// SimApplet.java
// This class provides a nice graphical user interface for the chaotic
// dynamics simulations.

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

public class SimApplet extends Applet implements Runnable {
	public void init() {
		int i,j;
		
		left_panel=new Panel();
		left_panel.setLayout(new GridLayout(8,1));
		system_choice=new Choice();
		system_choice.addItem("Harmonic Oscillator");
		system_choice.addItem("Coupled Oscillator");
		system_choice.addItem("Triple Oscillator");
		left_panel.add(system_choice);
		method_choice=new Choice();
		method_choice.addItem("Euler");
		method_choice.addItem("RK2");
		method_choice.addItem("RK4");
		method_choice.addItem("Symplectic Order 1");
		method_choice.addItem("Symplectic Order 2");
		method_choice.addItem("Symplectic Order 4");
		left_panel.add(method_choice);
		clear_button=new Button("Clear Section");
		left_panel.add(clear_button);
		restart_button=new Button("Restart System");
		left_panel.add(restart_button);
		section_button=new Button("Draw Section");
		left_panel.add(section_button);
		lyap_label=new Label("Lyap=0.0");
		left_panel.add(lyap_label);

		this.setLayout(new BorderLayout());
		bottom_panel=new Panel();
		bottom_panel.add(new Label("m1="));
		m1=new TextField("1.0");
		bottom_panel.add(m1);
		bottom_panel.add(new Label("m2="));
		m2=new TextField("1.0");
		bottom_panel.add(m2);
		bottom_panel.add(new Label("k1="));
		k1=new TextField("1.0");
		bottom_panel.add(k1);
		bottom_panel.add(new Label("k2="));
		k2=new TextField("1.0");
		bottom_panel.add(k2);
		bottom_panel.add(new Label("dt="));
		dt=new TextField("0.03");
		bottom_panel.add(dt);

		this.add("South",bottom_panel);
		this.add("West",left_panel);
		this.layout();

		pendulum=createImage(80,480-bottom_panel.size().height);
		section=createImage(400-left_panel.size().width,(480-bottom_panel.size().height)/2);
		section.getGraphics().setColor(Color.black);
		section.getGraphics().fillRect(0,0,section.getWidth(this),section.getHeight(this));
		energy=createImage(400-left_panel.size().width,(480-bottom_panel.size().height)/2);
		energy_vector=new Vector(101);

		thread=null;

		// Setup the system for Euler and regular Oscillator
		first_op=0;
		second_op=0;
		InitSystemState();
		ready_to_run=true;

		ball_y=new int[3];
	}

    public void start() {
        if(thread==null) {
            thread=new Thread(this);
            thread.start();
        }
    }

    public void stop() {
        if(thread!=null) {
            thread.stop();
            thread=null;
        }
    }

	public void run() {
		int i;

		try {
			while(true) {
				if(!ready_to_run) return;
				if(hold_ball==-1) {
					sys.Advance();
					lyap.Advance();
					lyap_label.setText("Lyap="+lyap.LyapMeasure());
				}
				DrawSection();
				DrawPendulum();
				DrawEnergy();
				repaint();
				Thread.sleep(5);
			}
		}
		catch(InterruptedException e) {
            thread.stop();
            thread=null;
        }
	}

	private void DrawPendulum() {
		if(pendulum==null) return;
		int i,y=0,y_prime=0;
		int draw_scale=20,default_length=100;
		Graphics g=pendulum.getGraphics();
		int xmax,ymax;

		ball_x=40+left_panel.size().width;
		xmax=pendulum.getWidth(this);
		ymax=pendulum.getHeight(this);
		g.setColor(Color.black);
		g.fillRect(0,0,xmax,ymax);
		g.setColor(Color.red);
		for(i=0; i<rule.NumStateVars()/2; i++) {
			try {
				if(i==hold_ball) {
					y_prime=mouse_y-10;
					sys.Set(i,(double)(y_prime-y-default_length)/draw_scale);
					sys.Set(i+rule.NumStateVars()/2,0.0);
				} else {
					y_prime=(int)(y+default_length+draw_scale*sys.Get(i));
				}
			}
			catch(System.OutOfRangeException e) {}
			ball_y[i]=y_prime+10;
			DrawSpring(g,40,y,y_prime);
			y=y_prime;
			if((Math.abs(mouse_x-ball_x)<20) && (Math.abs(mouse_y-ball_y[i])<20)) {
				g.fillOval(30,y,20,20);
			} else {
				g.drawOval(30,y,20,20);
			}
			y+=20;
		}
	}

	private void DrawSpring(Graphics g,int x,int y1,int y2) {
		int num_folds=8;
		int x_offset=5;
		int i;
		double y=y1,y_prime;

		for(i=0; i<num_folds; i++) {
			y_prime=y+(double)(y2-y1)/num_folds;
			if(i%2==0) {
				g.drawLine(x,(int)y,x+x_offset,(int)(y+y_prime)/2);
				g.drawLine(x+x_offset,(int)(y+y_prime)/2,x,(int)y_prime);
			} else {
				g.drawLine(x,(int)y,x-x_offset,(int)(y+y_prime)/2);
				g.drawLine(x-x_offset,(int)(y+y_prime)/2,x,(int)y_prime);
			}
			y=y_prime;
		}
	}

