Handle menu navigation

lib/main.rb

@@ -63,9 +63,12 @@ private
       focus: :sidebar,
       focused: true,
 
-      on_window_left: method(:on_window_left),
+      on_window_left:  method(:on_window_left),
       on_window_right: method(:on_window_right),
 
+      on_menu_up:   method(:on_menu_up),
+      on_menu_down: method(:on_menu_down),
+
       sidebar: {
         x: 0,
         y: 0,
@@ -190,4 +193,56 @@ private
       ).freeze,
     ).freeze
   end
+
+  def on_menu_up
+    active = state[:sidebar][:menu][:active]
+    top    = state[:sidebar][:menu][:top]
+    items  = state[:sidebar][:menu][:items]
+    height = state[:sidebar][:menu][:height]
+
+    active -= 1
+
+    active = items.count - 1 if active.negative?
+
+    if active < top
+      top = active
+    elsif active >= top + height
+      top = active - height + 1
+    end
+
+    @state = state.merge(
+      sidebar: state[:sidebar].merge(
+        menu: state[:sidebar][:menu].merge(
+          active: active,
+          top: top,
+        ).freeze,
+      ).freeze,
+    ).freeze
+  end
+
+  def on_menu_down
+    active = state[:sidebar][:menu][:active]
+    top    = state[:sidebar][:menu][:top]
+    items  = state[:sidebar][:menu][:items]
+    height = state[:sidebar][:menu][:height]
+
+    active += 1
+
+    active = 0 if active >= items.count
+
+    if active < top
+      top = active
+    elsif active >= top + height
+      top = active - height + 1
+    end
+
+    @state = state.merge(
+      sidebar: state[:sidebar].merge(
+        menu: state[:sidebar][:menu].merge(
+          active: active,
+          top: top,
+        ).freeze,
+      ).freeze,
+    ).freeze
+  end
 end

lib/widgets/main.rb

@@ -11,8 +11,13 @@ module Widgets
 
     def props=(_value)
       super
-      @sidebar.props = props[:sidebar]
-      @chat.props    = props[:chat]
+
+      @sidebar.props = props[:sidebar].merge(
+        on_menu_up:   props[:on_menu_up],
+        on_menu_down: props[:on_menu_down],
+      ).freeze
+
+      @chat.props = props[:chat]
     end
 
     def trigger(event)

lib/widgets/menu.rb

@@ -2,6 +2,15 @@
 
 module Widgets
   class Menu < Base
+    def trigger(event)
+      case event
+      when Events::Text::Up
+        props[:on_up].call
+      when Events::Text::Down
+        props[:on_down].call
+      end
+    end
+
   private
 
     def draw

lib/widgets/sidebar.rb

@@ -11,8 +11,17 @@ module Widgets
 
     def props=(_value)
       super
+
       @logo.props = props[:logo]
-      @menu.props = props[:menu]
+
+      @menu.props = props[:menu].merge(
+        on_up:   props[:on_menu_up],
+        on_down: props[:on_menu_down],
+      ).freeze
+    end
+
+    def trigger(event)
+      focus&.trigger event
     end
 
   private