package org.bouncycastle.asn1.x509;

import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1Object;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.DERSequence;

/**
 * <code>UserNotice</code> class, used in
 * <code>CertificatePolicies</code> X509 extensions (in policy
 * qualifiers).
 * <pre>
 * UserNotice ::= SEQUENCE {
 *      noticeRef        NoticeReference OPTIONAL,
 *      explicitText     DisplayText OPTIONAL}
 *
 * </pre>
 * 
 * @see PolicyQualifierId
 * @see PolicyInformation
 */
public class UserNotice 
    extends ASN1Object
{
    private final NoticeReference noticeRef;
    private final DisplayText     explicitText;
   
    /**
     * Creates a new <code>UserNotice</code> instance.
     *
     * @param noticeRef a <code>NoticeReference</code> value
     * @param explicitText a <code>DisplayText</code> value
     */
    public UserNotice(
        NoticeReference noticeRef, 
        DisplayText explicitText) 
    {
        this.noticeRef = noticeRef;
        this.explicitText = explicitText;
    }

    /**
     * Creates a new <code>UserNotice</code> instance.
     *
     * @param noticeRef a <code>NoticeReference</code> value
     * @param str the explicitText field as a String. 
     */
    public UserNotice(
        NoticeReference noticeRef, 
        String str) 
    {
        this(noticeRef, new DisplayText(str));
    }

    /**
     * Creates a new <code>UserNotice</code> instance.
     * <p>Useful from reconstructing a <code>UserNotice</code> instance
     * from its encodable/encoded form. 
     *
     * @param as an <code>ASN1Sequence</code> value obtained from either
     * calling @{link toASN1Primitive()} for a <code>UserNotice</code>
     * instance or from parsing it from a DER-encoded stream. 
     */
    private UserNotice(
       ASN1Sequence as) 
    {
       if (as.size() == 2)
       {
           noticeRef = NoticeReference.getInstance(as.getObjectAt(0));
           explicitText = DisplayText.getInstance(as.getObjectAt(1));
       }
       else if (as.size() == 1)
       {
           if (as.getObjectAt(0).toASN1Primitive() instanceof ASN1Sequence)
           {
               noticeRef = NoticeReference.getInstance(as.getObjectAt(0));
               explicitText = null;
           }
           else
           {
               explicitText = DisplayText.getInstance(as.getObjectAt(0));
               noticeRef = null;
           }
       }
       else if (as.size() == 0)       // neither field set!
       {
           noticeRef = null;
           explicitText = null;
       }
       else
       {
           throw new IllegalArgumentException("Bad sequence size: " + as.size());
       }
    }

    public static UserNotice getInstance(
        Object obj)
    {
        if (obj instanceof UserNotice)
        {
            return (UserNotice)obj;
        }

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

        return null;
    }

    public NoticeReference getNoticeRef()
    {
        return noticeRef;
    }
    
    public DisplayText getExplicitText()
    {
        return explicitText;
    }
    
    public ASN1Primitive toASN1Primitive()
    {
        ASN1EncodableVector av = new ASN1EncodableVector(2);
      
        if (noticeRef != null)
        {
            av.add(noticeRef);
        }
        
        if (explicitText != null)
        {
            av.add(explicitText);
        }
         
        return new DERSequence(av);
    }
}
