package ij.plugin.frame;
import ij.*;
import ij.gui.*;
import ij.process.*;
import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;

/** This plugin continuously plots ImageJ's memory utilization. 
    Click on the plot to force the JVM to do garbage collection. */
public class MemoryMonitor extends PlugInFrame {
    private static final int WIDTH=250, HEIGHT=90;
    private static final String LOC_KEY = "memory.loc";
    private static MemoryMonitor instance;
    private Image image;
    private Graphics2D g;
    private int frames;
    private double[] mem;
    private int index;
    private long value;
    private double defaultMax = 20*1024*1024; // 20MB
    private double max = defaultMax;
    private long maxMemory = IJ.maxMemory();
    private boolean done;

    public MemoryMonitor() {
        super("Memory");
        if (instance!=null) {
            WindowManager.toFront(instance);
            return;
        }
        instance = this;
        WindowManager.addWindow(this);
        
        setLayout(new BorderLayout());
        Canvas ic = new PlotCanvas();
        ic.setSize(WIDTH, HEIGHT);
        add(ic);
        setResizable(false);
        pack();
        Point loc = Prefs.getLocation(LOC_KEY);
        if (loc!=null)
            setLocation(loc);
        else
            GUI.center(this);
        image = createImage(WIDTH,HEIGHT);
        g = (Graphics2D)image.getGraphics();
        g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
        g.setColor(Color.white);
        g.fillRect(0, 0, WIDTH, HEIGHT);
        g.setFont(new Font("SansSerif",Font.PLAIN,12));
        show();
        ImageJ ij = IJ.getInstance();
        if (ij!=null) {
            addKeyListener(ij);
            ic.addKeyListener(ij);
            ic.addMouseListener(ij);
        }
        mem = new double[WIDTH+1];
        Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
        while (!done) {
            updatePlot();
            addText();
            ic.repaint();
            IJ.wait(50);
            frames++;
        }
    }
    
    void addText() {
        double value2 = (double)value/1048576L;
        String s = IJ.d2s(value2,value2>50?0:2)+"MB";
        if (maxMemory>0L) {
            double percent = value*100/maxMemory;
            s += " ("+(percent<1.0?"<1":IJ.d2s(percent,0)) + "%)";
        }
        g.drawString(s, 2, 15);
        String images = ""+WindowManager.getImageCount();
        g.drawString(images, WIDTH-(5+images.length()*8), 15);
    }

    void updatePlot() {
        double used = IJ.currentMemory();
        if (frames%10==0) value = (long)used;
        if (used>0.86*max) max *= 2.0;
        mem[index++] = used;
        if (index==mem.length) index = 0;
        double maxmax = 0.0;
        for (int i=0; i<mem.length; i++) {
            if (mem[i]>maxmax) maxmax= mem[i];
        }
        if (maxmax<defaultMax) max=defaultMax*2;
        if (maxmax<defaultMax/2) max = defaultMax;
        int index2 = index+1;
        if (index2==mem.length) index2 = 0;
        g.setColor(Color.white);
        g.fillRect(0, 0, WIDTH, HEIGHT);
        g.setColor(Color.black);    
        double scale = HEIGHT/max;
        int x1 = 0;
        int y1 = HEIGHT-(int)(mem[index2]*scale);
        for (int x2=1; x2<WIDTH; x2++) {
            index2++;
            if (index2==mem.length) index2 = 0;
            int y2 = HEIGHT-(int)(mem[index2]*scale);
            g.drawLine(x1, y1, x2, y2);
            x1=x2; y1=y2;
        }
    }

    public void close() {
        super.close();
        instance = null;
        Prefs.saveLocation(LOC_KEY, getLocation());
        done = true;
    }
    
    class PlotCanvas extends Canvas {
    
        public void update(Graphics g) {
            paint(g);
        }
        
        public void paint(Graphics g) {
            g.drawImage(image, 0, 0, null);
        }
        
    } 

}