Changes to support transport focus:

1) Added VolumeUp, VolumeDown, SeekForwad, SeekBack to Playback util
2) Updated GlobalHotkeys for (1)
3) Added support for UP/RIGHT to increase volume or seek forward, and DOWN/LEFT
   to decrease volume or seek back.

src/musikbox/app/layout/LibraryLayout.cpp

@@ -256,9 +256,20 @@ IWindowPtr LibraryLayout::FocusPrev() {
 }
 
 IWindowPtr LibraryLayout::GetFocus() {
-    return this->transportView->IsFocused()
-        ? this->transportView
-        : this->visibleLayout->GetFocus();
+    if (this->transportView->IsFocused()) {
+        return this->transportView;
+    }
+
+    /* if nothing in the visible layout is focused, go
+    ahead and focus the transport so the user has something
+    to interact with. */
+    IWindowPtr focused = this->visibleLayout->GetFocus();
+    if (!focused) {
+        this->transportView->FocusFirst();
+        return this->transportView;
+    }
+
+    return focused;
 }
 
 bool LibraryLayout::SetFocus(cursespp::IWindowPtr window) {

src/musikbox/app/util/GlobalHotkeys.cpp

@@ -57,11 +57,11 @@ bool GlobalHotkeys::Handle(const std::string& kn) {
         return true;
     }
     else if (Hotkeys::Is(Hotkeys::VolumeUp, kn)) {
-        this->transport.SetVolume(this->transport.Volume() + 0.05);
+        playback::VolumeUp(this->transport);
         return true;
     }
     else if (Hotkeys::Is(Hotkeys::VolumeDown, kn)) {
-        this->transport.SetVolume(this->transport.Volume() - 0.05);
+        playback::VolumeDown(this->transport);
         return true;
     }
     else if (Hotkeys::Is(Hotkeys::Previous, kn)) {
@@ -73,13 +73,11 @@ bool GlobalHotkeys::Handle(const std::string& kn) {
         return true;
     }
     else if (Hotkeys::Is(Hotkeys::SeekBack, kn)) {
-        double time = this->transport.Position();
-        this->transport.SetPosition(time - 10.0f);
+        playback::SeekBack(this->transport);
         return true;
     }
     else if (Hotkeys::Is(Hotkeys::SeekForward, kn)) {
-        double time = this->transport.Position();
-        this->transport.SetPosition(time + 10.0f);
+        playback::SeekForward(this->transport);
         return true;
     }
     else if (Hotkeys::Is(Hotkeys::ToggleRepeat, kn)) {

src/musikbox/app/util/Playback.cpp

@@ -68,19 +68,35 @@ namespace musik {
             void ToggleRepeatMode(PlaybackService& playback) {
                 PlaybackService::RepeatMode mode = playback.GetRepeatMode();
                 switch (mode) {
-                    case PlaybackService::RepeatNone:
-                        playback.SetRepeatMode(PlaybackService::RepeatList);
-                        break;
+                case PlaybackService::RepeatNone:
+                    playback.SetRepeatMode(PlaybackService::RepeatList);
+                    break;
 
-                    case PlaybackService::RepeatList:
-                        playback.SetRepeatMode(PlaybackService::RepeatTrack);
-                        break;
+                case PlaybackService::RepeatList:
+                    playback.SetRepeatMode(PlaybackService::RepeatTrack);
+                    break;
 
-                    default:
-                        playback.SetRepeatMode(PlaybackService::RepeatNone);
-                        break;
+                default:
+                    playback.SetRepeatMode(PlaybackService::RepeatNone);
+                    break;
                 }
             }
+
+            void VolumeUp(ITransport& transport) {
+                transport.SetVolume(transport.Volume() + 0.05);
+            }
+
+            void VolumeDown(ITransport& transport) {
+                transport.SetVolume(transport.Volume() - 0.05);
+            }
+
+            void SeekForward(ITransport& transport) {
+                transport.SetPosition(transport.Position() + 10.0f);
+            }
+
+            void SeekBack(ITransport& transport) {
+                transport.SetPosition(transport.Position() - 10.0f);
+            }
         }
     }
 }

src/musikbox/app/util/Playback.h

@@ -47,6 +47,11 @@ namespace musik {
                 musik::box::PlaybackService& playback,
                 cursespp::IWindowPtr focused);
 
