package org.bouncycastle.asn1.x9;

import org.bouncycastle.asn1.ASN1Choice;
import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1Null;
import org.bouncycastle.asn1.ASN1TaggedObject;
import org.bouncycastle.asn1.DERObject;
import org.bouncycastle.asn1.DERObjectIdentifier;

public class X962Parameters
    extends ASN1Encodable
    implements ASN1Choice
{
    private DERObject           params = null;

    public static X962Parameters getInstance(
        Object obj)
    {
        if (obj == null || obj instanceof X962Parameters) 
        {
            return (X962Parameters)obj;
        }
        
        if (obj instanceof DERObject) 
        {
            return new X962Parameters((DERObject)obj);
        }
        
        throw new IllegalArgumentException("unknown object in getInstance()");
    }
    
    public static X962Parameters getInstance(
        ASN1TaggedObject obj,
        boolean          explicit)
    {
        return getInstance(obj.getObject()); // must be explicitly tagged
    }
    
    public X962Parameters(
        X9ECParameters      ecParameters)
    {
        this.params = ecParameters.getDERObject();
    }

    public X962Parameters(
        DERObjectIdentifier  namedCurve)
    {
        this.params = namedCurve;
    }

    public X962Parameters(
        DERObject           obj)
    {
        this.params = obj;
    }

    public boolean isNamedCurve()
    {
        return (params instanceof DERObjectIdentifier);
    }

    public boolean isImplicitlyCA()
    {
        return (params instanceof ASN1Null);
    }

    public DERObject getParameters()
    {
        return params;
    }

    /**
     * Produce an object suitable for an ASN1OutputStream.
     * <pre>
     * Parameters ::= CHOICE {
     *    ecParameters ECParameters,
     *    namedCurve   CURVES.&id({CurveNames}),
     *    implicitlyCA NULL
     * }
     * </pre>
     */
    public DERObject toASN1Object()
    {
        return params;
    }
}
