Introduce common library for themes and fix tests

2026-01-07 04:46:56 +01:00 · 2025-12-16 21:39:13 -08:00
16 changed files with 286 additions and 148 deletions
--- a/PowerToys.slnx
+++ b/PowerToys.slnx
@@ -640,6 +640,7 @@
    </Project>
  </Folder>
  <Folder Name="/modules/LightSwitch/">
+    <Project Path="src/modules/LightSwitch/LightSwitchLib/LightSwitchLib.vcxproj" Id="79267138-2895-4346-9021-21408d65379f" />
    <Project Path="src/modules/LightSwitch/LightSwitchModuleInterface/LightSwitchModuleInterface.vcxproj" Id="38177d56-6ad1-4adf-88c9-2843a7932166" />
    <Project Path="src/modules/LightSwitch/LightSwitchService/LightSwitchService.vcxproj" Id="08e71c67-6a7e-4ca1-b04e-2fb336410bac" />
  </Folder>
--- a/src/modules/LightSwitch/LightSwitchLib/LightSwitchLib.vcxproj
+++ b/src/modules/LightSwitch/LightSwitchLib/LightSwitchLib.vcxproj
@@ -0,0 +1,123 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="..\..\..\..\packages\Microsoft.Windows.CppWinRT.2.0.240111.5\build\native\Microsoft.Windows.CppWinRT.props" Condition="Exists('..\..\..\..\packages\Microsoft.Windows.CppWinRT.2.0.240111.5\build\native\Microsoft.Windows.CppWinRT.props')" />
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug|x64">
+      <Configuration>Debug</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|x64">
+      <Configuration>Release</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|ARM64">
+      <Configuration>Debug</Configuration>
+      <Platform>ARM64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|ARM64">
+      <Configuration>Release</Configuration>
+      <Platform>ARM64</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <VCProjectVersion>17.0</VCProjectVersion>
+    <Keyword>Win32Proj</Keyword>
+    <ProjectGuid>{79267138-2895-4346-9021-21408d65379f}</ProjectGuid>
+    <RootNamespace>LightSwitchLib</RootNamespace>
+    <WindowsTargetPlatformVersion>10.0.26100.0</WindowsTargetPlatformVersion>
+    <ProjectName>LightSwitchLib</ProjectName>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <PlatformToolset>v143</PlatformToolset>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <PlatformToolset>v143</PlatformToolset>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <PlatformToolset>v143</PlatformToolset>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <PlatformToolset>v143</PlatformToolset>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="Shared">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup>
+    <OutDir>..\..\..\..\$(Platform)\$(Configuration)\$(MSBuildProjectName)\</OutDir>
+  </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <WarningLevel>Level3</WarningLevel>
+      <SDLCheck>true</SDLCheck>
+      <PreprocessorDefinitions>_LIB;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <ConformanceMode>true</ConformanceMode>
+      <PrecompiledHeader>Use</PrecompiledHeader>
+      <PrecompiledHeaderFile>pch.h</PrecompiledHeaderFile>
+      <AdditionalIncludeDirectories>
+        ./;
+        ..\..\..\common;
+        ..\..\..\common\logger;
+        ..\..\..\common\utils;
+        ..\..\..\..\deps\spdlog\include;
+        %(AdditionalIncludeDirectories)
+      </AdditionalIncludeDirectories>
+    </ClCompile>
+    <Link>
+      <SubSystem>Windows</SubSystem>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemGroup>
+    <ClInclude Include="pch.h" />
+    <ClInclude Include="ThemeHelper.h" />
+  </ItemGroup>
+  <ItemGroup>
+    <ClCompile Include="pch.cpp">
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">Create</PrecompiledHeader>
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'">Create</PrecompiledHeader>
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release|x64'">Create</PrecompiledHeader>