	private void DrawSection() {
		if(section==null) return;
		Graphics g=section.getGraphics();
		int xmax,ymax,x=0,y=0;
		double sv0,sv1,sv2;

		xmax=section.getWidth(this);
		ymax=section.getHeight(this);
		g.setColor(Color.white);
		g.drawString("Poincare section",0,20);
		g.setColor(Color.yellow);
		if(!do_section) {
			try {
			x=(int)((sys.Get(0)+3.0)/6.0*xmax);
			y=(int)((sys.Get(1)+3.0)/6.0*ymax);
			}
			catch(System.OutOfRangeException e) {}
			g.drawLine(x,y,x,y);
		} else {
			try {
			sv0=sys.Get(0);
			sv1=sys.Get(rule.NumStateVars()/2);
			sv2=sys.Get(rule.NumStateVars()-1);
			if((last_sv2<0) && (sv2>=0)) {
				x=(int)(((sv0+(last_sv0-sv0)*sv0/(last_sv2-sv2))+4.0)/8.0*xmax);
				y=(int)(((sv1+(last_sv1-sv1)*sv1/(last_sv2-sv2))+4.0)/8.0*ymax);
				g.drawLine(x,y,x,y);
			}
			last_sv0=sv0;
			last_sv1=sv1;
			last_sv2=sv2;
			}
			catch(System.OutOfRangeException e) {}
		}
	}

	private void DrawEnergy() {
		if(energy==null) return;
		Graphics g=energy.getGraphics();
		int xmax,ymax;
		int i,lim;
		double x1,y1,x2,y2;

		xmax=energy.getWidth(this);
		ymax=energy.getHeight(this);
		g.setColor(Color.black);
		g.fillRect(0,0,xmax,ymax);
		g.setColor(Color.white);
		g.drawString("Energy",0,20);
		g.setColor(Color.cyan);
		energy_vector.addElement(new Double(rule.Energy(sys.GetStateVector())));
		if(energy_vector.size()>100) {
			lim=energy_vector.size()/2;
			for(i=1; i<lim; i++) {
				energy_vector.removeElementAt(i);
			}
		}
		x1=0;
		y1=((Double)energy_vector.elementAt(0)).doubleValue()*ymax/5.0;
		for(i=1; i<energy_vector.size(); i++) {
			x2=(double)i*xmax/energy_vector.size();
			y2=((Double)energy_vector.elementAt(i)).doubleValue()*ymax/5.0;
			g.drawLine((int)x1,ymax-(int)y1,(int)x2,ymax-(int)y2);
			x1=x2;
			y1=y2;
		}
	}

	public void paint(Graphics g) {
		if(pendulum==null) return;
		g.drawImage(pendulum,left_panel.size().width,0,null);
		g.drawImage(section,80+left_panel.size().width,0,null);
		g.drawImage(energy,80+left_panel.size().width,(480-bottom_panel.size().height)/2,null);
	}

	public void update(Graphics g) {
		paint(g);
	}

	public boolean action(Event evt,Object o) {

		if(evt.target==restart_button) {
			InitSystemState();
		} else if(evt.target==clear_button) {
			section.getGraphics().setColor(Color.black);
			section.getGraphics().fillRect(0,0,section.getWidth(this),section.getHeight(this));
		} else if(evt.target==section_button) {
			if(do_section) {
				section_button.setLabel("Draw Section");
			} else {
				section_button.setLabel("Draw Flow");
			}
			do_section=!do_section;
		} else if(evt.target==system_choice) {
			if(system_choice.getSelectedIndex()==0) {
				if(first_op!=0) {
					first_op=0;
					InitSystemState();
				}
			} else if(system_choice.getSelectedIndex()==1) {
				if(first_op!=1) {
					first_op=1;
					InitSystemState();
				}
			} else if(system_choice.getSelectedIndex()==2) {
				if(first_op!=2) {
					first_op=2;
					InitSystemState();
				}
			}
		} else if(evt.target==method_choice) {
			if(method_choice.getSelectedIndex()==0) {
				if(second_op!=0) {
					second_op=0;
					InitSystemState();
				}
			} else if(method_choice.getSelectedIndex()==1) {
				if(second_op!=1) {
					second_op=1;
					InitSystemState();
				}
			} else if(method_choice.getSelectedIndex()==2) {
				if(second_op!=2) {
					second_op=2;
					InitSystemState();
				}
			} else if(method_choice.getSelectedIndex()==3) {
				if(second_op!=3) {
					second_op=3;
					InitSystemState();
				}
			} else if(method_choice.getSelectedIndex()==4) {
				if(second_op!=4) {
					second_op=4;
					InitSystemState();
				}
			} else if(method_choice.getSelectedIndex()==5) {
				if(second_op!=5) {
					second_op=5;
					InitSystemState();
				}
			}
		}
		return(true);
	}

