PowerToys/src/settings-ui/Settings.UI/ViewModels/PowerDisplayViewModel.cs

// Copyright (c) Microsoft Corporation
// The Microsoft Corporation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;

using global::PowerToys.GPOWrapper;
using ManagedCommon;
using Microsoft.PowerToys.Settings.UI.Helpers;
using Microsoft.PowerToys.Settings.UI.Library;
using Microsoft.PowerToys.Settings.UI.Library.Helpers;
using Microsoft.PowerToys.Settings.UI.Library.Interfaces;
using Microsoft.PowerToys.Settings.UI.Library.ViewModels.Commands;
using Microsoft.PowerToys.Settings.UI.Services;
using PowerDisplay.Common.Models;
using PowerDisplay.Common.Services;
using PowerDisplay.Common.Utils;
using PowerToys.Interop;

namespace Microsoft.PowerToys.Settings.UI.ViewModels
{
    public partial class PowerDisplayViewModel : PageViewModelBase
    {
        protected override string ModuleName => PowerDisplaySettings.ModuleName;

        private GeneralSettings GeneralSettingsConfig { get; set; }

        private ISettingsUtils SettingsUtils { get; set; }

        public ButtonClickCommand LaunchEventHandler => new ButtonClickCommand(Launch);

        public PowerDisplayViewModel(ISettingsUtils settingsUtils, ISettingsRepository<GeneralSettings> settingsRepository, ISettingsRepository<PowerDisplaySettings> powerDisplaySettingsRepository, Func<string, int> ipcMSGCallBackFunc)
        {
            // To obtain the general settings configurations of PowerToys Settings.
            ArgumentNullException.ThrowIfNull(settingsRepository);

            SettingsUtils = settingsUtils;
            GeneralSettingsConfig = settingsRepository.SettingsConfig;

            _settings = powerDisplaySettingsRepository.SettingsConfig;

            InitializeEnabledValue();

            // Initialize monitors collection using property setter for proper subscription setup
            // Parse capabilities for each loaded monitor to ensure UI displays correctly
            var loadedMonitors = _settings.Properties.Monitors;

            Logger.LogInfo($"[Constructor] Initializing with {loadedMonitors.Count} monitors from settings");

            foreach (var monitor in loadedMonitors)
            {
                // Parse capabilities to determine feature support
                ParseFeatureSupportFromCapabilities(monitor);
            }

            Monitors = new ObservableCollection<MonitorInfo>(loadedMonitors);

            // set the callback functions value to handle outgoing IPC message.
            SendConfigMSG = ipcMSGCallBackFunc;

            // Load profiles
            LoadProfiles();

            // Listen for monitor refresh events from PowerDisplay.exe
            NativeEventWaiter.WaitForEventLoop(
                Constants.RefreshPowerDisplayMonitorsEvent(),
                () =>
                {
                    Logger.LogInfo("Received refresh monitors event from PowerDisplay.exe");
                    ReloadMonitorsFromSettings();
                });
        }

        private void InitializeEnabledValue()
        {
            _isEnabled = GeneralSettingsConfig.Enabled.PowerDisplay;
        }

        public bool IsEnabled
        {
            get => _isEnabled;
            set
            {
                if (_isEnabled != value)
                {
                    _isEnabled = value;
                    OnPropertyChanged(nameof(IsEnabled));

                    GeneralSettingsConfig.Enabled.PowerDisplay = value;
                    OutGoingGeneralSettings outgoing = new OutGoingGeneralSettings(GeneralSettingsConfig);
                    SendConfigMSG(outgoing.ToString());
                }
            }
        }

        public bool RestoreSettingsOnStartup
        {
            get => _settings.Properties.RestoreSettingsOnStartup;
            set => SetSettingsProperty(_settings.Properties.RestoreSettingsOnStartup, value, v => _settings.Properties.RestoreSettingsOnStartup = v);
        }

