// Manifesto: $Id: slideshow.js,v 1.10 2007/11/19 01:06:49 spud Exp $
// license: GNU LGPL
// copyright 2001-2006: dada typo and contributors

// milliseconds between 10% changes in opacity
var fadeinterval = 60;
// milliseconds between slide changes
var changeinterval = 6000;

var ssct = 0;
var ssinited = false;
var ssplaying = false;
var blacked = false;

function blackout() {
	var b = document.body;
	var ss = getObjectRef("slideshow");
	var bg = dtDOM.buildElement("DIV","blackout",{ "class":"m_media"});
	dtDOM.setStyle(bg,"background","transparent url(/images/whiteout.png) top left repeat");
	dtDOM.setStyle(bg,"position","absolute");
	dtDOM.setStyle(bg,"top","0");
	dtDOM.setStyle(bg,"left","0");
	dtDOM.setStyle(bg,"height","100%");
	dtDOM.setStyle(bg,"width","100%");
	dtDOM.setStyle(bg,"textAlign","center");
	dtDOM.setStyle(bg,"verticalAlign","middle");
	dtDOM.setStyle(bg,"zIndex","200");
	// grab the existing nav bar and replace it in the blackout div
	var ssnav = getObjectRef("slideshownav");
	var bgnav = ss.removeChild(ssnav);
	dtDOM.removeClass(bgnav,"hidden");
	bg.appendChild(bgnav);
	var ssframe = dtDOM.buildElement("DIV","ssframe");
	dtDOM.setStyle(ssframe,"backgroundColor","#ffffff");
	dtDOM.setStyle(ssframe,"margin","20px auto");
	dtDOM.setStyle(ssframe,"height",(sscache[1].height + 40)+"px");
	dtDOM.setStyle(ssframe,"width",(sscache[1].width + 20)+"px");
	dtDOM.setStyle(ssframe,"textAlign","center");
	dtDOM.setStyle(ssframe,"verticalAlign","middle");
	var sstitle = getObjectRef("slidetitle");
	var bgtitle = ss.removeChild(sstitle);
	ssframe.appendChild(bgtitle);
	var ssbox = getObjectRef("slidebox");
	var bgbox = ss.removeChild(ssbox);
	ssframe.appendChild(bgbox);
	bg.appendChild(ssframe);
	b.appendChild(bg);
	blacked = true;
}
function restore() {
	var b = document.body;
	var bg = getObjectRef("blackout");
	var ss = getObjectRef("slideshow");
	var ssframe = getObjectRef("ssframe");
	var ssnav = getObjectRef("slideshownav");
	var rnav = bg.removeChild(ssnav);
	dtDOM.addClass(rnav,"hidden");
	ss.appendChild(rnav);
	var sstitle = getObjectRef("slidetitle");
	ss.appendChild(ssframe.removeChild(sstitle));
	var ssbox = getObjectRef("slidebox");
	ss.appendChild(ssframe.removeChild(ssbox));
	b.removeChild(bg);
	blacked = false;
}
function clearIntervals() {
	if (typeof inID != "undefined") clearInterval(inID);
	if (typeof outID != "undefined") clearInterval(outID);
	if (typeof ssID != "undefined") clearInterval(ssID);
}
function getNextImage() {
	if (ssct == sslength) alert("Trying to get a non-existant next image");
	ss_http = new AJAXobj(dtDOM.g_url+"rpc_reference.php");
	ss_http.rHandler = preloadSScacheForward;
	ss_http.dosend("module=media&t=slideshow&start="+ssct,"array");
}
function preloadSScacheForward() {
	if (ss_http.error != "") {
		alert(ss_http.error);
	} else {
		if (ss_http.responseCount) {
			// move current image to "previous" slot
			sscache[0] = sscache[1];
			var arr = ss_http.response[0];
			sscache[1] = { "id": arr[0], "src": arr[1], "caption": arr[2], "width": parseInt(arr[3]), "height": parseInt(arr[4]) };
			if (ss_http.responseCount > 1) {
				var arr = ss_http.response[1];
