package net.deterlab.abac;

import java.io.*;
import java.math.*;
import java.text.*;

import java.util.*;

import java.security.*;
import java.security.cert.*;

import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.*;

import javax.xml.crypto.*;
import javax.xml.crypto.dsig.*;
import javax.xml.crypto.dsig.dom.*;
import javax.xml.crypto.dsig.keyinfo.*;
import javax.xml.crypto.dsig.spec.*;

import org.xml.sax.*;
import org.w3c.dom.*;

/**
 * An ABAC credential formatted as a soon-to-be deprecated  abac-type version
 * 1.0 GENI credential.
 * @author <a href="http://abac.deterlab.net">ISI ABAC team</a>
 * @version 1.4
 */
public class GENICredentialv1_0 extends GENICredential implements Comparable {
    /**
     * Create an empty Credential.
     */
    public GENICredentialv1_0() {
	super();
    }
    /**
     * Create a credential from a head and tail role.  This credential has no
     * underlying certificate, and cannot be exported or used in real proofs.
     * make_cert can create a certificate for a credential initialized this
     * way.
     * @param head the Role at the head of the credential
     * @param tail the Role at the tail of the credential
     */
    public GENICredentialv1_0(Role head, Role tail) {
	super(head, tail);
    }

    /**
     * Create a credential from an attribute cert in a file. Throws an
     * exception if the cert file can't be opened or if there's a format
     * problem with the cert.  Note that catching
     * java.security.GeneralSecurityException catches most of the exceptions
     * this throws.
     * @param filename a String containing the filename to read
     * @param ids a Collection of Identities to use in validating the cert
     * @throws CertInvalidException if the stream is unparsable
     * @throws MissingIssuerException if none of the Identities can validate the
     *				    certificate
     * @throws BadSignatureException if the signature check fails
     */
    GENICredentialv1_0(String filename, Collection<Identity> ids) 
	throws ABACException { 
	super(filename, ids);
    }

    /**
     * Create a credential from an attribute cert in a file. Throws an
     * exception if the cert file can't be opened or if there's a format
     * problem with the cert.  Note that catching
     * java.security.GeneralSecurityException catches most of the exceptions
     * this throws.
     * @param file the File to read
     * @param ids a Collection of Identities to use in validating the cert
     * @throws CertInvalidException if the stream is unparsable
     * @throws MissingIssuerException if none of the Identities can validate the
     *				    certificate
     * @throws BadSignatureException if the signature check fails
     */
    GENICredentialv1_0(File file, Collection<Identity> ids) 
	    throws ABACException {
	super(file, ids);
    }

    /**
     * Create a credential from an InputStream.  Throws an exception if the
     * stream can't be parsed or if there's a format problem with the cert.
     * Note that catching java.security.GeneralSecurityException catches most
     * of the exceptions this throws.
     * @param s the InputStream to read
     * @param ids a Collection of Identities to use in validating the cert
     * @throws CertInvalidException if the stream is unparsable
     * @throws MissingIssuerException if none of the Identities can validate the
     *				    certificate
     * @throws BadSignatureException if the signature check fails
     */
    GENICredentialv1_0(InputStream s, Collection<Identity> ids) 
	    throws ABACException { 
	super(s, ids);
    }

    /**
     * Encode the abac credential's XML and set the validity.  This is straight
     * line code that directly builds the credential.
     * @param validity a long holding the number of seconds that the credential
     * is valid for.
     * @return a Node, the place to attach signatures
     * @throws ABACException if any of the XML construction fails
     */
    protected Node make_rt0_content(long validity) throws ABACException {
	DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
	DocumentBuilder db = null;
	SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
	StringBuffer expBuf = new StringBuffer();

	/* This is a weirdness to cope with the GENI format.  They have a naked
	 * xml:id specifier without any namespace declarations in the
	 * credential.  Notice that this is the opposite of the setting used in
	 * init to read a credential. */
	dbf.setNamespaceAware(false);

	if ( dbf == null ) 
	    throw new ABACException("Cannot get DocumentBuilderFactory!?");

	try {
	    db = dbf.newDocumentBuilder();
	}
	catch (ParserConfigurationException pe) {
	    throw new ABACException("Cannot get DocumentBuilder!?" + 
		    pe.getMessage(), pe);
	}

	doc = db.newDocument();
	if ( doc == null ) 
	    throw new ABACException("No Document");

	Element root = doc.createElement("signed-credential"); 
	Element cred = doc.createElement("credential");
	Element sig = doc.createElement("signatures");
	Element e = doc.createElement("type");
	Node text = doc.createTextNode("abac");

	doc.appendChild(root);

	cred.setAttribute("xml:id", "ref0");
	/* So that the signing code can find the section to sign */
	cred.setIdAttribute("xml:id", true);

	root.appendChild(cred);
	e.appendChild(text);
	cred.appendChild(e);

	m_expiration = new Date(System.currentTimeMillis() + 
		(1000L * validity ));
	df.setTimeZone(new SimpleTimeZone(0, "Z"));
	df.format(m_expiration, expBuf, new FieldPosition(0));
	e = doc.createElement("expires");
	text = doc.createTextNode(expBuf.toString());
	e.appendChild(text);
	cred.appendChild(e);

	e = doc.createElement("version");
	text = doc.createTextNode("1.0");
	e.appendChild(text);
	cred.appendChild(e);

	e = doc.createElement("rt0");
	text = doc.createTextNode(m_head + "<-" + m_tail);
	e.appendChild(text);
	cred.appendChild(e);

	root.appendChild(sig);
	return sig;
    }

    /**
     * Load the roles off the attribute cert.
     * @throws CertInvalidException if the certificate is badly formatted
     */
    protected void load_roles() throws CertInvalidException {
	if ( doc == null ) 
            throw new CertInvalidException("No credential");

	NodeList nodes = doc.getElementsByTagName("type");
	Node node = null;
        String roles = null;

	if (nodes == null || nodes.getLength() != 1) 
            throw new CertInvalidException("More than one type element?");

	node = nodes.item(0);
	if ( node == null ) 
            throw new CertInvalidException("bad rt0 element?");

	if ( !"abac".equals(node.getTextContent()) ) 
            throw new CertInvalidException("Not an abac type credential");

	nodes = doc.getElementsByTagName("rt0");
	if (nodes == null || nodes.getLength() != 1) 
            throw new CertInvalidException("More than one rt0 element?");

	node = nodes.item(0);

	if ( node == null ) 
            throw new CertInvalidException("bad rt0 element?");

	if ( (roles = node.getTextContent()) == null ) 
            throw new CertInvalidException("bad rt0 element (no text)?");

        String[] parts = roles.split("\\s*<--?\\s*");
        if (parts.length != 2)
            throw new CertInvalidException("Invalid attribute: " + roles);

        m_head = new Role(parts[0]);
        m_tail = new Role(parts[1]);
    }

    /**
     * Return a CredentialCredentialFactorySpecialization for GENICredentials.
     * Used by the CredentialFactory to parse and generate these kind of
     * credentials.  It basically wraps constuctor calls.
     * @return a CredentialFactorySpecialization for this kind of credential.
     */
    static public CredentialFactorySpecialization 
	    getCredentialFactorySpecialization() {
	return new CredentialFactorySpecialization() {
	    public Credential[] parseCredential(InputStream is, 
		    Collection<Identity> ids) throws ABACException {
		return new Credential[] { new GENICredentialv1_0(is, ids) }; 
	    }
	    public Credential generateCredential(Role head, Role tail,
		    KeyIDMap aliases) {
		return new GENICredentialv1_0(head, tail);
	    }
	};
    }
}