        public bool ShowSystemTrayIcon
        {
            get => _settings.Properties.ShowSystemTrayIcon;
            set
            {
                if (SetSettingsProperty(_settings.Properties.ShowSystemTrayIcon, value, v => _settings.Properties.ShowSystemTrayIcon = v))
                {
                    // Explicitly signal PowerDisplay to refresh tray icon
                    // This is needed because set_config() doesn't signal SettingsUpdatedEvent to avoid UI refresh issues
                    using var eventHandle = new System.Threading.EventWaitHandle(
                        false,
                        System.Threading.EventResetMode.AutoReset,
                        Constants.SettingsUpdatedPowerDisplayEvent());
                    eventHandle.Set();
                    Logger.LogInfo($"ShowSystemTrayIcon changed to {value}, signaled SettingsUpdatedPowerDisplayEvent");
                }
            }
        }

        public HotkeySettings ActivationShortcut
        {
            get => _settings.Properties.ActivationShortcut;
            set => SetSettingsProperty(_settings.Properties.ActivationShortcut, value, v => _settings.Properties.ActivationShortcut = v);
        }

        public string BrightnessUpdateRate
        {
            get => _settings.Properties.BrightnessUpdateRate;
            set => SetSettingsProperty(_settings.Properties.BrightnessUpdateRate, value, v => _settings.Properties.BrightnessUpdateRate = v);
        }

        private readonly List<string> _brightnessUpdateRateOptions = new List<string>
        {
            "never",
            "250ms",
            "500ms",
            "1s",
            "2s",
        };

        public List<string> BrightnessUpdateRateOptions => _brightnessUpdateRateOptions;

        public ObservableCollection<MonitorInfo> Monitors
        {
            get => _monitors;
            set
            {
                if (_monitors != null)
                {
                    _monitors.CollectionChanged -= Monitors_CollectionChanged;
                    UnsubscribeFromItemPropertyChanged(_monitors);
                }

                _monitors = value;

                if (_monitors != null)
                {
                    _monitors.CollectionChanged += Monitors_CollectionChanged;
                    SubscribeToItemPropertyChanged(_monitors);
                }

                OnPropertyChanged(nameof(Monitors));
                HasMonitors = _monitors?.Count > 0;

                // Update TotalMonitorCount for dynamic DisplayName
                UpdateTotalMonitorCount();
            }
        }

        public bool HasMonitors
        {
            get => _hasMonitors;
            set
            {
                if (_hasMonitors != value)
                {
                    _hasMonitors = value;
                    OnPropertyChanged();
                }
            }
        }

        private void Monitors_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
        {
            SubscribeToItemPropertyChanged(e.NewItems?.Cast<MonitorInfo>());
            UnsubscribeFromItemPropertyChanged(e.OldItems?.Cast<MonitorInfo>());

            HasMonitors = _monitors.Count > 0;
            _settings.Properties.Monitors = _monitors.ToList();
            NotifySettingsChanged();

            // Update TotalMonitorCount for dynamic DisplayName
            UpdateTotalMonitorCount();
        }

        /// <summary>
        /// Update TotalMonitorCount on all monitors for dynamic DisplayName formatting.
        /// When multiple monitors exist, DisplayName shows "Name N" format.
        /// </summary>
        private void UpdateTotalMonitorCount()
        {
            if (_monitors == null)
            {
                return;
            }

            var count = _monitors.Count;
            foreach (var monitor in _monitors)
            {
                monitor.TotalMonitorCount = count;
            }
        }

        public void UpdateMonitors(MonitorInfo[] monitors)
        {
            if (monitors == null)
            {
                Monitors = new ObservableCollection<MonitorInfo>();
                return;
            }

            // Create a lookup of existing monitors to preserve user settings
            var existingMonitors = _monitors.ToDictionary(m => GetMonitorKey(m), m => m);

            // Create new collection with merged settings
            var newCollection = new ObservableCollection<MonitorInfo>();
            foreach (var newMonitor in monitors)
            {
                var monitorKey = GetMonitorKey(newMonitor);

                // Parse capabilities to determine feature support
                ParseFeatureSupportFromCapabilities(newMonitor);

                // Check if we have an existing monitor with the same key
                if (existingMonitors.TryGetValue(monitorKey, out var existingMonitor))
                {
                    // Preserve user settings from existing monitor
                    newMonitor.EnableContrast = existingMonitor.EnableContrast;
                    newMonitor.EnableVolume = existingMonitor.EnableVolume;
                    newMonitor.EnableInputSource = existingMonitor.EnableInputSource;
                    newMonitor.IsHidden = existingMonitor.IsHidden;
                }

                newCollection.Add(newMonitor);
            }

            // Replace collection - property setter handles subscription management
            Monitors = newCollection;
        }

