/*
 * 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;

namespace ProtonVPN.Common.Legacy.Helpers;

public class StructConverter
{
    public static byte[] Pack(object[] items, bool littleEndian)
    {
        var outputBytes = new List<byte>();
        var flip = littleEndian != BitConverter.IsLittleEndian;

        foreach (var o in items)
        {
            var theseBytes = TypeAgnosticGetBytes(o);
            if (flip)
            {
                theseBytes = theseBytes.Reverse().ToArray();
            }

            outputBytes.AddRange(theseBytes);
        }

        return outputBytes.ToArray();
    }

    private static byte[] TypeAgnosticGetBytes(object o)
    {
        if (o is int i)
            return BitConverter.GetBytes(i);
        if (o is uint u)
            return BitConverter.GetBytes(u);
        if (o is long l)
            return BitConverter.GetBytes(l);
        if (o is ulong @ulong)
            return BitConverter.GetBytes(@ulong);
        if (o is short s)
            return BitConverter.GetBytes(s);
        if (o is ushort @ushort)
            return BitConverter.GetBytes(@ushort);
        if (o is byte || o is sbyte)
            return new[] { (byte)o };
        throw new ArgumentException("Unsupported object type found");
    }
}