/*
 * Copyrighted (C) 2002, Networks Associates Technology, Inc. 
 * All rights reserved
 */
package com.nailabs.abac.trust;

import com.nailabs.abac.process.*;
import com.nailabs.abac.test.*;
import edu.stanford.peer.rbtm.credential.*;
import java.util.*;
import java.io.*;

/**
 * A trust target graph node, representing a linking goal. This node has a 
 * triplet uniqueness based on the verifier, rolename, and subject. It can
 * have multiple parents (via linking monintor edges) and multiple childen
 * (via linking solution edges).
 */
public class LinkingGoalNode extends TTGNode implements SatisfactionListener {

    // Node state information constants

    /** Reserved for future use */
    public static final String OPAQUE = "opaque";

    private CompletionState state = new CompletionState();
    
    private int completionCount = 0;

    /** string constructor */
    public LinkingGoalNode(String goal) 
        throws TrustTargetParsingException, CredentialParsingException {
        this(new LinkingGoal(goal));
    }
    
    /** parsed object constructor */
    public LinkingGoalNode(Entity verifier, RoleName target, Entity subject) 
        throws TrustTargetParsingException, CredentialParsingException {
        this(new LinkingGoal(verifier, target, subject));
    }

    /** default constructor */
    public LinkingGoalNode(LinkingGoal goal) {
        super(goal);
        subName = "LinkingGoal";
        state.addObserver(this);
    }

    /** 
     * Notify observers that this node's completion state has been changed.
     */
    public void update(Observable obs, Object obj) {
        if(obs == state) {
            setChanged();
            notifyObservers(state);
        } else {
            super.update(obs, obj);
        }
    }


    /** 
     * Each distinct node type should know how to process itself, so this 
     * method should be overridden in subclasses. 
     * @param context A context w/helper functions required for processing
     */
    public void verifierProcess(NegotiationContext context) {
        //this case should not occur
    }
 
    /** 
     * Each distinct node type should know how to process itself, so this 
     * method should be overridden in subclasses. 
     * @param context A context w/helper functions required for processing
     */
    public void opponentProcess(NegotiationContext context) {
        TTG graph = context.getGraph();
        LinkingGoal goal = (LinkingGoal)getGoal();
        FrontierManager f = context.getFrontier();
        Entity verifier = goal.getVerifier();
        EntityExpression subject = goal.getSubject();
        HashSet solutions = new HashSet();

        debug("linking-goal", "Opponent processing " + goal);
        // (1) O adds a linking solution edge G <--< <V: A.r2 <<-?- S>, for 
        //     any A.r2 which is an element of sensitiveRole(O) or 
        //     A.r2 defined by a credentials in CsuperS(O)

        // collect the sensitive roles which match with r2
        Iterator sensitiveRoles =
            f.getAckPolicy().getSensitiveRoles().iterator();
        while(sensitiveRoles.hasNext()) {
            Role sensitive = (Role)sensitiveRoles.next();
            if(sensitive.getName().equals(getTargetRoleName())) {
                solutions.add(sensitive);
                debug("linking-goal", "found sensitive role = " + sensitive);
            }
        }
        // add the roles (r2) where it is definied by a credential
        Iterator defined = f.getCredentialsDefiningRole(getTargetRoleName());
        if(!defined.hasNext()) {
            debug("linking-goal", "no credentials foudn defining role: " +
                  getTargetRoleName());
        }
        while(defined.hasNext()) {
            StaticCredential credential = (StaticCredential)defined.next();
            Role solution = credential.getDefinedRole();
            solutions.add(solution);
            debug("linking-goal", "found matching r2 = " + solution);
        }
        // iterate through the solution and add the linking solution edges
        Iterator i = solutions.iterator();
        while(i.hasNext()) {
            try {
                Role solution = (Role)i.next();
                TrustTarget child = 
                    new TrustTarget(verifier, solution, subject);
                graph.addLinkingSolutionEdge(goal, child);
            } catch(Exception ex) {
                ex.printStackTrace();
            }
        }
        // (2) O can mark this node opponent-processed only after (1) is done.
        graph.setOpponentProcessed(goal);
    }

    public void addLinkingImplicationEdges(TrustTarget target) {
        NegotiationContext context = getContext();
        FrontierManager fm = context.getFrontier();

        Entity v = getVerifier();
        Entity b =  ((Role)target.getTargetRole()).getBase();
        TTG graph = getContext().getGraph();
        Iterator i = parents.values().iterator();
        
        while(i.hasNext()) {
            try {
                LinkTTNode parent = (LinkTTNode)i.next();
                RoleName r1 =  parent.getFirstRole().getName();   
                boolean subjectTraceable = fm.isSubjectTraceable(r1);
                if(context.getSelf().equals(getVerifier())) { 
                    // if we're the verifier
                    if(!subjectTraceable) {     
                        // check r1 that is not subject traceable
                        TrustTarget parentTarget = 
                            (TrustTarget)parent.getGoal();
                        TrustTarget child = 
                            new TrustTarget(v, parent.getFirstRole(), b);
                        graph.addLinkingImplicationEdge(parentTarget, child); 
                    }
                } else {
                    // else we are the opponent
                    if(subjectTraceable) {
                        // check r1 that is not subject traceable
                        TrustTarget parentTarget = 
                            (TrustTarget)parent.getGoal();
                        TrustTarget child = 
                            new TrustTarget(v, parent.getFirstRole(), b);
                        graph.addLinkingImplicationEdge(parentTarget, child); 
                    }                
                }
            } catch(Exception ex) {
                ex.printStackTrace();
            }
        }
    }

    /** 
     * A linking goal uses this interface to act as a monitor for its own
     * completion state and to add linking-implication edges 
     */ 
    public TTGNodeSet receive(TrustTarget target, SatisfactionState state) {
        // a satisfied linking solution does step 2 in linked role processing
        if(state.getState() == SatisfactionState.SATISFIED) {
            debug("linking-goal", "received SATISFIED from " + target);
            addLinkingImplicationEdges(target);
        }
        // Just in case we get unknown satisfaction state propagation check 
        //for it here to make certain we have an accurate completion count
        if(state.getState() != SatisfactionState.UNKNOWN) {
            completionCount++;
            if(completionCount <= children.size()) {
                this.state.setComplete(true);
            }
        }
        // if this node is complete, we should notify the parent(s) 
        if(isComplete()) {
            Iterator i = parents.values().iterator();
            notifyObservers(this.state);

            while(i.hasNext()) {
                LinkTTNode parent = (LinkTTNode)i.next();
                parent.receive((LinkingGoal)getGoal(), 
                               new CompletionState(true) );
            }
        }
        return new TTGNodeSet();
    }

    public boolean isComplete() { 
        return state.isComplete();
    }

    /** convenience method for extracting the target role name for this node */
    public RoleName getTargetRoleName() {
        return ((LinkingGoal)getGoal()).getTargetRoleName();
    }

    public String toXML() {
        // Add node state here (eg. in/complete, etc.)
        StringBuffer state = new StringBuffer("state=\"");
        state.append(this.state);
        // Add linking solutions if any */
        return toXML(state.toString(), "");
    }

}