import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.util.*;

public class XYApplet extends Applet {
    public XY experiment;
    private Canvas canvas = new XYCanvas(this);
    private Choice linearDimension = new Choice();
    private Button start = new Button("Start");
    private Button step = new Button("Step");
    private Button cont = new Button("Continue");
    private Button stop = new Button("Stop");
    private TextField temperature = new TextField("0.893", 6);
    private TextField field = new TextField("0", 6);
    private TextField angle = new TextField("1", 6);
    private TextField mctime = new TextField(4); 
    private TextField mx = new TextField(5);
    private TextField my = new TextField(5);
    private TextField energy = new TextField(5);
    private TextField meanMx = new TextField(5);
    private TextField meanMy = new TextField(5);
    private TextField meanE = new TextField(5);
    
    // 'r' for running, 't' for taking a MC step, 's' for stop  
    public char status = 's';          
    private int LChoices[] = {4, 8, 16, 32, 64, 128, 256};
    public int L;
    private double T, H, dtheta;

    public void init() {
        setBackground(Color.white);
        setLayout(new BorderLayout());
        Panel top = new Panel();
        Panel bottom = new Panel();
        top.setLayout(new FlowLayout());
        bottom.setLayout(new FlowLayout());

        for(int i=0; i<7; i++)
           linearDimension.addItem("" + LChoices[i]);
 
        top.add(new Label("L:"));
        top.add(linearDimension);
        top.add(new Label("  T:"));
        top.add(temperature);
        top.add(new Label("  H:"));
        top.add(field);
        top.add(new Label(" dtheta"));
        top.add(angle);
  	    top.add(start);
  	    top.add(step);
  	    top.add(cont);
     	top.add(stop);
        add(top, BorderLayout.NORTH);

        bottom.add(new Label("t:"));
        bottom.add(mctime);
        bottom.add(new Label("Mx:"));
        bottom.add(mx);
        bottom.add(new Label("My:"));
        bottom.add(my);;
        bottom.add(new Label("E:"));
        bottom.add(energy);
        bottom.add(new Label("<Mx>:"));
        bottom.add(meanMx);
        bottom.add(new Label("<My>:"));
        bottom.add(meanMy);
        bottom.add(new Label("<E>:"));
        bottom.add(meanE);
        add(bottom, BorderLayout.SOUTH);

        add(canvas, BorderLayout.CENTER);
        
        start.addActionListener(new StartListener());
        step.addActionListener(new StepListener());
        stop.addActionListener(new StopListener());
        cont.addActionListener(new ContListener());

        start.addMouseListener(new StartMouseAdapter());                                          
        step.addMouseListener(new StepMouseAdapter());
        stop.addMouseListener(new StopMouseAdapter());
        cont.addMouseListener(new ContMouseAdapter());

        mctime.setEditable(false);
        mx.setEditable(false);    
        my.setEditable(false);
        energy.setEditable(false);
        meanMx.setEditable(false);
        meanMy.setEditable(false);
        meanE.setEditable(false);

        
        L = 32;
        T = 1.5;
        H = 0;

        new MyThread().start();
    }

    private double setPrecision(double val, int numDigits) {
        int scale = 1;
        for(int i=0; i<numDigits; i++) scale *= 10;
        return (int)(val*scale)/(double)(scale);
    }

    public void displayVariables() {
        mctime.setText("" + experiment.time_counter);
        mx.setText("" + setPrecision(experiment.Mx, 2));     // two decimal places 
        my.setText("" + setPrecision(experiment.My, 2));
        energy.setText("" + setPrecision(experiment.E, 2));
        meanMx.setText("" + setPrecision(experiment.ave_Mx/experiment.time_counter, 2));
        meanMy.setText("" + setPrecision(experiment.ave_My/experiment.time_counter, 2));
        meanE.setText("" + setPrecision(experiment.ave_E/experiment.time_counter, 2));
    }

    // pressing the "Start" button always reinitializes the system 
    private class StartListener implements ActionListener {
        public void actionPerformed(ActionEvent e)  {
            L = LChoices[linearDimension.getSelectedIndex()];
            T = new Double(temperature.getText()).doubleValue();
            H = new Double(field.getText()).doubleValue();
            dtheta = new Double(angle.getText()).doubleValue();
         
            if(experiment == null) 
               experiment = new XY(L, T, H, dtheta);
            else
               experiment.reinitialize(L, T, H, dtheta);
            canvas.repaint();
            status = 'r';  // running
        } 
    }
   
    private class StartMouseAdapter extends MouseAdapter {
        public void mouseEntered(MouseEvent e) {
            showStatus("Initialize/Reinitialize the system with a random configuration and runs in an infinite loop.");
        }
        public void mouseExited(MouseEvent e) {
            showStatus("");
        }        
    }
    // pressing the "Step" button advances the simulation by one MC step, then stops
    private class StepListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            status = 't';
        }
    }
    
    private class StepMouseAdapter extends MouseAdapter {
        public void mouseEntered(MouseEvent e) {
            showStatus("Advances the simulation by one Monte Carlo step, then stops.");
        }
        public void mouseExited(MouseEvent e) {
            showStatus("");
        }
    }
    
    // pressing the "Continue" button advances the simulation and resets parameters if apply
    private class ContListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            if(experiment == null) {
               status = 's';
               return; 
            }
            
            double tempT = new Double(temperature.getText()).doubleValue();
            double tempH = new Double(field.getText()).doubleValue();
            double tempDtheta = new Double(angle.getText()).doubleValue();
            if(tempT != T) {
                T = tempT;
                experiment.resetT(T);
            }
            if(tempH != H) {
                H = tempH;
                experiment.resetH(H);
            }
            if(tempDtheta != dtheta) {
                dtheta = tempDtheta;
                experiment.resetDtheta(dtheta);
            }
            status = 'r';
        }
    }
    
    private class ContMouseAdapter extends MouseAdapter {
        public void mouseEntered(MouseEvent e) {
            showStatus("Resets magnetic field H and temperature T, and continues the simulation with the current configuration.");
        }
        public void mouseExited(MouseEvent e) {
            showStatus("");
        }
    }
    
    // pressing the "Stop" button stops the simulation
    private class StopListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            status = 's';
        }
    }

    private class StopMouseAdapter extends MouseAdapter {
        public void mouseEntered(MouseEvent e) {
            showStatus("Stops the simulation.");
        }
        public void mouseExited(MouseEvent e) {
            showStatus("");
        }
    }
  
    private class MyThread extends Thread {
        public void run() {
            for(;;) {
                if(experiment != null) 
                    if(status == 'r') {
                        experiment.onestep();
                        canvas.repaint();
                    }
                    else if(status == 't' && experiment != null) {
                        experiment.onestep();
                        canvas.repaint();
                        status = 's';
                    }     
                try {
                    sleep(50);
                } catch (InterruptedException e) { }
	    }
            
         }
 
    }


}