        /// <summary>
        /// Generate a unique key for monitor matching based on hardware ID and internal name.
        /// Uses shared MonitorMatchingHelper from PowerDisplay.Lib for consistency.
        /// </summary>
        private static string GetMonitorKey(MonitorInfo monitor)
        {
            // Use shared helper for consistent monitor matching logic
            return MonitorMatchingHelper.GetMonitorKey(monitor);
        }

        /// <summary>
        /// Parse feature support from capabilities VcpCodes list
        /// Sets support flags based on VCP code presence
        /// Uses shared MonitorFeatureHelper from PowerDisplay.Lib for consistency
        /// </summary>
        private static void ParseFeatureSupportFromCapabilities(MonitorInfo monitor)
        {
            if (monitor == null)
            {
                return;
            }

            // Use shared helper to parse feature support
            var result = PowerDisplay.Common.Utils.MonitorFeatureHelper.ParseFeatureSupport(
                monitor.VcpCodes,
                monitor.CapabilitiesRaw);

            monitor.CapabilitiesStatus = result.CapabilitiesStatus;
            monitor.SupportsBrightness = result.SupportsBrightness;
            monitor.SupportsContrast = result.SupportsContrast;
            monitor.SupportsColorTemperature = result.SupportsColorTemperature;
            monitor.SupportsVolume = result.SupportsVolume;
            monitor.SupportsInputSource = result.SupportsInputSource;
        }

        [System.Diagnostics.CodeAnalysis.SuppressMessage("Usage", "CA1816:Dispose methods should call SuppressFinalize", Justification = "Base class PageViewModelBase.Dispose() handles GC.SuppressFinalize")]
        public override void Dispose()
        {
            // Unsubscribe from monitor property changes
            UnsubscribeFromItemPropertyChanged(_monitors);

            // Unsubscribe from collection changes
            if (_monitors != null)
            {
                _monitors.CollectionChanged -= Monitors_CollectionChanged;
            }

            GC.SuppressFinalize(this);

            base.Dispose();
        }

        /// <summary>
        /// Subscribe to PropertyChanged events for items in the collection
        /// </summary>
        private void SubscribeToItemPropertyChanged(IEnumerable<MonitorInfo> items)
        {
            if (items != null)
            {
                foreach (var item in items)
                {
                    item.PropertyChanged += OnMonitorPropertyChanged;
                }
            }
        }

        /// <summary>
        /// Unsubscribe from PropertyChanged events for items in the collection
        /// </summary>
        private void UnsubscribeFromItemPropertyChanged(IEnumerable<MonitorInfo> items)
        {
            if (items != null)
            {
                foreach (var item in items)
                {
                    item.PropertyChanged -= OnMonitorPropertyChanged;
                }
            }
        }

        /// <summary>
        /// Handle PropertyChanged events from MonitorInfo objects
        /// </summary>
        private void OnMonitorPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
        {
            if (sender is MonitorInfo monitor)
            {
                Logger.LogDebug($"[PowerDisplayViewModel] Monitor {monitor.Name} property {e.PropertyName} changed");
            }

            // Update the settings object to keep it in sync
            _settings.Properties.Monitors = _monitors.ToList();

            // Save settings when any monitor property changes
            NotifySettingsChanged();

            // For feature visibility properties, explicitly signal PowerDisplay to refresh
            // This is needed because set_config() doesn't signal SettingsUpdatedEvent to avoid UI refresh issues
            if (e.PropertyName == nameof(MonitorInfo.EnableContrast) ||
                e.PropertyName == nameof(MonitorInfo.EnableVolume) ||
                e.PropertyName == nameof(MonitorInfo.EnableInputSource) ||
                e.PropertyName == nameof(MonitorInfo.EnableRotation) ||
                e.PropertyName == nameof(MonitorInfo.IsHidden))
            {
                SignalSettingsUpdated();
            }
        }

