using Microsoft.Win32;

namespace NetworkTool.Client.Services;

public sealed class PasswordStoreService
{
    private const string RegistryPath = @"Software\NetworkTool";
    private const string DevicePasswordPrefix = "DevicePassword_";

    public string LoadPassword(string deviceKey)
    {
        var valueName = GetValueName(deviceKey);
        if (string.IsNullOrWhiteSpace(valueName))
        {
            return string.Empty;
        }

        using var key = Registry.CurrentUser.OpenSubKey(RegistryPath, writable: false);
        return key?.GetValue(valueName) as string ?? string.Empty;
    }

    public void SavePassword(string deviceKey, string password)
    {
        var valueName = GetValueName(deviceKey);
        if (string.IsNullOrWhiteSpace(valueName))
        {
            return;
        }

        using var key = Registry.CurrentUser.CreateSubKey(RegistryPath);
        key.SetValue(valueName, password, RegistryValueKind.String);
    }

    public void ClearPassword(string deviceKey)
    {
        var valueName = GetValueName(deviceKey);
        if (string.IsNullOrWhiteSpace(valueName))
        {
            return;
        }

        using var key = Registry.CurrentUser.OpenSubKey(RegistryPath, writable: true);
        key?.DeleteValue(valueName, throwOnMissingValue: false);
    }

    private static string GetValueName(string deviceKey)
    {
        var normalized = new string(deviceKey
            .Where(char.IsLetterOrDigit)
            .Select(char.ToUpperInvariant)
            .ToArray());
        return string.IsNullOrWhiteSpace(normalized) ? string.Empty : DevicePasswordPrefix + normalized;
    }
}