1 files changed, 63 insertions, 0 deletions
diff --git a/src/win/gui/GodWindow.cpp b/src/win/gui/GodWindow.cpp
new file mode 100644
index 00000000..7bce83a3
--- /dev/null
+++ b/src/win/gui/GodWindow.cpp
@@ -0,0 +1,63 @@
+#include "cru/win/gui/GodWindow.hpp"
+
+#include "cru/common/Logger.hpp"
+#include "cru/win/gui/Exception.hpp"
+#include "cru/win/gui/UiApplication.hpp"
+#include "cru/win/gui/WindowClass.hpp"
+
+namespace cru::platform::gui::win {
+constexpr auto god_window_class_name = L"GodWindowClass";
+
+LRESULT CALLBACK GodWndProc(HWND hWnd, UINT uMsg, WPARAM wParam,
+                            LPARAM lParam) {
+  const auto app = WinUiApplication::GetInstance();
+
+  if (app) {
+    LRESULT result;
+    auto god_window = app->GetGodWindow();
+    if (god_window != nullptr) {
+      const auto handled = god_window->HandleGodWindowMessage(
+          hWnd, uMsg, wParam, lParam, &result);
+      if (handled) return result;
+    }
+  }
+  return DefWindowProcW(hWnd, uMsg, wParam, lParam);
+}
+
+GodWindow::GodWindow(WinUiApplication* application) {
+  application_ = application;
+
+  const auto h_instance = application->GetInstanceHandle();
+
+  god_window_class_ = std::make_unique<WindowClass>(god_window_class_name,
+                                                    GodWndProc, h_instance);
+
+  hwnd_ = CreateWindowEx(0, god_window_class_name, L"", 0, CW_USEDEFAULT,
+                         CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,
+                         HWND_MESSAGE, nullptr, h_instance, nullptr);
+
+  if (hwnd_ == nullptr)
+    throw Win32Error(::GetLastError(), "Failed to create god window.");
+}
+
+GodWindow::~GodWindow() {
+  if (!::DestroyWindow(hwnd_)) {
+    // Although this could be "safely" ignore.
+    log::TagWarn(log_tag, u"Failed to destroy god window.");
+  }
+}
+
+bool GodWindow::HandleGodWindowMessage(HWND hwnd, UINT msg, WPARAM w_param,
+                                       LPARAM l_param, LRESULT* result) {
+  WindowNativeMessageEventArgs args(
+      WindowNativeMessage{hwnd, msg, w_param, l_param});
+  message_event_.Raise(args);
+
+  if (args.IsHandled()) {
+    *result = args.GetResult();
+    return true;
+  }
+
+  return false;
+}
+}  // namespace cru::platform::gui::win