+      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'">Create</PrecompiledHeader>
+    </ClCompile>
+    <ClCompile Include="ThemeHelper.cpp" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\common\logger\logger.vcxproj">
+      <Project>{d9b8fc84-322a-4f9f-bbb9-20915c47ddfd}</Project>
+    </ProjectReference>
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <Import Project="..\..\..\..\deps\spdlog.props" />
+  <ImportGroup Label="ExtensionTargets">
+    <Import Project="..\..\..\..\packages\Microsoft.Windows.CppWinRT.2.0.240111.5\build\native\Microsoft.Windows.CppWinRT.targets" Condition="Exists('..\..\..\..\packages\Microsoft.Windows.CppWinRT.2.0.240111.5\build\native\Microsoft.Windows.CppWinRT.targets')" />
+  </ImportGroup>
+</Project>
--- a/src/modules/LightSwitch/LightSwitchLib/LightSwitchLib.vcxproj.filters
+++ b/src/modules/LightSwitch/LightSwitchLib/LightSwitchLib.vcxproj.filters
@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup>
+    <Filter Include="Source Files">
+      <UniqueIdentifier>{4FC737F1-C7A5-4376-A066-2A32D752A2FF}</UniqueIdentifier>
+      <Extensions>cpp;c;cc;cxx;c++;cppm;ixx;def;odl;idl;hpj;bat;asm;asmx</Extensions>
+    </Filter>
+    <Filter Include="Header Files">
+      <UniqueIdentifier>{93995380-89BD-4b04-88EB-625FBE52EBFB}</UniqueIdentifier>
+      <Extensions>h;hh;hpp;hxx;h++;hm;inl;inc;ipp;xsd</Extensions>
+    </Filter>
+    <Filter Include="Resource Files">
+      <UniqueIdentifier>{67DA6AB6-F800-4c08-8B7A-83BB121AAD01}</UniqueIdentifier>
+      <Extensions>rc;ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe;resx;tiff;tif;png;wav;mfcribbon-ms</Extensions>
+    </Filter>
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="pch.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="ThemeHelper.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+  </ItemGroup>
+  <ItemGroup>
+    <ClCompile Include="pch.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="ThemeHelper.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+  </ItemGroup>
+</Project>
--- a/src/modules/LightSwitch/LightSwitchService/ThemeHelper.cpp
+++ b/src/modules/LightSwitch/LightSwitchService/ThemeHelper.cpp
@@ -1,9 +1,6 @@
-#include <windows.h>
-#include <logger/logger_settings.h>
-#include <logger/logger.h>
-#include <utils/logger_helper.h>
+#include "pch.h"
 #include "ThemeHelper.h"
-#include <SettingsConstants.h>
+#include <logger/logger.h>

 // Controls changing the themes.

@@ -63,7 +60,7 @@ void SetSystemTheme(bool mode)
        if (mode) // if are changing to light mode 
        {
            ResetColorPrevalence();
-            Logger::info(L"[LightSwitchService] Reset ColorPrevalence to default when switching to light mode.");
+            Logger::info(L"[LightSwitchLib] Reset ColorPrevalence to default when switching to light mode.");
        }

        SendMessageTimeout(HWND_BROADCAST, WM_SETTINGCHANGE, 0, reinterpret_cast<LPARAM>(L"ImmersiveColorSet"), SMTO_ABORTIFHUNG, 5000, nullptr);
@@ -136,4 +133,4 @@ bool IsNightLightEnabled()

    RegCloseKey(hKey);
    return data[23] == 0x10 && data[24] == 0x00;
-}
+}
--- a/src/modules/LightSwitch/LightSwitchLib/ThemeHelper.h
+++ b/src/modules/LightSwitch/LightSwitchLib/ThemeHelper.h
@@ -0,0 +1,10 @@
+#pragma once
+
+inline constexpr wchar_t PERSONALIZATION_REGISTRY_PATH[] = L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize";
+inline constexpr wchar_t NIGHT_LIGHT_REGISTRY_PATH[] = L"Software\\Microsoft\\Windows\\CurrentVersion\\CloudStore\\Store\\DefaultAccount\\Current\\default$windows.data.bluelightreduction.bluelightreductionstate\\windows.data.bluelightreduction.bluelightreductionstate";
