Refactor RootLayout and UIHandler for improved structure and functionality

- Updated RootLayout to manage layout initialization and deinitialization more effectively.
- Removed unnecessary dependencies and streamlined event handling for keyboard events.
- Enhanced UIHandler to utilize shared pointers for app descriptors, improving memory management.
- Added methods for showing and hiding navigation elements in RootLayout.
- Introduced textarea widget with instant response by disabling animations.
- Improved error handling and logging throughout the UI components.

main/ui/ui_handler.h

@@ -1,12 +1,12 @@
 #pragma once
 
-#include "ui_app.h"
-#include "app_registry.h"
-#include "root_layout.h"
 #include "esp_err.h"
-
-// Forward declaration
-class RootLayout;
+#include "ui/apps/app.h"
+#include "ui/events.h"
+#include "ui/root_layout.h"
+#include "ui/interaction_handler.h"
+#include "lvgl.h"
+#include <memory>
 
 /**
  * @brief UI Handler - manages app lifecycle and rendering
@@ -20,6 +20,10 @@ class RootLayout;
  */
 class UIHandler {
 public:
+
+  UIHandler() = default;
+  ~UIHandler();
+
   /**
    * @brief Initialize the UI system with default layout
    *
@@ -28,6 +32,10 @@ public:
    * - App container (middle)
    * - Navigation bar (bottom)
    *
+   * And display the main screen.
+   *
+   * And initializes the InteractionHandler, callbacks, etc.
+   *
    * @return ESP_OK on success, error code otherwise
    */
   esp_err_t init(void);
@@ -42,45 +50,16 @@ public:
   esp_err_t deinit(void);
 
   /**
-   * @brief Switch to a new app
+   * @brief Switch to a new app by its descriptor
    *
    * Deinitializes the current app (if any), initializes the new app,
-   * and updates the display.
+   * and updates the display. Holds shared ownership of the descriptor
+   * to ensure the app remains valid while active.
    *
-   * @param app Pointer to the new app to switch to
+   * @param app_descriptor Shared pointer to the app descriptor
    * @return ESP_OK on success, error code otherwise
    */
-  esp_err_t switch_app(UIApp* app);
-
-  /**
-   * @brief Switch to an app by its descriptor
-   *
-   * Convenience method that extracts the UIApp from the descriptor
-   * and calls switch_app().
-   *
-   * @param app_descriptor Pointer to the app descriptor
-   * @return ESP_OK on success, error code otherwise
-   */
-  esp_err_t switch_app(AppDescriptor* app_descriptor);
-
-  /**
-   * @brief Get the currently active app
-   *
-   * @return Pointer to the active UIApp, or nullptr if none
-   */
-  UIApp* get_active_app(void) const {
-    return _active_app;
-  }
-
-  /**
-   * @brief Route a system event to the active app
-   *
-   * If an app is active, this forwards the event to it.
-   *
-   * @param event_type Type/ID of the event
-   * @param event_data Optional event data payload
-   */
-  void route_event(uint32_t event_type, void* event_data = nullptr);
+  esp_err_t switch_app(std::shared_ptr<AppDescriptor> app_descriptor);
 
   /**
    * @brief Display shutdown screen
@@ -91,7 +70,7 @@ public:
    * @param message Optional message to display (e.g., "Shutting down...")
    * @return ESP_OK on success, error code otherwise
    */
-  esp_err_t show_shutdown_screen(std::string message = "");
+  esp_err_t show_shutdown_screen(const std::string& message = "");
 
   /**
    * @brief Get the main screen object
@@ -99,35 +78,10 @@ public:
    * @return lv_obj_t* pointer to the main screen
    */
   lv_obj_t* get_main_screen(void) const {
-    return _main_screen;
+    return main_screen_;
   }
 
-  /**
-   * @brief Get the app container (where apps render)
-   *
-   * @return lv_obj_t* pointer to the app container
-   */
-  lv_obj_t* get_app_container(void) const {
-    return _root_layout ? _root_layout->get_app_container() : nullptr;
-  }
-
-  /**
-   * @brief Get the header object
-   *
-   * @return lv_obj_t* pointer to the header container
-   */
-  lv_obj_t* get_header(void) const {
-    return _root_layout ? _root_layout->get_header() : nullptr;
-  }
-
-  /**
-   * @brief Get the navigation bar object
-   *
-   * @return lv_obj_t* pointer to the navigation bar container
-   */
-  lv_obj_t* get_nav_bar(void) const {
-    return _root_layout ? _root_layout->get_nav_bar() : nullptr;
-  }
+  esp_err_t update_header_title(const std::string& title);
 
   /**
    * @brief Return to main screen (deinit app and show app icons)
@@ -140,8 +94,25 @@ public:
   esp_err_t return_to_main_screen(void);
 
 private:
-  lv_obj_t* _main_screen = nullptr;    ///< Root screen
-  RootLayout* _root_layout = nullptr;  ///< Root layout manager
-  UIApp* _active_app = nullptr;        ///< Currently active app
-  UIApp* _shutdown_app = nullptr;      ///< Cached shutdown app
+
+  // Handle back button press, route to active app if any
+  void on_back_button_pressed_(void);
+
+  // Helper to create the main screen layout
+  esp_err_t create_main_screen_(lv_obj_t* parent);
+
+  // Helper to destroy the main screen layout
+  esp_err_t destroy_main_screen_(void);
+
+  // delete copy constructor and assignment operator
+  // to prevent copying of the UIHandler instance
+  UIHandler(const UIHandler&) = delete;
+  UIHandler& operator=(const UIHandler&) = delete;
+
+
+  InteractionHandler interaction_handler_;  ///< Manages user interactions
+
+  lv_obj_t* main_screen_ = nullptr;    ///< Root screen
+  RootLayout root_layout_;            ///< Main screen layout manager
+  std::shared_ptr<AppDescriptor> active_descriptor_ = nullptr;  ///< Currently active app descriptor (shared ownership)
 };