AppSettingsService.cs

using System.ComponentModel;
using System.IO;
using System.Text.Json;

namespace ToastDesk;

public sealed class AppSettingsService
{
    private readonly string settingsPath;
    private readonly string legacySettingsPath;
    private readonly StartupRegistrationService startupRegistrationService;
    private bool isSaving;

    public AppSettingsService(StartupRegistrationService startupRegistrationService)
    {
        this.startupRegistrationService = startupRegistrationService;
        var settingsDir = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "ToastDesk");
        var legacySettingsDir = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "ToastDeck-A");
        settingsPath = Path.Combine(settingsDir, "settings.json");
        legacySettingsPath = Path.Combine(legacySettingsDir, "settings.json");
    }

    public AppSettings Load()
    {
        var settingsFileExists = File.Exists(settingsPath);
        var settings = LoadFromDisk();

        if (settingsFileExists)
        {
            startupRegistrationService.SetRegistered(settings.StartWithWindows);
            settings.StartWithWindows = startupRegistrationService.IsRegistered();
        }
        else
        {
            startupRegistrationService.SetRegistered(settings.StartWithWindows);
            Save(settings);
        }

        settings.PropertyChanged += OnSettingsChanged;
        return settings;
    }

    private AppSettings LoadFromDisk()
    {
        try
        {
            var path = File.Exists(settingsPath) ? settingsPath : legacySettingsPath;

            if (!File.Exists(path))
            {
                return new AppSettings();
            }

            return JsonSerializer.Deserialize<AppSettings>(File.ReadAllText(path)) ?? new AppSettings();
        }
        catch (JsonException)
        {
            return new AppSettings();
        }
        catch (IOException)
        {
            return new AppSettings();
        }
    }

    private void OnSettingsChanged(object? sender, PropertyChangedEventArgs e)
    {
        if (sender is not AppSettings settings || isSaving)
        {
            return;
        }

        if (e.PropertyName == nameof(AppSettings.StartWithWindows))
        {
            startupRegistrationService.SetRegistered(settings.StartWithWindows);
        }

        Save(settings);
    }

    private void Save(AppSettings settings)
    {
        try
        {
            isSaving = true;
            Directory.CreateDirectory(Path.GetDirectoryName(settingsPath)!);
            var json = JsonSerializer.Serialize(settings, new JsonSerializerOptions { WriteIndented = true });
            var tempPath = $"{settingsPath}.tmp";
            File.WriteAllText(tempPath, json);
            File.Move(tempPath, settingsPath, overwrite: true);
        }
        finally
        {
            isSaving = false;
        }
    }
}