namespace Qrakhen.Qamp.Core.Execution;

public class Instructions<T>(IEnumerable<T> instructions) : 
        ISteppable<T>,
        IPeekable<T>,
        ISeekable<long, T>
{
    private readonly T[] _instructions = instructions.ToArray();

    public long Position { get; private set; } = 0;

    public long Length => _instructions.LongLength;
    public bool Done => Position >= _instructions.Length;

    public T this[long offset] => offset < Length ? 
        _instructions[offset] :
        throw new ArgumentOutOfRangeException($"Tried to access offset beyond instruction length {offset}:{Length}");

    public T Seek(long position)
    {
        Position = position;
        return _instructions[Position];
    }

    public T Next()
    {
        return _instructions[Position++];
    }

    public T Peek(int delta = 0)
    {
        return _instructions[Position + delta];
    }
}