package jcgp.backend.population;

import jcgp.backend.resources.Resources;

public class Population {
	
	private Chromosome[] chromosomes;
	private final Resources resources;
	
	/**
	 * Initialise a random population according to the parameters specified
	 * in the resources.
	 * 
	 * @param resources the CGP resources
	 */
	public Population(Resources resources) {
		this.resources = resources;
		
		chromosomes = new Chromosome[resources.populationSize()];
		for (int c = 0; c < chromosomes.length; c++) {
			chromosomes[c] = new Chromosome(resources);
		}
	}
	
	/**
	 * Initialise a population of copies of the given chromosome.
	 * 
	 * @param parent
	 * @param resources
	 */
	public Population(Chromosome parent, Resources resources) {
		this.resources = resources;
		
		chromosomes = new Chromosome[resources.populationSize()];
		for (int c = 0; c < chromosomes.length; c++) {
			chromosomes[c] = new Chromosome(parent);
		}
	}

	/**
	 * Returns the indexed chromosome.
	 * 
	 * @param index
	 * @return
	 */
	public Chromosome getChromosome(int index) {
		return chromosomes[index];
	}
	
	/**
	 * @return a random chromosome from this population.
	 */
	public Chromosome getRandomChromosome() {
		return chromosomes[resources.getRandomInt(chromosomes.length)];
	}

	/**
	 * Copy a chromosome into a different position.
	 * After this returns, the target chromosome has
	 * identical connections and functions to the source
	 * one, though they are separate instances.
	 * 
	 * This method does nothing if source == target.
	 * 
	 * @param source 
	 * @param target
	 */
	public void copyChromosome(int source, int target) {
		if (source != target) {
			chromosomes[target].copyGenes(chromosomes[source]);
		}
	}
	
	public void reinitialise() {
		for (int c = 0; c < chromosomes.length; c++) {
			chromosomes[c].reinitialiseConnections();
		}
	}
	
}