//--
//-- TiddlyWiki-specific utility functions
//--

// Returns TiddlyWiki version string
function formatVersion(v)
{
	v = v || version;
	return v.major + "." + v.minor + "." + v.revision +
		(v.alpha ? " (alpha " + v.alpha + ")" : "") +
		(v.beta ? " (beta " + v.beta + ")" : "");
}

//# Compares two TiddlyWiki version objects
//# Returns +1 if v2 is later than v1
//#          0 if v2 is the same as v1
//#         -1 if v2 is earlier than v1
//# version without a beta number is later than a version with a beta number
function compareVersions(v1,v2)
{
	var x1,x2,i,a = ["major","minor","revision"];
	for(i = 0; i<a.length; i++) {
		x1 = v1[a[i]] || 0;
		x2 = v2[a[i]] || 0;
		if(x1<x2)
			return 1;
		if(x1>x2)
			return -1;
	}
	x1 = v1.beta || 9999;
	x2 = v2.beta || 9999;
	if(x1<x2)
		return 1;
	return x1 > x2 ? -1 : 0;
}

function merge(dst,src,preserveExisting)
{
	var i;
	for(i in src) {
		if(!preserveExisting || dst[i] === undefined)
			dst[i] = src[i];
	}
	return dst;
}

// Resolve the target object of an event
function resolveTarget(e)
{
	var obj;
	if(e.target)
		obj = e.target;
	else if(e.srcElement)
		obj = e.srcElement;
	if(obj.nodeType == 3) // defeat Safari bug
		obj = obj.parentNode;
	return obj;
}

// Returns a string containing the description of an exception, optionally prepended by a message
function exceptionText(e,message)
{
	var s = e.description || e.toString();
	return message ? "%0:\n%1".format([message,s]) : s;
}

// Displays an alert of an exception description with optional message
function showException(e,message)
{
	alert(exceptionText(e,message));
}

function alertAndThrow(m)
{
	alert(m);
	throw(m);
}

function glyph(name)
{
	var g = config.glyphs;
	var b = g.currBrowser;
	if(b == null) {
		b = 0;
		while(b < g.browsers.length-1 && !g.browsers[b]())
			b++;
		g.currBrowser = b;
	}
	if(!g.codes[name])
		return "";
	return g.codes[name][b];
}

function createTiddlyText(parent,text)
{
	return parent.appendChild(document.createTextNode(text));
}

function createTiddlyCheckbox(parent,caption,checked,onChange)
{
	var cb = document.createElement("input");
	cb.setAttribute("type","checkbox");
	cb.onclick = onChange;
	parent.appendChild(cb);
	cb.checked = checked;
	cb.className = "chkOptionInput";
	if(caption)
		wikify(caption,parent);
	return cb;
}

function createTiddlyElement(parent,element,id,className,text,attribs)
{
	var n,e = document.createElement(element);
	if(className != null)
		e.className = className;
	if(id != null)
		e.setAttribute("id",id);
	if(text != null)
		e.appendChild(document.createTextNode(text));
	if(attribs) {
		for(n in attribs) {
			e.setAttribute(n,attribs[n]);
		}
	}
	if(parent != null)
		parent.appendChild(e);
	return e;
}

function createTiddlyButton(parent,text,tooltip,action,className,id,accessKey,attribs)
{
	var i,btn = document.createElement("a");
	btn.setAttribute("href","javascript:;");
	if(action) {
		btn.onclick = action;
	}
	if(tooltip)
		btn.setAttribute("title",tooltip);
	if(text)
		btn.appendChild(document.createTextNode(text));
	btn.className = className || "button";
	if(id)
		btn.id = id;
	if(attribs) {
		for(i in attribs) {
			btn.setAttribute(i,attribs[i]);
		}
	}
	if(parent)
		parent.appendChild(btn);
	if(accessKey)
		btn.setAttribute("accessKey",accessKey);
	return btn;
}

