using System;
using System.Collections;
using System.IO;
using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.X509;
using Org.BouncyCastle.Utilities;

namespace Org.BouncyCastle.Crypto.Tls;

public class Certificate
{
	public static readonly Certificate EmptyChain = new Certificate(new X509CertificateStructure[0]);

	protected readonly X509CertificateStructure[] mCertificateList;

	public virtual int Length => mCertificateList.Length;

	public virtual bool IsEmpty => mCertificateList.Length == 0;

	public Certificate(X509CertificateStructure[] certificateList)
	{
		if (certificateList == null)
		{
			throw new ArgumentNullException("certificateList");
		}
		mCertificateList = certificateList;
	}

	public virtual X509CertificateStructure[] GetCertificateList()
	{
		return CloneCertificateList();
	}

	public virtual X509CertificateStructure GetCertificateAt(int index)
	{
		return mCertificateList[index];
	}

	public virtual void Encode(Stream output)
	{
		IList list = Platform.CreateArrayList(mCertificateList.Length);
		int num = 0;
		X509CertificateStructure[] array = mCertificateList;
		foreach (Asn1Encodable asn1Encodable in array)
		{
			byte[] encoded = asn1Encodable.GetEncoded("DER");
			list.Add(encoded);
			num += encoded.Length + 3;
		}
		TlsUtilities.CheckUint24(num);
		TlsUtilities.WriteUint24(num, output);
		foreach (byte[] item in list)
		{
			TlsUtilities.WriteOpaque24(item, output);
		}
	}

	public static Certificate Parse(Stream input)
	{
		int num = TlsUtilities.ReadUint24(input);
		if (num == 0)
		{
			return EmptyChain;
		}
		byte[] buffer = TlsUtilities.ReadFully(num, input);
		MemoryStream memoryStream = new MemoryStream(buffer, writable: false);
		IList list = Platform.CreateArrayList();
		while (memoryStream.Position < memoryStream.Length)
		{
			byte[] encoding = TlsUtilities.ReadOpaque24(memoryStream);
			Asn1Object obj = TlsUtilities.ReadAsn1Object(encoding);
			list.Add(X509CertificateStructure.GetInstance(obj));
		}
		X509CertificateStructure[] array = new X509CertificateStructure[list.Count];
		for (int i = 0; i < list.Count; i++)
		{
			array[i] = (X509CertificateStructure)list[i];
		}
		return new Certificate(array);
	}

	protected virtual X509CertificateStructure[] CloneCertificateList()
	{
		return (X509CertificateStructure[])mCertificateList.Clone();
	}
}