/**
  * Image Loader for the Plink Applet
  * @author Robert J Morton
  * @version 12 Dec 2007, 10 April 2012 
  * Modified for encapsulation in jar file Thu 02 Feb 2017 12:51:07 BRST
  * JFramed Sat 04 Mar 2017 12:03:33 BRT  */

import java.awt.*;             // abstract window tool kit for applet 
import java.awt.MediaTracker;  // for the new-fangled 1.1 event handling
import javax.imageio.*;
import java.awt.image.BufferedImage;
import java.io.*;   // file input/output handling
import java.net.*;  // for downloading data from the remote server

public class imgldr {
  private address hf;            // instance reference to search applet
  private MediaTracker tracker;  // to track when images have been loaded

  private boolean 
    loadingImages = true,  // true while in the process of loading images
    trackerError = false,  // true indicates that tracker encountered an error
    loadFTT = true,        // to avoid an erase and repaint of the loading of
    errorFTT = true;       // load-error message once per refresh cycle

  private int ls;     // load switch 0=file, 1=jar, 2=server
  private String cb;  // code base [URL path to image files on server]
  private String[] S = {"local directory","jar file","remote server"};


  imgldr(address hf, int ls, String cb) {
    this.hf = hf;  // instance reference to the movmap app
    this.ls = ls;  // load switch
    this.cb = cb;  // code base [URL path]

    /* Create a media tracker and register images with it. Media tracker
    monitors the progress of loading process for each image files. */

    tracker = new MediaTracker(hf); 

    System.out.println("Loading images...");
    hf.img = getImg("intapp.png");  // try to load the image file
    if(hf.img != null) {
      tracker.addImage(hf.img,0);
    }
  }


  private BufferedImage getImg(String F) {
    BufferedImage I = null;
    try {
      switch(ls) {
        case 0: I = ImageIO.read(new File(F)); break;
        case 1: I = ImageIO.read(getClass().getResourceAsStream(F)); break;
        case 2: I = ImageIO.read(new URL(cb + F));
      }
    } catch (IOException e) {
      System.out.println("Couldn't load " + F + " from " + S[ls] + ".");
      System.out.println(e);
    }
    return I;
  }


  boolean finished() {  // returns true when image loading has finished
    if(tracker == null) return true;
    if(loadingImages()) return false;
    if(trackingImages()) return false;
    return true;
  }


  private boolean loadingImages() {
    if(loadFTT) {       // if this is the first time through here
      System.out.println("Tracking progress...");
      loadFTT = false;  // avoid repeating display every cycle      
    }
    try {
      tracker.waitForAll();  // keep checking the tracker for a signal
    }

    /* If the tracker does not say anything, return without
    servicing the app's run() thread, otherwise, will drop
    through when tracker gives a completion signal. */

    catch (InterruptedException e) {
      System.out.println("Error: could not finish loading image.");
      System.out.println("" + e);
      return true;
    }  
    return false;
  }


  // Returns true when image loading has terminated.
  private boolean trackingImages() {

    /* If the image loading process still running, get 
    the status of the image loading process. */
    if(loadingImages) {
      int ts = tracker.statusAll(false);

      /* if the loading process has completed with an
      error, set the image loading failure flag */

      if((ts & MediaTracker.ERRORED) != 0) {
        trackerError = true;

        /* If this is the first time through on this image loading attempt,
        show the error message and set the error display flag false to 
        avoid re-displaying the message each pass. */

        if(errorFTT) {
          System.out.println("Error: couldn't load image.");
          errorFTT = false;
        }
      }

      /* if tracker has completed its task, set flag to indicate
      that image loading has terminated successfully. */

      if(ts == MediaTracker.COMPLETE) {
        loadingImages = false;
      }
    }

    /* else, the image loading process has just finished,
    so dispense with this instance of the Media Tracker
    and refresh message display if not already done. */

    else killTracker();
      return false;
  }


  /* If this instance of the Media Tracker still exists, remove 
  (de-register) the image from it and then destroy (garbage) it. */

  void killTracker() {
    if(tracker != null) {
      tracker.removeImage(hf.img,0);
      tracker = null;
    }
  }

  boolean TrackerError() {return trackerError;}
}