/**
 * Moobreeder is a simple cow breeding game to illustrate the principles of
 * selective breeding to KS3 pupils.
 *
 * (c) Daniel Vedder 2018, Amano Christian School
 * Licensed under the terms of the MIT license.
 * https://git.synoikos.de/daniel/moobreeder
 */

/*
 * This is a singleton class that holds the current herd.
 */

import java.util.ArrayList;
import java.util.Random;

public class Herd
{
	public static int initialSize = 4;
	private static Herd singleton;
	//allow other classes to access the RNG
	public static Random random; 
	
	private ArrayList<Cow> herd;
	private Cow[] parents;
	private Cow[] offspring;

	private Herd()
	{
		herd = new ArrayList<Cow>();
		parents = new Cow[] {null, null};
		offspring = new Cow[] {null, null};
		for (int i = 0; i < initialSize; i++) {
			String sex = "male";
			if ((i % 2) == 0) sex = "female";
			herd.add(new Cow(sex));
		}
	}

	public static Herd getInstance()
	{
		if (singleton == null) {
			random = new Random();
			singleton = new Herd();
		}
		return singleton;
	}

	public Cow getCow(int id)
	{
		for (int c = 0; c < herd.size(); c++) {
			if (herd.get(c).getID() == id)
				return herd.get(c);
		}
		return null;
	}

	public void removeCow(int id)
	{
		Cow c = getCow(id);
		if (c != null) herd.remove(c);
	}

	public void setParent(int id)
	{
		Cow p = getCow(id);
		if (p == null) return;
		if (p.getSex() == "male") parents[0] = p;
		else if (p.getSex() == "female") parents[1] = p;
	}

	public void removeParent(int id)
	{
		if (parents[0] != null && parents[0].getID() == id)
			parents[0] = null;
		else if (parents[1] != null && parents[1].getID() == id)
			parents[1] = null;
	}

	public String checkBreeding()
	{
		//TODO
		return "OK";
	}

	public void breed()
	{
		//TODO
		//randomly generate either one or two offspring
		//breed the parents to create the offspring
	}

	public void keepChild(int id)
	{
		int o = -1;
		if (offspring[0] != null && offspring[0].getID() == id) o = 0;
		else if (offspring[1] != null && offspring[1].getID() == id) o = 1;
		if (o >= 0) {
			herd.add(offspring[o]);
			offspring[o] = null;
		}
	}

	public void discardChild(int id)
	{
		int o = -1;
		if (offspring[0] != null && offspring[0].getID() == id) o = 0;
		else if (offspring[1] != null && offspring[1].getID() == id) o = 1;
		if (o >= 0) offspring[o] = null;
	}

	public void saveHerd(String filename)
	{
		//TODO save to binary file
	}

	public void loadHerd(String filename)
	{
		//TODO load from binary file
	}

	public void resetHerd()
	{
		singleton = null;
	}
}