differentiate top-bar between month and year views

* prev and next buttons change year in year view
* do not show month name in year view

Signed-off-by: Fabrizio Iannetti <fabrizio.iannetti@gmail.com>

src/main.rs

@@ -68,6 +68,8 @@ struct CalendarApp {
 enum Message {
     NextMonth,
     PrevMonth,
+    NextYear,
+    PrevYear,
     ViewModeSelected(ViewMode),
 }
 
@@ -107,6 +109,10 @@ impl Controls {
     const MODES : [ViewMode; 2] = [ViewMode::Month, ViewMode::Year];
 
     fn view<'a>(&'a self, month_name: &'a str, year: i32) -> Element<Message> {
+        let description = match self.mode {
+            Some(ViewMode::Month) => month_name,
+            _ => ""
+        };
         Row::new()
             .align_items(Alignment::Center)
             .padding(5)
@@ -120,16 +126,16 @@ impl Controls {
             )
             .push(
                 Button::new(Text::new("<"))
-                .on_press(Message::PrevMonth)
+                .on_press(self.get_msg_prev())
                 .style(theme::Button::Secondary),
             )
             .push(
                 Button::new(Text::new(">"))
-                    .on_press(Message::NextMonth)
+                    .on_press(self.get_msg_next())
                     .style(theme::Button::Secondary),
             )
             .push(
-                Text::new(month_name)
+                Text::new(description)
                     .width(Length::Fill)
                     .horizontal_alignment(alignment::Horizontal::Left)
                     .size(40),
@@ -142,6 +148,20 @@ impl Controls {
             )
             .into()
     }
+
+    fn get_msg_next(&self) -> Message {
+        match self.mode {
+            Some(ViewMode::Month) => Message::NextMonth,
+            _ => Message::NextYear
+        }
+    }
+
+    fn get_msg_prev(&self) -> Message {
+        match self.mode {
+            Some(ViewMode::Month) => Message::PrevMonth,
+            _ => Message::PrevYear
+        }
+    }
 }
 
 impl Application for CalendarApp {
@@ -175,6 +195,12 @@ impl Application for CalendarApp {
             Message::NextMonth => {
                 self.month = self.month + Months::new(1);
             }
+            Message::PrevYear => {
+                self.month = self.month - Months::new(12);
+            }
+            Message::NextYear => {
+                self.month = self.month + Months::new(12);
+            }
             Message::ViewModeSelected(mode) => {
                 self.controls.mode = Some(mode);
             }