package com.nailabs.abac.credential;

import java.io.File;
import java.io.FileInputStream;
import java.util.Iterator;
import java.util.HashSet;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Collection;
import java.security.PublicKey;
import edu.stanford.peer.rbtm.util.Predicate;
import edu.stanford.peer.rbtm.credential.Entity;
import edu.stanford.peer.rbtm.credential.EntityExpression;
import edu.stanford.peer.rbtm.credential.Role;
import edu.stanford.peer.rbtm.credential.RoleName;
import edu.stanford.peer.rbtm.credential.SimpleEntity;
import edu.stanford.peer.rbtm.credential.LinkedRole;
import edu.stanford.peer.rbtm.credential.StaticCredential;

import edu.stanford.peer.rbtm.engine.*;

import edu.stanford.rt.credential.*;
import edu.stanford.rt.parser.RTParser;

/**
 * An RTML-aware GraphEngine, formerly known as CredentialManager.
 */
public class RtmlEngine extends GraphEngine  {
    /** internal store of parsed RTML */
    protected CredentialStore store;

    /** static credential to credential domain mapping */
    protected HashMap indexByDomains = new HashMap();

    /** internal cache of entity hash id to short name mapping */
    private static Hashtable entityCache = new Hashtable(10); 

    public RtmlEngine() {
	super();
    }

    /** default constructor used for the opponents transmitted credentials*/
    public RtmlEngine(CredentialStore store) {
        super();
        this.store = store;
        importDomains(store);
    }

    /** predicated constructor used by oppo, sens, and simp frontiers */
    public RtmlEngine(CredentialStore store, Predicate p) {
        super(p);
        this.store = store;
        importDomains(store);
    }

    /** convenience method for looking up a shortname from a credential hash */
    public static String getShortName(String hash) { 
        return (String)entityCache.get(hash);
    }

    /** adds a new entity hash to short name (reverse) mapping */
    public static void addEntity(String hash, String shortName) {
        entityCache.put(hash, shortName);
    }

    /** add the static credentials which make up a credential domain */
    public void addDomain(CredentialDomain domain) {
        Iterator creds = convert(domain).iterator();
	try{
	    while(creds.hasNext()) {
		StaticCredential cred = (StaticCredential)creds.next();
		HashSet siblings = (HashSet)indexByDomains.get(domain);
		//System.out.println("Adding " + cred);
		addCredential(cred);
		if(siblings == null) {
		    siblings = new HashSet(1);
		    indexByDomains.put(domain, siblings);
		}
		siblings.add(cred);
	    }
	    store.addCredentialDomain(domain.getHashID(), domain);
	} catch(Exception ex) {
	    //ex.printStackTrace();
	}
    }
    
    /** 
     * removes a the domain for this credential and any othe credentials in 
     * the same domain.
     */
    public void removeCredential(RtmlCredential cred) {
	CredentialDomain domain = cred.getCredentialDomain();
	HashSet credSet = (HashSet)indexByDomains.get(domain);
	if(credSet != null) {
	    super.removeCredentials((Collection)credSet);
	}	
    }

    /** protected accessor method used for importing a set of cred domains */
    protected CredentialStore getCredentialStore() {
	return store;
    }

    /** importing domains is used publicly for credential discovery */
    public void importDomains(RtmlEngine engine) {
	importDomains(engine.getCredentialStore());
    }

    /** internal method for loading the engine from a credential store */
    public void importDomains(CredentialStore store) {
        HashMap domains = store.getCredentialDomains();
        Iterator i = domains.values().iterator();
        while(i.hasNext()) {
	    //System.out.println("domain = " + i.next().getClass());
            addDomain((CredentialDomain)i.next());
        }
    }
    

    /** convert a credential domain into a set of static credentials */
    public static Collection convert(CredentialDomain domain) {
        HashSet set = new HashSet();
        Iterator roles = domain.roleDefinitionIterator();
        int count = 0;
        while(roles.hasNext()) {
            //System.out.println("Role Definition # " + ++count);
            RoleDefinition def = (RoleDefinition)roles.next();
            Role head = (Role)
                RtmlExpression.convert(def.getHead(), domain);
            EntityExpression body = 
                RtmlExpression.convert(def.getBody(), domain);
            StaticCredential cred = new RtmlCredential(head, body, domain);
            //System.out.println("\tcred = " + cred);
            set.add(cred);
        }
        return set;
    }

    /** main method for a test application */
    public static void main(String argv[]) {
        if(argv.length < 1) {
            System.out.println("java com.nailabs.abac.credential.RtmlCredential  cred_store.xml");
            System.exit(1);
        }
        try {
            RTParser parser = new RTParser();
            //System domain is created here.
            RTContext context = new RTContext(parser);
            CredentialStore store = new CredentialStore(parser);

            parser.parseCredentialStore(new FileInputStream(new File(argv[0])),
                                        context, store);
            CredentialDomain domain = 
                store.getCredentialDomain(System.getProperty(
                  "com.nailabs.abac.credential.Hash", "FakeHashCredential01"));
            convert(domain);
        } catch(Exception ex) {
            ex.printStackTrace();
        }
    }

}