/*==================================================*
 $Id: slideshow.js,v 1.16 2003/10/14 12:39:00 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 function 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;
		
		// Name of the target window ("_blank")
		this.target = target;
		
		// Custom duration for the slide, in milliseconds.
		// This is an optional parameter.
		// this.timeout = 3000
		
		// Attributes for the target window:
		// width=n,height=n,resizable=yes or no,scrollbars=yes or no,
		// toolbar=yes or no,location=yes or no,directories=yes or no,
		// status=yes or no,menubar=yes or no,copyhistory=yes or no
		// Example: "width=200,height=300"
		this.attr = attr;
		
		// Create an image object for the slide
		if (document.images) {
			this.image = new Image();
		}
		
		// Flag to tell when load() has already been called
		this.loaded = false;

		//--------------------------------------------------
		this.load = function() {
			// This method loads the image for the slide
			if (!document.images) { return; }
			if (!this.loaded) {
				this.image.src = this.src;
				this.loaded = true;
			}
		}

		//--------------------------------------------------
		this.hotlink = function() {
			// This method jumps to the slide's link.
			// If a window was specified for the slide, then it opens a new window.
			var mywindow;
			
			if (!this.link) return; // If this slide does not have a link, do nothing
			
			// Open the link in a separate window?
			if (this.target) {
				// If window attributes are specified,
				// use them to open the new window
				if (this.attr) {
					mywindow = window.open(this.link, this.target, this.attr);
					
				} else {
					// If window attributes are not specified, do not use them
					// (this will copy the attributes from the originating window)
					mywindow = window.open(this.link, this.target);
				}
				
				// Pop the window to the front
				if (mywindow && mywindow.focus) mywindow.focus();
				
			} else {
				// Open the link in the current window
				location.href = this.link;
			}
		}
	}

//==================================================
// slideshow object
//==================================================
	function slideshow( slideshowname ) {
		// This is the constructor function 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 is 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 element on your HTML page.
		// For example, document.images.SLIDES1IMG
		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;
		
		// TEXTAREA element on your HTML page.
		// For example, document.SLIDES1FORM.SLIDES1TEXT
		// This is a depracated method for displaying the text,
		// but you might want to supply it for older browsers.
		this.textarea;
		
		// Milliseconds to pause between slides.
		// Individual slides can override this.
		this.timeout = 3000;
		
		// Hook functions to be called before and after updating the slide
		// this.pre_update_hook = function() { }
		// this.post_update_hook = function() { }
		
		// These are private variables
		this.slides = new Array();
		this.current = 0;
		this.timeoutid = 0;

		//--------------------------------------------------
		// Public methods
		//--------------------------------------------------
			this.add_slide = function(slide) {
				// Add a slide to the slideshow.
				// For example:
				// SLIDES1.add_slide(new slide("s1.jpg", "link.html"))
				
				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) {
				// This method implements the automatically running slideshow.
				// If you specify the "timeout" argument, then a new default
				// timeout will be set for the slideshow.
				
				// Make sure we're not already playing
				this.pause();
				
				// If the timeout argument was specified (optional)
				// then make it the new default
				if (timeout) {
					this.timeout = timeout;
				}
				
				// If the current slide has a custom timeout, use it;
				// otherwise use the default timeout
				if (typeof this.slides[ this.current ].timeout != 'undefined') {
					timeout = this.slides[ this.current ].timeout;
				} else {
					timeout = this.timeout;
				}
				
				// After the timeout, call this.loop()
				this.timeoutid = setTimeout( this.name + ".loop()", timeout);
			}

		//--------------------------------------------------
			this.pause = function() {
				// This method stops the slideshow if it is automatically running.
				
				if (this.timeoutid != 0) {
					
					clearTimeout(this.timeoutid);
					this.timeoutid = 0;
					
				}
			}

		//--------------------------------------------------
			this.update = function() {
				// This method updates the slideshow image on the page
				
				// Make sure the slideshow has been initialized correctly
				if (! this.valid_image()) { return; }
				
				// Call the pre-update hook function if one was specified
				if (typeof this.pre_update_hook == 'function') {
					this.pre_update_hook();
				}
				
				// Convenience variable for the current slide
				var slide = this.slides[ this.current ];
				
				// Determine if the browser supports filters
				var dofilter = false;
				if (this.image &&
				typeof this.image.filters != 'undefined' &&
				typeof this.image.filters[0] != 'undefined') {
					
					dofilter = true;
					
				}
				
				// Load the slide image if necessary
				slide.load();
				
				// Apply the filters for the image transition
				if (dofilter) {
					
					// If the user has specified a custom filter for this slide,
					// then set it now
					if (slide.filter &&
					this.image.style &&
					this.image.style.filter) {
						
						this.image.style.filter = slide.filter;
						
