// Navigate.java:   Applet to control the navigation demo
//
// Daniel.Schneider@tecfa.unige.ch  1/98
// this is basically a tiny subset of David Brown's descent applet
// ... needs probably some cleaning up

import java.awt.*;
import java.applet.*;

import vrml.external.field.*;
import vrml.external.Node;
import vrml.external.Browser;
import vrml.external.exception.*;


public class Navigate extends Applet {

  // The Browser
  Browser browser = null;
  
  // Various UI widgets
  Button entryButton, accrossButton, sideview1Button, sideview2Button, birdButton;
  
  // Various stuff in the VRML scene we hang on to
  Node root_node;
  Node entryVP, accrossVP, LinedUp1VP, LinedUp2VP, BirdsEyeVP;
  
  // "Aborted" state (used to disable some UI or code
  // if we've already had a fatal error)
  boolean aborted = false;
  
  /** Initialize the Applet */
  public void init() {
    
    // Connect to the browser
    browser = Browser.getBrowser(this);
    
    if (browser == null) {
      die("init: NULL browser!");
    }
    System.out.println("Got the browser: " + browser);
    
    // Add the buttons to the Java Panel
    add (entryButton = new Button("Entry"));
    add (accrossButton = new Button("Accross the Room"));
    add (sideview1Button = new Button("Side View 1"));
    add (sideview2Button = new Button("Side View 2"));
    add (birdButton = new Button("Bird's Eye"));
    
    // Misc other UI setup
    Color c = Color.white;
    System.out.println("Setting bg color to: " + c);
    setBackground(c);
    
    System.out.println("Navigate.init() done.");

    // Initialize some VRML stuff
    initScene();
  }
  
  /** Start the applet running */
  public void start(){
    System.out.println("Navigate Applet: start()...");
  }
  
  /** Stop the applet */
  public void stop(){
    System.out.println("Navigate Applet: stop()...");
  }
  
  /**
    * This applet is about to be unloaded.  Do final cleanup.
    */
  public void destroy() {
    System.out.println("Navigate Applet: destroy()...");
  }	
  
  
  /** Handle a fatal error condition */
  public void die(String s) {
    System.out.println("Navigate Applet: FATAL ERROR!");
    System.out.println("--> " + s);
    System.out.println("Navigate Applet: Aborting...\n");
    
    aborted = true;   // Causes update() to display a warning
  }


  /** Handle actions from AWT widgets */
  public boolean action(Event event, Object what) {

	if (event.target instanceof Button) {
	    Button b = (Button) event.target;

	    if (b == entryButton) {
	      bindToViewPoint(entryVP);
	    }
	    else if (b == accrossButton) {
	      bindToViewPoint(accrossVP);
	    }
	    else if (b == sideview1Button) {
	      bindToViewPoint(LinedUp1VP);
	    }
	    else if (b == sideview2Button) {
	      bindToViewPoint(LinedUp2VP);
	    }
	    else if (b == birdButton) {
	      bindToViewPoint(BirdsEyeVP);
	    }
	} // event.target instanceof Button

        return true;
  }


  /** Set up some stuff in the VRML scene */
  public void initScene() {
    System.out.println("initScene()...");
    
    // Get the ViewPoints
    try {
      entryVP = browser.getNode("Entry");
      accrossVP = browser.getNode("AcrossTheRoom");
      LinedUp1VP = browser.getNode("LinedUp1");
      LinedUp2VP = browser.getNode("LinedUp2");
      BirdsEyeVP = browser.getNode("BirdsEye");
    }
    catch(InvalidNodeException e){
      System.out.println("InvalidNodeException: " + e);
      die("initScene: VP node not found!");
      return;
    }
  }

  /** Move to the specified viewpoint */
  // the handles to the EventIN fields are generated when needed

  public void bindToViewPoint(Node vp) {
    System.out.println("bindToViewpoint(node '" + vp + "')...");
    
    EventInSFBool set_bind = null;
    try {
      set_bind = (EventInSFBool)vp.getEventIn("set_bind");
    }
    catch(InvalidEventInException e) {
      die("bindToViewpoint: InvalidEventInException: " + e);
      return;
    }
    System.out.println("bindToViewpoint: got the EventIn: "+set_bind);
    
    set_bind.setValue(true);
    System.out.println("bindToViewpoint() done.");
  }
  
}