				sscache[2] = { "id": arr[0], "src": arr[1], "caption": arr[2], "width": parseInt(arr[3]), "height": parseInt(arr[4]) };
				if (ss_http.responseCount == 3) {
					var arr = ss_http.response[2];
					nextpreload = new Image();
					nextpreload.src = arr[1];
				}
			} else {
				sscache[2] = null;
			}
		}
		//if (ssct == sslength - 1) alert("getNextImage leaves us with "+sscache[0]["caption"]+";"+sscache[1]["caption"]+";"+sscache[2]["caption"]);
	}
}
function getPrevImage() {
	if (ssct < 0) alert("Trying to get a non-existant prev image");
	ss_http = new AJAXobj(dtDOM.g_url+"rpc_reference.php");
	ss_http.rHandler = preloadSScacheBackward;
	ss_http.dosend("module=media&t=media&start="+(ssct - 1),"array");
}
function preloadSScacheBackward() {
	if (ss_http.error != "") {
		alert(ss_http.error);
	} else {
		if (ss_http.responseCount) {
			// move current image to "next" slot
			sscache[2] = sscache[1];
			// move new image to "prev" slot
			var arr = ss_http.response[0];
			sscache[0] = { "id": arr[0], "src": arr[1], "caption": arr[2], "width": parseInt(arr[3]), "height": parseInt(arr[4]) };
			// move second new image to "current" slot (or null if not present)
			var arr = ss_http.response[1];
			sscache[1] = { "id": arr[0], "src": arr[1], "caption": arr[2], "width": parseInt(arr[3]), "height": parseInt(arr[4]) };
		}
		//if (ssct < 1) alert("getPrevImage leaves us with "+sscache[0]["caption"]+";"+sscache[1]["caption"]+";"+sscache[2]["caption"]);
	}
}
function fadeIn() {
	// slowly increase the opacity of the new image until 1.0
	var opac = dtDOM.getStyle(imgblock,"opacity");
	if (parseFloat(opac) < 1) {
		dtDOM.setStyle(imgblock,"opacity",parseFloat(opac) + .1);
	} else {
		clearInterval(inID);
	}
}
function swapDataForward() {
	// swap old data with new dta
	var ssframe = getObjectRef("ssframe");
	dtDOM.setStyle(ssframe,"height",(sscache[2].height + 40)+"px");
	dtDOM.setStyle(ssframe,"width",(sscache[2].width + 20)+"px");
	imgblock.src = sscache[2]["src"];
	imgtitle.innerHTML = sscache[2]["caption"];
	//imgtitle.replaceChild(document.createTextNode(sscache[2]["caption"]),imgtitle.firstChild);
	imgct.replaceChild(document.createTextNode((ssct + 1) + " of "+sslength),imgct.firstChild);
}
function fadeOutForward() {
	// slowly reduce the opacity of the current image until it is 0, then stop repeating and start running fadeIn()
	if (ssct > 0) dtDOM.setStyle(ssrwbutton.firstChild,"opacity","1.0");
	var opac = dtDOM.getStyle(imgblock,"opacity");
	if (opac > 0) {
		dtDOM.setStyle(imgblock,"opacity",parseFloat(opac) - .1);
	} else {
		clearInterval(outID);
		swapDataForward();
		// fade in the new image
		inID = setInterval("fadeIn()",fadeinterval);
		if (ssct + 1 < sslength) {
			// grab the next batch
			getNextImage();
		} else {
			sscache[0] = sscache[1];
			sscache[1] = sscache[2];
			sscache[2] = null;
		}
	}
}
function imgForward() {
	if ((ssct + 1) < sslength) {
		ssct++;
		// preload the next image
		nextpreload = new Image();
		nextpreload.src = sscache[2]["src"];
		outID = setInterval("fadeOutForward()",fadeinterval);
		// if this is the last image, fade the FF button
		if (ssct + 1 == sslength) dtDOM.setStyle(ssffbutton.firstChild,"opacity","0.5");
	} else if (ssplaying) {
		clearIntervals();
		ssplaying = false;
