[FancyZones] Improve monitor work area handling (#3418)

* Initial design for improving handling of different engaged work areas in fancyzones.

* Remove active device id check in ZoneWindow.

* Remove concept of active device identifier in JSONHelpers.

* Refactor interface description and add new method.

* Simplify ZoneWindow initialization.

* Default value for active ZoneWindow during move/size.

* Add newline at the end of file.

* Use COM pointers for ZoneWindow instead of passing raw ptr.

* Solve few issues after merging with master.

* Fix typo in documentation.

src/modules/fancyzones/lib/MonitorWorkAreaHandler.cpp

@@ -0,0 +1,104 @@
+#include "pch.h"
+#include "MonitorWorkAreaHandler.h"
+#include "VirtualDesktopUtils.h"
+
+winrt::com_ptr<IZoneWindow> MonitorWorkAreaHandler::GetWorkArea(const GUID& desktopId, HMONITOR monitor)
+{
+    auto desktopIt = workAreaMap.find(desktopId);
+    if (desktopIt != std::end(workAreaMap))
+    {
+        auto& perDesktopData = desktopIt->second;
+        auto monitorIt = perDesktopData.find(monitor);
+        if (monitorIt != std::end(perDesktopData))
+        {
+            return monitorIt->second;
+        }
+    }
+    return nullptr;
+}
+
+winrt::com_ptr<IZoneWindow> MonitorWorkAreaHandler::GetWorkArea(HWND window)
+{
+    HMONITOR monitor = MonitorFromWindow(window, MONITOR_DEFAULTTONULL);
+    GUID desktopId{};
+    if (monitor && VirtualDesktopUtils::GetWindowDesktopId(window, &desktopId))
+    {
+        return GetWorkArea(desktopId, monitor);
+    }
+    return nullptr;
+}
+
+const std::unordered_map<HMONITOR, winrt::com_ptr<IZoneWindow>>& MonitorWorkAreaHandler::GetWorkAreasByDesktopId(const GUID& desktopId)
+{
+    if (workAreaMap.contains(desktopId))
+    {
+        return workAreaMap[desktopId];
+    }
+    return {};
+}
+
+std::vector<winrt::com_ptr<IZoneWindow>> MonitorWorkAreaHandler::GetAllWorkAreas()
+{
+    std::vector<winrt::com_ptr<IZoneWindow>> workAreas{};
+    for (const auto& [desktopId, perDesktopData] : workAreaMap)
+    {
+        std::transform(std::begin(perDesktopData),
+                       std::end(perDesktopData),
+                       std::back_inserter(workAreas),
+                       [](const auto& item) { return item.second; });
+    }
+    return workAreas;
+}
+
+void MonitorWorkAreaHandler::AddWorkArea(const GUID& desktopId, HMONITOR monitor, winrt::com_ptr<IZoneWindow>& workArea)
+{
+    if (!workAreaMap.contains(desktopId))
+    {
+        workAreaMap[desktopId] = {};
+    }
+    auto& perDesktopData = workAreaMap[desktopId];
+    perDesktopData[monitor] = std::move(workArea);
+}
+
+bool MonitorWorkAreaHandler::IsNewWorkArea(const GUID& desktopId, HMONITOR monitor)
+{
+    if (workAreaMap.contains(desktopId))
+    {
+        const auto& perDesktopData = workAreaMap[desktopId];
+        if (perDesktopData.contains(monitor))
+        {
+            return false;
+        }
+    }
+    return true;
+}
+
+void MonitorWorkAreaHandler::RegisterUpdates(const std::vector<GUID>& active, std::vector<GUID>& deleted)
+{
+    std::unordered_set<GUID> activeVirtualDesktops(std::begin(active), std::end(active));
+    for (auto desktopIt = std::begin(workAreaMap); desktopIt != std::end(workAreaMap);)
+    {
+        auto activeIt = activeVirtualDesktops.find(desktopIt->first);
+        if (activeIt == std::end(activeVirtualDesktops))
+        {
+            // register deleted virtual desktop
+            deleted.push_back(desktopIt->first);
+            desktopIt = workAreaMap.erase(desktopIt);
+        }
+        else
+        {
+            activeVirtualDesktops.erase(desktopIt->first); // virtual desktop already in map, skip it
+            ++desktopIt;
+        }
+    }
+    // register new virtual desktops, if any
+    for (const auto& id : activeVirtualDesktops)
+    {
+        workAreaMap[id] = {};
+    }
+}
+
+void MonitorWorkAreaHandler::Clear()
+{
+    workAreaMap.clear();
+}