[feat] add configuration to minimize to system tray when clicking the close button, refs #4

src/gui/tray/win_tray.cpp

@@ -0,0 +1,112 @@
+#include "win_tray.h"
+
+#include <SDL3/SDL.h>
+
+#include "localization.h"
+
+// callback for the message-only window that handles tray icon messages
+static LRESULT CALLBACK MsgWndProc(HWND hwnd, UINT msg, WPARAM wParam,
+                                   LPARAM lParam) {
+  WinTray* tray =
+      reinterpret_cast<WinTray*>(GetWindowLongPtr(hwnd, GWLP_USERDATA));
+  if (!tray) {
+    return DefWindowProc(hwnd, msg, wParam, lParam);
+  }
+
+  if (msg == WM_TRAY_CALLBACK) {
+    MSG tmpMsg = {};
+    tmpMsg.message = msg;
+    tmpMsg.wParam = wParam;
+    tmpMsg.lParam = lParam;
+    tray->HandleTrayMessage(&tmpMsg);
+    return 0;
+  }
+
+  return DefWindowProc(hwnd, msg, wParam, lParam);
+}
+
+WinTray::WinTray(HWND app_hwnd, HICON icon, const std::wstring& tooltip,
+                 int language_index)
+    : app_hwnd_(app_hwnd),
+      icon_(icon),
+      tip_(tooltip),
+      hwnd_message_only_(nullptr),
+      language_index_(language_index) {
+  WNDCLASS wc = {};
+  wc.lpfnWndProc = MsgWndProc;
+  wc.hInstance = GetModuleHandle(nullptr);
+  wc.lpszClassName = L"TrayMessageWindow";
+  RegisterClass(&wc);
+
+  // create a message-only window to receive tray messages
+  hwnd_message_only_ =
+      CreateWindowEx(0, wc.lpszClassName, L"TrayMsg", 0, 0, 0, 0, 0,
+                     HWND_MESSAGE, nullptr, wc.hInstance, nullptr);
+
+  // store pointer to this WinTray instance in window data
+  SetWindowLongPtr(hwnd_message_only_, GWLP_USERDATA,
+                   reinterpret_cast<LONG_PTR>(this));
+
+  // initialize NOTIFYICONDATA structure
+  ZeroMemory(&nid_, sizeof(nid_));
+  nid_.cbSize = sizeof(nid_);
+  nid_.hWnd = hwnd_message_only_;
+  nid_.uID = 1;
+  nid_.uFlags = NIF_ICON | NIF_MESSAGE | NIF_TIP;
+  nid_.uCallbackMessage = WM_TRAY_CALLBACK;
+  nid_.hIcon = icon_;
+  wcsncpy_s(nid_.szTip, tip_.c_str(), _TRUNCATE);
+}
+
+WinTray::~WinTray() {
+  RemoveTrayIcon();
+  if (hwnd_message_only_) DestroyWindow(hwnd_message_only_);
+}
+
+void WinTray::MinimizeToTray() {
+  Shell_NotifyIcon(NIM_ADD, &nid_);
+  // hide application window
+  ShowWindow(app_hwnd_, SW_HIDE);
+}
+
+void WinTray::RemoveTrayIcon() { Shell_NotifyIcon(NIM_DELETE, &nid_); }
+
+bool WinTray::HandleTrayMessage(MSG* msg) {
+  if (!msg || msg->message != WM_TRAY_CALLBACK) return false;
+
+  switch (LOWORD(msg->lParam)) {
+    case WM_LBUTTONDBLCLK:
+    case WM_LBUTTONUP: {
+      ShowWindow(app_hwnd_, SW_SHOW);
+      SetForegroundWindow(app_hwnd_);
+      break;
+    }
+
+    case WM_RBUTTONUP: {
+      POINT pt;
+      GetCursorPos(&pt);
+      HMENU menu = CreatePopupMenu();
+      AppendMenuW(menu, MF_STRING, 1001,
+                  localization::exit_program[language_index_]);
+
+      SetForegroundWindow(hwnd_message_only_);
+      int cmd =
+          TrackPopupMenu(menu, TPM_RETURNCMD | TPM_NONOTIFY | TPM_LEFTALIGN,
+                         pt.x, pt.y, 0, hwnd_message_only_, nullptr);
+      DestroyMenu(menu);
+
+      // handle menu command
+      if (cmd == 1001) {
+        // exit application
+        SDL_Event event;
+        event.type = SDL_EVENT_QUIT;
+        SDL_PushEvent(&event);
+      } else if (cmd == 1002) {
+        ShowWindow(app_hwnd_, SW_SHOW);  // show main window
+        SetForegroundWindow(app_hwnd_);
+      }
+      break;
+    }
+  }
+  return true;
+}