/*==================================================*
 $Id: slideshow.js,v 1.6 2003/02/24 22:34:24 pat Exp $  Copyright 2000-2003 Patrick Fitzgerald  http://slideshow.barelyfitz.com/

 This program is free software; you can redistribute it and/or modify  it under the terms of the GNU General Public License as published by  the Free Software Foundation; either version 2 of the License, or  (at your option) any later version.

 This program is distributed in the hope that it will be useful,  but WITHOUT ANY WARRANTY; without even the implied warranty of  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the  GNU General Public License for more details.

 You should have received a copy of the GNU General Public License  along with this program; if not, write to the Free Software  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA  *==================================================*/

// There are two objects defined in this file:
// "slide" - contains all the information for a single slide
// "slideshow" - consists of multiple slide objects and runs the slideshow

//##################################################
// slide object //##################################################

function slide(src,link,text,target,attr) {
// This is the constructor method for the slide object.
// It is called automatically when you create a new slide object. // For example: // s = new slide();

  // Image URL
  this.src = src;

  // Link URL
  this.link = link;

  // Text to display
  this.text = text;

  // Create an image object for the slide
  if (document.images) {
    this.image = new Image();
  }

  //--------------------------------------------------
  this.load = function() {
  // Load the image for the slide
    if (!document.images) { return; }
    if (!this.image.src) {
      this.image.src = this.src;
    }
  }

  //--------------------------------------------------
  this.hotlink = function() {
  // Jump to the slide's link.

    // Open the hotlink in the current window
    location.href = this.link;
  }
} // END OF SLIDE OBJECT

//##################################################
// slideshow object //##################################################

function slideshow( slideshowname ) {
// This is the constructor method for the slideshow object.
// It is called automatically when you create a new object.
// For example:
// ss = new slideshow("ss");

  // Name of this object
  // (required if you want your slideshow to auto-play)
  // For example, "SLIDES1"
  this.name = slideshowname;

  // When we reach the last slide, should we loop around to start the
  // slideshow again?
  this.repeat = true;

  // Number of images to pre-fetch.
  // -1 = preload all images.
  //  0 = load each image as it is used.
  //  n = pre-fetch n images ahead of the current image.
  // I recommend preloading all images unless you have large
  // images, or a large amount of images.
  this.prefetch = 1;

  // IMAGE object from your HTML page.
  // For example, document.images.SLIDES1IMG
  // Note: after you set this variable, you should call
  // the update() method to update the slideshow display.
  this.image;

  // ID of a DIV element on your HTML page that will contain the text.
  // For example, "slides2text"
  // Note: after you set this variable, you should call
  // the update() method to update the slideshow display.
  this.textid;

  // Milliseconds to pause between slides
  this.timeout = 3000;



//Parse URL

function getValue(varname)
{
  var url = window.location.href+("?");
  var qparts = url.split("?");
  if (qparts.length == 0)
   {
     return "0";
   }
  var query = qparts[1];
  var vars = query.split("&");
  var value = "";

  for (i=0;i<vars.length;i++)
   {
      var parts = vars[i].split("=");

	  if (parts[0] == varname)
	  {
		value = parts[1];

		break;
	  }
	}

	value = unescape(value);
	value.replace(/\+/g," ");
	return value;
}

	if (load_img = " ") this.current = 0
	if (load_img = "") this.current = 0
	if (load_img = null) this.current = 0

	else this.current = getValue("load_img") - 1;



  // These are private variables
  this.slides = new Array();
  // this.current = 0;
  this.timeoutid = 0;

  //--------------------------------------------------
  this.add_slide = function(slide) {
  // Add a slide to the slideshow.
  // For example:
  // SLIDES1.add_slide(new slide("s1.jpg", "link.html"))

    // If this version of JavaScript does not allow us to
    // change images, then we can't do the slideshow.
    if (!document.images) { return; }

    var i = this.slides.length;

    // Prefetch the slide image if necessary
    if (this.prefetch == -1) {
      slide.load();
    }

    this.slides[i] = slide;
  }

  //--------------------------------------------------
  this.play = function(timeout) {
  // Start the automatically-running slideshow.

