package edu.neu.ccs.evergreen.state;

import java.util.Random;

import org.apache.log4j.Logger;

import edu.neu.ccs.evergreen.model.Assignments;
import edu.neu.ccs.evergreen.model.State;

/**
 * Use a biased coin to decide if the next variable is true or false.
 */
public class MaxBiasNextState extends BiasNextState {
	private static final Logger LOGGER = Logger.getLogger(MaxBiasNextState.class);

	/**
	 * Create a new coin flipper with an optional reset percentage and seed.
	 * @param args Arguments
	 */
	public MaxBiasNextState(String args[])
	{
		long seed = 1;
		if (args.length > 0)
		{
			refresh = Double.parseDouble(args[0]);
			if ((refresh < 0) || (refresh > 1.0))
			{
				refresh = 0.5;
			}
		}
		if (args.length > 1)
		{
			seed = Long.parseLong(args[1], 10);
		}
		random = new Random(seed);
		LOGGER.info("Using refresh probability of " + refresh);
		LOGGER.info("Using random seed of " + seed);
	}

	
	@Override
	protected double calculateBias(State state, int maxOriginalVariable, Assignments bestAssignments) {
		return state.maxBias();
	}


	@Override
	protected boolean doRefresh() {
		return (doRefresh) || (random.nextDouble() < refresh);
	}
}