/************************************************************************\
|* gtf is a framework for analyzing two-player zero-sum games           *|
|* Copyright (C) 2005 Troels Bjerre Sorensen                            *|
|*                                                                      *|
|* This program is free software; you can redistribute it and/or modify *|
|* it under the terms of the GNU General Public License as published by *|
|* the Free Software Foundation; either version 2 of the License, or    *|
|* (at your option) any later version.                                  *|
|*                                                                      *|
|* This program is distributed in the hope that it will be useful, but  *|
|* WITHOUT ANY WARRANTY; without even the implied warranty of           *|
|* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU    *|
|* General Public License for more details.                             *|
|*                                                                      *|
|* You should have received a copy of the GNU General Public License    *|
|* along with this program; if not, write to the                        *|
|* Free Software Foundation, Inc., 59 Temple Place - Suite 330,         *|
|* Boston, MA 02111-1307, USA.                                          *|
\************************************************************************/

package gtf.game;

import gtf.util.*;
import java.util.*;

public class MixedStrategy<T extends Real<T>> extends Strategy<T> {
	public MixedStrategy(List<Strategy<T>> strategies, List<T> weights) {
		super(new HashMap<String, T>());

		if (strategies.size() != weights.size()) 
			throw new RuntimeException("MixedStrategy: Lists must be of same length.");
		T ZERO = weights.get(0).zero();
		T sum = ZERO;
		for (T weight : weights) {
			if (weight.isNegative()) throw new RuntimeException("MixedStrategy: Weights must be positive.");
			sum = sum.add(weight);
		}
		ListIterator<T> it = weights.listIterator();
		while (it.hasNext()) it.set(it.next().divide(sum));
		Set<String> choices = new HashSet<String>();
		it = weights.listIterator();
		for (Strategy<T> strat : strategies) {
			if (!it.next().isZero()) {
				choices.addAll(strat.vals.keySet());
			}
		}
		String[] keys = choices.toArray(new String[0]);
		Arrays.sort(keys, new StringLengthComparator());
		for (String key : keys) {
			T prob = ZERO;
			it = weights.listIterator();
			for (Strategy<T> strat : strategies) {
				prob = prob.add(it.next().multiply(strat.probOf(key)));
			}
			if (!prob.isZero()) {
				vals.put(key, prob);
			}
		}
	}
}