SettingsHelper.cs

namespace LocalSettingsJson;

public static class SettingsHelper
{
    /// <summary>
    /// Gets the name of the current application without its file extension.
    /// </summary>
    /// <remarks>This method attempts to retrieve the application name using the process path when available;
    /// otherwise, it falls back to the friendly name of the current application domain. The result may vary depending
    /// on the hosting environment and .NET runtime version.</remarks>
    /// <returns>A string containing the application's name without the file extension. Returns an empty string if the
    /// application name cannot be determined.</returns>
    public static string GetAppName()
    {
        // ProcessPath (.NET 6+, full exe path)
        if(!string.IsNullOrWhiteSpace(Environment.ProcessPath))
            return Path.GetFileNameWithoutExtension(Environment.ProcessPath);

        // fallback
        return !string.IsNullOrEmpty(AppDomain.CurrentDomain.FriendlyName)
            ? Path.GetFileNameWithoutExtension(AppDomain.CurrentDomain.FriendlyName)
            : "UnknownAppName";
    }

    /// <summary>
    /// Gets the default file path for the application's settings file in the local application data folder.
    /// </summary>
    /// <remarks>The returned path is suitable for storing user-specific application settings. The method
    /// combines the local application data folder, the application name, and the file name 'settings.json'.</remarks>
    /// <returns>A string containing the full path to the default settings file. The path is located in the application's
    /// subdirectory within the local application data folder.</returns>
    public static string GetDefaultAppDataPath()
    {
        var localAppData = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData);
        var appFolder = GetAppName();

        return Path.Combine(localAppData, appFolder, "settings.json");
    }

    
    /// <summary>
    /// Ensures that the directory for the specified file path exists, creating it if necessary.
    /// </summary>
    /// <remarks>This method does not create the file itself; it only ensures that the directory structure
    /// required for the file exists. If the directory already exists, no action is taken.</remarks>
    /// <param name="path">The full file path for which to ensure the containing directory exists. Cannot be null, empty, or whitespace.</param>
    /// <exception cref="InvalidOperationException">Thrown if the specified path is null, empty, or consists only of white-space characters.</exception>
    /// <exception cref="DirectoryNotFoundException">Thrown if the directory part of the specified path is null, empty, or consists only of white-space characters.</exception>
    internal static void EnsureFileExists(string path)
    {
        // verifing path
        if(string.IsNullOrWhiteSpace(path))
            throw new InvalidOperationException($"Invalid FilePath: '{path ?? "<null>"}'");

        // verifing dir
        var dir = Path.GetDirectoryName(path);
        if (string.IsNullOrWhiteSpace(dir))
            throw new DirectoryNotFoundException($"Invalid directory: '{dir ?? "<null>"}'");

        Directory.CreateDirectory(dir);     // creates a valid dir if doesn´t exist
    }
}