package org.bouncycastle.asn1.x509;

import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.DEREncodable;
import org.bouncycastle.asn1.DERObject;
import org.bouncycastle.asn1.DERIA5String;
import org.bouncycastle.asn1.DERObjectIdentifier;
import org.bouncycastle.asn1.DERSequence;

/**
 * Policy qualifiers, used in the X509V3 CertificatePolicies
 * extension.
 * 
 * <pre>
 *   PolicyQualifierInfo ::= SEQUENCE {
 *       policyQualifierId  PolicyQualifierId,
 *       qualifier          ANY DEFINED BY policyQualifierId }
 * </pre>
 */
public class PolicyQualifierInfo
    extends ASN1Encodable
{
   DERObjectIdentifier policyQualifierId;
   DEREncodable qualifier;

   /**
    * Creates a new <code>PolicyQualifierInfo</code> instance.
    *
    * @param policyQualifierId a <code>PolicyQualifierId</code> value
    * @param qualifier the qualifier, defined by the above field.
    */
   public PolicyQualifierInfo (DERObjectIdentifier policyQualifierId,
                               DEREncodable qualifier) 
   {
      this.policyQualifierId = policyQualifierId;
      this.qualifier = qualifier;
   }

   /**
    * Creates a new <code>PolicyQualifierInfo</code> containing a
    * cPSuri qualifier.
    *
    * @param cps the CPS (certification practice statement) uri as a
    * <code>String</code>.
    */
   public PolicyQualifierInfo (String cps) 
   {
      policyQualifierId = PolicyQualifierId.id_qt_cps;
      qualifier = new DERIA5String (cps);
   }

   /**
	* Creates a new <code>PolicyQualifierInfo</code> instance.
	*
	* @param a <code>PolicyQualifierInfo</code> X509 structure
	* encoded as an ASN1Sequence. 
	*/
   public PolicyQualifierInfo (ASN1Sequence as)
   {
		policyQualifierId = (DERObjectIdentifier) as.getObjectAt(0);
		qualifier = as.getObjectAt(1);
    }

   public static PolicyQualifierInfo getInstance (Object as) 
   {
        if (as instanceof PolicyQualifierInfo)
        {
            return (PolicyQualifierInfo)as;
        }
        else if (as instanceof ASN1Sequence)
        {
            return new PolicyQualifierInfo((ASN1Sequence)as);
        }

        throw new IllegalArgumentException("unknown object in getInstance.");
   }

   /**
    * Returns a DER-encodable representation of this instance. 
    *
    * @return a <code>DERObject</code> value
    */
   public DERObject toASN1Object() 
   {
      ASN1EncodableVector dev = new ASN1EncodableVector();
      dev.add(policyQualifierId);
      dev.add(qualifier);

      return new DERSequence(dev);
   }
}