/*
 * 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.Diagnostics;
using System.IO;
using ProtonVPN.Common.Core.Extensions;
using ProtonVPN.Common.Legacy.Helpers;

namespace ProtonVPN.Update.Files.UpdatesDirectory;

/// <summary>
/// Represents directory of downloaded updates, performs cleanup of outdated downloads.
/// </summary>
internal class UpdatesDirectory : IUpdatesDirectory
{
    private readonly string _path;
    private readonly Version _currentVersion;

    public UpdatesDirectory(string path, Version currentVersion)
    {
        Ensure.NotEmpty(path, nameof(path));

        _path = path;
        _currentVersion = currentVersion;
    }

    public string Path
    {
        get
        {
            Directory.CreateDirectory(_path);
            return _path;
        }
    }

    public void Cleanup()
    {
        string[] dirs = Directory.GetDirectories(_path);
        foreach (string dir in dirs)
        {
            Directory.Delete(dir, true);
        }
        DeleteOldFiles(_path, _currentVersion);
    }

    private static void DeleteOldFiles(string dir, Version currentVersion)
    {
        string[] files = Directory.GetFiles(dir, "*", SearchOption.TopDirectoryOnly);
        foreach (string file in files)
        {
            if (!IsExeFile(file) || FileVersion(file) < currentVersion)
            {
                File.Delete(file);
            }
        }
    }

    private static bool IsExeFile(string path) =>
        string.Equals(System.IO.Path.GetExtension(path), ".exe", StringComparison.OrdinalIgnoreCase);

    private static Version FileVersion(string path)
    {
        FileVersionInfo info = FileVersionInfo.GetVersionInfo(path);
        Version.TryParse(info.FileVersion, out Version version);
        return version != null
            ? version.Truncate()
            : new Version(0, 0, 0);
    }
}