/*
 *
 * This file provides the javascript to perform image rotation using a fade in/out
 * technique obtained and modified from http://www.brainerror.net/scripts_js_blendtrans.php
 *
 */

//
// arrays of photos and captions
//

var photo_array = new Array();
var photo_caption_array = new Array();

photo_array[0] = "images/2006-04-02-05-WhatsThatPlease-450x337.jpg";
photo_array[1] = "images/2006-04-02-09-Whoo-450x337.jpg";
photo_array[2] = "images/2006-04-02-10-HikerTrash-450x337.jpg";
photo_array[3] = "images/2006-06-18-08-AfternoonOnTundra-450x337.jpg";
photo_array[4] = "images/2006-06-18-02-DaveLaughs-450x337.jpg";
photo_array[5] = "images/2006-06-10-07-NahumStyleKing-450x337.jpg";
photo_array[6] = "images/2006-06-10-02-MostOfTheCrew-450x337.jpg";
photo_array[7] = "images/2006-03-25-02-Tracks-450x337.jpg";
photo_array[8] = "images/2006-01-01-ViewFromFirstFlatiron-450x337.jpg";
photo_array[9] = "images/20060624D1-45-RomAndJeniaAscendingUNotch-Sierras.JPG";
photo_array[10] = "images/20060626D2-08-Palisades-Sierras.JPG";
photo_array[11] = "images/20060626D2-43-AJOnSillSummit-Sierras.JPG";
photo_array[12] = "images/20060729D1-58-AJCanyoneering-LowerWolfCreek.JPG";
photo_array[13] = "images/20060811D2-03-Sunset-ZirkelWilderness.JPG";
photo_array[14] = "images/20060825D2-14-GrandCanyonOfTuolumneViews.JPG";
photo_array[15] = "images/20060903D3-49-MikeAndSteveRiverHikingInDinosaurNM-crop.jpg";
photo_array[16] = "images/20060909D1-45-GroupAtDiamondLake.JPG";
photo_array[17] = "images/20060928D2-18-DaveCanyoneering-ZionNP.JPG";
photo_array[18] = "images/20061001D1-47-TedCanyoneering-KolobCreekZionNP-crop.jpg";
photo_array[19] = "images/20061021D1-24-GroupCanyoneeringRoostArea-Utah.JPG";
photo_array[20] = "images/20061022D2-40-GroupCanyoneering-Utah.JPG";
photo_array[21] = "images/20061123D2-58-JonasandChuckCanyoneeringWestPasture-Utah-crop.jpg";
photo_array[22] = "images/IMG_0372.JPG";
photo_array[23] = "images/IMG_0458.JPG";
photo_array[24] = "images/Marmots.jpg";
photo_array[25] = "images/aai.jpg";
photo_array[26] = "images/aba.jpg";
photo_array[27] = "images/abk.jpg";
photo_array[28] = "images/ace_approaching_glass_lake.jpg";
photo_array[29] = "images/acn_sunrise_from_tremont.jpg";
photo_array[30] = "images/acv.jpg";
photo_array[31] = "images/adiBRAINARD_CABIN_MAR6&7.jpg";
photo_array[32] = "images/aek_Valleicto_Valley_in_San_Juans.jpg";
photo_array[33] = "images/afa.jpg";
photo_array[34] = "images/afi.jpg";
photo_array[35] = "images/ahgSTVRAINMTN0718.jpg";
photo_array[36] = "images/ahr_isabelle_glacier.jpg";
photo_array[37] = "images/aik.jpg";
photo_array[38] = "images/aim.jpg";
photo_array[39] = "images/ajc_butterly_on_aster.jpg";
photo_array[40] = "images/ajf_moose_and_two_calves.jpg";
photo_array[41] = "images/akg_Mandy_top_of_Buchanan_Pass.jpg";
photo_array[42] = "images/akn.jpg";
photo_array[43] = "images/amfMONARCH_LAKE_AUG7.jpg";
photo_array[44] = "images/anj.JPG";
photo_array[45] = "images/arf.JPG";

