package org.spongycastle.asn1.icao;

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.DERSequence;
import org.spongycastle.asn1.x509.AlgorithmIdentifier;

/**
 * The LDSSecurityObject object (V1.8).
 * <pre>
 * LDSSecurityObject ::= SEQUENCE {
 *   version                LDSSecurityObjectVersion,
 *   hashAlgorithm          DigestAlgorithmIdentifier,
 *   dataGroupHashValues    SEQUENCE SIZE (2..ub-DataGroups) OF DataHashGroup,
 *   ldsVersionInfo         LDSVersionInfo OPTIONAL
 *   -- if present, version MUST be v1 }
 *   
 * DigestAlgorithmIdentifier ::= AlgorithmIdentifier,
 * 
 * LDSSecurityObjectVersion :: INTEGER {V0(0)}
 * </pre>
 */

public class LDSSecurityObject 
    extends ASN1Object
    implements ICAOObjectIdentifiers    
{
    public static final int ub_DataGroups = 16;
    
    private ASN1Integer version = new ASN1Integer(0);
    private AlgorithmIdentifier digestAlgorithmIdentifier;
    private DataGroupHash[] datagroupHash;
    private LDSVersionInfo versionInfo;

    public static LDSSecurityObject getInstance(
        Object obj)
    {
        if (obj instanceof LDSSecurityObject)
        {
            return (LDSSecurityObject)obj;
        }
        else if (obj != null)
        {
            return new LDSSecurityObject(ASN1Sequence.getInstance(obj));            
        }
        
        return null;
    }    
    
    private LDSSecurityObject(
        ASN1Sequence seq)
    {
        if (seq == null || seq.size() == 0)
        {
            throw new IllegalArgumentException("null or empty sequence passed.");
        }
        
        Enumeration e = seq.getObjects();

        // version
        version = ASN1Integer.getInstance(e.nextElement());
        // digestAlgorithmIdentifier
        digestAlgorithmIdentifier = AlgorithmIdentifier.getInstance(e.nextElement());
      
        ASN1Sequence datagroupHashSeq = ASN1Sequence.getInstance(e.nextElement());

        if (version.getValue().intValue() == 1)
        {
            versionInfo = LDSVersionInfo.getInstance(e.nextElement());
        }

        checkDatagroupHashSeqSize(datagroupHashSeq.size());        
        
        datagroupHash = new DataGroupHash[datagroupHashSeq.size()];
        for (int i= 0; i< datagroupHashSeq.size();i++)
        {
            datagroupHash[i] = DataGroupHash.getInstance(datagroupHashSeq.getObjectAt(i));
        }
    }

    public LDSSecurityObject(
        AlgorithmIdentifier digestAlgorithmIdentifier, 
        DataGroupHash[]       datagroupHash)
    {
        this.version = new ASN1Integer(0);
        this.digestAlgorithmIdentifier = digestAlgorithmIdentifier;
        this.datagroupHash = datagroupHash;
        
        checkDatagroupHashSeqSize(datagroupHash.length);                      
    }    

    public LDSSecurityObject(
        AlgorithmIdentifier digestAlgorithmIdentifier,
        DataGroupHash[]     datagroupHash,
        LDSVersionInfo      versionInfo)
    {
        this.version = new ASN1Integer(1);
        this.digestAlgorithmIdentifier = digestAlgorithmIdentifier;
        this.datagroupHash = datagroupHash;
        this.versionInfo = versionInfo;

        checkDatagroupHashSeqSize(datagroupHash.length);
    }

    private void checkDatagroupHashSeqSize(int size)
    {
        if ((size < 2) || (size > ub_DataGroups))
        {
               throw new IllegalArgumentException("wrong size in DataGroupHashValues : not in (2.."+ ub_DataGroups +")");
        }
    }  

    public int getVersion()
    {
        return version.getValue().intValue();
    }

    public AlgorithmIdentifier getDigestAlgorithmIdentifier()
    {
        return digestAlgorithmIdentifier;
    }
    
    public DataGroupHash[] getDatagroupHash()
    {
        return datagroupHash;
    }

    public LDSVersionInfo getVersionInfo()
    {
        return versionInfo;
    }

    public ASN1Primitive toASN1Primitive()
    {
        ASN1EncodableVector seq = new ASN1EncodableVector();
        
        seq.add(version);
        seq.add(digestAlgorithmIdentifier);
                
        ASN1EncodableVector seqname = new ASN1EncodableVector();
        for (int i = 0; i < datagroupHash.length; i++) 
        {
            seqname.add(datagroupHash[i]);
        }            
        seq.add(new DERSequence(seqname));                   

        if (versionInfo != null)
        {
            seq.add(versionInfo);
        }

        return new DERSequence(seq);
    }
}