    // Make sure we're not already playing
    this.pause();

    // If a new timeout was specified (optional) set it here
    if (timeout) {
      this.timeout = timeout;
    }

    // After the timeout, call this.loop()
    this.timeoutid = setTimeout( this.name + ".loop()", this.timeout);
  }

  //--------------------------------------------------
  this.pause = function() {
  // Stops the slideshow if it is automatically running.

    if (this.timeoutid != 0)
    {
      clearTimeout(this.timeoutid);
      this.timeoutid = 0;
    }
  }

  //--------------------------------------------------
  this.update = function() {
  // Update the slideshow image and text on the page

    // Make sure the slideshow has been initialized correctly
    if (! this.valid_image()) { return; }

    // Load the slide image if necessary
    this.slides[ this.current ].load();

    // Pre-fetch the next slide image(s) if necessary
    if (this.prefetch > 0) {
      for (i = this.current + 1;
           i <= (this.current + this.prefetch) && i < this.slides.length;
           i++) {
        this.slides[i].load();
      }
    }

    // Update the image.
    this.image.src = this.slides[ this.current ].image.src;

    // Update the text
    this.display_text();
  }

  //--------------------------------------------------
  this.goto_slide = function(n) {
  // Jump to an individual slide number.
  // If you use slide number -1, then it jumps to the last slide.
  // You can use this to make links that go to a specific slide,
  // or to go to the beginning or end of the slideshow.
  // Thanks to Lennart Groetzbach (lennartg@web.de) for this code.
  // Examples:
  // <a href="javascript:myslides.goto_slide(0)">First</a>
  // <a href="javascript:myslides.goto_slide(-1)">Last</a>
  // <a href="javascript:myslides.goto_slide(5)">Catching a Fish</a>

    if (n == -1) {
      n = this.slides.length - 1;
    }

    if (n < this.slides.length && n >= 0) {
      this.current = n;
    }

    this.update();
  }

  //--------------------------------------------------
  this.next = function() {
  // Advance to the next slide.

    // Increment the image number
    if (this.current < this.slides.length - 1) {
      this.current++;
    } else if (this.repeat) {
      this.current = 0;
    }

    this.update();
  }

  //--------------------------------------------------
  this.previous = function() {
  // Go to the previous slide.

    // Decrement the slide number
    if (this.current > 0) {
      this.current--;
    } else if (this.repeat) {
      this.current = this.slides.length - 1;
    }

    this.update();
  }

  //--------------------------------------------------
  this.get_text = function() {
  //  Return the text of the current slide
    return(this.slides[ this.current ].text);
  }

  //--------------------------------------------------
  this.get_all_text = function(before_slide, after_slide) {
  // Return the text for all of the slides.
  // For the text of each slide, add "before_slide" in front of the
  // text, and "after_slide" after the text.
  // For example:
  // document.write("<ul>");
  // document.write(myslideshow.get_all_text("<li>","\n"));
  // document.write("</ul>");

    all_text = "";

    // Loop through all the slides in the slideshow
    for (i=0; i < this.slides.length; i++) {

      slide = this.slides[i];

      if (slide.text) {
        all_text += before_slide + slide.text + after_slide;
      }

    }

    return(all_text);
  }

  //--------------------------------------------------
  this.display_text = function(text) {
  // Display the text for the current slide

    // If the "text" arg was not supplied (usually it isn't),
    // get the text from the slideshow
    if (!text) {
      text = this.slides[ this.current ].text;
    }

    // If a textarea has been specified,
    // then change the text displayed in it
    if (this.textarea) {
      this.textarea.value = text;
    }

    // If a text id has been specified,
    // then change the contents of the HTML element
    if (this.textid) {
      // Make sure we don't cause an error
      // for browsers that do not support getElementById
      if (!document.getElementById){ return false; }

      r = document.getElementById(this.textid);
      if (!r){ return false; }
      r.innerHTML = text;
    }
  }

  //--------------------------------------------------
  this.hotlink = function() {
  // Call the hotlink() method for the current slide.

    this.slides[ this.current ].hotlink();
  }

  //--------------------------------------------------
  // Private methods
  //--------------------------------------------------

  //--------------------------------------------------
  this.loop = function() {
  // This method is for internal use only.
  // This method gets called automatically by a JavaScript timeout.
  // It advances to the next slide, then sets the next timeout.

    // Go to the next image
    this.next( );

    // Keep playing the slideshow
    this.play( );
  }

  //--------------------------------------------------
  this.valid_image = function() {
  // Returns 1 if a valid image has been set for the slideshow

    if (!this.image)
    {
      // Stop the slideshow
      this.pause;

      // Display an error message
      window.status = "Warning: slideshow image not initialized for " + this.name;

      return 0;
    }
    else {
      return 1;
    }
  }

}