FZ: warn w/ a toast if an elevated window cannot be dragged and offer learning more

src/common/notifications/fancyzones_notifications.h

@@ -0,0 +1,71 @@
+#pragma once
+
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#include <Windows.h>
+#include <limits>
+
+#include "../timeutil.h"
+namespace
+{
+    const inline wchar_t CANT_DRAG_ELEVATED_DONT_SHOW_AGAIN_REGISTRY_PATH[] = LR"(SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\DontShowMeThisDialogAgain\{e16ea82f-6d94-4f30-bb02-d6d911588afd})";
+    const inline int64_t disable_interval_in_days = 30;
+}
+
+inline bool disable_cant_drag_elevated_warning()
+{
+    HKEY key{};
+    if (RegCreateKeyExW(HKEY_CURRENT_USER,
+                        CANT_DRAG_ELEVATED_DONT_SHOW_AGAIN_REGISTRY_PATH,
+                        0,
+                        nullptr,
+                        REG_OPTION_NON_VOLATILE,
+                        KEY_ALL_ACCESS,
+                        nullptr,
+                        &key,
+                        nullptr) != ERROR_SUCCESS)
+    {
+        return false;
+    }
+    const auto now = timeutil::now();
+    const size_t buf_size = sizeof(now);
+    if (RegSetValueExW(key, nullptr, 0, REG_QWORD, reinterpret_cast<const BYTE*>(&now), sizeof(now)) != ERROR_SUCCESS)
+    {
+        RegCloseKey(key);
+        return false;
+    }
+    RegCloseKey(key);
+    return true;
+}
+
+inline bool is_cant_drag_elevated_warning_disabled()
+{
+    HKEY key{};
+    if (RegOpenKeyExW(HKEY_CURRENT_USER,
+                      CANT_DRAG_ELEVATED_DONT_SHOW_AGAIN_REGISTRY_PATH,
+                      0,
+                      KEY_READ,
+                      &key) != ERROR_SUCCESS)
+    {
+        return false;
+    }
+    std::wstring buffer(std::numeric_limits<time_t>::digits10 + 2, L'\0');
+    time_t last_disabled_time{};
+    DWORD time_size = static_cast<DWORD>(sizeof(last_disabled_time));
+    if (RegGetValueW(
+            key,
+            nullptr,
+            nullptr,
+            RRF_RT_REG_QWORD,
+            nullptr,
+            &last_disabled_time,
+            &time_size) != ERROR_SUCCESS)
+    {
+        RegCloseKey(key);
+        return false;
+    }
+    RegCloseKey(key);
+    return timeutil::diff::in_days(timeutil::now(), last_disabled_time) < disable_interval_in_days;
+    return false;
+}