					}
					this.image.filters[0].Apply();
				}
				
				// Update the image.
				this.image.src = slide.image.src;
				
				// Play the image transition filters
				if (dofilter) {
					this.image.filters[0].Play();
				}
				
				// Update the text
				this.display_text();
				
				// Call the post-update hook function if one was specified
				if (typeof this.post_update_hook == 'function') {
					this.post_update_hook();
				}
				
				// Do we need to pre-fetch images?
				if (this.prefetch > 0) {
					
					var next, prev, count;
					
					// Pre-fetch the next slide image(s)
					next = this.current;
					prev = this.current;
					count = 0;
					do {
						
						// Get the next and previous slide number
						// Loop past the ends of the slideshow if necessary
						if (++next >= this.slides.length) next = 0;
						if (--prev < 0) prev = this.slides.length - 1;
						
						// Preload the slide image
						this.slides[next].load();
						this.slides[prev].load();
						
						// Keep going until we have fetched
						// the designated number of slides
						
					} while (++count < this.prefetch);
				}
			}

		//--------------------------------------------------
			this.goto_slide = function(n) {
				// This method jumpts to the slide number you specify.
				// 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.
				// Examples:
				// onClick="myslides.goto_slide(0)"
				// onClick="myslides.goto_slide(-1)"
				// onClick="myslides.goto_slide(5)"
				
				if (n == -1) {
					n = this.slides.length - 1;
				}
				
				if (n < this.slides.length && n >= 0) {
					this.current = n;
				}
				
				this.update();
			}

		//--------------------------------------------------
			this.goto_random_slide = function(include_current) {
				// Picks a random slide (other than the current slide) and
				// displays it.
				// If the include_current parameter is true,
				// then 
				// See also: shuffle()
				
				var i;
				
				// Make sure there is more than one slide
				if (this.slides.length > 1) {
					
					// Generate a random slide number,
					// but make sure it is not the current slide
					do {
						i = Math.floor(Math.random()*this.slides.length);
					} while (i == this.current);
					
					// Display the slide
					this.goto_slide(i);
				}
			}

		//--------------------------------------------------
			this.next = function() {
				// This method advances 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() {
				// This method goes to the previous slide.
				
				// Decrement the image number
				if (this.current > 0) {
					this.current--;
				} else if (this.repeat) {
					this.current = this.slides.length - 1;
				}
				
				this.update();
			}

		//--------------------------------------------------
			this.shuffle = function() {
				// This method randomly shuffles the order of the slides.
				
				var i, i2, slides_copy, slides_randomized;
				
				// Create a copy of the array containing the slides
				// in sequential order
				slides_copy = new Array();
				for (i = 0; i < this.slides.length; i++) {
					slides_copy[i] = this.slides[i];
				}
				
				// Create a new array to contain the slides in random order
				slides_randomized = new Array();
				
				// To populate the new array of slides in random order,
				// loop through the existing slides, picking a random
				// slide, removing it from the ordered list and adding it to
				// the random list.
				
				do {
					
					// Pick a random slide from those that remain
					i = Math.floor(Math.random()*slides_copy.length);
					
					// Add the slide to the end of the randomized array
					slides_randomized[ slides_randomized.length ] =
					slides_copy[i];
					
					// Remove the slide from the sequential array,
					// so it cannot be chosen again
					for (i2 = i + 1; i2 < slides_copy.length; i2++) {
						slides_copy[i2 - 1] = slides_copy[i2];
					}
					slides_copy.length--;
					
					// Keep going until we have removed all the slides
					
				} while (slides_copy.length);
				
				// Now set the slides to the randomized array
				this.slides = slides_randomized;
			}

		//--------------------------------------------------
			this.get_text = function() {
				// This method returns 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(s.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 && typeof this.textarea.value != 'undefined') {
					this.textarea.value = text;
				}
				
				// If a text id has been specified,
				// then change the contents of the HTML element
				if (this.textid) {
					
					r = this.getElementById(this.textid);
					if (!r) { return false; }
					if (typeof r.innerHTML == 'undefined') { return false; }
					
					// Update the text
					r.innerHTML = text;
				}
			}

		//--------------------------------------------------
			this.hotlink = function() {
				// This method calls the hotlink() method for the current slide.
				
				this.slides[ this.current ].hotlink();
			}

		//--------------------------------------------------
			this.save_position = function(cookiename) {
				// Saves the position of the slideshow in a cookie,
				// so when you return to this page, the position in the slideshow
				// won't be lost.
				
				if (!cookiename) {
					cookiename = this.name + '_slideshow';
				}
				
				document.cookie = cookiename + '=' + this.current;
			}

		//--------------------------------------------------
			this.restore_position = function(cookiename) {
				// If you previously called slideshow_save_position(),
				// returns the slideshow to the previous state.
				
