, -5),
+                    KeyCode::PageDown if ui.log_open => scroll_log(ui, game, 5),
+                    _ => {}
+                }
             }
-            match key.code {
-                KeyCode::Char('q') | KeyCode::Esc => return Ok(()),
-                KeyCode::Up | KeyCode::Char('k') => game.try_move(0, -1),
-                KeyCode::Down | KeyCode::Char('j') => game.try_move(0, 1),
-                KeyCode::Left | KeyCode::Char('h') => game.try_move(-1, 0),
-                KeyCode::Right | KeyCode::Char('l') => game.try_move(1, 0),
+            // Wheel scrolls the open log; dragging the divider resizes it.
+            Event::Mouse(m) if ui.log_open => match m.kind {
+                MouseEventKind::ScrollUp => scroll_log(ui, game, -1),
+                MouseEventKind::ScrollDown => scroll_log(ui, game, 1),
+                MouseEventKind::Drag(_) => {
+                    // The divider sits at row `total - log_height`; dragging it up
+                    // (smaller row) grows the panel. Keep both regions usable.
+                    let total = terminal.size()?.height;
+                    let target = total.saturating_sub(m.row);
+                    ui.log_height = target.clamp(3, total.saturating_sub(3).max(3));
+                }
                 _ => {}
-            }
+            },
+            _ => {}
         }
     }
 }
 
-/// Render a single frame: a bordered block titled with the board name and
-/// controls, containing the board itself.
-fn draw(frame: &mut Frame, game: &GameState, caps: &TerminalCaps) {
-    let board = &game.board;
-    let block = Block::bordered()
-        .title(format!(" {} — arrows move · q quit ", board.name))
-        // Surface detected terminal capabilities in the bottom-right border.
-        .title_bottom(caps.summary_line().right_aligned());
-    // Draw the board inside the border, not over it.
-    let inner = block.inner(frame.area());
-    frame.render_widget(block, frame.area());
-    frame.render_widget(BoardWidget::new(board), inner);
+/// Adjusts the log scroll offset by `delta` lines, clamped so it can neither go
+/// above the newest message nor scroll past the oldest.
+fn scroll_log(ui: &mut Ui, game: &GameState, delta: i32) {
+    let max = game.log.len().saturating_sub(1) as i32;
+    ui.scroll = (ui.scroll as i32 + delta).clamp(0, max) as u16;
+}
+
+/// Render a single frame: the board in a bordered block, and — when open — a log
+/// panel across the bottom. When the panel is closed the latest log message is
+/// previewed in the board's bottom-left border after a `[l]og:` label.
+fn draw(frame: &mut Frame, game: &GameState, ui: &Ui) {
+    let board = &game.board;
+
+    if ui.log_open {
+        // Split the screen: board on top, log panel of `log_height` at the bottom.
+        let [board_area, log_area] =
+            Layout::vertical([Constraint::Min(3), Constraint::Length(ui.log_height)])
+                .spacing(Spacing::Overlap(1))
+                .areas(frame.area());
+
+        let block = Block::bordered().title(format!(" {} ", board.name)).merge_borders(MergeStrategy::Exact);
+        let inner = block.inner(board_area);
+        frame.render_widget(block, board_area);
+        frame.render_widget(BoardWidget::new(board), inner);
+
+        // Newest message on top: reverse the log into ratatui lines.
+        let log_block = Block::bordered()
+            .title(Span::styled(" [l]og: ", Style::default().fg(Color::DarkGray)))
+            .merge_borders(MergeStrategy::Exact);
+        let lines: Vec<Line> = game.log.iter().rev().map(logline_to_line).collect();
+        let paragraph = Paragraph::new(lines)
+            .block(log_block)
+            .scroll((ui.scroll, 0))
+            .wrap(Wrap { trim: false });
+        frame.render_widget(paragraph, log_area);
+    } else {
+        // Panel closed: board fills the screen, latest message in the border.
+        let mut block =
+            Block::bordered().title(format!(" {} ", board.name));
+        block = block.title_bottom(log_preview(game).left_aligned());
+        let inner = block.inner(frame.area());
+        frame.render_widget(block, frame.area());
+        frame.render_widget(BoardWidget::new(board), inner);
+    }
+}
+
+/// Builds the `[l]og: <latest message>` preview shown in the board's bottom-left
+/// border when the log panel is closed.
+fn log_preview(game: &GameState) -> Line<'static> {
+    let mut spans = vec![Span::styled(
+        " [l]og: ",
+        Style::default().fg(Color::DarkGray),
+    )];
+    if let Some(latest) = game.log.last() {
+        spans.extend(logline_to_line(latest).spans);
+    }
+    spans.push(Span::raw(" "));
+    Line::from(spans)
 }