+
+void SetSystemTheme(bool isLight);
+void SetAppsTheme(bool isLight);
+bool GetCurrentSystemTheme();
+bool GetCurrentAppsTheme();
+bool IsNightLightEnabled();
--- a/src/modules/LightSwitch/LightSwitchLib/pch.cpp
+++ b/src/modules/LightSwitch/LightSwitchLib/pch.cpp
@@ -0,0 +1 @@
+#include "pch.h"
--- a/src/modules/LightSwitch/LightSwitchLib/pch.h
+++ b/src/modules/LightSwitch/LightSwitchLib/pch.h
@@ -0,0 +1,5 @@
+#pragma once
+
+#define WIN32_LEAN_AND_MEAN             // Exclude rarely-used stuff from Windows headers
+#include <windows.h>
+#include <vector>
--- a/src/modules/LightSwitch/LightSwitchModuleInterface/ExportedFunctions.cpp
+++ b/src/modules/LightSwitch/LightSwitchModuleInterface/ExportedFunctions.cpp
@@ -0,0 +1,22 @@
+#include "pch.h"
+#include "ThemeHelper.h"
+
+extern "C" __declspec(dllexport) void __cdecl LightSwitch_SetSystemTheme(bool isLight)
+{
+    SetSystemTheme(isLight);
+}
+
+extern "C" __declspec(dllexport) void __cdecl LightSwitch_SetAppsTheme(bool isLight)
+{
+    SetAppsTheme(isLight);
+}
+
+extern "C" __declspec(dllexport) bool __cdecl LightSwitch_GetCurrentSystemTheme()
+{
+    return GetCurrentSystemTheme();
+}
+
+extern "C" __declspec(dllexport) bool __cdecl LightSwitch_GetCurrentAppsTheme()
+{
+    return GetCurrentAppsTheme();
+}
--- a/src/modules/LightSwitch/LightSwitchModuleInterface/LightSwitchModuleInterface.vcxproj
+++ b/src/modules/LightSwitch/LightSwitchModuleInterface/LightSwitchModuleInterface.vcxproj
@@ -166,7 +166,7 @@
  </ItemDefinitionGroup>
  <ItemDefinitionGroup>
    <ClCompile>
-      <AdditionalIncludeDirectories>..\..\..\common\inc;..\..\..\common\Telemetry;..\..\;..\..\..\;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalIncludeDirectories>..\LightSwitchLib;..\..\..\common\inc;..\..\..\common\Telemetry;..\..\;..\..\..\;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
    </ClCompile>
    <Link>
      <AdditionalDependencies Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'">$(CoreLibraryDependencies);%(AdditionalDependencies);advapi32.lib</AdditionalDependencies>
@@ -175,11 +175,11 @@
  <ItemGroup>
    <ClInclude Include="pch.h" />
    <ClInclude Include="resource.h" />
-    <ClInclude Include="ThemeHelper.h" />
    <ClInclude Include="trace.h" />
  </ItemGroup>
  <ItemGroup>
    <ClCompile Include="dllmain.cpp" />
+    <ClCompile Include="ExportedFunctions.cpp" />
    <ClCompile Include="pch.cpp">
      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">Create</PrecompiledHeader>
      <PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release|x64'">Create</PrecompiledHeader>
@@ -190,7 +190,6 @@
      <PrecompiledHeaderFile Condition="'$(Configuration)|$(Platform)'=='Debug|ARM64'">pch.h</PrecompiledHeaderFile>
      <PrecompiledHeaderFile Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'">pch.h</PrecompiledHeaderFile>
    </ClCompile>
-    <ClCompile Include="ThemeHelper.cpp" />
    <ClCompile Include="trace.cpp" />
  </ItemGroup>
  <ItemGroup>
@@ -206,6 +205,9 @@
    <ProjectReference Include="..\..\..\common\SettingsAPI\SettingsAPI.vcxproj">
      <Project>{6955446d-23f7-4023-9bb3-8657f904af99}</Project>
    </ProjectReference>
+    <ProjectReference Include="..\LightSwitchLib\LightSwitchLib.vcxproj">
+      <Project>{79267138-2895-4346-9021-21408d65379f}</Project>
+    </ProjectReference>
  </ItemGroup>
  <ItemGroup>
    <None Include="packages.config" />
--- a/src/modules/LightSwitch/LightSwitchModuleInterface/ThemeHelper.cpp
+++ b/src/modules/LightSwitch/LightSwitchModuleInterface/ThemeHelper.cpp
@@ -1,106 +0,0 @@
-#include "pch.h"
-#include <windows.h>
-#include "ThemeHelper.h"
-
-// Controls changing the themes.
