// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Microsoft.DotNet.Build.Tasks.Installers;

internal sealed class ArWriter : IDisposable
{
    private Stream _stream;
    private readonly bool _leaveOpen;

    public ArWriter(Stream output, bool leaveOpen)
    {
        _stream = output;
        _leaveOpen = leaveOpen;
        _stream.Write("!<arch>\n"u8);
    }

    public void AddEntry(ArEntry entry)
    {
        Write(Encoding.ASCII.GetBytes(entry.Name.PadRight(16, ' ').Substring(0, 16)));
        Write(Encoding.ASCII.GetBytes(entry.Timestamp.ToString().PadRight(12, ' ').Substring(0, 12)));
        Write(Encoding.ASCII.GetBytes(entry.OwnerID.ToString().PadRight(6, ' ').Substring(0, 6)));
        Write(Encoding.ASCII.GetBytes(entry.GroupID.ToString().PadRight(6, ' ').Substring(0, 6)));
        Write(Encoding.ASCII.GetBytes(Convert.ToString(entry.Mode, 8).PadRight(8, ' ').Substring(0, 8)));

        ulong length = (ulong)entry.DataStream.Length;

        Write(Encoding.ASCII.GetBytes(length.ToString().PadRight(10, ' ').Substring(0, 10)));
        Write(Encoding.ASCII.GetBytes("`\n"));
        entry.DataStream.CopyTo(_stream);

        if ((length % 2) == 1)
        {
            // Pad to even length with a newline
            _stream.WriteByte((byte)'\n');
        }
    }

    private void Write(byte[] data)
    {
        _stream.Write(data);
    }

    public void Dispose()
    {
        if (!_leaveOpen)
        {
            _stream.Dispose();
        }
    }
}