		dtDOM.showHide(ssplaybutton);
		dtDOM.showHide(sspausebutton);
	}
	return false;
}
function swapDataBackward() {
	// swap old data with new dta
	imgblock.src = sscache[0]["src"];
	imgtitle.innerHTML = sscache[0]["caption"];
	//imgtitle.replaceChild(document.createTextNode(sscache[0]["caption"]),imgtitle.firstChild);
	imgct.replaceChild(document.createTextNode((ssct + 1) + " of "+sslength),imgct.firstChild);
}
function fadeOutBackward() {
	// slowly reduce the opacity of the current image until it is 0, then start running fadeIn()
	var opac = dtDOM.getStyle(imgblock,"opacity");
	if (opac > 0) {
		dtDOM.setStyle(imgblock,"opacity",parseFloat(opac) - .1);
	} else {
		clearInterval(outID);
		swapDataBackward();
		// fade in the new image
		inID = setInterval("fadeIn()",fadeinterval);
		// grab the next batch
		if (ssct > 0) {
			getPrevImage();
		} else {
			sscache[2] = sscache[1];
			sscache[1] = sscache[0];
			sscache[0] = null;
			// alert("ssct == 0 leaves us with "+sscache[0]["caption"]+";"+sscache[1]["caption"]+";"+sscache[2]["caption"]);
		}
	}
}
function imgBackward() {
	if (sscache[0] === null) { alert("You are at the beginning of the slideshow."); return false; }
	dtDOM.setStyle(ssffbutton.firstChild,"opacity","1.0");
	if (ssct > 0) {
		ssct--;
		outID = setInterval("fadeOutBackward()",fadeinterval);
		// if this is the first image, fade the RW button
		if (ssct == 0) dtDOM.setStyle(ssrwbutton.firstChild,"opacity","0.5");
	} else {
		if (typeof inID != "undefined") clearInterval(inID);
		if (typeof outID != "undefined") clearInterval(outID);
	}
	return false;
}
function pauseSlideshow() {
	if (ssplaying) {
		clearIntervals();
		dtDOM.showHide(ssplaybutton);
		dtDOM.showHide(sspausebutton);
		ssplaying = false;
	}
	return false;
}			
function stopSlideshow() {
	if (!ssinited) return false;
	ssct = 0;
	imgblock.src = firstimg["src"];
	imgtitle.innerHTML = "Click on the image to begin the slideshow";
	//imgtitle.replaceChild(document.createTextNode(firstimg["caption"]),imgtitle.firstChild);
	imgct.replaceChild(document.createTextNode("1 of "+sslength),imgct.firstChild);
	sscache[2] = nextimg;
	dtDOM.setStyle(ssrwbutton.firstChild,"opacity","0.5");
	dtDOM.setStyle(ssffbutton.firstChild,"opacity","1.0");
	clearIntervals();
	restore();
	return false;
}
function initSlideshow() {
	imgblock = getObjectRef("slideimg");
	imgtitle = getObjectRef("slidetitle");
	imgct = getObjectRef("currentct");
	ssplaybutton = getObjectRef("ssplay");
	sspausebutton = getObjectRef("sspause");
	ssrwbutton = getObjectRef("ssrw");
	ssffbutton = getObjectRef("ssff");
	imgtitle.innerHTML = sscache[1]["caption"];
	//imgtitle.replaceChild(document.createTextNode(sscache[1]["caption"]),imgtitle.firstChild);
	ssinited = true;
}
function startSlideshow() {
	if (!ssinited) initSlideshow();
	if (!blacked) blackout();
	ssplaying = true;
	// handle restarting from the beginning if slideshow is at the end
	if (sscache[2] === null) stopSlideshow();
	dtDOM.showHide(ssplaybutton,"none");
	dtDOM.showHide(sspausebutton,"inline");
	ssID = setInterval("imgForward()",changeinterval);
	return false;
}
function displayImg() {
	window.location.href = js_g_url+"media/display/"+sscache[1]["id"]+"/index.php";
}