-static void ResetColorPrevalence()
-{
-    HKEY hKey;
-    if (RegOpenKeyEx(HKEY_CURRENT_USER,
-                     L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize",
-                     0,
-                     KEY_SET_VALUE,
-                     &hKey) == ERROR_SUCCESS)
-    {
-        DWORD value = 0; // back to default value
-        RegSetValueEx(hKey, L"ColorPrevalence", 0, REG_DWORD, reinterpret_cast<const BYTE*>(&value), sizeof(value));
-        RegCloseKey(hKey);
-
-        SendMessageTimeout(HWND_BROADCAST, WM_SETTINGCHANGE, 0, reinterpret_cast<LPARAM>(L"ImmersiveColorSet"), SMTO_ABORTIFHUNG, 5000, nullptr);
-
-        SendMessageTimeout(HWND_BROADCAST, WM_THEMECHANGED, 0, 0, SMTO_ABORTIFHUNG, 5000, nullptr);
-
-        SendMessageTimeout(HWND_BROADCAST, WM_DWMCOLORIZATIONCOLORCHANGED, 0, 0, SMTO_ABORTIFHUNG, 5000, nullptr);
-    }
-}
-
-void SetAppsTheme(bool mode)
-{
-    HKEY hKey;
-    if (RegOpenKeyEx(HKEY_CURRENT_USER,
-                     L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize",
-                     0,
-                     KEY_SET_VALUE,
-                     &hKey) == ERROR_SUCCESS)
-    {
-        DWORD value = mode;
-        RegSetValueEx(hKey, L"AppsUseLightTheme", 0, REG_DWORD, reinterpret_cast<const BYTE*>(&value), sizeof(value));
-        RegCloseKey(hKey);
-
-        SendMessageTimeout(HWND_BROADCAST, WM_SETTINGCHANGE, 0, reinterpret_cast<LPARAM>(L"ImmersiveColorSet"), SMTO_ABORTIFHUNG, 5000, nullptr);
-
-        SendMessageTimeout(HWND_BROADCAST, WM_THEMECHANGED, 0, 0, SMTO_ABORTIFHUNG, 5000, nullptr);
-    }
-}
-
-void SetSystemTheme(bool mode)
-{
-    HKEY hKey;
-    if (RegOpenKeyEx(HKEY_CURRENT_USER,
-                     L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize",
-                     0,
-                     KEY_SET_VALUE,
-                     &hKey) == ERROR_SUCCESS)
-    {
-        DWORD value = mode;
-        RegSetValueEx(hKey, L"SystemUsesLightTheme", 0, REG_DWORD, reinterpret_cast<const BYTE*>(&value), sizeof(value));
-        RegCloseKey(hKey);
-
-        if (mode) // if are changing to light mode
-        {
-            ResetColorPrevalence();
-        }
-
-        SendMessageTimeout(HWND_BROADCAST, WM_SETTINGCHANGE, 0, reinterpret_cast<LPARAM>(L"ImmersiveColorSet"), SMTO_ABORTIFHUNG, 5000, nullptr);
-
-        SendMessageTimeout(HWND_BROADCAST, WM_THEMECHANGED, 0, 0, SMTO_ABORTIFHUNG, 5000, nullptr);
-    }
-}
-
-bool GetCurrentSystemTheme()
-{
-    HKEY hKey;
-    DWORD value = 1; // default = light
-    DWORD size = sizeof(value);
-
-    if (RegOpenKeyEx(HKEY_CURRENT_USER,
-                     L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize",
-                     0,
-                     KEY_READ,
-                     &hKey) == ERROR_SUCCESS)
-    {
-        RegQueryValueEx(hKey, L"SystemUsesLightTheme", nullptr, nullptr, reinterpret_cast<LPBYTE>(&value), &size);
-        RegCloseKey(hKey);
-    }
-
-    return value == 1; // true = light, false = dark
-}
-
-bool GetCurrentAppsTheme()
-{
-    HKEY hKey;
-    DWORD value = 1;
-    DWORD size = sizeof(value);