				//Get cookie code by Shelley Powers
				
				if (!cookiename) {
					cookiename = this.name + '_slideshow';
				}
				
				var search = cookiename + "=";
				
				if (document.cookie.length > 0) {
					offset = document.cookie.indexOf(search);
					// if cookie exists
					if (offset != -1) { 
						offset += search.length;
						// set index of beginning of value
						end = document.cookie.indexOf(";", offset);
						// set index of end of cookie value
						if (end == -1) end = document.cookie.length;
						this.current = parseInt(unescape(document.cookie.substring(offset, end)));
					}
				}
			}

		//--------------------------------------------------
			this.noscript = function() {
				// This method is not for use as part of your slideshow,
				// but you can call it to get a plain HTML version of the slideshow
				// images and text.
				// You should copy the HTML and put it within a NOSCRIPT element, to
				// give non-javascript browsers access to your slideshow information.
				// This also ensures that your slideshow text and images are indexed
				// by search engines.
				
				$html = "\n";
				
				// Loop through all the slides in the slideshow
				for (i=0; i < this.slides.length; i++) {
					
					slide = this.slides[i];
					
					$html += '<P>';
					
					if (slide.link) {
						$html += '<a href="' + slide.link + '">';
					}
					
					$html += '<img src="' + slide.src + '" ALT="slideshow image">';
					
					if (slide.link) {
						$html += "<\/a>";
					}
					
					if (slide.text) {
						$html += "<BR>\n" + slide.text;
					}
					
					$html += "<\/P>" + "\n\n";
				}
				
				// Make the HTML browser-safe
				$html = $html.replace(/\&/g, "&amp;" );
				$html = $html.replace(/</g, "&lt;" );
				$html = $html.replace(/>/g, "&gt;" );
				
				return('<pre>' + $html + '</pre>');
			}

		//==================================================
		// 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.
				// If the next slide image has not completed loading yet,
				// then do not advance to the next slide yet.
				
				// Make sure the next slide image has finished loading
				if (this.current < this.slides.length - 1) {
					next_slide = this.slides[this.current + 1];
					if (next_slide.image.complete == null || next_slide.image.complete) {
						this.next();
					}
				} else { // we're at the last slide
					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)
				{
					return false;
				}
				else {
					return true;
				}
			}

		//--------------------------------------------------
			this.getElementById = function(element_id) {
				// This method returns the element corresponding to the id
				
				if (document.getElementById) {
					return document.getElementById(element_id);
				}
				else if (document.all) {
					return document.all[element_id];
				}
				else if (document.layers) {
					return document.layers[element_id];
				} else {
					return undefined;
				}
			}

		//==================================================
		// Deprecated methods
		// I don't recommend the use of the following methods,
		// but they are included for backward compatibility.
		// You can delete them if you don't need them.
		//==================================================

		//--------------------------------------------------
			this.set_image = function(imageobject) {
				// This method is deprecated; you should use
				// the following code instead:
				// s.image = document.images.myimagename;
				// s.update();
				
				if (!document.images)
					return;
				this.image = imageobject;
			}

		//--------------------------------------------------
			this.set_textarea = function(textareaobject) {
				// This method is deprecated; you should use
				// the following code instead:
				// s.textarea = document.form.textareaname;
				// s.update();
				
				this.textarea = textareaobject;
				this.display_text();
			}

		//--------------------------------------------------
			this.set_textid = function(textidstr) {
				// This method is deprecated; you should use
				// the following code instead:
				// s.textid = "mytextid";
				// s.update();
				
				this.textid = textidstr;
				this.display_text();
			}
	}

	function RunSlideShow() {
		
		if (ShowSlidesText) {
			document.write('<DIV ID="SLIDESTEXT">');
			nodivtext = SLIDES.get_all_text("<li>", "<p>\n");
			if (nodivtext) {
				document.write("<UL>\n" + nodivtext + "\n</UL>");
			}
			document.write('</DIV>');
		}
		document.write('<a href="javascript:SLIDES.hotlink()"><img name="SLIDESIMG" src="pic1.jpg" STYLE="');
		if (DefaultFilter != "") {
			document.write('filter:'+DefaultFilter);
		}
		document.write('" BORDER=0 alt="Slideshow image"></a>');
		
		if (document.images) {
		  SLIDES.image = document.images.SLIDESIMG;
		  SLIDES.textid = "SLIDESTEXT";
		  SLIDES.update();
		  SLIDES.play();
		}
	}