StatefulWidgets (#7)

* trait EventHandler
* StatefulWidget: AppWidget, CountdownWidget
* StatefulWidget: TimerWidget

src/widgets/countdown.rs

@@ -1,12 +1,16 @@
 use ratatui::{
     buffer::Buffer,
+    crossterm::event::KeyCode,
     layout::{Constraint, Layout, Rect},
-    widgets::{Paragraph, Widget},
+    widgets::{Paragraph, StatefulWidget, Widget},
 };
 
-use crate::clock::{self, Clock};
+use crate::{
+    clock::{self, Clock},
+    events::{Event, EventHandler},
+};
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct Countdown {
     headline: String,
     clock: Clock<clock::Countdown>,
@@ -18,13 +22,33 @@ impl Countdown {
     }
 }
 
-impl Widget for Countdown {
-    fn render(mut self, area: Rect, buf: &mut Buffer) {
-        let h = Paragraph::new(self.headline).centered();
-        let c = Paragraph::new(self.clock.format()).centered();
+impl EventHandler for Countdown {
+    fn update(&mut self, event: Event) {
+        match event {
+            Event::Tick => {
+                self.clock.tick();
+            }
+            Event::Key(key) if key.code == KeyCode::Char('s') => {
+                self.clock.toggle_pause();
+            }
+            Event::Key(key) if key.code == KeyCode::Char('r') => {
+                self.clock.reset();
+            }
+            _ => {}
+        }
+    }
+}
+
+pub struct CountdownWidget;
+
+impl StatefulWidget for &CountdownWidget {
+    type State = Countdown;
+    fn render(self, area: Rect, buf: &mut Buffer, state: &mut Self::State) {
+        let h = Paragraph::new(state.headline.clone()).centered();
+        let c = Paragraph::new(state.clock.format()).centered();
         let [v1, v2] = Layout::vertical([Constraint::Length(1), Constraint::Length(1)]).areas(area);
 
         h.render(v1, buf);
-        c.render(v2, buf)
+        c.render(v2, buf);
     }
 }