package tournament;

import java.util.Random;
import java.util.Vector;

/**
 * Handles the selection of maps for each game. In the constructor a Vector
 * containing all of the maps to choose from and a Vector containing all of the
 * bots that are playing are passed in. In each bot a random 32 bit hex value
 * which was set according to a hex value selected by each bot writer is XOR
 * together to form the seed for the Java random number generator. The method
 * nextMap then gets the next int in the range of the number of maps and then
 * returns that map.
 * 
 * @author Jason
 */
public class MapPicker {
	/** The particular instantiation of the Java random class */
	private Random generator;
	/**
	 * A vector containing all of the available maps for this class to choose
	 * between
	 */
	private Vector<Map> maps;
	/** The number of maps that are available to choose between */
	private int numMaps;
	/**
	 * The seed that was calculated for the XORing of each bot writers chosen
	 * value
	 */
	private int seed;
	/**
	 * The next iD number
	 */
	private int iD;
	/** A Vector Containing all of the bots */
	private Vector<Bot> bots;
	private MapPicker upper;

	/**
	 * Constructor for the Map Picker class. Calculates the seed from the
	 * preselected 32 bit hex numbers each bot writer provided and creates the
	 * instantiation of the Random class.
	 * 
	 * @param bots
	 *            A vector containing all the bots that are playing in the
	 *            tournament that this Map picker is picking for.
	 * @param maps
	 *            A vector containing all of the availible maps to choose
	 *            between.
	 */
	public MapPicker(Vector<Bot> bots, Vector<Map> maps) {
		this.bots = bots;
		seed = 0;
		for (int i = 0; i < bots.size(); i++) {
			seed = seed ^ bots.get(i).getRandomHex();
		}
		generator = new Random(seed);
		this.maps = maps;
		numMaps = maps.size();
		iD = 0;
		upper = null;
	}
	
	/**
	 * Constructor for the Map Picker class. Calculates the seed from the
	 * preselected 32 bit hex numbers each bot writer provided and creates the
	 * instantiation of the Random class.
	 * 
	 * @param bots
	 *            A vector containing all the bots that are playing in the
	 *            tournament that this Map picker is picking for.
	 * @param maps
	 *            A vector containing all of the availible maps to choose
	 *            between.
	 */
	public MapPicker(Vector<Bot> bots, Vector<Map> maps, MapPicker upper) {
		this.bots = bots;
		seed = 0;
		for (int i = 0; i < bots.size(); i++) {
			seed = seed ^ bots.get(i).getRandomHex();
		}
		generator = new Random(seed);
		this.maps = maps;
		numMaps = maps.size();
		this.upper = upper;
		this.iD = 0;
	}

	/**
	 * Returns the next randomly selected map to be played on.
	 * 
	 * @return Map, the next randomly selected map to be played on.
	 */
	public Map nextMap() {
		return maps.get(generator.nextInt(numMaps));
	}

	/**
	 * Returns the iD number with which to number all games and then increments
	 * it for the next use
	 * 
	 * @return iD
	 */
	public int nextID() {
		if(upper != null){
			return upper.nextID();
		}
		return iD++;
	}

	/**
	 * Generates a Map picker for a pair of bots using the random numbers of
	 * every other bot as a seed.
	 * 
	 * @param host
	 *            The first bot this MapPicker is being Generated for
	 * @param away
	 *            The second bot this MapPicker is being Generated for
	 * @return MapPicker for a pair of bots
	 */
	public MapPicker ourMapPicker(Bot host, Bot away) {
		Vector<Bot> otherBot = new Vector<Bot>();
		for (int i = 0; i < bots.size(); i++) {
			if (!(bots.get(i).getName().equals(host.getName()))) {
				if (!(bots.get(i).getName().equals(away.getName()))) {
					otherBot.add(bots.get(i));
				}
			}
		}
		return new MapPicker(otherBot, this.maps, this);
	}
}