package org.spongycastle.asn1.cms;

import java.util.Enumeration;

import org.spongycastle.asn1.ASN1EncodableVector;
import org.spongycastle.asn1.ASN1Integer;
import org.spongycastle.asn1.ASN1Object;
import org.spongycastle.asn1.ASN1Primitive;
import org.spongycastle.asn1.ASN1Sequence;
import org.spongycastle.asn1.ASN1Set;
import org.spongycastle.asn1.ASN1TaggedObject;
import org.spongycastle.asn1.BERSequence;
import org.spongycastle.asn1.DERTaggedObject;

/**
 * <a href="http://tools.ietf.org/html/rfc5652#section-6.1">RFC 5652</a> EnvelopedData object.
 * <pre>
 * EnvelopedData ::= SEQUENCE {
 *     version CMSVersion,
 *     originatorInfo [0] IMPLICIT OriginatorInfo OPTIONAL,
 *     recipientInfos RecipientInfos,
 *     encryptedContentInfo EncryptedContentInfo,
 *     unprotectedAttrs [1] IMPLICIT UnprotectedAttributes OPTIONAL 
 * }
 * </pre>
 */
public class EnvelopedData
    extends ASN1Object
{
    private ASN1Integer              version;
    private OriginatorInfo          originatorInfo;
    private ASN1Set                 recipientInfos;
    private EncryptedContentInfo    encryptedContentInfo;
    private ASN1Set                 unprotectedAttrs;

    public EnvelopedData(
        OriginatorInfo          originatorInfo,
        ASN1Set                 recipientInfos,
        EncryptedContentInfo    encryptedContentInfo,
        ASN1Set                 unprotectedAttrs)
    {
        version = new ASN1Integer(calculateVersion(originatorInfo, recipientInfos, unprotectedAttrs));

        this.originatorInfo = originatorInfo;
        this.recipientInfos = recipientInfos;
        this.encryptedContentInfo = encryptedContentInfo;
        this.unprotectedAttrs = unprotectedAttrs;
    }

    public EnvelopedData(
        OriginatorInfo          originatorInfo,
        ASN1Set                 recipientInfos,
        EncryptedContentInfo    encryptedContentInfo,
        Attributes              unprotectedAttrs)
    {
        version = new ASN1Integer(calculateVersion(originatorInfo, recipientInfos, ASN1Set.getInstance(unprotectedAttrs)));

        this.originatorInfo = originatorInfo;
        this.recipientInfos = recipientInfos;
        this.encryptedContentInfo = encryptedContentInfo;
        this.unprotectedAttrs = ASN1Set.getInstance(unprotectedAttrs);
    }

    /**
     * @deprecated use getInstance()
     */
    public EnvelopedData(
        ASN1Sequence seq)
    {
        int     index = 0;
        
        version = (ASN1Integer)seq.getObjectAt(index++);
        
        Object  tmp = seq.getObjectAt(index++);

        if (tmp instanceof ASN1TaggedObject)
        {
            originatorInfo = OriginatorInfo.getInstance((ASN1TaggedObject)tmp, false);
            tmp = seq.getObjectAt(index++);
        }

        recipientInfos = ASN1Set.getInstance(tmp);
        
        encryptedContentInfo = EncryptedContentInfo.getInstance(seq.getObjectAt(index++));
        
        if(seq.size() > index)
        {
            unprotectedAttrs = ASN1Set.getInstance((ASN1TaggedObject)seq.getObjectAt(index), false);
        }
    }
    
    /**
     * Return an EnvelopedData object from a tagged object.
     *
     * @param obj the tagged object holding the object we want.
     * @param explicit true if the object is meant to be explicitly
     *              tagged false otherwise.
     * @exception IllegalArgumentException if the object held by the
     *          tagged object cannot be converted.
     */
    public static EnvelopedData getInstance(
        ASN1TaggedObject obj,
        boolean explicit)
    {
        return getInstance(ASN1Sequence.getInstance(obj, explicit));
    }
    
    /**
     * Return an EnvelopedData object from the given object.
     * <p>
     * Accepted inputs:
     * <ul>
     * <li> null &rarr; null
     * <li> {@link EnvelopedData} object
     * <li> {@link org.spongycastle.asn1.ASN1Sequence#getInstance(java.lang.Object) ASN1Sequence} input formats with EnvelopedData structure inside
     * </ul>
     *
     * @param obj the object we want converted.
     * @exception IllegalArgumentException if the object cannot be converted.
     */
    public static EnvelopedData getInstance(
        Object obj)
    {
        if (obj instanceof EnvelopedData)
        {
            return (EnvelopedData)obj;
        }
        
        if (obj != null)
        {
            return new EnvelopedData(ASN1Sequence.getInstance(obj));
        }
        
        return null;
    }

    public ASN1Integer getVersion()
    {
        return version;
    }
    
    public OriginatorInfo getOriginatorInfo()
    {
        return originatorInfo;
    }

    public ASN1Set getRecipientInfos()
    {
        return recipientInfos;
    }

    public EncryptedContentInfo getEncryptedContentInfo()
    {
        return encryptedContentInfo;
    }

    public ASN1Set getUnprotectedAttrs()
    {
        return unprotectedAttrs;
    }

    /** 
     * Produce an object suitable for an ASN1OutputStream.
     */
    public ASN1Primitive toASN1Primitive()
    {
        ASN1EncodableVector  v = new ASN1EncodableVector();
        
        v.add(version);

        if (originatorInfo != null)
        {
            v.add(new DERTaggedObject(false, 0, originatorInfo));
        }

        v.add(recipientInfos);
        v.add(encryptedContentInfo);

        if (unprotectedAttrs != null)
        {
            v.add(new DERTaggedObject(false, 1, unprotectedAttrs));
        }
        
        return new BERSequence(v);
    }

    public static int calculateVersion(OriginatorInfo originatorInfo, ASN1Set recipientInfos, ASN1Set unprotectedAttrs)
    {
        int version;

        if (originatorInfo != null || unprotectedAttrs != null)
        {
            version = 2;
        }
        else
        {
            version = 0;

            Enumeration e = recipientInfos.getObjects();

            while (e.hasMoreElements())
            {
                RecipientInfo   ri = RecipientInfo.getInstance(e.nextElement());

                if (ri.getVersion().getValue().intValue() != version)
                {
                    version = 2;
                    break;
                }
            }
        }

        return version;
    }
}
