package edu.stanford.peer.rbtm.engine;

import java.util.*;

import edu.stanford.peer.rbtm.credential.*;
import edu.stanford.peer.rbtm.util.*;


public class LinkedRoleProofNode extends AbstractProofNode
{
	private BackwardLinkingMonitor  monitor;

    protected LinkedRoleProofNode(ProofGraph graph, LinkedRole re, int trackType) {
		super(graph, re, trackType);
	}


    public HashSet getChain(int size, EntityExpression target) {
        if(target.equals(getRoleExp())) {
            return new HashSet(size);
        }
        System.out.println("\n+++++ this = " + getRoleExp());	
        ResultEvidenceMap solutions = getBackwardSolutions();
        HashSet soln = (HashSet)solutions.getResultEvidence(target);
        System.out.println("solutions = " + solutions);
        System.out.println("soln = " + soln);
        //In the end, there can be only ONE . . . 
        ProofNode nextNode =(ProofNode)soln.iterator().next();
        System.out.println("\n+++++ next = " + nextNode.getRoleExp() );
        size++;
        HashSet set = nextNode.getChain(size, target);
        Role aDotR1 = ((LinkedRole)getRoleExp()).getFirstRole();
        System.out.println("\n+++++ A.r1 = " + aDotR1);
        Entity b = ((Role)nextNode.getRoleExp()).getBase();
        System.out.println("\n+++++ B = " + b);
        HashSet results = 
            getGraph().getChain((EntityExpression)aDotR1, (EntityExpression)b);
        System.out.println("\n+++++ results  = " + results);
        Iterator evidence = results.iterator();
        while(evidence.hasNext()) {
            set.add((Credential)evidence.next());
        }
        return set;
    }


    public void additionalBackwardProcess() {
		if (monitor != null) {
			return;
		}
        Role firstRole = (Role) ((LinkedRole)getRoleExp()).getFirstRole();
        ProofNode node = getGraph().addBackwardNode(firstRole);
        monitor = new BackwardLinkingMonitor();
        node.addBackwardListener(monitor);
	//if(addRole)backwardSolutionAdded(this, getRoleExp());
    }

    class BackwardLinkingMonitor implements BackwardSolutionListener {
        public void backwardSolutionAdded(ProofNode s,  BackwardSolution re) {
	    if (re instanceof Entity) {
		Role  r = new Role((Entity)re, 
		   ((LinkedRole)getRoleExp()).getSecondRoleName());
		ProofNode node = getGraph().addBackwardNode(r);
		node.addChild(LinkedRoleProofNode.this, s);
	    }
        }
	
	public String toString() {
	    return "Monitor " + getRoleExp();
	}
    }

	public void additionalForwardProcess() {
	}
} // End of class LinkedRoleProofNode