// --- BEGIN COPYRIGHT BLOCK ---
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; version 2 of the License.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
// (C) 2007 Red Hat, Inc.
// All rights reserved.
// --- END COPYRIGHT BLOCK ---
package netscape.security.x509;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import netscape.security.util.DerEncoder;
import netscape.security.util.DerInputStream;
import netscape.security.util.DerOutputStream;
import netscape.security.util.DerValue;
import netscape.security.util.ObjectIdentifier;
import sun.io.ByteToCharConverter;


/**
 * X.500 Attribute-Value-Assertion (AVA):  an attribute, as identified by
 * some attribute ID, has some particular value.  Values are as a rule ASN.1
 * printable strings.  A conventional set of type IDs is recognized when
 * parsing (and generating) RFC 1779 syntax strings.
 *
 * <P>AVAs are components of X.500 relative names.  Think of them as being
 * individual fields of a database record.  The attribute ID is how you
 * identify the field, and the value is part of a particular record.
 *
 * @see X500Name
 * @see RDN
 * @see LdapDNStrConverter
 *
 * @version 1.14
 *
 * @author David Brownell
 * @author Amit Kapoor
 * @author Hemma Prafullchandra
 */
// public ... when RDN is public and X.500Names can be
// constructed using RDNs, and all three classes are cleaner
public final class AVA implements DerEncoder
{
    ObjectIdentifier	oid;
    DerValue		value;

    /** 
     * Constructs an AVA from a Ldap DN string with one AVA component 
     * using the global default LdapDNStrConverter. 
     * @see LdapDNStrConverter
     * @param avaString a Ldap DN string with one AVA component.
     */
    public AVA(String avaString)
	throws IOException
    {
	AVA ava;
	ava = LdapDNStrConverter.getDefault().parseAVA(avaString);
	oid = ava.getOid();
	value = ava.getValue();
    }

    /**
     * Like AVA(String) with a DER encoding order given for Directory Strings.
     */
    public AVA(String avaString, byte[] tags)
	throws IOException
    {
	AVA ava;
	ava = LdapDNStrConverter.getDefault().parseAVA(avaString, tags);
	oid = ava.getOid();
	value = ava.getValue();
    }

    /** 
     * Constructs an AVA from a Ldap DN string containing one AVA 
     * component using the specified LdapDNStrConverter.
     * @see LdapDNStrConverter
     * @param avaString a Ldap DN string containing one AVA.
     * @param ldapDNStrConverter a LdapDNStrConverter 
     */
    public AVA(String avaString, LdapDNStrConverter ldapDNStrConverter)
	throws IOException
    {
	AVA ava;
	ava = ldapDNStrConverter.parseAVA(avaString);
	oid = ava.getOid();
	value = ava.getValue();
    }

    /** 
     * Constructs an AVA from an OID and DerValue.
     * @param type an ObjectIdentifier
     * @param val a DerValue
     */
    public AVA(ObjectIdentifier type, DerValue val)
	throws IOException
    {
	oid = type;
	value = val;
    }

    /**
     * Constructs an AVA from an input stream of UTF8 bytes that form
     * a Ldap DN string. Then parse the Ldap DN string using the global
     * default LdapDNStrConverter.
     * <br>
     * Parses an RFC 1779 style AVA string:  CN=fee fie foe fum
     * or perhaps with quotes.  Not all defined AVA tags are supported;
     * of current note are X.400 related ones (PRMD, ADMD, etc).
     *
     * This terminates at unescaped AVA separators ("+") or RDN
     * separators (",", ";"), or DN terminators (">"), and removes
     * cosmetic whitespace at the end of values.
     * 
     * @see LdapDNStrConverter
     * @param in the input stream.
     */
    public AVA (InputStream in) throws IOException
    {
	StringBuffer	temp = new StringBuffer ();
	AVA 		a;
	byte[]		buf = new byte[in.available()];
	char[]		converted_chars;
	ByteToCharConverter bcc;

	// convert from UTF8 bytes to java string then parse it.
	in.read(buf);
	try {
	    bcc = ByteToCharConverter.getConverter("UTF8");
	}
	catch (java.io.UnsupportedEncodingException e) {
	    throw new IOException("UTF8 encoding not supported");
	}
	converted_chars = bcc.convertAll(buf);
	temp.append(converted_chars);

	a = LdapDNStrConverter.getDefault().parseAVA(temp.toString());
	oid = a.getOid();
	value = a.getValue();
    }

