using System.Buffers;

using Spectre.Console.Cli;

namespace Geekeey.Extensions.Process.Tests.Dummy.Commands;

internal sealed class EchoStdinCommand : AsyncOutputCommand<EchoStdinCommand.Settings>
{
	public sealed class Settings : OutputCommandSettings
	{
		[CommandOption("--length")] public long Length { get; init; } = long.MaxValue;
	}

	public override async Task<int> ExecuteAsync(CommandContext context, Settings settings)
	{
		using var tty = Terminal.Connect();
		using var buffer = MemoryPool<byte>.Shared.Rent(81920);

		var count = 0L;
		while (count < settings.Length)
		{
			var bytesWanted = (int)Math.Min(buffer.Memory.Length, settings.Length - count);

			var bytesRead = await tty.Stdin.BaseStream.ReadAsync(buffer.Memory[..bytesWanted]);
			if (bytesRead <= 0)
				break;

			foreach (var writer in tty.GetWriters(settings.Target))
			{
				await writer.BaseStream.WriteAsync(buffer.Memory[..bytesRead]);
			}

			count += bytesRead;
		}

		return 0;
	}
}