-
-    if (RegOpenKeyEx(HKEY_CURRENT_USER,
-                     L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize",
-                     0,
-                     KEY_READ,
-                     &hKey) == ERROR_SUCCESS)
-    {
-        RegQueryValueEx(hKey, L"AppsUseLightTheme", nullptr, nullptr, reinterpret_cast<LPBYTE>(&value), &size);
-        RegCloseKey(hKey);
-    }
-
-    return value == 1; // true = light, false = dark
-}
--- a/src/modules/LightSwitch/LightSwitchModuleInterface/ThemeHelper.h
+++ b/src/modules/LightSwitch/LightSwitchModuleInterface/ThemeHelper.h
@@ -1,5 +0,0 @@
-#pragma once
-void SetSystemTheme(bool dark);
-void SetAppsTheme(bool dark);
-bool GetCurrentSystemTheme();
-bool GetCurrentAppsTheme();
--- a/src/modules/LightSwitch/LightSwitchService/LightSwitchService.vcxproj
+++ b/src/modules/LightSwitch/LightSwitchService/LightSwitchService.vcxproj
@@ -55,6 +55,7 @@
      <PreprocessorDefinitions>%(PreprocessorDefinitions)</PreprocessorDefinitions>
      <AdditionalIncludeDirectories>
        ./../;
+        ..\LightSwitchLib;
        ..\..\..\common;
        ..\..\..\common\logger;
        ..\..\..\common\utils;
@@ -78,7 +79,6 @@
    <ClCompile Include="LightSwitchStateManager.cpp" />
    <ClCompile Include="NightLightRegistryObserver.cpp" />
    <ClCompile Include="SettingsConstants.cpp" />
-    <ClCompile Include="ThemeHelper.cpp" />
    <ClCompile Include="ThemeScheduler.cpp" />
    <ClCompile Include="WinHookEventIDs.cpp" />
  </ItemGroup>
@@ -92,7 +92,6 @@
    <ClInclude Include="NightLightRegistryObserver.h" />
    <ClInclude Include="SettingsConstants.h" />
    <ClInclude Include="SettingsObserver.h" />
-    <ClInclude Include="ThemeHelper.h" />
    <ClInclude Include="ThemeScheduler.h" />
    <ClInclude Include="WinHookEventIDs.h" />
  </ItemGroup>
@@ -109,6 +108,9 @@
    <ProjectReference Include="..\..\..\common\Telemetry\EtwTrace\EtwTrace.vcxproj">
      <Project>{8f021b46-362b-485c-bfba-ccf83e820cbd}</Project>
    </ProjectReference>
+    <ProjectReference Include="..\LightSwitchLib\LightSwitchLib.vcxproj">
+      <Project>{79267138-2895-4346-9021-21408d65379f}</Project>
+    </ProjectReference>
  </ItemGroup>
  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
  <Import Project="..\..\..\..\deps\spdlog.props" />
@@ -116,4 +118,4 @@
    <Import Project="..\..\..\..\packages\Microsoft.Windows.ImplementationLibrary.1.0.231216.1\build\native\Microsoft.Windows.ImplementationLibrary.targets" Condition="Exists('..\..\..\..\packages\Microsoft.Windows.ImplementationLibrary.1.0.231216.1\build\native\Microsoft.Windows.ImplementationLibrary.targets')" />
    <Import Project="..\..\..\..\packages\Microsoft.Windows.CppWinRT.2.0.240111.5\build\native\Microsoft.Windows.CppWinRT.targets" Condition="Exists('..\..\..\..\packages\Microsoft.Windows.CppWinRT.2.0.240111.5\build\native\Microsoft.Windows.CppWinRT.targets')" />
  </ImportGroup>
-</Project>
+</Project>
--- a/src/modules/LightSwitch/LightSwitchService/SettingsConstants.h
+++ b/src/modules/LightSwitch/LightSwitchService/SettingsConstants.h
@@ -12,6 +12,3 @@ enum class SettingId