	public boolean lostFocus(Event evt,Object what) {
		if((evt.target!=m1) && (evt.target!=m2) && (evt.target!=k1) && (evt.target!=k2) && (evt.target!=dt)) return(false);
		SetSystemVals();
		return(true);
	}

	private void SetSystemVals() {
		double dm1,dm2,dk1,dk2;
		double time_step=0.03;
		Oscillator osc;
		CoupledOsc cosc;
		TripOsc tosc;

		try {
			dm1=Double.valueOf(m1.getText()).doubleValue();
		}
		catch(NumberFormatException ex) {
			dm1=1.0;
			m1.setText("1.0");
		}
		try {
			dm2=Double.valueOf(m2.getText()).doubleValue();
		}
		catch(NumberFormatException ex) {
			dm2=1.0;
			m2.setText("1.0");
		}
		try {
			dk1=Double.valueOf(k1.getText()).doubleValue();
		}
		catch(NumberFormatException ex) {
			dk1=1.0;
			k1.setText("1.0");
		}
		try {
			dk2=Double.valueOf(k2.getText()).doubleValue();
		}
		catch(NumberFormatException ex) {
			dk2=1.0;
			k2.setText("1.0");
		}
		try {
			time_step=Double.valueOf(dt.getText()).doubleValue();
		}
		catch(NumberFormatException ex) {
			time_step=0.03;
			dt.setText("0.03");
		}
		if(first_op==0) {
			osc=(Oscillator)rule;
			osc.k1=dk1;
			osc.m1=dm1;
		} else if(first_op==1) {
			cosc=(CoupledOsc)rule;
			cosc.k1=dk1;
			cosc.m1=dm1;
			cosc.k2=dk2;
			cosc.m2=dm2;
		} else if(first_op==2) {
			tosc=(TripOsc)rule;
			tosc.k1=dk1;
			tosc.m1=dm1;
			tosc.k2=dk2;
			tosc.m2=dm2;
		}
		sys.SetTimeStep(time_step);
		lyap.GetMirror().SetTimeStep(time_step);
	}

	private void InitSystemState() {
		int i;
		double time_step;

		switch(first_op) {
			case 0:
				rule=new Oscillator();
				break;
			case 1:
				rule=new CoupledOsc();
				break;
			case 2:
				rule=new TripOsc();
				break;
		}
		switch(second_op) {
			case 0:
				sys=new Euler(rule);
				break;
			case 1:
				sys=new Trapazoid(rule);
				break;
			case 2:
				sys=new RK4(rule);
				break;
			case 3:
				sys=new SimMap1(rule);
				break;
			case 4:
				sys=new SimMap2(rule);
				break;
			case 5:
				sys=new SimMap4(rule);
				break;
		}
		for(i=0; i<rule.NumStateVars(); i++) {
			try {
				if(i<rule.NumStateVars()/2) sys.Set(i,0.7*Math.pow(-1.0,(double)i));
				else sys.Set(i,0.0);
			}
			catch(System.OutOfRangeException e) {}
		}
		lyap=new LyapMeasure(sys,1e-2);
		SetSystemVals();
		if(section!=null) {
			section.getGraphics().setColor(Color.black);
			section.getGraphics().fillRect(0,0,section.getWidth(this),section.getHeight(this));
		}
	}

	public boolean mouseDown(Event evt,int x,int y) {
		int i;
	
		mouse_x=x;
		mouse_y=y;
		for(i=0; i<rule.NumStateVars()/2; i++) {
			if((Math.abs(x-ball_x)<20) && (Math.abs(y-ball_y[i])<20)) {
				hold_ball=i;
				return(true);
			}
		}
		return(false);
	}

	public boolean mouseDrag(Event evt,int x,int y) {
		mouse_x=x;
		mouse_y=y;
		return(true);
	}

	public boolean mouseMove(Event evt,int x,int y) {
		mouse_x=x;
		mouse_y=y;
		return(true);
	}

	public boolean mouseUp(Event evt,int x,int y) {
		mouse_x=x;
		mouse_y=y;
		hold_ball=-1;
		return(true);
	}

	private System sys;
	private DeltaClass rule;
	private Panel left_panel;
	private Choice system_choice;
	private Choice method_choice;
	private Button clear_button;
	private Button restart_button;
	private Button section_button;
	private boolean do_section=false;
	private int first_op,second_op;
	private Panel bottom_panel;
	private TextField m1,m2,k1,k2,dt;
	private Thread thread;
	private Image pendulum;
	private Image section;
	private Image energy;
	private Vector energy_vector;
	private double max_energy;
	private double last_sv0=1.0;
	private double last_sv1=0.0;
	private double last_sv2=0.0;
	private boolean ready_to_run=false;
	private LyapMeasure lyap;
	private Label lyap_label;

	private int mouse_x,mouse_y;
	private int ball_x,ball_y[];
	private int hold_ball=-1;  // -1 is not holding, else is # of ball.
}