photo_caption_array[0] = "What's that please? - Boulder Grand Slam, 4/2/2006";
photo_caption_array[1] = "Whoo! - Boulder Grand Slam, 4/2/2006";
photo_caption_array[2] = "17 miles and 8,500 vertical feet later. - Boulder Grand Slam, 4/2/2006";
photo_caption_array[3] = "Bard Peak Trek - 6/18/2006";
photo_caption_array[4] = "Dave Becker Laughs - 6/18/2006";
photo_caption_array[5] = "Crock Master - Lost Creek Trek - 6/10/2006";
photo_caption_array[6] = "Lost Creek Crew - 6/10/2006";
photo_caption_array[7] = "Cross Country Skiing - 3/25/2006";
photo_caption_array[8] = "New Years Day Trek - 2006";
photo_caption_array[9] = "Rom and Jenia Ascending U Notch - Sierras - 6/24/2006";
photo_caption_array[10] = "Palisades - Sierras - 6/26/2006";
photo_caption_array[11] = "AJ On Sill Summit - Sierras - 6/26/2006";
photo_caption_array[12] = "AJ Canyoneering - Lower Wolf Creek - 7/29/2006";
photo_caption_array[13] = "Sunset - ZirkelWilderness - 8/11/2006";
photo_caption_array[14] = "Grand Canyon Of Tuolumne Views - 8/25/2006";
photo_caption_array[15] = "Mike and Steve River Hiking in Dinosaur NM - 9/3/2006";
photo_caption_array[16] = "Group at Diamond Lake - 9/9/2006";
photo_caption_array[17] = "Dave Canyoneering - Zion NP - 9/28/2006";
photo_caption_array[18] = "Ted Canyoneering - Kolob Creek Zion NP - 10/1/2006";
photo_caption_array[19] = "Group Canyoneering Roost Area - Utah - 10/21/2006";
photo_caption_array[20] = "Group Canyoneering -Utah - 10/22/2006";
photo_caption_array[21] = "Jonas and Chuck Canyoneering West Pasture - Utah - 11/23/2006";
photo_caption_array[22] = "Ben and Nahum - Zirkel Wilderness - 2006";
photo_caption_array[23] = "Yosemite Sunset - Yosemite NP - 2006";
photo_caption_array[24] = "Chaos Marmots";
photo_caption_array[25] = "Lots of food!";
photo_caption_array[26] = "Post-hike beer at Southern Sun";
photo_caption_array[27] = "Loch Lake, RMNP";
photo_caption_array[28] = "Hiking up to Glass Lake";
photo_caption_array[29] = "Sunrise on Tremont";
photo_caption_array[30] = "Lost Creek Wilderness";
photo_caption_array[31] = "Brainard Cabin";
photo_caption_array[32] = "Vellecito Valley in the San Juans";
photo_caption_array[33] = "Mountain goats in the San Juans";
photo_caption_array[34] = "Lawn Lake, RMNP";
photo_caption_array[35] = "Approaching St. Vrain Peak";
photo_caption_array[36] = "Isabelle Glacier";
photo_caption_array[37] = "Down the snow covered trail";
photo_caption_array[38] = "Nahum and Dave moving down into Paradise Park";
photo_caption_array[39] = "Butterfly on aster";
photo_caption_array[40] = "Moose and two calves";
photo_caption_array[41] = "Mandy at top of Buchannan Pass";
photo_caption_array[42] = "Lots of gorgeous wildflowers!";
photo_caption_array[43] = "Monarch Lake";
photo_caption_array[44] = "Taking the trails less traveled";
photo_caption_array[45] = "Jack O' Lanterns over Boulder!";

//
// configuration variables 
//

var numImgs = photo_array.length; 
var delayMs = 5000;

// variables used to try not to repeat the same images too often.
var prevImgArray = new Array();
var prevImgArrayLen = 10; 

// initialize to -1
for (var i = 0; i < prevImgArrayLen; i++) {
	prevImgArray[i] = -1;
}


// Save previous imgId to prevImgArray.  We set each array entry to 
// the previous one, and then set the first one to the new imgId.

function updatePrevImgArray(imgId) {
	for (var i = prevImgArrayLen - 1; i > 0; i--) {
		prevImgArray[i] = prevImgArray[i - 1];
	}
	prevImgArray[0] = imgId;
} 


// iterate thru the prevImgArray[] and ensure that the imgId we are
// about to display is not one of the previous 10 images displayed.

function notPrevImg(imgId) {
	var bRetVal = false;

	for (var i = 0; i < prevImgArrayLen; i++) {
		if (prevImgArray[i] != imgId) {
			bRetVal = true;
		}
		else {
			// if we have found a previous image that is the same as that 
			// which we are about to display, we break out of this loop to 
			// avoid resetting our return value if the next image is different
			// from this one!
			bRetVal = false;
			break; 
		}
	}
	return bRetVal;
}


//
// functions
//

function slideShow(imgId) {
	// get the currently loaded image file, note that the src will be the 
	// fully qualified URL of the image, not just "image/*.jpg", so we extract
	// just the "image/*.jpg" from the URL for comparison here.

	var randomImgSrcStr = document.getElementById('randomImg').src;
	var randomImgSrcArray = randomImgSrcStr.split("/");
	var randomImgSrc = randomImgSrcArray[randomImgSrcArray.length - 2] + "/" + 
		randomImgSrcArray[randomImgSrcArray.length - 1];

	if (imgId == -1) {
		// get a new random number first, ensuring it is not the same as the currently loaded photo
		do
		{
			imgId = parseInt(Math.random() * photo_array.length); 
			imgId = (isNaN(imgId)) ? 0 : imgId;
			if (imgId == photo_array.length) {
				imgId = imgId - 1;
			}
		}
		while (notPrevImg(imgId) == false);
	} // end called in body onload event with -1 as the imgId

	updatePrevImgArray(imgId);

