NdsFile.cs

namespace NdsForge;

public sealed class NdsFile
{
    private readonly IImageDataSource _source;

    internal NdsFile(
        IImageDataSource source,
        int id,
        string name,
        string fullPath,
        NdsRegion data,
        NdsDirectory parent)
    {
        _source = source;
        Id = id;
        Name = name;
        FullPath = fullPath;
        Data = data;
        Parent = parent;
    }

    public int Id { get; }

    public string Name { get; }

    public string FullPath { get; }

    public NdsRegion Data { get; }

    public NdsDirectory Parent { get; }

    public Stream OpenRead() => new ImageSliceStream(_source, Data);

    public async ValueTask CopyToAsync(Stream destination, CancellationToken cancellationToken = default)
    {
        ArgumentNullException.ThrowIfNull(destination);
        if (!destination.CanWrite)
        {
            throw new ArgumentException("The NitroFS file destination must be writable.", nameof(destination));
        }
 
        using Stream source = OpenRead();
        await source.CopyToAsync(destination, cancellationToken).ConfigureAwait(false);
    }

    public async ValueTask<byte[]> ReadAllBytesAsync(CancellationToken cancellationToken = default)
    {
        if (Data.Length > Array.MaxLength)
        {
            throw new IOException($"NitroFS file {FullPath} is too large to materialize as a byte array.");
        }
 
        byte[] data = new byte[Data.Length];
        await _source.ReadExactlyAsync(Data.Offset, data, cancellationToken).ConfigureAwait(false);
        return data;
    }
}