Add Settings view, widget, and keybindings

Introduce Settings view handling in key events and widgets.
Add `Enter` action with its keybinding.
Refactor keybinding lookup to use `Option<&KeyBinding>` for missing
entries.
Update view option generation to safely filter possible values.
Export `settings_keybindings` and `settings_widget` from their modules.

src/app/keybind.rs

@@ -1,6 +1,6 @@
 use crate::app::{
     App, View,
-    keybindings::{default_view_keybindings, main_menu_keybindings},
+    keybindings::{default_view_keybindings, main_menu_keybindings, settings_keybindings},
 };
 use ratatui::crossterm::event::KeyEvent;
 use std::io::Result;
@@ -8,6 +8,7 @@ use std::io::Result;
 pub fn handle_keybindings(app: &mut App, key_event: KeyEvent) -> Result<()> {
     match app.view {
         View::MainMenu => main_menu_keybindings(app, &key_event),
+        View::Settings => settings_keybindings(app, &key_event),
         _ => default_view_keybindings(app, &key_event),
     }
 

src/app/keybindings/keybindings.rs

@@ -9,6 +9,7 @@ pub enum Action {
     Up,
     Down,
     Space,
+    Enter,
     Esc,
 }
 
@@ -84,6 +85,15 @@ pub static KEYBINDINGS: &[KeyBinding] = &[
         symbol: "Space",
         description: "Select",
     },
+    KeyBinding {
+        action: Action::Enter,
+        code: KeyCode::Enter,
+        kind: KeyEventKind::Press,
+        modifiers: KeyModifiers::NONE,
+        group: Group::Select,
+        symbol: "Enter",
+        description: "Submit",
+    },
     KeyBinding {
         action: Action::Esc,
         code: KeyCode::Esc,
@@ -106,23 +116,36 @@ pub fn event_to_action(event: &KeyEvent) -> Option<Action> {
         .map(|b| b.action)
 }
 
-fn used_groups_in_view(keybindings: &Vec<&'static KeyBinding>) -> HashSet<Group> {
-    keybindings.iter().map(|b| b.group).collect()
+fn used_groups_in_view(keybindings: &Vec<Option<&'static KeyBinding>>) -> HashSet<Group> {
+    keybindings
+        .iter()
+        .filter_map(|b| b.map(|binding| binding.group))
+        .collect()
 }
 
-pub fn binding_for_view(view: View) -> (HashSet<Group>, Vec<&'static KeyBinding>) {
-    let main_menu_keybindings: Vec<&'static KeyBinding> = vec![
-        binding_for(Action::Up).unwrap(),
-        binding_for(Action::Down).unwrap(),
-        binding_for(Action::Space).unwrap(),
-        binding_for(Action::Quit).unwrap(),
-        binding_for(Action::Quit2).unwrap(),
+pub fn binding_for_view(view: View) -> (HashSet<Group>, Vec<Option<&'static KeyBinding>>) {
+    let main_menu_keybindings: Vec<Option<&'static KeyBinding>> = vec![
+        binding_for(Action::Up),
+        binding_for(Action::Down),
+        binding_for(Action::Space),
+        binding_for(Action::Quit),
+        binding_for(Action::Quit2),
     ];
 
-    let default_keybindings: Vec<&'static KeyBinding> = vec![
-        binding_for(Action::Quit).unwrap(),
-        binding_for(Action::Quit2).unwrap(),
-        binding_for(Action::Esc).unwrap(),
+    let settings_keybinding: Vec<Option<&'static KeyBinding>> = vec![
+        binding_for(Action::Up),
+        binding_for(Action::Down),
+        binding_for(Action::Space),
+        binding_for(Action::Enter),
+        binding_for(Action::Quit),
+        binding_for(Action::Quit2),
+        binding_for(Action::Esc),
+    ];
+
+    let default_keybindings: Vec<Option<&'static KeyBinding>> = vec![
+        binding_for(Action::Quit),
+        binding_for(Action::Quit2),
+        binding_for(Action::Esc),
     ];
 
     match view {
@@ -130,6 +153,10 @@ pub fn binding_for_view(view: View) -> (HashSet<Group>, Vec<&'static KeyBinding>
             used_groups_in_view(&main_menu_keybindings),
             main_menu_keybindings,
         ),
+        View::Settings => (
+            used_groups_in_view(&settings_keybinding),
+            settings_keybinding,
+        ),
         _ => (
             used_groups_in_view(&default_keybindings),
             default_keybindings,

src/app/keybindings/mod.rs

@@ -1,9 +1,11 @@
 pub mod default;
 pub mod keybindings;
 pub mod main_menu;
+pub mod settings;
 
