package jcgp.backend.modules.fitness;

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

import jcgp.backend.population.Chromosome;
import jcgp.backend.population.Population;
import jcgp.backend.resources.Resources;
import jcgp.backend.resources.parameters.IntegerParameter;
import jcgp.backend.resources.parameters.Parameter;

/**
 * 
 * This fitness function module implements a simple test case evaluator.
 * 
 * A TestCase object is a 
 * 
 * 
 * @author Eduardo Pedroni
 *
 */
public abstract class TestCaseProblem<U> extends Problem {
	
	public static class TestCase<T> {

		private T[] inputs;
		private T[] outputs;
		
		public TestCase(T[] inputs, T[] outputs) {
			this.inputs = inputs;
			this.outputs = outputs;
		}
		
		public T getInput(int index) {
			return inputs[index];
		}
		
		public T getOutput(int index) {
			return outputs[index];
		}
		
		public T[] getInputs() {
			return inputs;
		}
		
		public T[] getOutputs() {
			return outputs;
		}
	}
	
	private ArrayList<TestCase<U>> testCases;
	private IntegerParameter maxFitness;
	
	public TestCaseProblem() {
		maxFitness = new IntegerParameter(0, "Max fitness", true, false) {
			@Override
			public void validate(int newValue) {
				// blank
			}
		};
		testCases = new ArrayList<TestCase<U>>();
	}
	
	
	@Override
	public void evaluate(Population population, Resources resources) {
		// for every chromosome in the population
		for (int i = 0; i < resources.getInt("popSize"); i++) {
			// assume an initial fitness of 0
			int fitness = 0;
			// for each test case
			for (int t = 0; t < testCases.size(); t++) {
				population.getChromosome(i).setInputs(testCases.get(t).getInputs());
				// check each output
				for (int o = 0; o < resources.getInt("outputs"); o++) {
					if (population.getChromosome(i).getOutput(o).calculate() == testCases.get(t).getOutput(o)) {
						fitness++;
					}
				}
			}
			// assign the resulting fitness to the respective individual
			population.getChromosome(i).setFitness(fitness);
		}
	}
	
	@Override
	public Parameter[] getLocalParameters() {
		return new Parameter[]{maxFitness};
	}
	
	private int getMaxFitness() {
		int fitness = 0;
		
		for (TestCase<U> tc : testCases) {
			fitness += tc.getOutputs().length;
		}
		
		return fitness;
	}
	
	public void setTestCases(List<TestCase<U>> testCases) {
		this.testCases.clear();
		this.testCases.addAll(testCases);
		maxFitness.set(getMaxFitness());
	}
	
	@Override
	public boolean isPerfectSolution(Chromosome fittest) {
		return fittest.getFitness() >= maxFitness.get();
	}
}