Add main layout view and status bar

Fix #4

src/ui/layout.rs

@@ -0,0 +1,91 @@
+use std::collections::{HashMap};
+
+use cursive::direction::Direction;
+use cursive::event::{Event, EventResult, AnyCb};
+use cursive::traits::View;
+use cursive::view::{IntoBoxedView, Selector};
+use cursive::vec::Vec2;
+use cursive::Printer;
+
+pub struct Layout {
+    views: HashMap<String, Box<dyn View>>,
+    statusbar: Box<dyn View>,
+    focus: Option<String>
+}
+
+impl Layout {
+    pub fn new<T: IntoBoxedView>(status: T) -> Layout {
+        Layout {
+            views: HashMap::new(),
+            statusbar: status.as_boxed_view(),
+            focus: None
+        }
+    }
+
+    pub fn add_view<S: Into<String>, T: IntoBoxedView>(&mut self, id: S, view: T) {
+        let s = id.into();
+        self.views.insert(s.clone(), view.as_boxed_view());
+        self.focus = Some(s);
+    }
+
+    pub fn view<S: Into<String>, T: IntoBoxedView>(mut self, id: S, view: T) -> Self {
+        (&mut self).add_view(id, view);
+        self
+    }
+
+    pub fn set_view<S: Into<String>>(&mut self, id: S) {
+        let s = id.into();
+        self.focus = Some(s);
+    }
+}
+
+impl View for Layout {
+    fn draw(&self, printer: &Printer<'_, '_>) {
+        if let Some(ref id) = self.focus {
+            let v = self.views.get(id).unwrap();
+            let printer = &printer
+                .offset((0, 0))
+                .cropped((printer.size.x, printer.size.y - 2))
+                .focused(true);
+            v.draw(printer);
+        }
+
+        self.statusbar.draw(&printer.offset((0, printer.size.y - 2)));
+    }
+
+    fn required_size(&mut self, constraint: Vec2) -> Vec2 {
+        Vec2::new(constraint.x, constraint.y)
+    }
+
+    fn on_event(&mut self, event: Event) -> EventResult {
+        if let Some(ref id) = self.focus {
+            let v = self.views.get_mut(id).unwrap();
+            v.on_event(event)
+        } else {
+            EventResult::Ignored
+        }
+    }
+
+    fn layout(&mut self, size: Vec2) {
+        if let Some(ref id) = self.focus {
+            let v = self.views.get_mut(id).unwrap();
+            v.layout(Vec2::new(size.x, size.y - 1));
+        }
+    }
+
+    fn call_on_any<'a>(&mut self, s: &Selector, c: AnyCb<'a>) {
+        if let Some(ref id) = self.focus {
+            let v = self.views.get_mut(id).unwrap();
+            v.call_on_any(s, c);
+        }
+    }
+
+    fn take_focus(&mut self, source: Direction) -> bool {
+        if let Some(ref id) = self.focus {
+            let v = self.views.get_mut(id).unwrap();
+            v.take_focus(source)
+        } else {
+            false
+        }
+    }
+}