Canned Messages via InkHUD menu (#7096)

* Allow observers to respond to AdminMessage requests
Ground work for CannedMessage getters and setters

* Enable CannedMessage config in apps for InkHUD devices

* Migrate the InkHUD::Events AdminModule observer
Use the new AdminModule_ObserverData struct

* Bare-bones NicheGraphics util to access canned messages
Handles loading and parsing. Handle admin messages for setting and getting.

* Send canned messages via on-screen menu

* Change ThreadedMessageApplet from Observer to Module API
Allows us to intercept locally generated packets ('loopbackOK = true'), to handle outgoing canned messages.

* Fix: crash getting empty canned message string via Client API

* Move file into Utils subdir

* Move an include statement from .cpp to .h

* Limit strncpy size of dest, not source
Wasn't critical in ths specific case, but definitely a mistake.

src/graphics/niche/InkHUD/Applets/System/Menu/MenuApplet.h

@@ -6,10 +6,12 @@
 #include "graphics/niche/InkHUD/InkHUD.h"
 #include "graphics/niche/InkHUD/Persistence.h"
 #include "graphics/niche/InkHUD/SystemApplet.h"
+#include "graphics/niche/Utils/CannedMessageStore.h"
 
 #include "./MenuItem.h"
 #include "./MenuPage.h"
 
+#include "Channels.h"
 #include "concurrency/OSThread.h"
 
 namespace NicheGraphics::InkHUD
@@ -36,12 +38,18 @@ class MenuApplet : public SystemApplet, public concurrency::OSThread
 
     void execute(MenuItem item);  // Perform the MenuAction associated with a MenuItem, if any
     void showPage(MenuPage page); // Load and display a MenuPage
+
+    void populateSendPage();      // Dynamically create MenuItems including canned messages
+    void populateRecipientPage(); // Dynamically create a page of possible destinations for a canned message
     void populateAppletPage();    // Dynamically create MenuItems for toggling loaded applets
     void populateAutoshowPage();  // Dynamically create MenuItems for selecting which applets can autoshow
     void populateRecentsPage();   // Create menu items: a choice of values for settings.recentlyActiveSeconds
+
     uint16_t getSystemInfoPanelHeight();
     void drawSystemInfoPanel(int16_t left, int16_t top, uint16_t width,
-                             uint16_t *height = nullptr); // Info panel at top of root menu
+                             uint16_t *height = nullptr);                   // Info panel at top of root menu
+    void sendText(NodeNum dest, ChannelIndex channel, const char *message); // Send a text message to mesh
+    void freeCannedMessageResources();                                      // Clear MenuApplet's canned message processing data
 
     MenuPage currentPage = MenuPage::ROOT;
     uint8_t cursor = 0;       // Which menu item is currently highlighted
@@ -51,6 +59,37 @@ class MenuApplet : public SystemApplet, public concurrency::OSThread
 
     std::vector<MenuItem> items; // MenuItems for the current page. Filled by ShowPage
 
+    // Data for selecting and sending canned messages via the menu
+    // Placed into a sub-class for organization only
+    class CannedMessages
+    {
+      public:
+        // Share NicheGraphics component
+        // Handles loading, getting, setting
+        CannedMessageStore *store;
+
+        // One canned message
+        // Links the menu item to the true message text
+        struct MessageItem {
+            std::string label;   // Shown in menu. Prefixed, and UTF-8 chars parsed
+            std::string rawText; // The message which will be sent, if this item is selected
+        } *selectedMessageItem;
+
+        // One possible destination for a canned message
+        // Links the menu item to the intended recipient
+        // May represent either broadcast or DM
+        struct RecipientItem {
+            std::string label; // Shown in menu
+            NodeNum dest = NODENUM_BROADCAST;
+            uint8_t channelIndex = 0;
+        } *selectedRecipientItem;
+
+        // These lists are generated when the menu page is populated
+        // Cleared onBackground (when MenuApplet closes)
+        std::vector<MessageItem> messageItems;
+        std::vector<RecipientItem> recipientItems;
+    } cm;
+
     Applet *borrowedTileOwner = nullptr; // Which applet we have temporarily replaced while displaying menu
 };