refactor: split common/mod.rs into per-widget modules

crates/lore-tui/src/view/common/help_overlay.rs

@@ -0,0 +1,173 @@
+//! Centered modal listing keybindings for the current screen.
+
+use ftui::core::geometry::Rect;
+use ftui::render::cell::{Cell, PackedRgba};
+use ftui::render::drawing::Draw;
+use ftui::render::frame::Frame;
+
+use crate::commands::CommandRegistry;
+use crate::message::Screen;
+
+/// Render a centered help overlay listing keybindings for the current screen.
+///
+/// The overlay is a bordered modal that lists all commands from the
+/// registry that are available on the current screen.
+#[allow(clippy::too_many_arguments)]
+pub fn render_help_overlay(
+    frame: &mut Frame<'_>,
+    area: Rect,
+    registry: &CommandRegistry,
+    screen: &Screen,
+    border_color: PackedRgba,
+    text_color: PackedRgba,
+    muted_color: PackedRgba,
+    scroll_offset: usize,
+) {
+    if area.height < 5 || area.width < 20 {
+        return;
+    }
+
+    // Overlay dimensions: 60% of screen, capped.
+    let overlay_width = (area.width * 3 / 5).clamp(30, 70);
+    let overlay_height = (area.height * 3 / 5).clamp(8, 30);
+
+    let overlay_x = area.x + (area.width.saturating_sub(overlay_width)) / 2;
+    let overlay_y = area.y + (area.height.saturating_sub(overlay_height)) / 2;
+    let overlay_rect = Rect::new(overlay_x, overlay_y, overlay_width, overlay_height);
+
+    // Draw border.
+    let border_cell = Cell {
+        fg: border_color,
+        ..Cell::default()
+    };
+    frame.draw_border(
+        overlay_rect,
+        ftui::render::drawing::BorderChars::ROUNDED,
+        border_cell,
+    );
+
+    // Title.
+    let title = " Help (? to close) ";
+    let title_x = overlay_x + (overlay_width.saturating_sub(title.len() as u16)) / 2;
+    let title_cell = Cell {
+        fg: border_color,
+        ..Cell::default()
+    };
+    frame.print_text_clipped(title_x, overlay_y, title, title_cell, overlay_rect.right());
+
+    // Inner content area (inside border).
+    let inner = Rect::new(
+        overlay_x + 2,
+        overlay_y + 1,
+        overlay_width.saturating_sub(4),
+        overlay_height.saturating_sub(2),
+    );
+
+    // Get commands for this screen.
+    let commands = registry.help_entries(screen);
+    let visible_lines = inner.height as usize;
+
+    let key_cell = Cell {
+        fg: text_color,
+        ..Cell::default()
+    };
+    let desc_cell = Cell {
+        fg: muted_color,
+        ..Cell::default()
+    };
+
+    for (i, cmd) in commands.iter().skip(scroll_offset).enumerate() {
+        if i >= visible_lines {
+            break;
+        }
+        let y = inner.y + i as u16;
+
+        // Key binding label (left).
+        let key_label = cmd
+            .keybinding
+            .as_ref()
+            .map_or_else(String::new, |kb| kb.display());
+        let label_end = frame.print_text_clipped(inner.x, y, &key_label, key_cell, inner.right());
+
+        // Spacer + description (right).
+        let desc_x = label_end.saturating_add(2);
+        if desc_x < inner.right() {
+            frame.print_text_clipped(desc_x, y, cmd.help_text, desc_cell, inner.right());
+        }
+    }
+
+    // Scroll indicator if needed.
+    if commands.len() > visible_lines + scroll_offset {
+        let indicator = format!("({}/{})", scroll_offset + visible_lines, commands.len());
+        let ind_x = inner.right().saturating_sub(indicator.len() as u16);
+        let ind_y = overlay_rect.bottom().saturating_sub(1);
+        frame.print_text_clipped(ind_x, ind_y, &indicator, desc_cell, overlay_rect.right());
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::commands::build_registry;
+    use crate::message::Screen;
+    use ftui::render::grapheme_pool::GraphemePool;
+
+    macro_rules! with_frame {
+        ($width:expr, $height:expr, |$frame:ident| $body:block) => {{
+            let mut pool = GraphemePool::new();
+            let mut $frame = Frame::new($width, $height, &mut pool);
+            $body
+        }};
+    }
+
+    fn white() -> PackedRgba {
+        PackedRgba::rgb(0xFF, 0xFF, 0xFF)
+    }
+
+    fn gray() -> PackedRgba {
+        PackedRgba::rgb(0x80, 0x80, 0x80)
+    }
+
+    #[test]
+    fn test_help_overlay_renders_border() {
+        with_frame!(80, 24, |frame| {
+            let registry = build_registry();
+            render_help_overlay(
+                &mut frame,
+                Rect::new(0, 0, 80, 24),
+                &registry,
+                &Screen::Dashboard,
+                gray(),
+                white(),
+                gray(),
+                0,
+            );
+
+            // The overlay should have non-empty cells in the center area.
+            let has_content = (20..60u16).any(|x| {
+                (8..16u16).any(|y| {
+                    let cell = frame.buffer.get(x, y).unwrap();
+                    !cell.is_empty()
+                })
+            });
+            assert!(has_content, "Expected help overlay in center area");
+        });
+    }
+
+    #[test]
+    fn test_help_overlay_tiny_terminal_noop() {
+        with_frame!(15, 4, |frame| {
+            let registry = build_registry();
+            render_help_overlay(
+                &mut frame,
+                Rect::new(0, 0, 15, 4),
+                &registry,
+                &Screen::Dashboard,
+                gray(),
+                white(),
+                gray(),
+                0,
+            );
+        });
+    }
+}