/*
 * Copyright (c) 2023 Proton AG
 *
 * This file is part of ProtonVPN.
 *
 * ProtonVPN is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * ProtonVPN is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with ProtonVPN.  If not, see <https://www.gnu.org/licenses/>.
 */

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Win32;

namespace ProtonVPN.Common.Legacy.OS.Systems;

public class SystemState : ISystemState
{
    private readonly List<string> _keysExist = new()
    {
        @"SOFTWARE\Microsoft\Windows\CurrentVersion\Component Based Servicing\RebootPending",
        @"SOFTWARE\Microsoft\Windows\CurrentVersion\Component Based Servicing\RebootInProgress",
        @"SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\RebootRequired",
        @"SOFTWARE\Microsoft\Windows\CurrentVersion\Component Based Servicing\PackagesPending",
        @"SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update\PostRebootReporting",
    };

    private readonly Dictionary<string, List<string>> _valuesEqual = new()
    {
        {@"SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce", new List<string> {"DVDRebootSignal"}},
    };

    public bool PendingReboot()
    {
        return _keysExist.Any(DoesSubKeyExist) || DoesAnyValueMatch()
            ? true
            : PendingUpdates();
    }

    private bool DoesAnyValueMatch()
    {
        foreach (KeyValuePair<string, List<string>> item in _valuesEqual)
        {
            using (RegistryKey key = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(item.Key))
            {
                string value = (string)key?.GetValue("");
                if (value != null && item.Value.Contains(value))
                {
                    return true;
                }
            }
        }

        return false;
    }

    private bool DoesSubKeyExist(string keyName)
    {
        using (RegistryKey key = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(keyName))
        {
            return key != null;
        }
    }

    private bool PendingUpdates()
    {
        object val;
        using (RegistryKey key = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Updates"))
        {
            val = key?.GetValue("UpdateExeVolatile");
        }

        if (val != null)
        {
            int.TryParse((string)val, out int result);
            if (result != 0)
            {
                return true;
            }
        }

        using (RegistryKey key = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(
            @"SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Services\Pending"))
        {
            return key?.SubKeyCount > 0;
        }
    }
}