    ChangeSystem,
    ChangeApps
 };
-
-constexpr wchar_t PERSONALIZATION_REGISTRY_PATH[] = L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize";
-constexpr wchar_t NIGHT_LIGHT_REGISTRY_PATH[] = L"Software\\Microsoft\\Windows\\CurrentVersion\\CloudStore\\Store\\DefaultAccount\\Current\\default$windows.data.bluelightreduction.bluelightreductionstate\\windows.data.bluelightreduction.bluelightreductionstate";
--- a/src/modules/LightSwitch/LightSwitchService/ThemeHelper.h
+++ b/src/modules/LightSwitch/LightSwitchService/ThemeHelper.h
@@ -1,6 +0,0 @@
-#pragma once
-void SetSystemTheme(bool dark);
-void SetAppsTheme(bool dark);
-bool GetCurrentSystemTheme();
-bool GetCurrentAppsTheme();
-bool IsNightLightEnabled();
--- a/src/modules/LightSwitch/Tests/LightSwitch.UITests/LightSwitch.UITests.csproj
+++ b/src/modules/LightSwitch/Tests/LightSwitch.UITests/LightSwitch.UITests.csproj
@@ -19,4 +19,9 @@
 	  <PackageReference Include="MSTest" />
 	  <ProjectReference Include="..\..\..\..\common\UITestAutomation\UITestAutomation.csproj" />
  </ItemGroup>
+
+  <Target Name="CopyNativeDll" AfterTargets="Build">
+    <Copy SourceFiles="$(SolutionDir)$(Platform)\$(Configuration)\PowerToys.LightSwitchModuleInterface.dll" DestinationFolder="$(OutputPath)" SkipUnchangedFiles="true" />
+    <Copy SourceFiles="$(SolutionDir)$(Platform)\$(Configuration)\LightSwitchLib\LightSwitchLib.lib" DestinationFolder="$(OutputPath)" SkipUnchangedFiles="true" Condition="Exists('$(SolutionDir)$(Platform)\$(Configuration)\LightSwitchLib\LightSwitchLib.lib')" ContinueOnError="true" />
+  </Target>
 </Project>
--- a/src/modules/LightSwitch/Tests/LightSwitch.UITests/TestHelper.cs
+++ b/src/modules/LightSwitch/Tests/LightSwitch.UITests/TestHelper.cs
@@ -5,6 +5,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using System.Windows.Forms;
 using Microsoft.PowerToys.UITest;
@@ -17,6 +18,20 @@ namespace LightSwitch.UITests
    {
        private static readonly string[] ShortcutSeparators = { " + ", "+", " " };

+        [DllImport("PowerToys.LightSwitchModuleInterface.dll", CallingConvention = CallingConvention.Cdecl)]
+        private static extern void LightSwitch_SetSystemTheme(bool isLight);
+
+        [DllImport("PowerToys.LightSwitchModuleInterface.dll", CallingConvention = CallingConvention.Cdecl)]
+        private static extern void LightSwitch_SetAppsTheme(bool isLight);
+
+        [DllImport("PowerToys.LightSwitchModuleInterface.dll", CallingConvention = CallingConvention.Cdecl)]
+        [return: MarshalAs(UnmanagedType.I1)]
+        private static extern bool LightSwitch_GetCurrentSystemTheme();
+
+        [DllImport("PowerToys.LightSwitchModuleInterface.dll", CallingConvention = CallingConvention.Cdecl)]
+        [return: MarshalAs(UnmanagedType.I1)]
+        private static extern bool LightSwitch_GetCurrentAppsTheme();
+
        /// <summary>
        /// Performs common test initialization: navigate to settings, enable toggle, verify shortcut
        /// </summary>
@@ -127,8 +142,7 @@ namespace LightSwitch.UITests
        /// <param name="testBase">The test base instance</param>
