using System;
using Org.BouncyCastle.Utilities;

namespace Org.BouncyCastle.Asn1.X509;

public class DigestInfo : Asn1Encodable
{
	private readonly byte[] digest;

	private readonly AlgorithmIdentifier algID;

	public AlgorithmIdentifier AlgorithmID => algID;

	public static DigestInfo GetInstance(Asn1TaggedObject obj, bool explicitly)
	{
		return GetInstance(Asn1Sequence.GetInstance(obj, explicitly));
	}

	public static DigestInfo GetInstance(object obj)
	{
		if (obj is DigestInfo)
		{
			return (DigestInfo)obj;
		}
		if (obj is Asn1Sequence)
		{
			return new DigestInfo((Asn1Sequence)obj);
		}
		throw new ArgumentException("unknown object in factory: " + Platform.GetTypeName(obj), "obj");
	}

	public DigestInfo(AlgorithmIdentifier algID, byte[] digest)
	{
		this.digest = digest;
		this.algID = algID;
	}

	private DigestInfo(Asn1Sequence seq)
	{
		if (seq.Count != 2)
		{
			throw new ArgumentException("Wrong number of elements in sequence", "seq");
		}
		algID = AlgorithmIdentifier.GetInstance(seq[0]);
		digest = Asn1OctetString.GetInstance(seq[1]).GetOctets();
	}

	public byte[] GetDigest()
	{
		return digest;
	}

	public override Asn1Object ToAsn1Object()
	{
		return new DerSequence(algID, new DerOctetString(digest));
	}
}