 pub use default::default_view_keybindings;
 pub use keybindings::{
     Action, Group, KEYBINDINGS, KeyBinding, binding_for, binding_for_view, event_to_action,
 };
 pub use main_menu::main_menu_keybindings;
+pub use settings::settings_keybindings;

src/app/keybindings/settings.rs

@@ -0,0 +1,16 @@
+use crate::app::{
+    App, View,
+    keybindings::{Action, event_to_action},
+};
+use ratatui::crossterm::event::KeyEvent;
+
+pub fn settings_keybindings(app: &mut App, key_event: &KeyEvent) {
+    if let Some(action) = event_to_action(&key_event) {
+        match action {
+            Action::Quit => app.exit = true,
+            Action::Quit2 => app.exit = true,
+            Action::Esc => app.view = View::MainMenu,
+            _ => (),
+        }
+    }
+}

src/app/widget.rs

@@ -1,6 +1,6 @@
 use crate::app::{
     App, View,
-    widgets::{default_view_widget, main_menu_widget},
+    widgets::{default_view_widget, main_menu_widget, settings_widget},
 };
 use ratatui::{buffer::Buffer, layout::Rect, widgets::Widget};
 
@@ -11,6 +11,7 @@ impl Widget for &App {
     {
         match self.view {
             View::MainMenu => main_menu_widget(self, area, buf),
+            View::Settings => settings_widget(self, area, buf),
             _ => default_view_widget(self, area, buf),
         }
     }

src/app/widgets/keybindings.rs

@@ -26,9 +26,15 @@ impl KeybindingsWidget {
 
             let grouped_lines: Vec<Line<'_>> = keybindings
                 .iter()
-                .filter(|b| b.group == group)
-                .map(|b| {
-                    Line::from_iter([b.symbol.red().bold(), " - ".into(), b.description.into()])
+                .filter(|b| b.as_ref().map_or(false, |kb| kb.group == group))
+                .filter_map(|b| {
+                    b.as_ref().map(|kb| {
+                        Line::from_iter([
+                            kb.symbol.red().bold(),
+                            " - ".into(),
+                            kb.description.into(),
+                        ])
+                    })
                 })
                 .collect();
 

src/app/widgets/main_menu.rs

@@ -12,15 +12,15 @@ fn view_options() -> Vec<(usize, String)> {
     View::value_variants()
         .iter()
         .enumerate()
-        .map(|(i, v)| {
-            let name = v
-                .to_possible_value()
-                .unwrap()
-                .get_name()
-                .replace('-', " ")
-                .to_uppercase()
-                .to_string();
-            (i, name)
+        .filter_map(|(i, v)| {
+            v.to_possible_value().map(|possible_value| {
+                let name = possible_value
+                    .get_name()
+                    .replace('-', " ")
+                    .to_uppercase()
+                    .to_string();
+                (i, name)
+            })
         })
         .filter(|(_, v)| v != "MAIN MENU")
         .collect()

src/app/widgets/mod.rs

@@ -1,7 +1,9 @@
 pub mod default;
 pub mod keybindings;
 pub mod main_menu;
+pub mod settings;
 
 pub use default::default_view_widget;
 pub use keybindings::KeybindingsWidget;
 pub use main_menu::main_menu_widget;
+pub use settings::settings_widget;

src/app/widgets/settings.rs

@@ -0,0 +1,41 @@
+use crate::app::{App, widgets::KeybindingsWidget};
+use ratatui::{
+    buffer::Buffer,
+    layout::{Alignment, Constraint, Layout, Rect},
+    style::Stylize,
+    widgets::{Block, Borders, Padding, Paragraph, Widget},
+};
+
+pub fn settings_widget(app: &App, area: Rect, buf: &mut Buffer) {
+    let vertical_layout: Layout = Layout::vertical([
+        Constraint::Length(10),
+        Constraint::Fill(1),
+        Constraint::Length(4),
+    ]);
+
+    let [title_area, main_area, keybindings_area] = vertical_layout.areas(area);
+
+    Paragraph::new("War in tunnels")
+        .alignment(Alignment::Left)
+        .yellow()
+        .block(
+            Block::new()
+                .gray()
+                .borders(Borders::LEFT | Borders::TOP | Borders::RIGHT)
+                .padding(Padding::new(1, 1, 1, 1)),
+        )
+        .render(title_area, buf);
+
+    Paragraph::new("Settings")
+        .alignment(Alignment::Center)
+        .yellow()
+        .block(
+            Block::new()
+                .gray()
+                .borders(Borders::LEFT | Borders::RIGHT)
+                .padding(Padding::new(1, 1, 1, 1)),
+        )
+        .render(main_area, buf);
+
+    KeybindingsWidget::new(app.view).render(keybindings_area, buf);
+}