import java.util.Set;
import java.util.HashSet;
import java.lang.Integer;


/**
 * <p>
 * Scheduler for synchronous communication round scheduling.
 * This determines the order in which various robots will iterate through
 * the broadcast, recieve, update cycle.
 * </p>
 * @author     Michael Schuresko
 * @version    %I%, %G%
 * @since      1.0
*/

public class SynchronousScheduler implements ICommunicationScheduler
{
    double m_lfTStep;
    Set<Integer> m_setRobots;
    boolean m_bVerbose;

    /**
     * Constructor
     * @param lfTStep time between rounds (uniform)
     * @param nRobots number of robots
     */
    public SynchronousScheduler(double lfTStep, int nRobots)
    {
	m_bVerbose = false;
	populate(lfTStep, nRobots);
    }

    /**
     * Constructor -- can we eliminate the no-argument constructor?
     */
    public SynchronousScheduler()
    {
	m_bVerbose = false;
	populate(1.0, 11);
    }

    /**
     * internal function to populate scheduler params
     * Used mostly be constructors
     */
    protected void populate(double lfTStep, int nRobots)
    {
	if(m_bVerbose) {
	    System.out.println("Populating with "+nRobots+"robots");
	}
	m_lfTStep = lfTStep;
	m_setRobots = new HashSet<Integer>(nRobots);
	for(int i = 0; i < nRobots; ++i) {
	    m_setRobots.add(new Integer(i));
	}
    }

    /**
     * Gets the time of the next communication round.
     * Useful for the differential equation solver,
     * as these communication times are usually discontinuities
     * @param lfCurrTime absolute current time
     * @return absolute time of next communication round (not "time till next
     * round").
     */
    public double getNextRoundTime(double lfCurrTime)
    {
	int nTimes = (int)Math.floor((lfCurrTime+1.00001*m_lfTStep)/m_lfTStep);

	return m_lfTStep*nTimes;
    }

    /**
     * Gets the time of the next communication round,
     * populates setActiveAgents 
     * with the indices of those agents which are active on this round.
     * @param lfCurrTime current time
     * @param nTotalAgents agents are index 0 through nTotalAgents-1
     * @param setActiveAgents initially empty, then populated with
     * indices (of type Integer) of agents to fire next round.
     * @return absolute time of next communication round
     */
    public double getNextRoundAndFiringSchedule(double lfCurrTime, 
						int nTotalAgents,
						Set<Integer> setActiveAgents)
    {
	setActiveAgents.addAll(m_setRobots);
	return getNextRoundTime(lfCurrTime);
    }
}