+            void VolumeUp(musik::core::audio::ITransport& transport);
+            void VolumeDown(musik::core::audio::ITransport& transport);
+            void SeekForward(musik::core::audio::ITransport& transport);
+            void SeekBack(musik::core::audio::ITransport& transport);
+
             void PauseOrResume(musik::core::audio::ITransport& transport);
 
             void ToggleRepeatMode(PlaybackService& playback);

src/musikbox/app/window/TransportWindow.cpp

@@ -41,6 +41,7 @@
 #include <cursespp/Text.h>
 
 #include <app/util/Duration.h>
+#include <app/util/Playback.h>
 
 #include <core/debug.h>
 #include <core/library/LocalLibraryConstants.h>
@@ -130,7 +131,7 @@ void tokenize(const std::string& format, TokenList& tokens) {
 
 /* writes the colorized formatted string to the specified window. accounts for
 utf8 characters and ellipsizing */
-size_t writePlayingFormat(
+static size_t writePlayingFormat(
     WINDOW *w,
     std::string title,
     std::string album,
@@ -198,12 +199,19 @@ size_t writePlayingFormat(
     return (width - remaining);
 }
 
+static inline bool inc(const std::string& kn) {
+    return (kn == "KEY_UP" || kn == "KEY_RIGHT");
+}
+
+static inline bool dec(const std::string& kn) {
+    return (kn == "KEY_DOWN" || kn == "KEY_LEFT");
+}
+
 TransportWindow::TransportWindow(musik::box::PlaybackService& playback)
 : Window(nullptr)
 , playback(playback)
 , transport(playback.GetTransport())
-, focus(FocusNone)
-{
+, focus(FocusNone) {
     this->SetFrameVisible(false);
     this->playback.TrackChanged.connect(this, &TransportWindow::OnPlaybackServiceTrackChanged);
     this->playback.ModeChanged.connect(this, &TransportWindow::OnPlaybackModeChanged);
@@ -243,6 +251,31 @@ void TransportWindow::Show() {
     this->Update();
 }
 
+bool TransportWindow::KeyPress(const std::string& kn) {
+    if (this->focus == FocusVolume) {
+        if (inc(kn)) {
+            playback::VolumeUp(this->transport);
+            return true;
+        }
+        else if (dec(kn)) {
+            playback::VolumeDown(this->transport);
+            return true;
+        }
+    }
+    else if (this->focus == FocusTime) {
+        if (inc(kn)) {
+            playback::SeekForward(this->transport);
+            return true;
+        }
+        else if (dec(kn)) {
+            playback::SeekBack(this->transport);
+            return true;
+        }
+    }
+
+    return false;
+}
+
 bool TransportWindow::FocusNext() {
     this->SetFocus((FocusTarget)(((int) this->focus + 1) % 3));
     return (this->focus != FocusNone);

src/musikbox/app/window/TransportWindow.h

@@ -35,6 +35,7 @@
 #pragma once
 
 #include <cursespp/Window.h>
+#include <cursespp/IKeyHandler.h>
 #include <core/library/track/Track.h>
 #include <app/service/PlaybackService.h>
 #include <sigslot/sigslot.h>
@@ -44,6 +45,7 @@ namespace musik {
     namespace box {
         class TransportWindow :
             public cursespp::Window,
+            public cursespp::IKeyHandler,
 #if (__clang_major__ == 7 && __clang_minor__ == 3)
             public std::enable_shared_from_this<TransportWindow>,
 #endif
@@ -62,6 +64,7 @@ namespace musik {
                 virtual void ProcessMessage(cursespp::IMessage &message);
                 virtual void Show();
                 virtual void OnFocusChanged(bool focused);
+                virtual bool KeyPress(const std::string& key);
 
                 void SetFocus(FocusTarget target);
                 FocusTarget GetFocus() const;