//# Create a link to an external resource
//#   place - element where the link should be created
//#   url - link target
//#   label - link text (optional)
function createExternalLink(place,url,label)
{
	var link = document.createElement("a");
	link.className = "externalLink";
	link.href = url;
	var f = config.messages.externalLinkTooltip;
	link.title = f ? f.format([url]) : url;
	if(config.options.chkOpenInNewWindow)
		link.target = "_blank";
	place.appendChild(link);
	if(label)
		createTiddlyText(link, label);
	return link;
}

function getTiddlyLinkInfo(title,currClasses)
{
	var classes = currClasses ? currClasses.split(" ") : [];
	classes.pushUnique("tiddlyLink");
	var tiddler = store.fetchTiddler(title);
	var subTitle;
	if(tiddler) {
		subTitle = tiddler.getSubtitle();
		classes.pushUnique("tiddlyLinkExisting");
		classes.remove("tiddlyLinkNonExisting");
		classes.remove("shadow");
	} else {
	    var f;
		classes.remove("tiddlyLinkExisting");
		classes.pushUnique("tiddlyLinkNonExisting");
		if(store.isShadowTiddler(title)) {
			f = config.messages.shadowedTiddlerToolTip;
			classes.pushUnique("shadow");
		} else {
			f = config.messages.undefinedTiddlerToolTip;
			classes.remove("shadow");
		}
		subTitle = f ? f.format([title]) : "";
	}
	if(typeof config.annotations[title]=="string")
		subTitle = config.annotations[title];
	return {classes: classes.join(" "),subTitle: subTitle};
}

// Event handler for clicking on a tiddly link
function onClickTiddlerLink(ev)
{
	var e = ev || window.event;
	var target = resolveTarget(e);
	var link = target;
	var title = null;
	var fields = null;
	var noToggle = null;
	do {
		title = link.getAttribute("tiddlyLink");
		fields = link.getAttribute("tiddlyFields");
		noToggle = link.getAttribute("noToggle");
		link = link.parentNode;
	} while(title == null && link != null);
	if(!store.isShadowTiddler(title)) {
		var f = fields ? fields.decodeHashMap() : {};
		fields = String.encodeHashMap(merge(f,config.defaultCustomFields,true));
	}
	if(title) {
		var toggling = e.metaKey || e.ctrlKey;
		if(config.options.chkToggleLinks)
			toggling = !toggling;
		if(noToggle)
			toggling = false;
		if(store.getTiddler(title))
			fields = null;
		story.displayTiddler(target,title,null,true,null,fields,toggling);
	}
	clearMessage();
	return false;
}

//# Create a link to a particular tiddler
//#   place - element where the link should be created
//#   title - title of target tiddler
//#   includeText - flag for whether to include the title as the text of the link
//#   className - custom CSS class for the link
//#   linkedFromTiddler - tiddler from which to inherit extended fields
//#   noToggle - flag to force the link to open the target, even if chkToggleLinks is on
function createTiddlyLink(place,title,includeText,className,isStatic,linkedFromTiddler,noToggle)
{
	var title = jQuery.trim(title);
	var text = includeText ? title : null;
	var i = getTiddlyLinkInfo(title,className);
	var btn = isStatic ? createExternalLink(place,store.getTiddlerText("SiteUrl",null) + "#" + title) : createTiddlyButton(place,text,i.subTitle,onClickTiddlerLink,i.classes);
	if(isStatic)
		btn.className += ' ' + className;
	btn.setAttribute("refresh","link");
	btn.setAttribute("tiddlyLink",title);
	if(noToggle)
		btn.setAttribute("noToggle","true");
	if(linkedFromTiddler) {
		var fields = linkedFromTiddler.getInheritedFields();
		if(fields)
			btn.setAttribute("tiddlyFields",fields);
	}
	return btn;
}

function refreshTiddlyLink(e,title)
{
	var i = getTiddlyLinkInfo(title,e.className);
	e.className = i.classes;
	e.title = i.subTitle;
}

function createTiddlyDropDown(place,onchange,options,defaultValue)
{
	var sel = createTiddlyElement(place,"select");
	sel.onchange = onchange;
	var t;
	for(t=0; t<options.length; t++) {
		var e = createTiddlyElement(sel,"option",null,null,options[t].caption);
		e.value = options[t].name;
		if(options[t].name == defaultValue)
			e.selected = true;
	}
	return sel;
}