    /**
     * Constructs an AVA from a Der Input Stream.
     * @param in the Der Input Stream.
     */
    public AVA(DerInputStream in) throws IOException
    {
	DerValue	assertion = in.getDerValue ();

	/*
	 * Individual attribute value assertions are SEQUENCE of two values.
	 * That'd be a "struct" outside of ASN.1.
	 */
	if (assertion.tag != DerValue.tag_Sequence)
	    throw new CertParseError ("X500 AVA, not a sequence");

        ObjectIdentifier o = assertion.data.getOID();
        oid = X500NameAttrMap.getDefault().getOid(o);
        if (oid == null) {
		// NSCP #329837
		// if this OID is not recongized in our map (table),
		// it is fine. we just store it as regular OID.
                oid = o;
        }
	value = assertion.data.getDerValue ();

	if (assertion.data.available () != 0)
	    throw new CertParseError ("AVA, extra bytes = "
		+ assertion.data.available ());
    }

    // other public methods.

    /** 
     * Returns true if another AVA has the same OID and DerValue.
     * @param other the other AVA.
     * @return ture iff other AVA has same oid and value.
     */
    public boolean equals (AVA other)
    {
	return oid.equals (other.oid) && value.equals (other.value);
    }

    /** 
     * Compares the AVA with an Object, returns true if the object is 
     * an AVA and has the same OID and value.
     * @param other the other object.
     * @return true iff other object is an AVA and has same oid and value.
     */
    public boolean equals (Object other)
    {
	if (other instanceof AVA)
	    return equals ((AVA)other);
	else
	    return false;
    }

    /**
     * Encodes the AVA to a Der output stream.
     * AVAs are encoded as a SEQUENCE of two elements.
     * @param out The Der output stream.
     */
    public void encode (DerOutputStream out) throws IOException
    {
	derEncode(out);
    }
 
   /**
     * DER encode this object onto an output stream.
     * Implements the <code>DerEncoder</code> interface.
     *
     * @param out 
     * the output stream on which to write the DER encoding.
     *
     * @exception IOException on encoding error.
     */
    public void derEncode (OutputStream out) throws IOException
    {
	DerOutputStream		tmp = new DerOutputStream ();
	DerOutputStream		tmp2 = new DerOutputStream ();

	tmp.putOID (oid);
	value.encode (tmp);
	tmp2.write (DerValue.tag_Sequence, tmp);
	out.write(tmp2.toByteArray());
    }

    /**
     * Returns a Ldap DN string with one AVA component using 
     * the global default LdapDNStrConverter.
     * @return a Ldap DN string 
     * @exception IOException if an error occurs during conversion.
     * @see LdapDNStrConverter
     */
    public String toLdapDNString()
	throws IOException
    {
	LdapDNStrConverter v = LdapDNStrConverter.getDefault();
	return v.encodeAVA(this);
    }

    /**
     * Returns a Ldap DN string with one AVA component using the specified 
     * LdapDNStrConverter.
     * @return a Ldap DN string 
     * @param ldapDNStrConverter a Ldap DN String Converter 
     * @exception IOException if an error occurs during the conversion.
     * @see LdapDNStrConverter
     */
    public String toLdapDNString(LdapDNStrConverter ldapDNStrConverter)
	throws IOException
    {
	return ldapDNStrConverter.encodeAVA(this);
    }

    /**
     * Returns a Ldap DN string with the AVA component using the global
     * default LdapDNStrConverter, or null if an error occurs in conversion.
     * @return a Ldap DN string containing the AVA, or null if an 
     *		error occurs in the conversion.
     */ 
    public String toString()
    {
	String s;
	try {
	    // NOTE that a LdapDNString is returned here to match the 
	    // original source from sun. Could also return the raw value
	    // (before Ldap escaping) here.
	    s = toLdapDNString();
	}
	catch (IOException e) {
	    return null;
	}
	return s;
    }

    /** 
     * Returns the OID in the AVA.
     * @return the ObjectIdentifier in this AVA.
     */
    public ObjectIdentifier getOid()
    {
	return oid;
    }

    /** 
     * Returns the value in this AVA as a DerValue
     * @return attribute value in this AVA.
     */
    public DerValue getValue()
    {
	return value;
    }

}