        /// <summary>
        /// Signal PowerDisplay.exe that settings have been updated and need to be applied
        /// </summary>
        private void SignalSettingsUpdated()
        {
            try
            {
                using var eventHandle = new System.Threading.EventWaitHandle(
                    false,
                    System.Threading.EventResetMode.AutoReset,
                    Constants.SettingsUpdatedPowerDisplayEvent());
                eventHandle.Set();
                Logger.LogInfo("Signaled SettingsUpdatedPowerDisplayEvent for feature visibility change");
            }
            catch (Exception ex)
            {
                Logger.LogError($"Failed to signal SettingsUpdatedPowerDisplayEvent: {ex.Message}");
            }
        }

        public void Launch()
        {
            var actionMessage = new PowerDisplayActionMessage
            {
                Action = new PowerDisplayActionMessage.ActionData
                {
                    PowerDisplay = new PowerDisplayActionMessage.PowerDisplayAction
                    {
                        ActionName = "Launch",
                        Value = string.Empty,
                    },
                },
            };

            SendConfigMSG(JsonSerializer.Serialize(actionMessage, SettingsSerializationContext.Default.PowerDisplayActionMessage));
        }

        /// <summary>
        /// Trigger PowerDisplay.exe to apply color temperature to a specific monitor
        /// Called after user confirms color temperature change in Settings UI
        /// </summary>
        /// <param name="monitorInternalName">Internal name (ID) of the monitor</param>
        /// <param name="colorTemperature">Color temperature value to apply</param>
        public void ApplyColorTemperatureToMonitor(string monitorInternalName, int colorTemperature)
        {
            // Set the pending operation in settings
            _settings.Properties.PendingColorTemperatureOperation = new ColorTemperatureOperation
            {
                MonitorId = monitorInternalName,
                ColorTemperatureVcp = colorTemperature,
            };

            // Save settings to persist the operation
            SettingsUtils.SaveSettings(_settings.ToJsonString(), PowerDisplaySettings.ModuleName);

            // Send IPC message to trigger PowerDisplay to process the operation
            var actionMessage = new PowerDisplayActionMessage
            {
                Action = new PowerDisplayActionMessage.ActionData
                {
                    PowerDisplay = new PowerDisplayActionMessage.PowerDisplayAction
                    {
                        ActionName = "ApplyColorTemperature",
                        Value = string.Empty,
                        MonitorId = monitorInternalName,
                        ColorTemperature = colorTemperature,
                    },
                },
            };

            SendConfigMSG(JsonSerializer.Serialize(actionMessage, SettingsSerializationContext.Default.PowerDisplayActionMessage));
        }

        /// <summary>
        /// Reload monitor list from settings file (called when PowerDisplay.exe signals monitor changes)
        /// </summary>
        private void ReloadMonitorsFromSettings()
        {
            try
            {
                Logger.LogInfo("Reloading monitors from settings file");

                // Read fresh settings from file
                var updatedSettings = SettingsUtils.GetSettingsOrDefault<PowerDisplaySettings>(PowerDisplaySettings.ModuleName);
                var updatedMonitors = updatedSettings.Properties.Monitors;

                // Check for pending color temperature operation to avoid race conditions
                // If there's a pending operation, we should preserve the local ColorTemperatureVcp value
                // because the Settings UI just set it and PowerDisplay hasn't processed it yet
                var pendingColorTempOp = updatedSettings.Properties.PendingColorTemperatureOperation;
                var pendingColorTempMonitorId = pendingColorTempOp?.MonitorId;
                var pendingColorTempValue = pendingColorTempOp?.ColorTemperatureVcp ?? 0;

                if (!string.IsNullOrEmpty(pendingColorTempMonitorId))
                {
                    Logger.LogInfo($"[ReloadMonitors] Found pending color temp operation for monitor: {pendingColorTempMonitorId}, will preserve local value");
                }

                Logger.LogInfo($"[ReloadMonitors] Loaded {updatedMonitors.Count} monitors from settings");

                // Parse capabilities for each monitor
                foreach (var monitor in updatedMonitors)
                {
                    ParseFeatureSupportFromCapabilities(monitor);
                }

                // Update existing MonitorInfo objects instead of replacing the collection
                // This preserves XAML x:Bind bindings which reference specific object instances
                if (Monitors == null)
                {
                    // First time initialization - create new collection
                    Monitors = new ObservableCollection<MonitorInfo>(updatedMonitors);
                }
                else
                {
                    // Create a dictionary for quick lookup by InternalName
                    var updatedMonitorsDict = updatedMonitors.ToDictionary(m => m.InternalName, m => m);

