/* Copyright 2003, Carnegie Mellon, All Rights Reserved */

package edu.cmu.minorthird.classify;

import edu.cmu.minorthird.classify.algorithms.knn.*;


/**
 * A wrapper around on OnlineClassifierLearner that counts the number
 * of mistakes if makes.
 *
 * @author William Cohen
 */

public class MistakeCountingOnlineLearner extends OnlineClassifierLearner
{
	private OnlineClassifierLearner innerLearner;
	private int numMistakes, numExamples;
	private boolean reportMistakes;

	public MistakeCountingOnlineLearner()
	{
		//this(new VotedPerceptron(),true);
		this(new KnnLearner(),true);
	}

	public MistakeCountingOnlineLearner(OnlineClassifierLearner innerLearner)
	{
		this(innerLearner,true);
	} 

	public MistakeCountingOnlineLearner(OnlineClassifierLearner innerLearner,boolean reportMistakes) 
	{ 
		this.innerLearner = innerLearner; 
		this.reportMistakes = reportMistakes;
		numMistakes = numExamples = 0;
	}

	@Override
	public ClassifierLearner copy() 
	{ 
		return new MistakeCountingOnlineLearner((OnlineClassifierLearner)innerLearner.copy(),reportMistakes);
	}

	@Override
	public void completeTraining() 
	{ 
		innerLearner.completeTraining();
		if (reportMistakes) {
			System.out.println(numMistakes+" mistakes in "+numExamples+" examples for "+innerLearner);
		}
	}

	@Override
	public void addExample(Example answeredQuery)
	{
		ClassLabel predicted = innerLearner.getClassifier().classification(answeredQuery.asInstance());
		if (!answeredQuery.getLabel().isCorrect(predicted)) numMistakes++;
		numExamples++;
		innerLearner.addExample(answeredQuery);
	}

	@Override
	public Classifier getClassifier() 
	{
		return innerLearner.getClassifier();
	}

	@Override
	public void setSchema(ExampleSchema schema)
	{
		innerLearner.setSchema(schema);
	}

	@Override
	public ExampleSchema getSchema(){
		return innerLearner.getSchema();
	}

	@Override
	public void reset() 
	{
		innerLearner.reset();
		numMistakes = numExamples = 0;
	}

	/** Report the number of mistakes made by the inner learner. */
	public int getNumberOfMistakes() 
	{ 
		return numMistakes; 
	}

	/** Report the number of examples sent to the inner learner. */
	public int getTotalNumberOfExamples() 
	{ 
		return numExamples; 
	}

	@Override
	public String toString() 
	{
		return 
		"[MistakeCountingOnlineLearner: "+
		numMistakes+"/"+numExamples+" mistakes for "+innerLearner+"]";
	}
}