package stoppers;

import java.lang.*;
import java.io.*;
import main.BetterTokenizer;
import main.Cell;
import main.GeneralInput;
import main.Model;

/** The NoChangeStop stops when the trajectory of a given node stabilizes or StopTime is reached.
 * The trajectory is stable if the time-derivative divided by absolute value is less than thresholdChange or
 * if the derivative is negative and the value is less that thresholdAbs.
 * Returns the derivative divided by the value of the node
 */
public class NoChangeStop extends SimpleStop	{
	
	int			nodeNum;
	float			thresholdChange, thresholdAbs, interval;
	
	/** Values of the given node in each cell the last time we checked them. */
	float	[]		lastValues;
	
	/** Whether the values for the given node satisfid the no change criterion. */
	boolean	[]	good;
	
	/** The first time at which to check for stability. */
	float 		firstStabilityCheckTime;

	// No arg constructor for instantiating by name
	public NoChangeStop() { this(1); }
	
	public NoChangeStop(float stop_time) {
		stopTime = stop_time;
	}
	
	public void init(Model model) {
		super.init(model);
		lastValues = new float[model.numCells];
		good = new boolean[model.numCells];
		for(int cell = 0; cell < model.numCells; cell++) {
			lastValues[cell] = model.cells[cell].getValue(nodeNum);
			good[cell] = false;
		}
	}
	
	public boolean stop(float time) {
		boolean	done = true;
		int			cell;
		float		val, deriv;
		
		// trivial reasons to return
		if(time < firstStabilityCheckTime) return false;
		if(time < lastTime + interval)	return false;
		if(time > stopTime) return true;

		score = 0;
		for(cell = 0; cell < model.numCells; cell++) {
			val = model.cells[cell].getValue(nodeNum);
			deriv = (val - lastValues[cell]) / (time - lastTime);
			if(Math.abs(deriv / val) > thresholdChange && !(val < thresholdAbs && deriv < 0)) {
				done = false;
				good[cell] = false;
			}
			else good[cell] = true;
			score += Math.abs(deriv);
			lastValues[cell] = val;
		}
		
		lastTime = time;
		return done;
	}
	
	public void reset() {
		lastTime = -10;
		for(int cell = 0; cell < model.numCells; cell++)
			lastValues[cell] = model.cells[cell].getValue(nodeNum);
		score = 10000;
		super.reset();
	}
	
	public boolean getGood(int cell) { return good[cell]; }
	
	protected void loadParameter(String info, BetterTokenizer tokenizer) throws Exception {
		if(info.equals("Node")) { GeneralInput.nextToken(tokenizer); nodeNum = model.cells[0].getNodeNum(tokenizer.sval); }
		else if(info.equals("AbsoluteThreshold")) { GeneralInput.nextToken(tokenizer); thresholdAbs = ((float)tokenizer.nval); }
		else if(info.equals("FirstStabilityCheckTime")) { GeneralInput.nextToken(tokenizer); firstStabilityCheckTime = ((float)tokenizer.nval); }
		else if(info.equals("ChangeThreshold")) { GeneralInput.nextToken(tokenizer); thresholdChange = ((float)tokenizer.nval); }
		else if(info.equals("Interval")) { GeneralInput.nextToken(tokenizer); interval = ((float)tokenizer.nval); }
		else super.loadParameter(info,tokenizer);
	}
			
}