                    // Update existing monitors or remove ones that no longer exist
                    for (int i = Monitors.Count - 1; i >= 0; i--)
                    {
                        var existingMonitor = Monitors[i];
                        if (updatedMonitorsDict.TryGetValue(existingMonitor.InternalName, out var updatedMonitor))
                        {
                            // Monitor still exists - update its properties in place
                            Logger.LogInfo($"[ReloadMonitors] Updating existing monitor: {existingMonitor.InternalName}");

                            // Preserve local ColorTemperatureVcp if there's a pending operation for this monitor
                            // This prevents race condition where PowerDisplay's stale data overwrites user's selection
                            if (existingMonitor.InternalName == pendingColorTempMonitorId && pendingColorTempValue > 0)
                            {
                                var preservedColorTemp = existingMonitor.ColorTemperatureVcp;
                                existingMonitor.UpdateFrom(updatedMonitor);
                                existingMonitor.ColorTemperatureVcp = preservedColorTemp;
                                Logger.LogInfo($"[ReloadMonitors] Preserved local ColorTemperatureVcp: 0x{preservedColorTemp:X2} for monitor with pending operation");
                            }
                            else
                            {
                                existingMonitor.UpdateFrom(updatedMonitor);
                            }

                            updatedMonitorsDict.Remove(existingMonitor.InternalName);
                        }
                        else
                        {
                            // Monitor no longer exists - remove from collection
                            Logger.LogInfo($"[ReloadMonitors] Removing monitor: {existingMonitor.InternalName}");
                            Monitors.RemoveAt(i);
                        }
                    }

                    // Add any new monitors that weren't in the existing collection
                    foreach (var newMonitor in updatedMonitorsDict.Values)
                    {
                        Logger.LogInfo($"[ReloadMonitors] Adding new monitor: {newMonitor.InternalName}");
                        Monitors.Add(newMonitor);
                    }
                }

                // Update internal settings reference
                _settings.Properties.Monitors = updatedMonitors;

                Logger.LogInfo($"Successfully reloaded {updatedMonitors.Count} monitors");
            }
            catch (Exception ex)
            {
                Logger.LogError($"Failed to reload monitors from settings: {ex.Message}");
            }
        }

        private Func<string, int> SendConfigMSG { get; }

        private bool _isEnabled;
        private PowerDisplaySettings _settings;
        private ObservableCollection<MonitorInfo> _monitors;
        private bool _hasMonitors;

        // Profile-related fields
        private ObservableCollection<PowerDisplayProfile> _profiles = new ObservableCollection<PowerDisplayProfile>();

        /// <summary>
        /// Collection of available profiles (for button display)
        /// </summary>
        public ObservableCollection<PowerDisplayProfile> Profiles
        {
            get => _profiles;
            set
            {
                if (_profiles != value)
                {
                    _profiles = value;
                    OnPropertyChanged();
                }
            }
        }

        public void RefreshEnabledState()
        {
            InitializeEnabledValue();
            OnPropertyChanged(nameof(IsEnabled));
        }

        private bool SetSettingsProperty<T>(T currentValue, T newValue, Action<T> setter, [CallerMemberName] string propertyName = null)
        {
            if (EqualityComparer<T>.Default.Equals(currentValue, newValue))
            {
                return false;
            }

            setter(newValue);
            OnPropertyChanged(propertyName);
            NotifySettingsChanged();
            return true;
        }

        /// <summary>
        /// Load profiles from disk
        /// </summary>
        private void LoadProfiles()
        {
            try
            {
                var profilesData = ProfileService.LoadProfiles();

                // Load profile objects (no Custom - it's not a profile anymore)
                Profiles.Clear();
                foreach (var profile in profilesData.Profiles)
                {
                    Profiles.Add(profile);
                }

                Logger.LogInfo($"Loaded {Profiles.Count} profiles");
            }
            catch (Exception ex)
            {
                Logger.LogError($"Failed to load profiles: {ex.Message}");
                Profiles.Clear();
            }
        }

        /// <summary>
        /// Apply a profile to monitors
        /// </summary>
        public void ApplyProfile(PowerDisplayProfile profile)
        {
            try
            {
                if (profile == null || !profile.IsValid())
                {
                    Logger.LogWarning("Invalid profile");
                    return;
                }

