package com.nailabs.abac.credential;

import java.io.*;
import java.util.*;
import edu.stanford.peer.rbtm.credential.*;
import edu.stanford.peer.rbtm.engine.*;
import edu.stanford.peer.rbtm.util.*;
import edu.stanford.rt.parser.*;
import edu.stanford.rt.credential.*;
 
/** 
 * A service object which encapsulates the functions of a CredentialManager
 * that are necessary for remote and local discovery.
 */
public class DiscoveryService {
    /** The graphine which performs the actual searches */
    protected RtmlEngine engine;
    /** An RTML parser which can be shared for all discovery services */
    protected static RTParser parser = null;
    /** AN RTML context which can be shared across all discovery services */
    protected static RTContext context = null;

    static {
	try {
	    parser = new RTParser();
	    context = new RTContext(parser);
	} catch(Exception ex) {
	    ex.printStackTrace();
	}
    }

    /** Default constructor */
    public DiscoveryService(String storeFile) {
	try {
	    parser = new RTParser();
	    context = new RTContext(parser);
	    CredentialStore store = new CredentialStore(parser);
	    parser.parseCredentialStore
		(new FileInputStream(new File(storeFile)), context, store);
	    this.engine = new RtmlEngine(store);
	} catch (Exception ex) {
	    //ex.printStackTrace();
	}
    }

    /** 
     * For each result in the map, match the RTML for the domain of the 
     * rtml credential.
     */
    protected String[] soapify(ResultEvidenceMap map) {
	Object results[] = map.resultSet().toArray();
	int max = results.length;
	String[] evidence = new String[max];
	for(int i = 0; i < max; i++) {
	    Object obj = map.getResultEvidence(results[i]);
	    if(obj instanceof RtmlCredential) {
		RtmlCredential cred = (RtmlCredential)obj;
		evidence[i] = cred.toXML();
	    } else {
		evidence[i] = results[i] + " -" + obj.toString();
	    }
	}
	return evidence;
    }

    /**
     * Convert a collection of <CODE>RTMLCredential</CODE> instances into a 
     * set of their <CODE>CredentialDomain</CODE> instances.
     */
    protected String[] soapify(Collection c) {
	//String[] credentials = new String[c.size()];
	HashSet credentials = new HashSet(c.size());
	Iterator results = c.iterator();
	String output[];
	int i = 0;
	
	while(results.hasNext()) {
	    Object obj = results.next();
	    if(obj instanceof RtmlCredential) {
		RtmlCredential cred = (RtmlCredential)obj;
		//credentials[i++] = cred.toXML();
		credentials.add(cred.toXML());
	    } else {
		//credentials[i++] = obj.toString();
		credentials.add(obj.toString());
	    }
	}
	output = new String[credentials.size()];
	results = credentials.iterator(); 
	for(i = 0; results.hasNext(); i++) {
	    output[i] = results.next().toString();
	}
	return output;
    }

    /**
     * For a specified entity name, return all <code>CredentialDomain</code>
     * instances which were issued by the entity.
     */
    public String[] getCredentialsIssuedBy(String entityName) {
	Entity e = new RtmlEntity(entityName);
	return soapify(engine.getCredentialsIssuedBy(e));
	//return soapify(engine.backwardSearch(e));
    }

    /**
     * For the specified role, return all <code>CredentialDomain</code> 
     * instances which define the specified role (entity.role).
     */
    public String[] findCredentialsDefiningRole(String entity, String role) {
	Entity e = new RtmlEntity(entity);
	edu.stanford.peer.rbtm.credential.Role r = 
	    new edu.stanford.peer.rbtm.credential.Role(e, role);
	Iterator results = engine.findCredentialsDefiningRole(r);
        HashSet evidence = new HashSet();
	StringBuffer buff = new StringBuffer("DefiningRole(");
	buff.append(entity).append(".").append(role).append(") = ");
        while(results.hasNext()) {
	    Object result = results.next();
	    //System.out.println("def result = " + result);
	    buff.append(result.toString()).append(" ");
	    evidence.add(result);
        }
	System.out.println(buff.toString());
	return soapify(evidence);
    }

    /**
     * For a given entity expression, find the <code>CredentialDomain</code>
     * instances which define credentials that have the entity expression as 
     * a subject.
     */
    public String[] findCredentialsBySubject(String expr) {
	EntityExpression ee = null;
	try {
	    ee = StaticCredential.getEntityExpression(expr);
	    ee = RtmlExpression.convert(ee);
	} catch (Exception cpe) {
	    cpe.printStackTrace();
	}
	Iterator results = engine.findCredentialsBySubject(ee);
	HashSet evidence = new HashSet();
	StringBuffer buff = new StringBuffer("BySubject(");
	buff.append(expr).append(") = ");
	while(results.hasNext()) {
	    Object result = results.next();
	    //System.out.println("subj result = " + result);
	    buff.append(result).append(" ");
	    if(!evidence.contains(result)) {
		evidence.add(result);
	    }
	}
	System.out.println(buff.toString());
	return soapify(evidence);
    }

    /**
     * Add a new <code>CredentialDomain</code> to the underlying 
     * <code>CredentialStore</code>.
     * @param xml an xml block which defined a <code>CredentialDomain</code>
     */
    public void addCredentialDomain(String xml) {
	try {
	    InputStream in = new ByteArrayInputStream(xml.getBytes());
	    CredentialDomain domain = 
		parser.parseCredentialDomain(in, context);
	    synchronized(engine) {
		engine.addDomain(domain);
	    }
	} catch(Exception ex) {
	    ex.printStackTrace();
	}
    }

}