package org.bouncycastle.asn1.cms;

import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1GeneralizedTime;
import org.bouncycastle.asn1.ASN1Object;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.ASN1TaggedObject;
import org.bouncycastle.asn1.DEROctetString;
import org.bouncycastle.asn1.DERSequence;

/**
 * <a href="https://tools.ietf.org/html/rfc5652#section-6.2.2">RFC 5652</a>:
 * Content encryption key delivery mechanisms.
 * <p>
 * <pre>
 * RecipientKeyIdentifier ::= SEQUENCE {
 *     subjectKeyIdentifier SubjectKeyIdentifier,
 *     date GeneralizedTime OPTIONAL,
 *     other OtherKeyAttribute OPTIONAL
 * }
 *
 * SubjectKeyIdentifier ::= OCTET STRING
 * </pre>
 */
public class RecipientKeyIdentifier
    extends ASN1Object
{
    private ASN1OctetString      subjectKeyIdentifier;
    private ASN1GeneralizedTime  date;
    private OtherKeyAttribute    other;

    public RecipientKeyIdentifier(
        ASN1OctetString         subjectKeyIdentifier,
        ASN1GeneralizedTime     date,
        OtherKeyAttribute       other)
    {
        this.subjectKeyIdentifier = subjectKeyIdentifier;
        this.date = date;
        this.other = other;
    }

    public RecipientKeyIdentifier(
        byte[]                  subjectKeyIdentifier,
        ASN1GeneralizedTime     date,
        OtherKeyAttribute       other)
    {
        this.subjectKeyIdentifier = new DEROctetString(subjectKeyIdentifier);
        this.date = date;
        this.other = other;
    }

    public RecipientKeyIdentifier(
        byte[]         subjectKeyIdentifier)
    {
        this(subjectKeyIdentifier, null, null);
    }

    private RecipientKeyIdentifier(
        ASN1Sequence seq)
    {
        subjectKeyIdentifier = ASN1OctetString.getInstance(
                                                    seq.getObjectAt(0));

        switch(seq.size())
        {
        case 1:
            break;
        case 2:
            if (seq.getObjectAt(1) instanceof ASN1GeneralizedTime)
            {
                date = ASN1GeneralizedTime.getInstance(seq.getObjectAt(1));
            }
            else
            {
                other = OtherKeyAttribute.getInstance(seq.getObjectAt(2));
            }
            break;
        case 3:
            date  = ASN1GeneralizedTime.getInstance(seq.getObjectAt(1));
            other = OtherKeyAttribute.getInstance(seq.getObjectAt(2));
            break;
        default:
            throw new IllegalArgumentException("Invalid RecipientKeyIdentifier");
        }
    }

    /**
     * Return a RecipientKeyIdentifier object from a tagged object.
     *
     * @param ato the tagged object holding the object we want.
     * @param isExplicit 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 RecipientKeyIdentifier getInstance(ASN1TaggedObject ato, boolean isExplicit)
    {
        return getInstance(ASN1Sequence.getInstance(ato, isExplicit));
    }

    /**
     * Return a RecipientKeyIdentifier object from the given object.
     * <p>
     * Accepted inputs:
     * <ul>
     * <li> null &rarr; null
     * <li> {@link RecipientKeyIdentifier} object
     * <li> {@link org.bouncycastle.asn1.ASN1Sequence#getInstance(java.lang.Object) ASN1Sequence} input formats with RecipientKeyIdentifier structure inside
     * </ul>
     *
     * @param obj the object we want converted.
     * @exception IllegalArgumentException if the object cannot be converted.
     */
    public static RecipientKeyIdentifier getInstance(Object obj)
    {
        if (obj instanceof RecipientKeyIdentifier)
        {
            return (RecipientKeyIdentifier)obj;
        }

        if(obj != null)
        {
            return new RecipientKeyIdentifier(ASN1Sequence.getInstance(obj));
        }

        return null;
    }

    public ASN1OctetString getSubjectKeyIdentifier()
    {
        return subjectKeyIdentifier;
    }

    public ASN1GeneralizedTime getDate()
    {
        return date;
    }

    public OtherKeyAttribute getOtherKeyAttribute()
    {
        return other;
    }


    /**
     * Produce an object suitable for an ASN1OutputStream.
     */
    public ASN1Primitive toASN1Primitive()
    {
        ASN1EncodableVector v = new ASN1EncodableVector(3);

        v.add(subjectKeyIdentifier);

        if (date != null)
        {
            v.add(date);
        }

        if (other != null)
        {
            v.add(other);
        }

        return new DERSequence(v);
    }
}