                Logger.LogInfo($"Applying profile: {profile.Name}");

                // Create pending operation
                var operation = new ProfileOperation(profile.Name, profile.MonitorSettings);
                _settings.Properties.PendingProfileOperation = operation;

                // Save settings
                NotifySettingsChanged();

                // Send custom action to trigger profile application
                SendConfigMSG(
                    string.Format(
                        CultureInfo.InvariantCulture,
                        "{{ \"action\": {{ \"PowerDisplay\": {{ \"action_name\": \"ApplyProfile\", \"value\": \"{0}\" }} }} }}",
                        profile.Name));

                // Signal PowerDisplay to apply profile
                using (var eventHandle = new System.Threading.EventWaitHandle(
                    false,
                    System.Threading.EventResetMode.AutoReset,
                    Constants.ApplyProfilePowerDisplayEvent()))
                {
                    eventHandle.Set();
                }

                Logger.LogInfo($"Profile '{profile.Name}' applied successfully");
            }
            catch (Exception ex)
            {
                Logger.LogError($"Failed to apply profile: {ex.Message}");
            }
        }

        /// <summary>
        /// Create a new profile
        /// </summary>
        public void CreateProfile(PowerDisplayProfile profile)
        {
            try
            {
                if (profile == null || !profile.IsValid())
                {
                    Logger.LogWarning("Invalid profile");
                    return;
                }

                Logger.LogInfo($"Creating profile: {profile.Name}");

                var profilesData = ProfileService.LoadProfiles();
                profilesData.SetProfile(profile);
                ProfileService.SaveProfiles(profilesData);

                // Reload profile list
                LoadProfiles();

                Logger.LogInfo($"Profile '{profile.Name}' created successfully");
            }
            catch (Exception ex)
            {
                Logger.LogError($"Failed to create profile: {ex.Message}");
            }
        }

        /// <summary>
        /// Update an existing profile
        /// </summary>
        public void UpdateProfile(string oldName, PowerDisplayProfile newProfile)
        {
            try
            {
                if (newProfile == null || !newProfile.IsValid())
                {
                    Logger.LogWarning("Invalid profile");
                    return;
                }

                Logger.LogInfo($"Updating profile: {oldName} -> {newProfile.Name}");

                var profilesData = ProfileService.LoadProfiles();

                // Remove old profile and add updated one
                profilesData.RemoveProfile(oldName);
                profilesData.SetProfile(newProfile);
                ProfileService.SaveProfiles(profilesData);

                // Reload profile list
                LoadProfiles();

                Logger.LogInfo($"Profile updated to '{newProfile.Name}' successfully");
            }
            catch (Exception ex)
            {
                Logger.LogError($"Failed to update profile: {ex.Message}");
            }
        }

        /// <summary>
        /// Delete a profile
        /// </summary>
        public void DeleteProfile(string profileName)
        {
            try
            {
                if (string.IsNullOrEmpty(profileName))
                {
                    return;
                }

                Logger.LogInfo($"Deleting profile: {profileName}");

                var profilesData = ProfileService.LoadProfiles();
                profilesData.RemoveProfile(profileName);
                ProfileService.SaveProfiles(profilesData);

                // Reload profile list
                LoadProfiles();

                Logger.LogInfo($"Profile '{profileName}' deleted successfully");
            }
            catch (Exception ex)
            {
                Logger.LogError($"Failed to delete profile: {ex.Message}");
            }
        }

        private void NotifySettingsChanged()
        {
            // Skip during initialization when SendConfigMSG is not yet set
            if (SendConfigMSG == null)
            {
                return;
            }

            // Persist locally first so settings survive even if the module DLL isn't loaded yet.
            SettingsUtils.SaveSettings(_settings.ToJsonString(), PowerDisplaySettings.ModuleName);

            // Using InvariantCulture as this is an IPC message
            // This message will be intercepted by the runner, which passes the serialized JSON to
            // PowerDisplay Module Interface's set_config() method, which then applies it in-process.
            SendConfigMSG(
                   string.Format(
                       CultureInfo.InvariantCulture,
                       "{{ \"powertoys\": {{ \"{0}\": {1} }} }}",
                       PowerDisplaySettings.ModuleName,
                       _settings.ToJsonString()));
        }
    }
}