        public static void CleanupTest(UITestBase testBase)
        {
-            // TODO: Make sure the task kills?
-            // CloseLightSwitch(testBase);
+            CloseLightSwitch(testBase);

            // Ensure we're attached to settings after cleanup
            try
@@ -141,6 +155,51 @@ namespace LightSwitch.UITests
            }
        }

+        /// <summary>
+        /// Switch to white/light theme for both system and apps
+        /// </summary>
+        /// <param name="testBase">The test base instance</param>
+        public static void CloseLightSwitch(UITestBase testBase)
+        {
+            // Kill LightSwitch process before setting themes
+            KillLightSwitchProcess();
+
+            // Set both themes to light (white)
+            SetSystemTheme(true);
+            SetAppsTheme(true);
+        }
+
+        /// <summary>
+        /// Kill the LightSwitch service process if it's running
+        /// </summary>
+        private static void KillLightSwitchProcess()
+        {
+            try
+            {
+                var processes = System.Diagnostics.Process.GetProcessesByName("PowerToys.LightSwitchService");
+                foreach (var process in processes)
+                {
+                    try
+                    {
+                        process.Kill();
+                        process.WaitForExit(2000);
+                    }
+                    catch
+                    {
+                        // Ignore errors killing individual processes
+                    }
+                    finally
+                    {
+                        process.Dispose();
+                    }
+                }
+            }
+            catch
+            {
+                // Ignore errors enumerating processes
+            }
+        }
+
        /// <summary>
        /// Perform a update time test operation
        /// </summary>
@@ -408,24 +467,22 @@ namespace LightSwitch.UITests
        /* Helpers */
        private static int GetSystemTheme()
        {
-            using var key = Registry.CurrentUser.OpenSubKey(@"Software\Microsoft\Windows\CurrentVersion\Themes\Personalize");
-            if (key is null)
-            {
-                return 1;
-            }
-
-            return (int)key.GetValue("SystemUsesLightTheme", 1);
+            return LightSwitch_GetCurrentSystemTheme() ? 1 : 0;
        }

        private static int GetAppsTheme()
        {
-            using var key = Registry.CurrentUser.OpenSubKey(@"Software\Microsoft\Windows\CurrentVersion\Themes\Personalize");
-            if (key is null)
-            {
-                return 1;
-            }
+            return LightSwitch_GetCurrentAppsTheme() ? 1 : 0;
+        }

-            return (int)key.GetValue("AppsUseLightTheme", 1);
+        private static void SetSystemTheme(bool isLight)
+        {
+            LightSwitch_SetSystemTheme(isLight);
+        }
+
+        private static void SetAppsTheme(bool isLight)
+        {
+            LightSwitch_SetAppsTheme(isLight);
        }

        private static string GetHelpTextValue(string helpText, string key)