package org.bouncycastle.asn1.cms;

import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.ASN1TaggedObject;
import org.bouncycastle.asn1.BERSequence;
import org.bouncycastle.asn1.BERTaggedObject;
import org.bouncycastle.asn1.DEREncodable;
import org.bouncycastle.asn1.DERObject;
import org.bouncycastle.asn1.DERObjectIdentifier;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;

public class EncryptedContentInfo
    implements DEREncodable
{
	private DERObjectIdentifier contentType;
	private AlgorithmIdentifier contentEncryptionAlgorithm;
	private ASN1OctetString     encryptedContent;
	
	public EncryptedContentInfo(
        DERObjectIdentifier contentType, 
        AlgorithmIdentifier contentEncryptionAlgorithm,
        ASN1OctetString     encryptedContent)
    {
		this.contentType = contentType;
		this.contentEncryptionAlgorithm = contentEncryptionAlgorithm;
		this.encryptedContent = encryptedContent;
	}
	
	public EncryptedContentInfo(
        ASN1Sequence seq)
    {
		contentType = (DERObjectIdentifier)seq.getObjectAt(0);
		contentEncryptionAlgorithm = AlgorithmIdentifier.getInstance(
                                                        seq.getObjectAt(1));
		if (seq.size() > 2)
        {
			encryptedContent = ASN1OctetString.getInstance(
                                (ASN1TaggedObject)seq.getObjectAt(2), false);
		}
	}

    /**
     * return an EncryptedContentInfo object from the given object.
     *
     * @param obj the object we want converted.
     * @exception IllegalArgumentException if the object cannot be converted.
     */
	public static EncryptedContentInfo getInstance(
        Object obj)
    {
		if (obj == null || obj instanceof EncryptedContentInfo)
        {
			return (EncryptedContentInfo)obj;
		}
		
		if (obj instanceof ASN1Sequence)
        {
			return new EncryptedContentInfo((ASN1Sequence)obj);
		}
		
		throw new IllegalArgumentException("Invalid EncryptedContentInfo: "
                                                + obj.getClass().getName());
	}

	public DERObjectIdentifier getContentType()
    {
		return contentType;
	}

	public AlgorithmIdentifier getContentEncryptionAlgorithm()
    {
		return contentEncryptionAlgorithm;
	}

	public ASN1OctetString getEncryptedContent()
    {
		return encryptedContent;
	}

    /** 
     * Produce an object suitable for an ASN1OutputStream.
     * <pre>
     * EncryptedContentInfo ::= SEQUENCE {
     * 	contentType ContentType,
     * 	contentEncryptionAlgorithm ContentEncryptionAlgorithmIdentifier,
     * 	encryptedContent [0] IMPLICIT EncryptedContent OPTIONAL 
     * }
     * </pre>
     */
	public DERObject getDERObject()
    {
        ASN1EncodableVector  v = new ASN1EncodableVector();
		
		v.add(contentType);
		v.add(contentEncryptionAlgorithm);

		if (encryptedContent != null)
        {
			v.add(new BERTaggedObject(false, 0, encryptedContent));
		}
		
		return new BERSequence(v);
	}
}
