/*
 * Created on Jan 31, 2005
 *
 */
package aima.probability;

import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;

/**
 * @author Ravi Mohan
 *  
 */
public class BayesNetNode {
	private String variable;

	List<BayesNetNode> parents, children;

	ProbabilityDistribution distribution;

	public BayesNetNode(String variable) {
		this.variable = variable;
		parents = new ArrayList<BayesNetNode>();
		children = new ArrayList<BayesNetNode>();
		distribution = new ProbabilityDistribution(variable);
	}

	private void addParent(BayesNetNode node) {
		if (!(parents.contains(node))) {
			parents.add(node);
		}
	}

	private void addChild(BayesNetNode node) {
		if (!(children.contains(node))) {
			children.add(node);
		}
	}

	public void influencedBy(BayesNetNode parent1) {
		addParent(parent1);
		parent1.addChild(this);
		distribution = new ProbabilityDistribution(parent1.getVariable());
	}

	public void influencedBy(BayesNetNode parent1, BayesNetNode parent2) {
		influencedBy(parent1);
		influencedBy(parent2);
		distribution = new ProbabilityDistribution(parent1.getVariable(),
				parent2.getVariable());
	}

	public void setProbability(boolean b, double d) {
		distribution.set(b, d);
		if (isRoot()) {
			distribution.set(!b, 1.0 - d);
		}

	}

	private boolean isRoot() {
		return (parents.size() == 0);
	}

	public void setProbability(boolean b, boolean c, double d) {
		distribution.set(b, c, d);

	}

	public String getVariable() {
		return variable;
	}

	public List<BayesNetNode> getChildren() {
		return children;
	}

	public List<BayesNetNode>  getParents() {
		return parents;
	}

	public String toString() {
		return variable;
	}

	public double probabilityOf(Hashtable conditions) {
		return distribution.probabilityOf(conditions);
	}

	public Boolean isTrueFor(double probability,Hashtable<String,Boolean> modelBuiltUpSoFar) {
		Hashtable<String, Boolean> conditions =  new Hashtable<String,Boolean>();
		if (isRoot()) {
			conditions.put(getVariable(),Boolean.TRUE);
		}else{
			for (int i=0;i<parents.size();i++){
				BayesNetNode parent =  (BayesNetNode)parents.get(i);
				conditions.put(parent.getVariable(),modelBuiltUpSoFar.get(parent.getVariable()));
			}		
		}
		double trueProbability = probabilityOf(conditions);
		if (probability <= trueProbability) {
			return Boolean.TRUE;
		}
		else{
			return Boolean.FALSE;
		}
	}
	
	public boolean equals(Object o ){

		if( this == o ) {
			return true;
		}
		if((o == null) || (this.getClass() != o.getClass())){
			return false;
		}
		BayesNetNode another = (BayesNetNode)o;
		return variable.equals(another.variable);
	}


}