package org.bouncycastle.asn1.pkcs;

import org.bouncycastle.asn1.*;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;

/**
 * The EncryptedData object.
 * <pre>
 *      EncryptedData ::= SEQUENCE {
 *           version Version,
 *           encryptedContentInfo EncryptedContentInfo
 *      }
 *
 *
 *      EncryptedContentInfo ::= SEQUENCE {
 *          contentType ContentType,
 *          contentEncryptionAlgorithm  ContentEncryptionAlgorithmIdentifier,
 *          encryptedContent [0] IMPLICIT EncryptedContent OPTIONAL
 *    }
 *
 *    EncryptedContent ::= OCTET STRING
 * </pre>
 */
public class EncryptedData
    extends ASN1Encodable
{
    ASN1Sequence                data;
    DERObjectIdentifier         bagId;
    DERObject                   bagValue;

    public static EncryptedData getInstance(
         Object  obj)
    {
         if (obj instanceof EncryptedData)
         {
             return (EncryptedData)obj;
         }
         else if (obj instanceof ASN1Sequence)
         {
             return new EncryptedData((ASN1Sequence)obj);
         }

         throw new IllegalArgumentException("unknown object in factory");
    }
     
    public EncryptedData(
        ASN1Sequence seq)
    {
        int version = ((DERInteger)seq.getObjectAt(0)).getValue().intValue();

        if (version != 0)
        {
            throw new IllegalArgumentException("sequence not version 0");
        }

        this.data = (ASN1Sequence)seq.getObjectAt(1);
    }

    public EncryptedData(
        DERObjectIdentifier     contentType,
        AlgorithmIdentifier     encryptionAlgorithm,
        DEREncodable            content)
    {
        ASN1EncodableVector v = new ASN1EncodableVector();

        v.add(contentType);
        v.add(encryptionAlgorithm.getDERObject());
        v.add(new BERTaggedObject(false, 0, content));

        data = new BERSequence(v);
    }
        
    public DERObjectIdentifier getContentType()
    {
        return (DERObjectIdentifier)data.getObjectAt(0);
    }

    public AlgorithmIdentifier getEncryptionAlgorithm()
    {
        return AlgorithmIdentifier.getInstance(data.getObjectAt(1));
    }

    public ASN1OctetString getContent()
    {
        if (data.size() == 3)
        {
            DERTaggedObject o = (DERTaggedObject)data.getObjectAt(2);

            return ASN1OctetString.getInstance(o.getObject());
        }

        return null;
    }

    public DERObject toASN1Object()
    {
        ASN1EncodableVector  v = new ASN1EncodableVector();

        v.add(new DERInteger(0));
        v.add(data);

        return new BERSequence(v);
    }
}
