[refactor] organize GUI code by responsibility

src/gui/features/devices/session_device_manager.h

@@ -0,0 +1,72 @@
+#ifndef CROSSDESK_GUI_SESSION_DEVICE_MANAGER_H_
+#define CROSSDESK_GUI_SESSION_DEVICE_MANAGER_H_
+
+#include <SDL3/SDL.h>
+
+#include <cstddef>
+#include <cstdint>
+#include <string>
+#include <vector>
+
+#include "device_controller.h"
+#include "device_controller_factory.h"
+#include "display_info.h"
+#include "screen_capturer_factory.h"
+#include "speaker_capturer_factory.h"
+
+namespace crossdesk {
+
+class GuiRuntime;
+
+// Owns media capture/playback and remote input devices for the active GUI
+// session. GuiRuntime supplies application intent; this class handles device
+// creation, updates and teardown.
+class SessionDeviceManager {
+public:
+  explicit SessionDeviceManager(GuiRuntime &owner);
+
+  void Initialize();
+  void UpdateInteractions();
+  void DestroyDevices();
+  void DestroyFactories();
+
+  int InitializeScreenCapturer();
+  int StartScreenCapturer();
+  int StopScreenCapturer();
+  int StartSpeakerCapturer();
+  int StopSpeakerCapturer();
+  int StartMouseController();
+  int StopMouseController();
+  int StartKeyboardCapturer();
+  int StopKeyboardCapturer();
+
+  int InitializeAudioOutput();
+  int DestroyAudioOutput();
+  void PushAudio(const char *data, size_t size);
+
+  bool SendKeyboardCommand(int key_code, bool is_down, uint32_t scan_code,
+                           bool extended);
+  void SendMouseCommand(const RemoteAction &action, int selected_display);
+  int SwitchDisplay(int display_id);
+  void ResetToInitialDisplay();
+
+  const std::vector<DisplayInfo> &display_info_list() const;
+
+private:
+  GuiRuntime &owner_;
+  SDL_AudioStream *output_stream_ = nullptr;
+  ScreenCapturerFactory *screen_capturer_factory_ = nullptr;
+  ScreenCapturer *screen_capturer_ = nullptr;
+  SpeakerCapturerFactory *speaker_capturer_factory_ = nullptr;
+  SpeakerCapturer *speaker_capturer_ = nullptr;
+  DeviceControllerFactory *device_controller_factory_ = nullptr;
+  MouseController *mouse_controller_ = nullptr;
+  KeyboardCapturer *keyboard_capturer_ = nullptr;
+  std::vector<DisplayInfo> display_info_list_;
+  uint64_t last_frame_time_ = 0;
+  std::string last_video_frame_stream_id_;
+};
+
+} // namespace crossdesk
+
+#endif // CROSSDESK_GUI_SESSION_DEVICE_MANAGER_H_