package org.bouncycastle.asn1.x500.style;

import java.io.IOException;
import java.util.Enumeration;
import java.util.Hashtable;

import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.ASN1ParsingException;
import org.bouncycastle.asn1.DERUTF8String;
import org.bouncycastle.asn1.x500.AttributeTypeAndValue;
import org.bouncycastle.asn1.x500.RDN;
import org.bouncycastle.asn1.x500.X500Name;
import org.bouncycastle.asn1.x500.X500NameStyle;

This class provides some default behavior and common implementation for a
X500NameStyle. It should be easily extendable to support implementing the
desired X500NameStyle.
/**
 * This class provides some default behavior and common implementation for a
 * X500NameStyle. It should be easily extendable to support implementing the
 * desired X500NameStyle.
 */
public abstract class AbstractX500NameStyle
    implements X500NameStyle
{

    
Tool function to shallow copy a Hashtable.
Params:
paramsMap – table to copy
Returns:
the copy of the table/**
     * Tool function to shallow copy a Hashtable.
     *
     * @param paramsMap table to copy
     * @return the copy of the table
     */
    public static Hashtable copyHashTable(Hashtable paramsMap)
    {
        Hashtable newTable = new Hashtable();

        Enumeration keys = paramsMap.keys();
        while (keys.hasMoreElements())
        {
            Object key = keys.nextElement();
            newTable.put(key, paramsMap.get(key));
        }

        return newTable;
    }

    private int calcHashCode(ASN1Encodable enc)
    {
        String value = IETFUtils.valueToString(enc);
        value = IETFUtils.canonicalize(value);
        return value.hashCode();
    }

    public int calculateHashCode(X500Name name)
    {
        int hashCodeValue = 0;
        RDN[] rdns = name.getRDNs();

        // this needs to be order independent, like equals
        for (int i = 0; i != rdns.length; i++)
        {
            if (rdns[i].isMultiValued())
            {
                AttributeTypeAndValue[] atv = rdns[i].getTypesAndValues();

                for (int j = 0; j != atv.length; j++)
                {
                    hashCodeValue ^= atv[j].getType().hashCode();
                    hashCodeValue ^= calcHashCode(atv[j].getValue());
                }
            }
            else
            {
                hashCodeValue ^= rdns[i].getFirst().getType().hashCode();
                hashCodeValue ^= calcHashCode(rdns[i].getFirst().getValue());
            }
        }

        return hashCodeValue;
    }


    
For all string values starting with '#' is assumed, that these are
already valid ASN.1 objects encoded in hex.
 All other string values are send to encodeStringValue(ASN1ObjectIdentifier, String). 
 Subclasses should overwrite encodeStringValue(ASN1ObjectIdentifier, String) to change the encoding of specific types. 
Params:
oid – the DN name of the value.
value – the String representation of the value./**
     * For all string values starting with '#' is assumed, that these are
     * already valid ASN.1 objects encoded in hex.
     * <p>
     * All other string values are send to
     * {@link AbstractX500NameStyle#encodeStringValue(ASN1ObjectIdentifier, String)}.
     * </p>
     * Subclasses should overwrite
     * {@link AbstractX500NameStyle#encodeStringValue(ASN1ObjectIdentifier, String)}
     * to change the encoding of specific types.
     *
     * @param oid the DN name of the value.
     * @param value the String representation of the value.
     */
    public ASN1Encodable stringToValue(ASN1ObjectIdentifier oid, String value)
    {
        if (value.length() != 0 && value.charAt(0) == '#')
        {
            try
            {
                return IETFUtils.valueFromHexString(value, 1);
            }
            catch (IOException e)
            {
                throw new ASN1ParsingException("can't recode value for oid " + oid.getId());
            }
        }

        if (value.length() != 0 && value.charAt(0) == '\\')
        {
            value = value.substring(1);
        }

        return encodeStringValue(oid, value);
    }

    
Encoded every value into a UTF8String.

Subclasses should overwrite
this method to change the encoding of specific types.

Params:
oid – the DN oid of the value
value – the String representation of the value
Returns:
a the value encoded into a ASN.1 object. Never returns null./**
     * Encoded every value into a UTF8String.
     * <p>
     * Subclasses should overwrite
     * this method to change the encoding of specific types.
     * </p>
     *
     * @param oid the DN oid of the value
     * @param value the String representation of the value
     * @return a the value encoded into a ASN.1 object. Never returns <code>null</code>.
     */
    protected ASN1Encodable encodeStringValue(ASN1ObjectIdentifier oid, String value)
    {
        return new DERUTF8String(value);
    }

    public boolean areEqual(X500Name name1, X500Name name2)
    {
        RDN[] rdns1 = name1.getRDNs();
        RDN[] rdns2 = name2.getRDNs();

        if (rdns1.length != rdns2.length)
        {
            return false;
        }

        boolean reverse = false;

        if (rdns1[0].getFirst() != null && rdns2[0].getFirst() != null)
        {
            reverse = !rdns1[0].getFirst().getType().equals(rdns2[0].getFirst().getType());  // guess forward
        }

        for (int i = 0; i != rdns1.length; i++)
        {
            if (!foundMatch(reverse, rdns1[i], rdns2))
            {
                return false;
            }
        }

        return true;
    }

    private boolean foundMatch(boolean reverse, RDN rdn, RDN[] possRDNs)
    {
        if (reverse)
        {
            for (int i = possRDNs.length - 1; i >= 0; i--)
            {
                if (possRDNs[i] != null && rdnAreEqual(rdn, possRDNs[i]))
                {
                    possRDNs[i] = null;
                    return true;
                }
            }
        }
        else
        {
            for (int i = 0; i != possRDNs.length; i++)
            {
                if (possRDNs[i] != null && rdnAreEqual(rdn, possRDNs[i]))
                {
                    possRDNs[i] = null;
                    return true;
                }
            }
        }

        return false;
    }

    protected boolean rdnAreEqual(RDN rdn1, RDN rdn2)
    {
        return IETFUtils.rDNAreEqual(rdn1, rdn2);
    }
}