	// We fade out and photo and then fade a new one in with a brief interval of 
	// only the background.	 So blendImage() is not used any more.
	// setTimeout("blendImage(" + imgId + ")", delayMs); 

	setTimeout("fadeOutImage(" + imgId + ")", delayMs); 

	// calculate new random image, ensuring it is not the same as the currrently loaded photo
	var newImgId;
	do
	{
		newImgId = parseInt(Math.random() * photo_array.length); 
		newImgId = (isNaN(imgId)) ? 0 : newImgId;
		if (newImgId == photo_array.length) {
			newImgId = newImgId - 1;
		}
	}
	while (notPrevImg(newImgId) == false);

	setTimeout("slideShow(" + newImgId + ")", delayMs * 3);
} // end slideShow()


function fadeOutImage(imgId) {
	var speed = 10;
	var timer = 0;

	// fade out the image
	for (i = 99; i >= 0; i--) {
		setTimeout("changeOpac(" + i + ",'randomImg')", (timer * speed)); 
		timer++;
	} 

	// fade in the new image in the next interval
	setTimeout("fadeInImage(" + imgId + ")", delayMs / 5);

	// clear caption
	document.getElementById('pImgCaption').innerHTML = "<br>";
}


function fadeInImage(imgId) {
	var speed = 10; 
	var timer = 0; 

	//make image transparent 
	changeOpac(0, 'randomImg'); 
	
	//make new image
	document.getElementById('randomImg').src = photo_array[imgId]; 

	for (i = 0; i < 100; i++) {
		setTimeout("changeOpac(" + i + ",'randomImg')", (timer * speed)); 
		timer++;
	} 

	// set new caption
	document.getElementById('pImgCaption').innerHTML = photo_caption_array[imgId]; 
}  // end fadeInImage()
	

// MDD - NOTE - Due to difficulties with achieving the fade in/out I choose
// to fade out and then fade in, in two separate steps, rather than fade from
// one photo to another.  In FireFox there was usually a nasty flicker and in 
// IE7 on some systems there was no fade at all, although that still happens.
// Basically I think it is nicer to avoid the flickering images on FireFox.

function blendImage(imgId) {
	var speed = 10; 
	var timer = 0; 

	//set the current image as background 
	document.getElementById('imgDiv').style.backgroundImage = "url(" + 
		document.getElementById('randomImg').src + ")"; 

	//make image transparent 
	changeOpac(0, 'randomImg'); 
	
	//make new image
	document.getElementById('randomImg').src = photo_array[imgId]; 

	//
	// fade in image - note to mostly avoid the flickering seen in mozilla, which
	// according the author of these scripts is due to:
	// 
	// "The first bug is rather obvious, when fading in there is a flickering 
	// just before the transition finishes. This is because the semi-transparant 
	// image is converted to a fully visible one. You can prevent this from 
	// happening by making the image only 99% visible (-moz-opacity: 0.99)."
	//
	// So below we iterate to less than 100.  But this doesn't work all the 
	// time but it works most of the time.
	//

	for (i = 0; i < 100; i++) {
		setTimeout("changeOpac(" + i + ",'randomImg')", (timer * speed)); 
		timer++;
	} 

	// set new caption
	document.getElementById('pImgCaption').innerHTML = photo_caption_array[imgId]; 
}  // end blendImage()


function changeOpac(opacity, id) {
	//change the opacity for different browsers 
	var object = document.getElementById(id).style; 
	object.opacity = (opacity / 100); 
	object.MozOpacity = (opacity / 100); 
	object.KhtmlOpacity = (opacity / 100); 
	object.filter = "alpha(opacity=" + opacity + ")";
} // end changeOpac()


//
// Write link content a-CommentLink
//

function writeCommentLink() {
	var aCommentLink1 = document.getElementById("a-CommentLink1");
	var aCommentLink2 = document.getElementById("a-CommentLink2");

	aCommentLink1.href = "mailto:emailgnome@boulderchaos.org";
	aCommentLink1.innerHTML = "&#101;&#109;&#097;&#105;&#108;&#103;&#110;&#111;&#109;&#101;&#064;&#098;&#111;&#117;&#108;&#100;&#101;&#114;&#099;&#104;&#097;&#111;&#115;&#046;&#111;&#114;&#103;";

	aCommentLink2.href = "mailto:emailgnome@boulderchaos.org";
	aCommentLink2.innerHTML = "&#101;&#109;&#097;&#105;&#108;&#103;&#110;&#111;&#109;&#101;&#064;&#098;&#111;&#117;&#108;&#100;&#101;&#114;&#099;&#104;&#097;&#111;&#115;&#046;&#111;&#114;&#103;";
} // end writeCommentLink()