// IncrementalFolder.java
//
//
// Copyright 2004, Ethan Bolker and Bogdan Calota

package edu.umb.cs.eb.folding;

import java.awt.Point;
import java.util.*;

/**
 * Incremental approximation algorithm searching for minimal energy.
 *
 * Backtrack for lookAhead acid placements, find the minimum so far,
 * and then place step of the tentatively placed acids.
 */

public class IncrementalFolder extends BruteForceFolder
{
    public static final int defaultLookAhead = 8;
    public static final int defaultStep = 4;

    // at each step:
    // number of acids to place greedily
    private int lookAhead = defaultLookAhead; 

    // number of acids to pin down 
    private int step = defaultStep;

    public String getName() 
    {
	return "Incremental folding - " + 
	    "lookahead: " + lookAhead +
	    " step: " + step;
    }

    public IncrementalFolder( Polypeptide pp, Grid g, 
			      int lookAhead, int step  )
    {
// 	super(pp);
	this( pp, g );
	this.lookAhead = lookAhead;
	this.step      = step;
    }

//     public IncrementalFolder( Grid g, Polypeptide pp )
    public IncrementalFolder( Polypeptide pp, Grid g )
    {
	super( pp, g );
    }

    public void setLookAhead( int lookAhead ) 
    {
	this.lookAhead = lookAhead;
    }

    public void setStep( int step ) 
    {

	this.step = step;
    }

    protected void placeRestOfAcids()
    {
	int current = 2; // ready to place 3rd acid
	while( current < numAcids ) {
	    resetEnergy();
	    int localLookAhead = Math.min( current+lookAhead, numAcids);
	    recurse( grid.getNextDirection( acids[current-2].next ),
		     current, localLookAhead );
	    restore();
	    // unplace some acids
	    for (int i = current+step; i < localLookAhead; i++) {
		grid.unset(acids[i]);
	    }
	    current += step;
	}
    }

    public static void main( String[] args )
    {
	Options opts = new Options
	    ("help", 
	     "step:4 lookahead:8 table:standard length:10 seed:10",
	     args);
	if (opts.isOpt("help")) {
	    System.out.println("usage: java IncrementalFolder " +
			       "\n    [-help] [-lookahead n] [-step s] " + 
			       "\n    [-table standard|virtual] " +
			       "\n    [-length len] [-seed seed ]");
	    System.exit(0);
	}
	args = opts.getShiftArray();
	Polypeptide pp = null;
	try {
	    pp = PolypeptideFactory.getInstance().createPolypeptide
		("",
		 false,
		 true,
		 ""+opts.getIntOpt("length"),
		 ""+opts.getIntOpt("seed"),
		 opts.getOpt("table"));
	}
	catch( FoldingException e ) {
	    System.out.println(e);
	    System.exit(0);
	}
	IncrementalFolder folder = 
	    new IncrementalFolder(pp, new HexGrid(pp));	
	folder.setLookAhead( opts.getIntOpt("lookahead") );
	folder.setStep( opts.getIntOpt("step") );
	folder.fold();
	System.out.println(folder.report());
    }
}