//=====================================================================
// File: LorenzApplet.java
//
// Applied Math 303, Term Project
// Blair Fraser, 2303725
//=====================================================================

import java.applet.Applet;
import java.awt.*;
import java.lang.*;

public class LorenzApplet extends Applet implements Runnable {

  LorenzCanvas equationCanvas;
  Thread thread;
  Button stopStart;
  TextField xText, yText, zText;


  public void init() {
    setLayout(new BorderLayout());

    //----------------
    // Get parameters
    //----------------
    String str = new String();

    str = getParameter("initial_x");
    double initialx = Double.valueOf(str).doubleValue();

    str = getParameter("initial_y");
    double initialy = Double.valueOf(str).doubleValue();

    str = getParameter("initial_z");
    double initialz = Double.valueOf(str).doubleValue();

    str = getParameter("time_step");
    double stepSize = Double.valueOf(str).doubleValue();

    str = getParameter("interface_on");
    boolean buttonsOn=true;
    if(str!=null){ Boolean.valueOf(str).booleanValue();}


    str = getParameter("maximum_x");
    double domainMaxx = Double.valueOf(str).doubleValue();

    str = getParameter("minimum_x");
    double domainMinx = Double.valueOf(str).doubleValue();

    str = getParameter("maximum_y");
    double domainMaxy = Double.valueOf(str).doubleValue();

    str = getParameter("minimum_y");
    double domainMiny = Double.valueOf(str).doubleValue();   


    //----------------------------
    // Create the equation canvas
    //----------------------------
    equationCanvas = new LorenzCanvas();
    equationCanvas.setInitialState(0.0, initialx, initialy, initialz);
    equationCanvas.setDomain(domainMaxx,domainMinx,domainMaxy,domainMiny);
    equationCanvas.setTimeStep(stepSize);

    //-----------------------------
    // Create buttons if nessasary 
    //-----------------------------  
    if(buttonsOn) {

      //-------------------------
      // Parameter 1 = initial x
      //-------------------------
      Panel param1Panel = new Panel();
      param1Panel.setLayout(new BorderLayout());
      param1Panel.add("West", new Label("Initial x"));
      xText = new TextField(initialx+"", 8);
      param1Panel.add("East", xText);

      //-------------------------
      // Parameter 2 = initial y
      //-------------------------
      Panel param2Panel = new Panel();
      param2Panel.setLayout(new BorderLayout());
      param2Panel.add("West", new Label("Initial y"));
      yText = new TextField(initialy+"", 8);
      param2Panel.add("East", yText);

      Panel param3Panel = new Panel();
      param3Panel.setLayout(new BorderLayout());
      param3Panel.add("West", new Label("initial z"));
      zText = new TextField(initialz+"", 8);
      param3Panel.add("East", zText);

      Panel panelNo1 = new Panel();
      panelNo1.setLayout(new GridLayout(1, 3));
      panelNo1.add(param1Panel);
      panelNo1.add(param2Panel);
      panelNo1.add(param3Panel);


      //-------------------------------------------
      // Control Bar Panel, entire user interface.
      //-------------------------------------------

      Panel controlBar = new Panel();
      controlBar.setLayout(new BorderLayout());
      stopStart = new Button("Restart with new settings");
      controlBar.add("North", stopStart);
      controlBar.add("South", panelNo1);

      add("South", controlBar);


    } else {
      //-------------------------------------------------
      // If interface is off, just add a restart button.
      //-------------------------------------------------
      add("South", new Button("Restart"));
    }

    add("Center",equationCanvas);
    show();
  }


  //=====================================================================
  // start
  //
  // Start the thread.
  //=====================================================================
  public void start() {
    thread = new Thread(this);
    thread.start();
  }


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

  //=====================================================================
  // run
  //
  // Run the thread, this is the main loop of the applet.
  //=====================================================================
  public void run() {
    while(true) {
      try {
        thread.sleep(25);
      }catch(InterruptedException e) {
        break;
      }
      equationCanvas.increment();
      equationCanvas.repaint();
    }
  }
  
  //=====================================================================
  // handle action
  //
  // How to handle a button click.
  //=====================================================================
  public boolean action(Event evt, Object arg) {
  
    if(evt.target instanceof Button) {

      if(arg.equals("Restart with new settings")) {
        double initx = Double.valueOf(xText.getText()).doubleValue();
        double inity = Double.valueOf(yText.getText()).doubleValue();
        double initz = Double.valueOf(zText.getText()).doubleValue();
        equationCanvas.setInitialState(0.0, initx, inity, initz);
        equationCanvas.restart();

      } else if(arg.equals("Restart")) {
        equationCanvas.restart();
      }
      return(true);
    }
    return(false);
  }
}