//==============================================================================
//
//Copyright (c) 2002-
//Authors:
//* Dave Parker <david.parker@comlab.ox.ac.uk> (University of Oxford)
//
//------------------------------------------------------------------------------
//
//This file is part of PRISM.
//
//PRISM 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.
//
//PRISM 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 PRISM; if not, write to the Free Software Foundation,
//Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
//==============================================================================

package explicit;

import java.util.*;

import prism.ModelType;
import prism.PrismException;

/**
* Simple explicit-state representation of a DTMC, constructed (implicitly) as the uniformised DTMC of a CTMC.
* This class is read-only: most of data is pointers to other model info.
*/
public class DTMCUniformisedSimple implements DTMC
{
	// Parent CTMC
	protected CTMCSimple ctmc;
	// Uniformisation rate
	protected double q;
	// Number of extra transitions added (just for stats)
	protected int numExtraTransitions;

	/**
	 * Constructor: create from CTMC and uniformisation rate q.
	 */
	public DTMCUniformisedSimple(CTMCSimple ctmc, double q)
	{
		this.ctmc = ctmc;
		this.q = q;
		int numStates = ctmc.getNumStates();
		numExtraTransitions = 0;
		for (int i = 0; i < numStates; i++) {
			if (ctmc.getTransitions(i).get(i) == 0 && ctmc.getTransitions(i).sumAllBut(i) < q) {
				numExtraTransitions++;
			}
		}
	}

	/**
	 * Constructor: create from CTMC and its default uniformisation rate.
	 */
	public DTMCUniformisedSimple(CTMCSimple ctmc)
	{
		this(ctmc, ctmc.getDefaultUniformisationRate());
	}

	// Accessors (for Model)

	public ModelType getModelType()
	{
		return ModelType.DTMC;
	}

	public int getNumStates()
	{
		return ctmc.getNumStates();
	}

	public int getNumInitialStates()
	{
		return ctmc.getNumInitialStates();
	}

	public Iterable<Integer> getInitialStates()
	{
		return ctmc.getInitialStates();
	}

	public int getFirstInitialState()
	{
		return ctmc.getFirstInitialState();
	}

	public boolean isInitialState(int i)
	{
		return ctmc.isInitialState(i);
	}

	public int getNumTransitions()
	{
		return ctmc.getNumTransitions() + numExtraTransitions;
	}

	public boolean isSuccessor(int s1, int s2)
	{
		// TODO
		throw new Error("Not yet supported");
	}

	public boolean allSuccessorsInSet(int s, BitSet set)
	{
		// TODO
		throw new Error("Not yet supported");
	}

	public boolean someSuccessorsInSet(int s, BitSet set)
	{
		// TODO
		throw new Error("Not yet supported");
	}

	public int getNumChoices(int s)
	{
		// Always 1 for a DTMC
		return 1;
	}

	public void checkForDeadlocks() throws PrismException
	{
		// No deadlocks by definition
	}

	public void checkForDeadlocks(BitSet except) throws PrismException
	{
		// No deadlocks by definition
	}

	public BitSet findDeadlocks(boolean fix) throws PrismException
	{
		// No deadlocks by definition
		return new BitSet();
	}

	public void exportToPrismExplicit(String baseFilename) throws PrismException
	{
		throw new PrismException("Export not yet supported");
	}

	public void exportToPrismExplicitTra(String filename) throws PrismException
	{
		throw new PrismException("Export not yet supported");
	}

	public void exportToDotFile(String filename) throws PrismException
	{
		throw new PrismException("Export not yet supported");
	}

	public void exportToDotFile(String filename, BitSet mark) throws PrismException
	{
		throw new PrismException("Export not yet supported");
	}

	public String infoString()
	{
		return ctmc.infoString() + " + " + numExtraTransitions + " self-loops";
	}

	// Accessors (for DTMC)

	public double getTransitionReward(int s)
	{
		// TODO
		throw new Error("Not yet supported");
	}

	public void mvMult(double vect[], double result[], BitSet subset, boolean complement)
	{
		int s, numStates;
		numStates = ctmc.getNumStates();
		// Loop depends on subset/complement arguments
		if (subset == null) {
			for (s = 0; s < numStates; s++)
				result[s] = mvMultSingle(s, vect);
		} else if (complement) {
			for (s = subset.nextClearBit(0); s < numStates; s = subset.nextClearBit(s + 1))
				result[s] = mvMultSingle(s, vect);
		} else {
			for (s = subset.nextSetBit(0); s >= 0; s = subset.nextSetBit(s + 1))
				result[s] = mvMultSingle(s, vect);
		}
	}

	public double mvMultSingle(int s, double vect[])
	{
		int k;
		double sum, d, prob;
		Distribution distr;

		distr = ctmc.getTransitions(s);
		sum = d = 0.0;
		for (Map.Entry<Integer, Double> e : distr) {
			k = (Integer) e.getKey();
			prob = (Double) e.getValue();
			// Non-diagonal entries
			if (k != s) {
				sum += prob;
				d += (prob / q) * vect[k];
			}
		}
		// Diagonal entry
		if (sum < q) {
			d += (1 - sum/q) * vect[s];
		}

		return d;
	}

	public void mvMultRew(double vect[], double result[], BitSet subset, boolean complement)
	{
		int s, numStates;
		numStates = ctmc.getNumStates();
		// Loop depends on subset/complement arguments
		if (subset == null) {
			for (s = 0; s < numStates; s++)
				result[s] = mvMultRewSingle(s, vect);
		} else if (complement) {
			for (s = subset.nextClearBit(0); s < numStates; s = subset.nextClearBit(s + 1))
				result[s] = mvMultRewSingle(s, vect);
		} else {
			for (s = subset.nextSetBit(0); s >= 0; s = subset.nextSetBit(s + 1))
				result[s] = mvMultRewSingle(s, vect);
		}
	}

	public double mvMultRewSingle(int s, double vect[])
	{
		// TODO
		throw new Error("Not yet supported");
	}

	@Override
	public String toString()
	{
		String s = "";
		s += "ctmc: " + ctmc;
		s = ", q: " + q;
		return s;
	}

	@Override
	public boolean equals(Object o)
	{
		if (o == null || !(o instanceof DTMCUniformisedSimple))
			return false;
		DTMCUniformisedSimple dtmc = (DTMCUniformisedSimple) o;
		if (!ctmc.equals(dtmc.ctmc))
			return false;
		if (q != dtmc.q)
			return false;
		if (numExtraTransitions != dtmc.numExtraTransitions)
			return false;
		return true;
	}
}